Systems, devices and methods for exchanging wireless signals

Abstract

Systems, devices, and methods for establishing a wireless link between two or more wireless devices are described herein. In some variations, a wireless system may include a first device configured to transmit a feedback signal. The system may also include a second device including a transducer array, a processor, and a supply device. The transducer array may be configured to receive a feedback signal on one or more transducer elements of the transducer array. The supply device includes one or more predetermined transmit voltage levels. The processor may be configured to process feedback signals received by one or more transducer elements of the transducer array to generate feedback signal data. The processor may be further configured to determine a transducer array configuration based at least in part on the feedback signal data and one or more predetermined transmit voltage levels. The second device is configured to exchange one or more wireless signals with the first device using a transducer array configuration.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. Provisional Application Serial No. 63 / 477,131, filed December 23, 2022, the contents of which are hereby incorporated by reference in their entirety. Technical Field

[0003] The devices, systems, and methods herein relate to exchanging wireless signals between two or more wireless devices in a wireless system. Background Art

[0004] A wireless system may include a wireless link between two or more wireless devices of the wireless system. This wireless link may be used for one or more of wireless power transfer, wireless data communication, wireless command transmission, wireless signal transmission, combinations thereof, and the like. For example, a wireless implantable device may be wirelessly powered by an external wireless device and may communicate wirelessly with the external wireless device. The presence of heterogeneous media in the wireless link (such as different tissue structures within the body and / or relative motion between wireless devices) may limit the reliability and / or efficiency of the wireless link. Furthermore, practical constraints such as hardware complexity, device size, cost, and power dissipation may pose additional challenges to implementing a reliable and secure wireless link, particularly for a wireless link between an implantable device and an external wireless device (e.g., a handheld device placed on a patient's skin to wirelessly power the implantable device). Therefore, additional devices, systems, and methods may be desirable to establish a reliable, efficient, and secure wireless link between two or more wireless devices of a wireless system. Summary of the Invention

[0005] Described herein are systems, devices, and methods for exchanging wireless signals between wireless devices in a wireless system. Generally, the system may be configured to exchange one or more of wireless power, wireless data, and wireless commands between wireless devices. In some variations, the systems, devices, and methods described herein may allow for mitigation of variations in a wireless link over time (e.g., due to movement and / or rotation of one wireless device relative to another wireless device in the wireless system), thereby allowing reliable, efficient, and rapid wireless powering or charging of another wireless device based on wireless power transmitted by one wireless device in the wireless system. In some variations, the systems, devices, and methods described herein may allow for mitigation of multipath interference in heterogeneous tissue media to facilitate efficient and / or reliable exchange of wireless signals (e.g., power, data, commands) between a wireless implantable device and an external wireless device. In some embodiments, a system configured to exchange wireless power or data may include: a first device, the first device being configured to send a feedback signal; and a second device, the second device comprising a transducer array, a processor, and a supply device, wherein the transducer array may be configured to receive the feedback signal on one or more transducer elements of the transducer array, the supply device may include one or more predetermined transmit voltage levels, the processor may be configured to process the feedback signal received by the one or more transducer elements of the transducer array to generate feedback signal data, and determine the transducer array configuration based at least in part on the feedback signal data and the one or more predetermined transmit voltage levels of the supply device, and the second device may be configured to use the transducer array configuration to exchange one or more wireless signals with the first device.

[0006] In some variations, the feedback signal data may include one or more of the following: an absolute amplitude or magnitude of the feedback signal received by one or more transducer elements of the transducer array, a relative amplitude or magnitude, an absolute signal strength, a relative signal strength, an energy of the signal in one or more frequency bands, apodization, an absolute phase, a relative phase, an absolute time delay, a relative time delay, an absolute time of arrival, a relative time of arrival, a frequency, a time duration, a number of cycles, an absolute signal-to-noise ratio, and a relative signal-to-noise ratio. In some variations, the transducer array configuration may include one or more of the following: a selected set of transducer elements, apodization applied to one or more transducer elements of the transducer array for transmitting a wireless signal to the first device, a signal strength, a voltage level, a current level, a pulse width, a pulse width modulation, a duty cycle, a phase, a time delay, a frequency, and a transmission duration.

[0007] In some variations, the processor may be further configured to determine transmit apodization of transducer elements of the transducer array. In some variations, the processor may be further configured to select a set of transducer elements for the transducer array configuration based on one or more of: the transmit apodization of the transducer elements, one or more predetermined transmit voltage levels of the supply device, and one or more predetermined target signal strengths at the first device. In some variations, the transmit apodization of the transducer elements may be proportional to the relative signal strength of feedback signals received by the transducer elements of the transducer array in one or more frequency bands. In some variations, the transmit apodization of two or more transducer elements may be substantially equal.

[0008] In some variations, the second device may further include one or more transmitter circuits configured to apply a transmit signal to one or more transducer elements of the transducer array, and the processor may be configured to determine transmitter circuit data corresponding to the one or more transmitter circuits based at least in part on the feedback signal data. In some variations, the transmitter circuit data may include one or more of the following: efficiency, power dissipation, energy dissipation, current dissipation, voltage drop, heat dissipation, temperature, temperature rise, input power, input energy, input current, input voltage, output power, output energy, output current, and output voltage of the one or more transmitter circuits. In some variations, the processor may further be configured to determine a transmit apodization of the transducer element based at least in part on the transmitter circuit data.

[0009] In some embodiments, the supply device may include a plurality of predetermined transmit voltage levels, the processor may be further configured to select one or more predetermined transmit voltage levels based at least in part on the feedback signal data and the plurality of predetermined transmit voltage levels, and the transducer array configuration may further include the selected one or more predetermined transmit voltage levels for exchanging one or more wireless signals with the first device.

[0010] In some variations, the supply may include a first predetermined transmit voltage level and a second predetermined transmit voltage level, and the transducer array configuration may include the first predetermined transmit voltage level for transmitting wireless power and the second predetermined transmit voltage level for transmitting one or more of wireless data and commands to the first device. In some variations, the first predetermined transmit voltage level may be greater than or substantially equal to the second predetermined transmit voltage level.

[0011] In some variations, the first device may comprise an implantable medical device, and the second device may comprise an external wireless device configured to be physically separate from the first device. In some variations, the first device may comprise an external wireless device, and the second device may comprise an implantable medical device configured to be physically separate from the first device. In some variations, the second device may be further configured to send wireless commands to the first device, and the first device may be configured to send a feedback signal in response to receiving the wireless commands. In some variations, the first device may be configured to send the feedback signal at one or more predetermined recurring intervals.

[0012] Also described is a method for exchanging wireless signals in a wireless system. In some variations, a method for exchanging wireless signals in a wireless system may include the following steps: transmitting a feedback signal from a first device of the wireless system to a second device of the wireless system; receiving the feedback signal using one or more transducer elements of a transducer array of the second device; processing, using a processor of the second device, the feedback signal received using the one or more transducer elements of the transducer array to generate feedback signal data; determining, using the processor of the second device, a transducer array configuration of the second device based at least in part on the feedback signal data and one or more predetermined transmit voltage levels of a supply of the second device; and exchanging one or more wireless signals with the first device using the transducer array configuration of the second device.

[0013] In some variations, the feedback signal data may include one or more of the following: absolute amplitude or magnitude, relative amplitude or magnitude, absolute signal strength, relative signal strength, energy of the signal in one or more frequency bands, apodization, absolute phase, relative phase, absolute time delay, relative time delay, absolute arrival time, relative arrival time, frequency, time duration, number of cycles, absolute signal-to-noise ratio, and relative signal-to-noise ratio of the feedback signal received by one or more transducer elements of the transducer array. In some variations, the transducer array configuration may include one or more of the following: a selected set of transducer elements, apodization applied to one or more transducer elements of the transducer array for transmitting wireless signals to the first device, signal strength, voltage level, current level, pulse width, pulse width modulation, duty cycle, phase, time delay, frequency, and transmission duration.

[0014] In some variations, the method may include determining, using a processor of the second device, transmit apodization for transducer elements of the transducer array. In some variations, the method may also include selecting, using the processor of the second device, a set of transducer elements for the transducer array configuration based on one or more of the transmit apodization for the transducer elements, one or more predetermined transmit voltage levels of the supply device, and one or more predetermined target signal strengths at the first device. In some variations, the transmit apodization for the transducer elements may be proportional to the relative signal strength of feedback signals received by the transducer elements of the transducer array in one or more frequency bands. In some variations, the transmit apodization for two or more transducer elements may be substantially equal.

[0015] In some variations, the method may further include determining, using a processor of the second device, transmitter circuit data corresponding to one or more transmitter circuits of the second device based at least in part on the feedback signal data, the one or more transmitter circuits being configured to apply a transmit signal to one or more transducer elements of the transducer array. In some variations, the transmitter circuit data may include one or more of: efficiency, power dissipation, energy dissipation, current dissipation, voltage drop, heat dissipation, temperature, temperature rise, input power, input energy, input current, input voltage, output power, output energy, output current, and output voltage of the one or more transmitter circuits. In some variations, the method may further include determining a transmit apodization of the transducer element based at least in part on the transmitter circuit data.

[0016] In some variations, the method may further include: selecting, using a processor of the second device, one or more predetermined transmit voltage levels of the supply device from a plurality of predetermined transmit voltage levels of the supply device based at least in part on the feedback signal data, and exchanging one or more wireless signals with the first device using a transducer array configuration including the selected one or more predetermined transmit voltage levels. In some variations, the method may further include: transmitting wireless power to the first device using a first predetermined transmit voltage level of the supply device, and transmitting one or more of wireless data and commands to the first device using a second predetermined transmit voltage level of the supply device. In some variations, the first predetermined transmit voltage level may be greater than or substantially equal to the second predetermined transmit voltage level.

[0017] In some variations, the first device may comprise an implantable medical device, and the second device may comprise an external wireless device configured to be physically separate from the first device. In some variations, the first device may comprise an external wireless device, and the second device may comprise an implantable medical device configured to be physically separate from the first device. In some variations, the method may further comprise: sending one or more wireless commands from the second device to the first device, and sending one or more feedback signals from the first device to the second device in response to receiving the one or more wireless commands. In some variations, the method may further comprise: sending the feedback signal from the first device at one or more predetermined recurring intervals.

[0018] Also described are systems configured to exchange wireless power or data based on one or more transmitter circuits. In some variations, a system configured to exchange wireless power or data may include: a first device configured to transmit a feedback signal; a second device comprising a transducer array, a processor, and one or more transmitter circuits, wherein the transducer array may be configured to receive the feedback signal at one or more transducer elements of the transducer array, the one or more transmitter circuits may be configured to apply the transmit signal to the one or more transducer elements of the transducer array, the processor may be configured to process the feedback signal received by the one or more transducer elements of the transducer array to generate feedback signal data, determine transmitter circuit data corresponding to the one or more transmitter circuits based at least in part on the feedback signal data, and determine a transducer array configuration based at least in part on the feedback signal data and the transmitter circuit data, and the second device may be configured to exchange one or more wireless signals with the first device using the transducer array configuration.

[0019] In some variations, the feedback signal data may include one or more of the following: absolute amplitude or magnitude, relative amplitude or magnitude, absolute signal strength, relative signal strength, energy of the signal in one or more frequency bands, apodization, absolute phase, relative phase, absolute time delay, relative time delay, absolute arrival time, relative arrival time, frequency, time duration, number of cycles, absolute signal-to-noise ratio, and relative signal-to-noise ratio of the feedback signal received by one or more transducer elements of the transducer array. In some variations, the transmitter circuit data may include one or more of the following: efficiency, power dissipation, energy dissipation, current dissipation, voltage drop, heat dissipation, temperature, temperature rise, input power, input energy, input current, input voltage, output power, output energy, output current, and output voltage of one or more transmitter circuits.

[0020] In some variations, the transducer array configuration may include one or more of: a selected set of transducer elements, an apodization applied to one or more transducer elements of the transducer array for transmitting a wireless signal to the first device, signal strength, voltage level, current level, pulse width, pulse width modulation, duty cycle, phase, time delay, frequency, and transmit duration. In some variations, the processor may be further configured to determine transmit apodization for the transducer elements of the transducer array.

[0021] In some variations, the processor may be further configured to select a set of transducer elements for the transducer array configuration based on one or more of: transmit apodization of the transducer elements, transmitter circuit data, and one or more predetermined target signal strengths at the first device. In some variations, the transducer array configuration may include one or more transmit voltage levels, and the processor is configured to determine the one or more transmit voltage levels based at least in part on the selected set of transducer elements of the transducer array configuration. In some variations, the transmit apodization of the transducer elements may be proportional to the relative signal strength of feedback signals received by the transducer elements of the transducer array in one or more frequency bands. In some variations, the transmit apodization of two or more transducer elements may be substantially equal.

[0022] In some variations, the first device may comprise an implantable medical device, and the second device may comprise an external wireless device configured to be physically separate from the first device. In some variations, the first device may comprise an external wireless device, and the second device may comprise an implantable medical device configured to be physically separate from the first device. In some variations, the second device may be further configured to send one or more wireless commands to the first device, and the first device may be configured to send one or more feedback signals in response to receiving the one or more wireless commands. In some variations, the first device may be configured to send the feedback signal at one or more predetermined recurring intervals.

[0023] Also described are methods for exchanging wireless signals in a wireless system based on one or more transmitter circuits. In some variations, a method for exchanging wireless signals in a wireless system may include the following steps: transmitting a feedback signal from a first device of the wireless system to a second device of the wireless system; receiving the feedback signal using one or more transducer elements of a transducer array of the second device; processing, using a processor of the second device, the feedback signal received using the one or more transducer elements of the transducer array to generate feedback signal data; determining, using the processor of the second device, transmitter circuit data corresponding to one or more transmitter circuits of the second device based at least in part on the feedback signal data, the one or more transmitter circuits being configured to apply a transmit signal to the one or more transducer elements of the transducer array; determining, using the processor of the second device, a transducer array configuration of the second device based at least in part on the feedback signal data and the transmitter circuit data; and exchanging one or more wireless signals with the first device using the transducer array configuration of the second device.

[0024] In some variations, the feedback signal data may include one or more of the following: absolute amplitude or magnitude, relative amplitude or magnitude, absolute signal strength, relative signal strength, energy of the signal in one or more frequency bands, apodization, absolute phase, relative phase, absolute time delay, relative time delay, absolute arrival time, relative arrival time, frequency, time duration, number of cycles, absolute signal-to-noise ratio, and relative signal-to-noise ratio of the feedback signal received by one or more transducer elements of the transducer array. In some variations, the transmitter circuit data may include one or more of the following: efficiency, power dissipation, energy dissipation, current dissipation, voltage drop, heat dissipation, temperature, temperature rise, input power, input energy, input current, input voltage, output power, output energy, output current, and output voltage of one or more transmitter circuits.

[0025] In some embodiments, the transducer array configuration may include one or more of: a selected set of transducer elements, toe-off applied to one or more transducer elements of the transducer array for transmitting a wireless signal to the first device, signal strength, voltage level, current level, pulse width, pulse width modulation, duty cycle, phase, time delay, frequency, and transmission duration.

[0026] In some variations, the method may further include: determining, using a processor of the second device, transmit apodization for transducer elements of the transducer array. In some variations, the method may further include: selecting, using the processor of the second device, a set of transducer elements for the transducer array configuration based on one or more of: the transmit apodization for the transducer elements, transmitter circuit data, and one or more predetermined target signal strengths at the first device. In some variations, the method may further include: determining, using the processor of the second device, one or more transmit voltage levels for the transducer array configuration based at least in part on the selected set of transducer elements of the transducer array configuration. In some variations, the transmit apodization for the transducer elements is proportional to the relative signal strength of feedback signals received by the transducer elements of the transducer array in one or more frequency bands. In some variations, the transmit apodization for two or more transducer elements may be substantially equal.

[0027] In some variations, the first device may comprise an implantable medical device, and the second device may comprise an external wireless device configured to be physically separate from the first device. In some variations, the first device may comprise an external wireless device, and the second device may comprise an implantable medical device configured to be physically separate from the first device. In some variations, the method may further comprise: sending a wireless command from the second device to the first device, and sending a feedback signal from the first device to the second device in response to receiving the wireless command. In some variations, the method may further comprise: sending the feedback signal from the first device at one or more predetermined recurring intervals.

[0028] Also described are systems configured to exchange wireless power or data. In some variations, a system configured to exchange wireless power or data may include: a first device comprising a first transducer, a first processor, and an energy storage device, wherein the first transducer may be configured to receive a first wireless power signal from a second device, the energy storage device may be configured to charge based on the received first wireless power signal, the first processor may be configured to determine a charging duration corresponding to one or more predetermined conditions, and the first device may be configured to send a feedback signal based on the charging duration, wherein the second device may include a second transducer and a second processor, wherein the second transducer may be configured to receive the feedback signal, the second processor may be configured to process the feedback signal to generate feedback signal data, and determine a transducer configuration based at least in part on the feedback signal data, and the second device may be configured to send a second wireless power signal to the first device based on the transducer configuration.

[0029] In some variations, the predetermined condition may include one or more of the following: an absolute or relative time duration corresponding to the received first wireless power signal, an absolute or relative time duration corresponding to a voltage generated by the first device in response to the received first wireless power signal, an absolute or relative time duration corresponding to a current generated by the first device in response to the received first wireless power signal, an absolute or relative power level corresponding to the received first wireless power signal, an absolute or relative energy level corresponding to the received first wireless power signal, an absolute or relative voltage level generated by the first device in response to the received first wireless power signal, and an absolute or relative current level generated by the first device in response to the received first wireless power signal. In some variations, the first processor may be configured to digitize the charging duration.

[0030] In some variations, the feedback signal may comprise one or more of a digital representation of the charging duration and an analog representation of the charging duration. In some variations, the feedback signal data may comprise one or more of the following: a digital representation of the charging duration, an analog representation of the charging duration, an absolute amplitude or magnitude of the feedback signal received by the second transducer, a relative amplitude or magnitude, an absolute signal strength, a relative signal strength, energy of the signal in one or more frequency bands, apodization, absolute phase, relative phase, absolute time delay, relative time delay, absolute time of arrival, relative time of arrival, frequency, time duration, number of cycles, absolute signal-to-noise ratio, and relative signal-to-noise ratio.

[0031] In some embodiments, the feedback signal data may include one or more of the following: a mean, median, mode, variance, standard deviation, minimum, maximum, percentiles, histogram, statistical distribution, frequency, and probability of one or more charging durations corresponding to one or more first wireless power signals received by the first transducer from the second device.

[0032] In some variations, the transducer configuration may include one or more of: an absolute or relative duration of the second wireless power signal, one or more absolute or relative power levels of the second wireless power signal, one or more absolute or relative amplitudes of the second wireless power signal, an absolute or relative pulse repetition frequency of the second wireless power signal, and an absolute or relative frequency of the second wireless power signal.

[0033] In some variations, the duration of the second wireless power signal may be configured to be substantially equal to or greater than the charging duration. In some variations, the duration of the second wireless power signal is configured to be substantially equal to or greater than one or more of the following: a mean of one or more charging durations, a median of one or more charging durations, a mode of one or more charging durations, and a value corresponding to one or more charging durations corresponding to one or more first wireless power signals received by the first transducer from the second device.

[0034] In some variations, the second transducer may comprise one or more transducer arrays comprising one or more transducer elements. In some variations, the transducer configuration may comprise one or more of: a selected set of transducer elements, apodization applied to the one or more transducer elements for transmitting one or more wireless power signals to the first device, signal strength, voltage level, current level, pulse width, pulse repetition rate, pulse width modulation, duty cycle, phase, time delay, frequency, and transmission duration.

[0035] In some variations, the first device may comprise an implantable medical device, and the second device may comprise an external wireless device configured to be physically separate from the first device. In some variations, the first wireless power signal and the second wireless power signal may comprise ultrasonic or acoustic signals.

[0036] Also described is a method of exchanging wireless signals in a wireless system. In some variations, a method of exchanging wireless signals in a wireless system may include the following steps: receiving a first wireless power signal at a first transducer of a first device of the wireless system from a second device of the wireless system, wherein the first device may include an energy storage device and a first processor, and the second device may include a second transducer and a second processor; charging the energy storage device based on the received first wireless power signal; determining, using the first processor, a charging duration corresponding to one or more predetermined conditions; sending a feedback signal from the first device to the second device based on the charging duration; receiving the feedback signal using a second transducer; processing the feedback signal using the second processor to generate feedback signal data; determining, using the second processor, a transducer configuration based at least in part on the feedback signal data; and sending a second wireless power signal from the second device to the first device based on the transducer configuration.

[0037] In some embodiments, the predetermined condition may include one or more of the following: an absolute or relative time duration corresponding to the received first wireless power signal, an absolute or relative time duration corresponding to a voltage generated by the first device in response to the received first wireless power signal, an absolute or relative time duration corresponding to a current generated by the first device in response to the received first wireless power signal, an absolute or relative power level corresponding to the received first wireless power signal, an absolute or relative energy level corresponding to the received first wireless power signal, an absolute or relative voltage level generated by the first device in response to the received first wireless power signal, and an absolute or relative current level generated by the first device in response to the received first wireless power signal.

[0038] In some variations, the method may include: digitizing the charge duration using the first processor. In some variations, the method may include: encoding or modulating the feedback signal using the first processor with one or more of a digital representation of the charge duration and an analog representation of the charge duration.

[0039] In some variations, the feedback signal data may include one or more of the following: a digital representation of charging duration, an analog representation of charging duration, an absolute amplitude or magnitude of the feedback signal received by the second transducer, a relative amplitude or magnitude, an absolute signal strength, a relative signal strength, energy of the signal in one or more frequency bands, apodization, absolute phase, relative phase, absolute time delay, relative time delay, absolute time of arrival, relative time of arrival, frequency, time duration, number of cycles, absolute signal-to-noise ratio, and relative signal-to-noise ratio. In some variations, the feedback signal data may include one or more of the following: a mean, median, mode, variance, standard deviation, minimum, maximum, percentile, histogram, statistical distribution, frequency, and probability of one or more charging durations corresponding to one or more first wireless power signals received by the first transducer from the second device.

[0040] In some variations, the transducer configuration may include one or more of: an absolute or relative duration of the second wireless power signal, one or more absolute or relative power levels of the second wireless power signal, one or more absolute or relative amplitudes of the second wireless power signal, an absolute or relative pulse repetition frequency of the second wireless power signal, and an absolute or relative frequency of the second wireless power signal.

[0041] In some variations, the duration of the second wireless power signal may be configured to be substantially equal to or greater than the charging duration. In some variations, the duration of the second wireless power signal may be configured to be substantially equal to or greater than one or more of the following: a mean of one or more charging durations, a median of one or more charging durations, a mode of one or more charging durations, and a value corresponding to one or more first wireless power signals received by the first transducer from the second device.

[0042] In some variations, the second transducer may comprise one or more transducer arrays comprising one or more transducer elements. In some variations, the transducer configuration may comprise one or more of: a selected set of transducer elements, apodization applied to the one or more transducer elements for transmitting one or more wireless power signals to the first device, signal strength, voltage level, current level, pulse width, pulse repetition rate, pulse width modulation, duty cycle, phase, time delay, frequency, and transmission duration.

[0043] In some variations, the first device may comprise an implantable medical device, and the second device may comprise an external wireless device configured to be physically separate from the first device. In some variations, the first wireless power signal and the second wireless power signal may comprise ultrasonic or acoustic signals.

[0044] Also described are devices configured for charging. In some variations, a wireless implantable device may include: a transducer configured to receive a wireless power signal; a power circuit coupled to the transducer and configured to recover at least a portion of the wireless power signal received by the transducer; an energy storage device coupled to the power circuit and configured to charge based on the portion of the wireless power signal recovered by the power circuit; and a processor coupled to one or more of the power circuit, the energy storage device, and the transducer, wherein the processor may be configured to determine charging parameters corresponding to one or more predetermined conditions and adjust parameters of one or more of the power circuit, the energy storage device, and the transducer based at least in part on the charging parameters.

[0045] In some variations, the power circuit may include one or more of the following: an AC-DC converter, a reconfigurable AC-DC converter, a rectifier, a reconfigurable rectifier, a DC-DC converter, a reconfigurable DC-DC converter, a linear regulator, a switching regulator, a switched capacitor voltage regulator, a boost converter, a buck converter, a switched capacitor DC-DC converter, a charging circuit, a battery charging circuit, a current source, a voltage source, a constant current (CC) charging circuit, a constant voltage (CV) charging circuit, a trickle charging circuit, a pulsed charging circuit, a current limiter circuit, and a voltage limiter circuit. In some variations, the energy storage device may include one or more of the following: a battery, a rechargeable battery, a capacitor, and an inductor.

[0046] In some embodiments, the charging parameters may include one or more of the following: an absolute or relative time duration corresponding to the wireless power signal received by the transducer, an absolute or relative time duration of the voltage generated by the transducer in response to the received wireless power signal, an absolute or relative time duration of the current generated by the transducer in response to the received wireless power signal, an absolute or relative time duration corresponding to the wireless power signal recovered by the power circuit, an absolute or relative time duration of the voltage generated by the power circuit in response to the recovered wireless power signal, an absolute or relative time duration of the current generated by the power circuit in response to the recovered wireless power signal, an absolute or relative time duration corresponding to the charging of the energy storage device, and an absolute or relative charging rate of the energy storage device. In some embodiments, the charging parameters may include an absolute or relative voltage level corresponding to the energy storage device, an absolute or relative current level corresponding to the energy storage device, an absolute or relative power level corresponding to the energy storage device, an absolute or relative energy level corresponding to the energy storage device, an absolute or relative voltage level corresponding to the power circuit, an absolute or relative current level corresponding to the power circuit, an absolute or relative power level corresponding to the power circuit, an absolute or relative voltage level corresponding to the transducer, an absolute or relative current level corresponding to the transducer, and an absolute or relative power level corresponding to the transducer.

[0047] In some variations, the processor may be configured to digitize charging parameters. In some variations, the parameters of the power circuit adjusted by the processor may include one or more of the following: charging current level, charging voltage level, charging mode, switching frequency of the AC-DC converter, switching frequency of the DC-DC converter, load current of the AC-DC converter, load current of the DC-DC converter, configuration of the matching network, and a signal applied to a switch coupled to the power circuit. In some variations, the parameters of the power circuit adjusted by the processor may include one or more of the following: selection of capacitors, selection of batteries, number of capacitors, number of batteries, capacitance value, and a signal applied to a switch coupled to the energy storage device. In some variations, the parameters of the transducer adjusted by the processor may include one or more of the following: selection of transducer elements, impedance coupled to the transducer, matching network coupled to the transducer, and a signal applied to a switch coupled to the transducer.

[0048] In some variations, the transducer may comprise an acoustic transducer, and the wireless power signal may comprise an acoustic power signal. In some variations, the acoustic transducer may comprise an ultrasonic transducer, and the acoustic power signal may comprise an ultrasonic power signal.

[0049] Also described are methods of charging a wireless device. In some variations, a method of charging a wireless implantable device may include the following steps: receiving a wireless power signal using a transducer of the wireless implantable device; recovering at least a portion of the received wireless power signal using a power circuit coupled to the transducer; charging an energy storage device coupled to the power circuit based on the recovered portion of the received wireless power signal; determining charging parameters corresponding to one or more predetermined conditions using a processor coupled to one or more of the power circuit, the energy storage device, and the transducer; and adjusting parameters of one or more of the power circuit, the energy storage device, and the transducer using the processor based at least in part on the charging parameters.

[0050] In some variations, the power circuit may include one or more of the following: an AC-DC converter, a reconfigurable AC-DC converter, a rectifier, a reconfigurable rectifier, a DC-DC converter, a reconfigurable DC-DC converter, a linear regulator, a switching regulator, a switched capacitor voltage regulator, a boost converter, a buck converter, a switched capacitor DC-DC converter, a charging circuit, a battery charging circuit, a current source, a voltage source, a constant current (CC) charging circuit, a constant voltage (CV) charging circuit, a trickle charging circuit, a pulsed charging circuit, a current limiter circuit, and a voltage limiter circuit. In some variations, the energy storage device may include one or more of the following: a battery, a rechargeable battery, a capacitor, and an inductor.

[0051] In some embodiments, the charging parameters may include one or more of the following: an absolute or relative time duration corresponding to the wireless power signal received by the transducer, an absolute or relative time duration of the voltage generated by the transducer in response to the received wireless power signal, an absolute or relative time duration of the current generated by the transducer in response to the received wireless power signal, an absolute or relative time duration corresponding to the wireless power signal recovered by the power circuit, an absolute or relative time duration of the voltage generated by the power circuit in response to the recovered wireless power signal, an absolute or relative time duration of the current generated by the power circuit in response to the recovered wireless power signal, an absolute or relative time duration corresponding to the charging of the energy storage device, and an absolute or relative charging rate of the energy storage device. In some variations, the charging parameters may include an absolute or relative voltage level corresponding to the energy storage device, an absolute or relative current level corresponding to the energy storage device, an absolute or relative power level corresponding to the energy storage device, an absolute or relative energy level corresponding to the energy storage device, an absolute or relative voltage level corresponding to the power circuit, an absolute or relative current level corresponding to the power circuit, an absolute or relative power level corresponding to the power circuit, an absolute or relative voltage level corresponding to the transducer, an absolute or relative current level corresponding to the transducer, and an absolute or relative power level corresponding to the transducer. In some variations, the processor may be configured to digitize the charging parameters.

[0052] In some variations, the parameters of the power circuit adjusted by the processor may include one or more of the following: charging current level, charging voltage level, charging mode, switching frequency of the AC-DC converter, switching frequency of the DC-DC converter, load current of the AC-DC converter, load current of the DC-DC converter, configuration of the matching network, and a signal applied to a switch coupled to the power circuit. In some variations, the parameters of the power circuit adjusted by the processor may include one or more of the following: capacitor selection, battery selection, number of capacitors, number of batteries, capacitance value, and a signal applied to a switch coupled to the energy storage device. In some variations, the parameters of the transducer adjusted by the processor may include one or more of the following: transducer element selection, impedance coupled to the transducer, matching network coupled to the transducer, and a signal applied to a switch coupled to the transducer.

[0053] In some variations, the transducer may comprise an acoustic transducer, and the wireless power signal may comprise an acoustic power signal. In some variations, the acoustic transducer may comprise an ultrasonic transducer, and the acoustic power signal may comprise an ultrasonic power signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 is a schematic block diagram of an illustrative variation of a wireless system.

[0055] Figure 2 is a cross-sectional schematic diagram of an illustrative variation of a wireless system.

[0056] Figure 3 is a flow chart of an illustrative variation of a method for exchanging wireless signals with a device based on a feedback signal.

[0057] Figure 4 is a timing diagram of exemplary variations of feedback signals and feedback signal data.

[0058] Figure 5 is a flow chart of an illustrative variation of another method for exchanging wireless signals with a device based on a feedback signal.

[0059] Figure 6 is a timing diagram of an exemplary variation of a received feedback signal having a stable amplitude.

[0060] Figure 7 is a cross-sectional schematic diagram of illustrative variations of ultrasound beams and transmitted signal intensities of an ultrasound transducer array.

[0061] Figure 8 is a flow chart of an illustrative variation of a method for exchanging wireless signals with a device based on a link scan signal.

[0062] Figure 9 is a timing diagram of illustrative variations of signals used in a method of exchanging wireless signals with a device.

[0063] Figure 10 is a flow chart of an exemplary variation of a method for exchanging wireless signals with a device based on a link scan signal and a feedback signal.

[0064] Figure 11 is a flow chart of an illustrative variation of a method of decoding a data signal in a wireless system.

[0065] Figure 12 is a timing diagram of an illustrative variation of signals used in a method of decoding a data signal in a wireless system.

[0066] Figure 13 is a timing diagram of another exemplary variation of signals used in a method of decoding a data signal in a wireless system.

[0067] Figure 14 is a timing diagram of an illustrative variation of signals used in a method for decoding a data signal in a wireless system based on a combined data signal and matched filtering.

[0068] Figure 15 is a flow chart of an illustrative variation of a method of decoding a data signal in a wireless system.

[0069] Figure 16 is a flow chart of an illustrative variation of a method of decoding a data signal in a wireless system based on a predistorted data signal.

[0070] Figure 17 is a flow chart of an illustrative variation of a method of decoding a data signal in a wireless system based on delayed and summed data signals.

[0071] Figure 18 is a flow chart of an illustrative variation of a method of calibrating a wireless system.

[0072] Figure 19 is a schematic block diagram of an illustrative variation of a wireless system configured for calibration.

[0073] Figure 20 is a schematic block diagram of an illustrative variation of a wireless system configured for exchanging wireless signals.

[0074] Figure 21 is an illustrative variation of a method for exchanging wireless signals with a device based on one or more predetermined transmit voltage levels.

[0075] Figure 22 is an illustrative variation of a method for exchanging wireless signals with a device using a transmitter circuit.

[0076] Figure 23 is an illustrative variation of a method of exchanging wireless signals with a device based on charging duration.

[0077] Figure 24 are illustrative variations of a method of charging a wireless device. DETAILED DESCRIPTION

[0078] I. System

[0079] A. Overview

[0080] This document generally describes systems, devices, and methods for establishing a wireless link between two or more wireless devices in a wireless system. Generally, a wireless system may include one or more wireless monitors or wireless implantable devices or implantable medical devices, and one or more wireless devices or external wireless devices. The wireless implantable devices may be wirelessly powered or recharged using wireless power transfer via the external wireless devices. The wireless implantable devices may also wirelessly communicate data and / or commands bidirectionally with the external wireless devices.

[0081] Figure 1The present invention is a schematic block diagram of an exemplary variation of a wireless system (100) including a wireless implantable device (110) and a wireless device (114), each of which is described in more detail herein. The wireless device (114) can transmit wireless downlink signals (140) to the wireless implantable device (110), the wireless downlink signals including one or more of the following: power, data, commands, signals, combinations thereof, etc. The wireless device (114) can receive wireless uplink signals (150) from the wireless implantable device (110), the wireless uplink signals including one or more of the following: power, data, commands, signals, combinations thereof, etc. Each of these signals is also described in more detail herein.

[0082] Figure 2 is an exemplary variation of a system comprising a first device (210) implanted in the heart and surrounded by tissue (270) and a rib cage or rib (272), together with an external second device (214), the first device comprising one or more transducer arrays (220), the one or more transducer arrays comprising one or more transducer elements (222). In some variations, the second device (214) can be placed on the patient's chest. The second device (214) can be configured to send a downlink signal (242) to the first device (210), the downlink signal comprising one or more of the following: an interrogation signal, a power signal, a downlink command, a downlink data signal, etc. The first device (210) can be configured to generate a wireless signal (252), the wireless signal comprising one or more of the following: a feedback signal, an uplink data signal, a reflected signal from the first device (210), a backscattered signal from the first device (210), etc. In some variations, the first device (210) may be movable relative to the second device (214) along a spatial path (280) or a periodic trajectory.

[0083] In some variations, the systems, devices, and methods disclosed herein may include one or more of the systems, devices, and methods described in International Application No. PCT / US2020 / 027468, filed on April 9, 2020, International Application No. PCT / US2020 / 041696, filed on July 10, 2020, International Application No. PCT / US2021 / 036258, filed on June 7, 2021, and International Application No. PCT / US2022 / 035574, filed on June 29, 2022, the contents of each of which are hereby incorporated by reference in their entirety.

[0084] B. Wireless monitor

[0085] Generally speaking, a wireless monitor can be configured to perform one or more functions, including but not limited to sensing, monitoring, stimulating, delivering therapy, combinations thereof, and the like. In some variations, a wireless monitor can receive and / or transmit one or more of wireless power, wireless data, wireless commands, and wireless signals to and from an external wireless device or another wireless monitor. For example, a wireless monitor can be configured to monitor, measure, and / or process one or more physiological parameters of a patient.

[0086] In some variations, the wireless monitors described herein may be configured to perform only a subset of the measurement, processing, data storage, and / or signaling steps described herein. In some variations, the wireless monitors may include only a subset of the components or blocks described herein. For example, in some variations, the wireless monitors may include only a transducer, a power circuit, and a processor. As another example, in some variations, the wireless monitors may include one or more transducers, power circuits, processors, sensors, and memory. In some variations, in addition to the components described herein, the wireless monitors may include other components (e.g., sensors, stimulators, delivery and / or anchoring mechanisms, mechanical components that enable deployment within the body or organ, or other components).

[0087] In some variations, the wireless monitor may be implanted in a patient or animal. In some variations, a wireless monitor as described herein may be coupled (e.g., attached) to an implantable device or any portion of an implantable device. For example, one or more wireless monitors may be attached to a prosthetic heart valve or stent. As another example, one or more wireless monitors may be attached to one or more of: a pulse generator, and / or one or more leads of a pacemaker, an implantable cardioverter-defibrillator, and / or a cardiac resynchronization therapy device. In some variations, the wireless monitor may be implanted within or on one or more of a cardiac structure (e.g., a heart valve, a cardiac chamber), a vascular structure (e.g., a pulmonary artery, any other blood vessel), a body lumen, a body cavity, a tissue, an organ, etc.

[0088] In some variations, a wireless monitor may include one or more components or blocks described herein for an implantable device. In some variations, an implantable device may include one or more components or blocks described herein for a wireless monitor. For example, a wireless monitor may include one or more of the following: a transducer, a power circuit, an energy storage device, a sensor, a processor, a memory, a wireless transmitter, a wireless receiver, a multiplexer circuit, combinations thereof, and the like.

[0089] C. Implantable Devices

[0090] Generally speaking, the implantable devices, wireless implantable devices, or implantable medical devices described herein may be configured to be implanted in a patient or animal. In some variations, the implantable device may be a wireless implantable device. In some variations, the wireless implantable device may receive and / or transmit one or more of wireless power, wireless data, wireless commands, and wireless signals to and from an external wireless device or another wireless implantable device. In some variations, the wireless implantable device may be configured to perform one or more functions including, but not limited to, sensing, monitoring, stimulating, delivering therapy, combinations thereof, and the like. In some variations, the wireless implantable device may be a wireless monitor.

[0091] In some variations, the implantable device may include one or more of the following: a prosthetic heart valve, a prosthetic heart valve catheter, a valve leaflet coaptation device, an annuloplasty ring, a valve repair device (e.g., a clip, a tampon), an atrial septal occluder, an atrial appendage occluder, a ventricular assist device, a pacemaker (e.g., including a lead, a pulse generator), an implantable cardioverter-defibrillator (e.g., including a lead, a pulse generator), a cardiac resynchronization therapy device (e.g., including a lead, a pulse generator), an implantable cardiac monitor, a stent (e.g., a coronary or peripheral stent, a fabric stent, a metal stent), a stent graft, a stent, an embolic protection device, an embolic coil, an endovascular plug, a vascular patch, a vascular closure device, an atrial shunt, a parachute device for treating heart failure, a cardiac loop recorder, combinations thereof, etc. For example, the prosthetic heart valve may include one or more of the following: a transcatheter heart valve (THV), a self-expanding THV, a balloon-expandable THV, a surgical bioprosthetic heart valve, a mechanical valve, etc.

[0092] In general, the implantable devices described herein can be located in or near (e.g., adjacent to, proximal to) any area within the body, including but not limited to heart valves (e.g., aortic valve, mitral valve), heart chambers (e.g., left ventricle or LV, left atrium or LA, right ventricle or RV, right atrium or RA), blood vessels (e.g., pulmonary artery, aorta, superficial femoral artery, coronary arteries, pulmonary veins, etc.), cardiac tissue (e.g., myocardium or heart wall, atrial septum), gastrointestinal tract (e.g., stomach, esophagus), bladder, combinations thereof, etc.

[0093] like Figure 1 As shown, the wireless implantable device (110) may include a transducer (120), a processor (130), and a power circuit (160). The wireless device (114) may include a transducer (120) and a processor (130). Each of these components is described in more detail herein.

[0094] a. Transducer

[0095] In general, the transducers described herein can be configured to convert between wireless energy modes and electrical signals. In some variations, the transducer of a device can be configured to exchange one or more of wireless power, wireless signals, wireless data, wireless commands, combinations thereof, and the like with another device and / or another transducer of the same device. In some variations, the transducer (120) can be configured to receive and / or transmit signals using one or more of mechanical waves (e.g., sound waves, ultrasonic waves, or ultrasound waves, vibration waves), magnetic fields (e.g., induced magnetic fields), electric fields (e.g., capacitive electric fields), electromagnetic waves (e.g., radio frequency waves, or RF waves, light waves), current coupling, surface waves, combinations thereof, and the like, and convert the signals to and / or from electrical signals to signals. The transducers as described herein can be included in one or more of a wireless implantable device, a wireless monitor, an external wireless device, and the like (e.g., any of the devices described herein).

[0096] In some variations, the transducer (120) may comprise one or more of an ultrasonic transducer, a radio frequency (RF) transducer (e.g., a coil, an RF antenna), a capacitive transducer, combinations thereof, or the like. In some variations, the ultrasonic transducer may comprise one or more of a piezoelectric device, a capacitive micromachined ultrasonic transducer (CMUT), a piezoelectric micromachined ultrasonic transducer (PMUT), combinations thereof, or the like. In some variations, the ultrasonic transducer may convert pressure and / or force into an electrical signal, and / or vice versa. In some variations, the transducer (120) may comprise one or more ultrasonic transducers, which may be of one or more types, including but not limited to piston-type (e.g., rod, plate), cylindrical-type, ring-type, spherical-type (e.g., shell), curved-type (e.g., rod, diaphragm), flexure-type, combinations thereof, or the like. In some variations, the piezoelectric device may be made of one or more of lead zirconate titanate (PZT), PMN-PT, barium titanate (BaTiO3), polyvinylidene fluoride (PVDF), lithium niobate (LiNbO3), any derivatives thereof, or the like. In some variations, a radio frequency (RF) transducer may be configured to transmit and / or receive near-field and / or non-near-field (e.g., far-field) signals. For example, an RF antenna may be configured for non-near-field transmission and / or reception of power, data, and / or other signals. An RF coil may be configured for near-field (e.g., inductive) transmission and / or reception of power, data, and / or other signals.

[0097] In some variations, the transducer (120) may include one or more ultrasonic transducers configured to perform one or more of: receiving wireless power, transmitting data to / receiving data from another wireless device, and transmitting signals to / receiving signals from another wireless device. For example, the ultrasonic transducer of the wireless monitor may be designed to operate at a frequency between about 20 kHz and about 20 MHz to receive power from an external wireless device. Operating within this frequency range may facilitate miniaturization of the ultrasonic transducer to millimeter or submillimeter dimensions, which may facilitate integration of one or more wireless monitors into another implantable device (e.g., a transcatheter heart valve, a stent). In some variations, the ultrasonic transducer may have an impedance having a real part on the order of about hundreds of ohms to about hundreds of kiloohms (e.g., between about 100 Ω and about 500 kΩ). In some variations, the ultrasonic transducer may have an impedance having a real part on the order of tens of ohms.

[0098] In some variations, the transducer (120) may comprise a single transducer element (e.g., an ultrasonic piezoelectric device), which may allow for miniaturization of the wireless monitor. In some variations, the single transducer element may be configured to receive a power signal (e.g., ultrasonic power) transmitted from an external wireless device and convert the signal into electrical power. Additionally or alternatively, the single transducer element may be configured to receive downlink data (e.g., using ultrasonic signals) and / or other signals from an external wireless device or wireless monitor. In some variations, the single transducer element may be configured to transmit uplink data (e.g., using ultrasonic signals) and / or other signals to an external wireless device or wireless monitor. In some variations, the single transducer element may comprise an ultrasonic transducer configured to perform one or more of the following: receive ultrasonic power from another device (e.g., an external wireless device), perform bidirectional ultrasonic data communication or signal exchange (e.g., uplink and downlink) with another device (e.g., an external wireless device, a wireless monitor), combinations thereof, and the like.

[0099] In some variations, the transducer (120) may include more than one transducer element or one or more arrays of transducer elements. For example, the transducer (120) may include an array of ultrasonic transducer elements. As another example, a first transducer element may include an RF coil configured to receive power and transmit data and / or other signals to an external wireless device. A second transducer element may include an ultrasonic transducer configured to transmit and / or receive other signals. In some variations, the ultrasonic transducer of the external wireless device may include one or more arrays of ultrasonic transducer elements configured to generate an ultrasonic beam for one or more of power transfer, data transfer, and / or other signal exchange with the wireless monitor.

[0100] In some variations, a transducer (120) comprising a plurality of transducer elements may be configured to perform a set of predetermined functions. For example, a first transducer element may be configured to recover wireless power, a second transducer element may be configured to receive data and / or signals, and a third transducer element may be configured to transmit data and / or signals.

[0101] The small transducer size may allow for miniaturization of one or more wireless monitors, which may facilitate attachment of one or more wireless monitors to another implantable device, such as a cardiac implantable device (e.g., a prosthetic heart valve), and / or may allow for minimally invasive delivery of the wireless monitor or wireless implantable device into the body (e.g., via percutaneous or transcatheter techniques). In some variations, the transducer may have a diameter of less than about 10 cm. 3 volume.

[0102] In some variations, a transducer (e.g., an ultrasound transducer) of a wireless monitor may be oriented or angled toward one or more of a transducer of another wireless monitor, a transducer of an external wireless device, a combination thereof, etc. This may facilitate reliability in transmitting / receiving power, data, and / or other signals between a wireless monitor and an external wireless device, or between two wireless monitors.

[0103] In some variations, a wireless monitor may include one or more transducers. In some variations, one or more wireless monitors may share one or more transducers. For example, in some variations, more than one wireless monitor may be connected to a transducer (e.g., an RF coil) having more than one feed or port. For example, a support device may include an RF coil having two or more feeds or ports, to which two or more wireless monitors may be connected. In some variations, two or more wireless monitors may be connected to a single feed or port of a transducer (e.g., two or more wireless monitors may be connected in parallel at a single feed or port of an RF coil).

[0104] b. Power circuit

[0105] In general, the power circuits described herein can be configured to recover, regulate, detect, select, combine, store, and / or supply power or energy or to charge energy storage devices. For example, the power circuit can be configured to recover wireless power received by a transducer and convert it into usable energy for powering one or more circuit blocks of a wireless monitor. In some variations, the power circuit can include one or more energy storage elements (e.g., batteries, capacitors) configured to store energy received by the transducer. The power circuit can be further configured to control (e.g., regulate, limit) the power provided to one or more components (e.g., circuit blocks) of the wireless monitor. The combination of the power circuit and transducer described herein can be used to transfer power, data, and / or signals between an external wireless device and one or more low-power devices (e.g., wireless monitors) implanted in a patient. In some variations, the power circuit (160) can include one or more of the following: power recovery circuitry, power management circuitry, power detector circuitry, power distribution circuitry, combinations thereof, and the like.

[0106] In some variations, the power circuit (160) may include an AC-DC converter configured to convert an alternating current (AC) voltage to a DC voltage. For example, the power circuit (160) may include a rectifier configured to convert the AC voltage at the terminals of the transducer to a DC voltage rail. The rectifier may include one or more of the following: a passive rectifier, an active rectifier, a passive voltage multiplier, a combination thereof, or the like. In some variations, the power circuit (160) may include a DC-DC converter configured to convert a DC voltage rail to another DC voltage rail. For example, the power circuit (160) may include a switched capacitor DC-DC converter, a charge pump, a combination thereof, or the like. In some variations, the power circuit (160) may include a voltage regulator (e.g., a low dropout regulator (LDO) circuit, a voltage clamp circuit) configured to generate a regulated or constant DC voltage rail. In some variations, the power circuit (160) may include one or more reference generation circuits, such as a current reference circuit, a bandgap reference circuit, a voltage reference circuit, combinations thereof, or the like.

[0107] In some variations, the power circuit (160) may be configured to recover and / or combine wireless power received by multiple transducer elements located on the wireless monitor. For example, such a power circuit connected to the multiple transducer elements may perform one or more of the following: AC power combining, DC power combining, DC voltage combining, DC current combining, any combination thereof, etc.

[0108] In some variations, the power circuit (160) may include a power detector circuit configured to detect or measure power and / or energy at one or more of its inputs. In some variations, the power detector circuit may be configured to provide one or more supply voltages or powers to one or more circuit blocks in the wireless monitor based on the detection of power at one or more inputs. In some variations, the power detector circuit may include one or more of: a power ORing circuit, a power combining circuit, a power selection circuit, one or more diodes, and one or more switches, as described herein. A power ORing circuit, a power combining circuit, or a power selection circuit may generally operate on multiple power sources at its inputs and generate one or more power or voltage supplies at its outputs. For example, a power combining circuit may combine power from multiple sources. For example, a power selection circuit may select power from one of the multiple power sources.

[0109] In some variations, the power circuit (160) may include an energy storage device comprising one or more of the following: a capacitor, a supercapacitor, a rechargeable or secondary battery, a non-rechargeable or primary battery, a combination thereof, etc. In some variations, the power circuit (160) may include a rechargeable battery for energy storage along with a capacitor in parallel with the battery, wherein the capacitor may sink / supply at least a portion of the current during charge / discharge transients of the rechargeable battery.

[0110] In some variations, the power circuit (160) may be separate from the energy storage device. In some variations, the power circuit (160) may not include any energy storage device, and the wireless monitor may be powered by another device (e.g., an external wireless device, another wireless monitor, etc.) during operation of the wireless monitor. In some variations, power may be provided to the wireless monitor until the wireless monitor completes a set of predetermined functions, and the wireless monitor may remain inactive until the wireless monitor is powered again. A power circuit without an energy storage device may allow for a reduction in the size of the power circuit and the wireless monitor.

[0111] In some variations, the power circuit (160) may include one or more charging circuits for charging one or more energy storage devices (e.g., capacitors, batteries) of a device (e.g., a wireless implantable device). In some variations, the power circuit (160) may include a battery charging circuit or battery charger (e.g., a charging current source, a charging voltage source, a constant current or CC charging circuit, a constant voltage or CV charging circuit, combinations thereof, etc.), a capacitor charging circuit, combinations thereof, etc. In some variations, the power circuit (160) may include a matching network (e.g., consisting of only capacitors, consisting of capacitors, inductors, and / or resistors, etc.) that can be configured to achieve a favorable impedance or power match with a transducer that can be configured to receive wireless power. This can facilitate improving the efficiency of wireless power recovery and enable faster charging of the energy storage device based on the recovered wireless power.

[0112] In some variations, the power circuit (160) may be adaptable or adjustable. For example, in some variations, a processor of a wireless device or wireless implantable device may be configured to adjust or adapt parameters of the power circuit based on predetermined conditions (e.g., adjusting a charging current level, a charging voltage level, a charging mode (such as CC or CV), a switching frequency of a boost converter or active rectifier, a load current of a boost converter or rectifier, a matching network, combinations thereof, etc.), as described herein.

[0113] In some variations, the systems, devices, and methods disclosed herein may include one or more of the systems, devices, and methods described in U.S. Patent No. 9,544,068, filed May 13, 2014, U.S. Patent No. 10,177,606, filed September 30, 2016, U.S. Patent No. 10,014,570, filed December 7, 2016, and International Application No. PCT / US2020 / 041696, filed July 10, 2020, the contents of each of which are hereby incorporated by reference in their entirety.

[0114] c. Energy storage equipment

[0115] Generally speaking, the energy storage devices described herein can be configured to store energy that can be used to power one or more circuit blocks of a wireless implantable device or wireless monitor. In some variations, the energy storage device can include one or more of the following: a capacitor, a supercapacitor, a rechargeable or secondary battery, a non-rechargeable or primary battery, a combination thereof, and the like.

[0116] In some variations, the energy storage device of the wireless implantable device (110) may include a battery (e.g., a rechargeable battery) having a capacity of less than about 100 milliwatt-hours (about 360 joules). In some variations, the energy storage device of the wireless implantable device (110) may include a battery (e.g., a rechargeable battery) having a capacity of less than about 10 milliwatt-hours (36 joules). Such a battery may be significantly smaller in size than batteries used in conventional implantable devices (such as pacemakers or deep brain stimulators), thereby allowing the wireless implantable device (110) to be miniaturized to sizes on the order of centimeters, millimeters, or less than a millimeter.

[0117] In some variations, the energy storage device of the wireless implantable device (110) may include a capacitor having a capacitance between about 0.1 nanofarad (nF) and about 100 microfarads (μF). Such a capacitor may be on-chip (i.e., included within an integrated circuit) or off-chip. In some variations, the wireless implantable device (110) may include multiple energy storage devices, each of which may include any type of energy storage device described herein.

[0118] In some variations, the energy storage device may be adaptable or adjustable. For example, in some variations, a processor of a wireless device or wireless implantable device may be configured to adjust or adapt parameters of the energy storage device (e.g., selecting a capacitor configured to charge, adjusting the number of storage capacitors, adjusting the capacitance value, selecting a battery configured to charge, adjusting the number of batteries, controlling switches in a network connected to the capacitors and / or batteries, combinations thereof, etc.) based on predetermined conditions, as described herein.

[0119] d.Sensor

[0120] In general, the sensors described herein may be configured to sense or measure one or more parameters. In some variations, the sensors may include one or more of the following: a pressure sensor, a flow sensor, a transducer (e.g., an ultrasonic transducer, an infrared / optical photodiode, an infrared / optical LED, an RF antenna, an RF coil), a temperature sensor, an electrical sensor (e.g., using electrodes to measure impedance, electromyography or EMG, electrocardiography or ECG, etc.), a magnetic sensor (e.g., an RF coil), an electromagnetic sensor (e.g., an infrared photodiode, an optical photodiode, an RF antenna), a neural sensor (e.g., for sensing neural action potentials), a force sensor (e.g., a strain gauge), a flow or Velocity sensors (e.g., hot wire anemometers, vortex flowmeters), acceleration sensors (e.g., accelerometers), chemical sensors (e.g., pH sensors, protein sensors, glucose sensors), oxygen sensors (e.g., pulse oximetry sensors, myocardial oxygen consumption sensors), audio sensors (e.g., microphones for detecting heart murmurs, artificial valve murmurs, auscultation), sensors for sensing other physiological parameters (e.g., sensors for sensing heart rate, respiratory rate, arrhythmias, heart wall motion), stimulators (e.g., for stimulation and / or pacing functions), combinations thereof, etc.

[0121] In some variations, one or more pressure sensors (alternatively referred to as pressure transducers) may be used for one or more of the following: monitoring cardiac function and / or heart failure (e.g., measuring pressure in the LV, RV, LA, RA, pulmonary artery, aorta, etc.), monitoring prosthetic valves (e.g., monitoring valve pressure gradients to monitor stenosis), monitoring stent devices (e.g., measuring pressure in the lumen), estimating and / or validating blood flow velocity measurements (e.g., using Bernoulli's equation), combinations thereof, etc. In some variations, the one or more pressure sensors may be of types including, but not limited to, absolute pressure sensors, gauge pressure sensors, sealed pressure sensors, differential pressure sensors, barometric pressure sensors, combinations thereof, etc. In some variations, the one or more pressure sensors may be based on one or more pressure sensing technologies including, but not limited to, resistive (e.g., piezoresistive, using a strain gauge or membrane to create a pressure-sensitive resistor, etc.), capacitive (e.g., using a diaphragm or membrane to create a pressure-sensitive capacitor, etc.), piezoelectric, optical, resonant (e.g., pressure-sensitive resonant frequency of a structure, etc.), combinations thereof, etc. In some variations, the pressure sensor may be fabricated using micro-electromechanical systems (MEMS) technology. In some variations, the pressure sensor may include one or more of a stagnation pressure sensor, a static pressure sensor, and the like.

[0122] In some variations, the sensor may comprise a stimulator for stimulating muscles and / or neurons or nerves of one or more of cardiac tissue (e.g., the bundle of HIS, the atrioventricular node), cardiac chambers (e.g., the atrial septal wall, the lateral wall of the LV), vascular walls, combinations thereof, etc. For example, one or more stimulators may be used to stimulate the LV wall for pacing and / or cardiac resynchronization. In some variations, the stimulator may comprise an electrical stimulator (e.g., an electrode), an ultrasonic stimulator (e.g., an ultrasonic transducer), an optical stimulator (e.g., an optical LED), an infrared stimulator (e.g., an infrared LED), a thermal stimulator (e.g., an electrode to generate heat in tissue), combinations thereof, etc.

[0123] In some variations, a sensor may include one or more of a sensing transducer and a sensing circuit. In some variations, the sensing circuit may include one or more of the following: a signal conditioning circuit, an analog front end (AFE), an amplifier, a front-end amplifier (FEA), an instrumentation amplifier, a filter, an anti-aliasing filter, an analog-to-digital converter (ADC), a comparator, a reference generator, a supply generator, a digital controller, a bias circuit, a clock circuit, a timer circuit, an oscillator, combinations thereof, and the like.

[0124] In some variations, the sensor may be configured to measure a physiological parameter of the patient. In some variations, the physiological parameter of the patient may include one or more of the following: intracardiac pressure, intravascular pressure, blood pressure, blood velocity, blood flow, blood oxygen level, heart rate, respiratory rate, temperature, voltage (e.g., electrical voltage generated by tissue, such as ECG, EMG, etc.), current, impedance (e.g., tissue impedance, thoracic impedance, etc.), neural signals, heart sounds, combinations thereof, etc.

[0125] e.Processor

[0126] In general, a processor (e.g., a CPU) as described herein can receive, send, and / or process data and / or other signals and / or control one or more components of a system (e.g., control one or more circuit blocks of a wireless monitor). A processor can be configured to receive, process, compile, calculate, store, access, read, write, send, and / or generate data and / or other signals. Additionally or alternatively, one or more blocks of a processor of a wireless monitor can be configured to control one or more other blocks of the processor and / or one or more components of the wireless monitor (e.g., a transducer, a power circuit, a memory, a sensor, a wireless transmitter, a wireless receiver, etc.). A processor as described herein can be included in one or more of a wireless monitor, a wireless implantable device, an external wireless device, and the like.

[0127] In some variations, the processor (130) of the wireless device (114) may be configured to process a signal (e.g., a feedback signal) and take action (e.g., generate feedback signal data). In some variations, the processor (130) of the wireless device (114) may be configured to process a signal (e.g., a feedback signal), generate data (e.g., feedback signal data), and determine a transducer configuration (e.g., signal strength and delay applied to elements of a transducer array) used by the wireless device to power the wireless implantable device (110), as described in detail herein. For example, the processor may include an amplifier, a phase detector, a frequency detector, a digital signal processor, an analog signal processor, an integrator, an adder circuit, a multiplier circuit, a finite state machine, combinations thereof, or the like for performing such calculations. In some variations, the processor (130) of the wireless device (114) and / or the wireless implantable device (110) may be configured to process one or more wireless signals transmitted over a wireless link (e.g., a link between the wireless implantable device 110 and the wireless device 114) to determine a pulsation response of the wireless system.

[0128] In some variations, the processor (130) of the wireless implantable device (110) may be configured to process parameters measured by sensors (e.g., physiological parameters of the patient) and generate parameter data (e.g., physiological parameter data). In some variations, the processor (130) may be configured to control one or more circuit blocks of the wireless implantable device (110) and / or the wireless device (114). For example, the processor (130) may be configured to control a wireless transmitter of the wireless implantable device (110) to adjust one or more parameters of the wireless transmitter (e.g., transmission frequency). In some variations, the processor (130) of the wireless implantable device (110) and / or the wireless device (114) may be configured to monitor one or more circuit blocks or components of the wireless implantable device (110) and / or the wireless device (114). In some variations, the processor (130) of the wireless implantable device (110) may be configured to digitize an analog signal (e.g., a signal received by a transducer).

[0129] In some variations, the processor (130) may include data communication circuitry, which may be a data receiver, configured to access or receive data and / or other signals from one or more of a transducer, a sensor (e.g., a pressure sensor), and a storage medium (e.g., a memory, a flash drive, a memory card). For example, the processor may include one or more of the following to receive data and / or signals via the transducer: a signal receiver (e.g., to detect an interrogation signal), an envelope detector circuit, an amplifier (e.g., a low noise amplifier or LNA), a filter, a frequency detector circuit, a phase detector circuit, a comparator circuit, a decoder circuit, combinations thereof, and the like.

[0130] In some variations, the processor (130) may include any suitable processing device configured to run and / or execute a set of instructions or codes, and may include one or more data processors, image processors, graphics processing units (GPUs), physical processing units, digital signal processors (DSPs), analog signal processors, mixed signal processors, machine learning processors, deep learning processors, finite state machines (FSMs), compression processors (e.g., data compression to reduce data rates and / or memory requirements), cryptographic processors (e.g., for secure wireless data and / or power transfer), and / or central processing units (CPUs). The processor may include, for example, a general purpose processor, a field programmable gate array (FPGA), an application specific integrated circuit (ASIC), a processor board, etc. The processor may be configured to run and / or execute application processes and / or other modules, processes, and / or functions associated with the system. The underlying device technology may be provided in a variety of component types (e.g., metal oxide semiconductor field effect transistor (MOSFET) technology such as complementary metal oxide semiconductor (CMOS), bipolar technology such as emitter coupled logic (ECL), polymer technology (e.g., silicon conjugated polymer and metal conjugated polymer-metal structures), mixed analog and digital, etc.).

[0131] The systems, devices, and / or methods described herein may be implemented by software (implemented on hardware), hardware, or a combination thereof. Hardware modules may include, for example, a general-purpose processor (or microprocessor or microcontroller), a field programmable gate array (FPGA), a graphics processing unit (GPU), a central processing unit (CPU), and / or an application-specific integrated circuit (ASIC). Software modules (implemented on hardware) may be expressed in a variety of software languages ​​(e.g., computer code), including C, C++, Python, Ruby, Visual and / or other object-oriented, procedural or other programming languages ​​and development tools. Examples of computer code include, but are not limited to, microcode or microinstructions, machine instructions (such as those generated by a compiler), code for generating web services, and files containing higher-level instructions executed by a computer using an interpreter. Additional examples of computer code include, but are not limited to, control signals, encrypted code, and compressed code.

[0132] In some variations, the processor (130) of the wireless implantable device (110) may include one or more of the following: an envelope detection circuit, an energy detector circuit, a power detector circuit, a voltage sensor, a time-to-digital converter (TDC) circuit, an integrator circuit, a sampling circuit, an analog-to-digital converter (ADC) circuit, a timer circuit, a clock, a counter, an oscillator, a phase-locked loop (PLL), a frequency-locked loop (FLL), combinations thereof, etc. In some variations, the processor (130) may include an amplifier, a phase detector, a frequency detector, a digital signal processor, an integrator, an adder circuit, a multiplier circuit, a finite state machine, combinations thereof, etc. for performing calculations.

[0133] In some variations, the processor (130) of the wireless implantable device (110) may include data communication circuitry, which may be a data transmitter or a wireless transmitter, which may be configured to generate or transmit data and / or other signals through one or more of a transducer, a storage medium, and the like. For example, the processor (130) of the wireless implantable device (110) may include one or more of: a signal transmitter, an uplink data transmitter, an oscillator, a power amplifier, a mixer, an impedance matching circuit, a switch, a driver circuit, combinations thereof, and the like to generate or transmit data and / or signals through a transducer. In some variations, the first processor may be included in the wireless monitor or the wireless implantable device, and the second processor may be included in the external wireless device.

[0134] f. Memory

[0135] In general, the implantable devices, wireless monitors, and / or wireless devices described herein may include memory configured to store data and / or information. In some variations, the memory may be of one or more types, including, but not limited to, random access memory (RAM), static RAM (SRAM), dynamic RAM (DRAM), resistive random access memory (ReRAM or RRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), standard cell-based memory (SCM), shift register, read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), flash memory (e.g., NOR, NAND), embedded flash memory, volatile memory, non-volatile memory, one-time programmable (OTP) memory, combinations thereof, and the like.

[0136] In some variations, the memory may store instructions and / or data for causing the processor to execute modules, processes, and / or functions associated with the wireless monitor and / or external wireless device (e.g., executing a search algorithm). Some variations described herein may involve a computer storage product having a non-transitory computer-readable medium (also referred to as a non-transitory processor-readable medium) having instructions or computer code thereon for performing various computer-implemented operations. The computer-readable medium (or processor-readable medium) is non-transitory in the sense that it may not itself include transitory propagating signals (e.g., propagating electromagnetic waves carrying information on a transmission medium such as space or a cable). The medium and computer code (also referred to as code or algorithm) may be those designed and constructed for one or more specific purposes.

[0137] In some variations, the memory may be configured to store sensor data (e.g., physiological parameter data), received data and / or data generated by the wireless monitor (e.g., data generated by the wireless monitor's processor, calibration parameters, etc.), and / or data generated by an external wireless device (e.g., reference feedback signals in frequency domain representation and / or time domain representation). In some variations, the memory of the wireless monitor may be configured to store data generated when processing signals sensed by a sensor (e.g., blood pressure data sensed by a pressure sensor that may be included in the wireless monitor). In some variations, the memory may be configured to temporarily or permanently store data.

[0138] g. Wireless transmitter

[0139] In general, a wireless transmitter of a wireless implantable device or a wireless monitor may be configured to wirelessly transmit one or more of wireless signals, wireless data, wireless commands, and wireless power. For example, the wireless transmitter of the wireless implantable device (110) may include one or more of the following: a signal transmitter, an uplink data transmitter, an oscillator, a clock circuit, a power amplifier, a mixer, an impedance matching circuit, a switch, a driver circuit, a combination thereof, etc., to generate and / or wirelessly transmit data and / or signals through the transducer (120) of the wireless implantable device (110).

[0140] h. Wireless receiver

[0141] In general, a wireless receiver of a wireless implantable device or a wireless monitor can be configured to wirelessly receive one or more of wireless signals, wireless data, wireless commands, and wireless power. For example, the wireless receiver of the wireless implantable device (110) can include one or more of the following: a signal receiver, a data recovery circuit, a clock recovery circuit, a clock circuit, a power recovery circuit, an envelope detector, a wake-up receiver circuit, a data demodulator, an amplifier, a mixer, an analog-to-digital converter (ADC), a phase-locked loop (PLL), a frequency-locked loop (FLL), an impedance matching circuit, a switch, a coherent receiver circuit, a non-coherent receiver circuit, a combination thereof, etc., to wirelessly receive data and / or signals through the transducer (120) of the wireless implantable device (110).

[0142] i. Multiplexer circuit

[0143] In general, the multiplexers or multiplexer circuits described herein can be configured to decouple one or more of a power signal, a data signal, and / or other signals received and / or transmitted by a transducer. This is done to avoid interference between these signals and to ensure proper operation of a wireless device (such as a wireless monitor, a wireless implantable device, and / or an external wireless device). For example, a multiplexer in a wireless monitor can be configured to decouple a power signal from a data signal received by the transducer of the wireless monitor from an external wireless device, such that the power signal is provided to a power circuit for power recovery and regulation, and the data signal is provided to a wireless receiver or processor for data recovery.

[0144] In some embodiments, the multiplexer may include one or more of: a transmit / receive switch, passive devices (e.g., diodes, relays, MEMS circuits, blockers, passive switches), a circulator, frequency selection (e.g., using filters, impedance matching networks), a direct wired connection, combinations thereof, etc.

[0145] In some variations, the transmit / receive switch may be driven based on timing control or time multiplexing, such that the wireless monitor receives one or more of the power signal, data signal, and other signals at different times. In some variations, the transmit / receive switch may be driven based on amplitude selection, wherein one or more of the power signal, data signal, and other signals have different amplitudes. In some variations, the transmit / receive switch may be driven based on frequency selection or frequency multiplexing, wherein one or more of the power signal, data signal, and other signals have different frequencies. In some variations, the transmit / receive switch may be implemented using depletion-mode transistors to operate when the wireless monitor may not have power, stored energy, or established voltage rails.

[0146] D. Wireless devices

[0147] In general, a wireless device or external wireless device may refer to any device that is physically separate from a wireless implantable device or wireless monitor. In some variations, the external wireless device may include one or more blocks described herein in the context of a wireless implantable device, including but not limited to a transducer, a power circuit, an energy storage device, a sensor, a processor, a memory, a wireless transmitter, a wireless receiver, a multiplexer circuit, combinations thereof, and the like. Variations of these blocks as explained herein in the context of a wireless implantable device may also apply here.

[0148] In some variations, the transducer of the external wireless device may comprise a plurality of ultrasound transducer elements or an ultrasound array configured to exchange wireless signals (transmit and / or receive) with one or more wireless implantable devices. As another example, in some variations, the transducer of the external wireless device may comprise one or more RF coils and / or RF antennas. In some variations, the processor of the external wireless device may perform one or more of the following: processing data and / or signals received from one or more wireless monitors, processing data received from one or more other wireless devices, combinations thereof, and the like.

[0149] In some variations, the external wireless device may perform one or more functions including, but not limited to: transmitting one or more of wireless power, data, and other signals to one or more wireless implantable devices, receiving one or more of wireless data and other signals from one or more wireless implantable devices, processing data and / or signals, performing sensing and / or actuation (e.g., measuring blood pressure, heart rate, heart rate variability, ECG, EKG, thoracic impedance, respiratory rate or respiration, patient activity level, heart sounds, temperature, weight, blood glucose, blood oxygen, combinations thereof, etc.), storing data or information in a memory, communicating with other external wireless devices (e.g., tablets, phones, computers) via wires and / or using a wireless link (e.g., Bluetooth), displaying or providing data or information (e.g., visual display on a screen or monitor, audio signal), generating alerts / notifications (e.g., visual, audio, vibration) to a user (e.g., patient, nurse, physician), combinations thereof, etc.

[0150] In some variations, the external wireless device may be located at one or more locations including, but not limited to: external to the body (e.g., as a wearable device, a band, a belt, a handheld device, a probe connected to a measuring device, a device placed on the skin, a device attached to the skin using an adhesive, a device attached to the skin using other techniques, a device that does not contact the patient, a laptop, a computer, a mobile phone, a smartwatch, etc.), permanently implanted within the body (e.g., implanted subcutaneously, along the outer wall of an organ, implanted under a muscle, implanted outside the heart wall, etc.), temporarily implanted (e.g., for a predetermined amount of time) within the body (e.g., on a catheter or probe inserted through a blood vessel, esophagus, or chest wall for use during surgery or a procedure), combinations thereof, etc. In some variations, the external wireless device may have different shapes or forms including, but not limited to, planar, conformal to the body or organ, flexible, stretchable, flat, shaped like a probe, etc.

[0151] In some variations, the external wireless device may further include a communication device configured to allow a user and / or healthcare professional to control one or more devices of the wireless system. The communication device may include a network interface configured to connect the external wireless device to another system (e.g., the Internet, a remote server, a database) via a wired or wireless connection. In some variations, the external wireless device may communicate with other devices (e.g., a cell phone, a tablet, a computer, a smartwatch, etc.) via one or more wired and / or wireless networks. In some variations, the network interface may include one or more of a radio frequency receiver / transmitter, an optical (e.g., infrared) receiver / transmitter, an acoustic or ultrasonic receiver / transmitter, etc. configured to communicate with one or more devices and / or networks. The network interface may communicate with one or more of the external wireless device, network, database, and server via wires and / or wirelessly.

[0152] The network interface may include RF circuitry configured to receive and / or transmit RF signals. The RF circuitry may convert electrical signals into electromagnetic signals or convert electromagnetic signals into electrical signals, and communicate with a communication network and other communication devices via electromagnetic signals. The RF circuitry may include well-known circuitry for performing these functions, including but not limited to an antenna system, an RF transceiver, one or more amplifiers, a tuner, one or more oscillators, a mixer, a digital signal processor, a CODEC chipset, a subscriber identity module (SIM) card, memory, and the like.

[0153] Wireless communications by any device may use any of a variety of communication standards, protocols, and technologies, including, but not limited to, Global System for Mobile Communications (GSM), Enhanced Data GSM Environment (EDGE), High Speed ​​Downlink Packet Access (HSDPA), High Speed ​​Uplink Packet Access (HSUPA), Evolution-Data-Only (EV-DO), HSPA, HSPA+, Dual Cell HSPA (DC-HSPDA), Long Term Evolution (LTE), Near Field Communication (NFC), Wideband Code Division Multiple Access (W-CDMA), Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Bluetooth, Wireless Fidelity (WiFi) (e.g., IEEE 802.11a, IEEE 802.11b, IEEE 802.11g, IEEE 802.11d), IEEE 802.11e, IEEE 802.11f, IEEE 802.11g, IEEE 802.11g, IEEE 802.11f, IEEE 802.11g, IEEE 802.11g, IEEE 802.11g, IEEE 802.11g, IEEE 802.11b, IEEE 802.11f, IEEE 802.11g ...g, IEEE 802.11g, IEEE 802.11g, 802.11n, etc.), Voice over Internet Protocol (VoIP), Wi-MAX, email protocols (e.g., Internet Message Access Protocol (IMAP) and / or Post Office Protocol (POP)), instant messaging (e.g., Extensible Messaging and Presence Protocol (XMPP), Session Initiation Protocol for Instant Messaging and Presence Leveraging Extensions (SIMPLE), Instant Messaging and Presence Service (IMPS)), and / or Short Message Service (SMS), or any other suitable communication protocol. In some embodiments, the devices herein may communicate directly with each other without sending data over a network (e.g., via NFC, Bluetooth, WiFi, RFID, etc.).

[0154] The communication device may also include a user interface configured to allow a user (e.g., a subject or patient, a predetermined contact such as a partner, a family member, a healthcare professional, etc.) to control the external wireless device. The communication device may allow the user to interact with and / or control the external wireless device directly and / or remotely. For example, the user interface of the external wireless device may include an input device for the user to input commands and an output device for the user to receive output (e.g., a blood pressure reading on a display device).

[0155] In some variations, the output device of the user interface may output one or more of the following: information regarding the coupling of the external wireless device to the tissue or skin, information regarding the wireless link between the external wireless device and the wireless monitor (e.g., whether a reliable link has been established), data measured by one or more of the wireless monitor and the external wireless device (e.g., physiological parameter data), combinations thereof, etc. In some variations, the output device of the user interface may include one or more of a display device and an audio device. Data analysis generated by the server may be displayed via an output device (e.g., a display) of the external wireless device. Data used to find a transducer configuration or ensure adequate coupling of the external wireless device to the tissue may be received via the network interface and output visually and / or audibly via one or more output devices of the external wireless device. In some variations, the output device may include a display device comprising at least one of the following: a light emitting diode (LED), a liquid crystal display (LCD), an electroluminescent display (ELD), a plasma display panel (PDP), a thin film transistor (TFT), an organic light emitting diode (OLED), an electronic paper / electronic ink display, a laser display, and / or a holographic display.

[0156] In some variations, the audio device may audibly output one or more of any data, commands, instructions to the user, alerts, notifications, and the like. For example, the audio device may output an audible alert when the link between the wireless monitor and the external wireless device is disturbed or interrupted and may require manual adjustment by the user. In some variations, the audio device may include at least one of a speaker, a piezoelectric audio device, a magnetostrictive speaker, and / or a digital speaker. In some variations, the user may use the audio device and a communication channel to communicate with other users. For example, the user may establish an audio communication channel (e.g., a VoIP call) with a remote healthcare professional.

[0157] In some variations, the user interface may include an input device (e.g., a touch screen) and an output device (e.g., a display device) and may be configured to receive input data from one or more of the wireless monitor, an external wireless device, a network, a database, and a server. For example, user control of an input device (e.g., a keyboard, buttons, touch screen) may be received by the user interface and then processed by the processor and memory so that the user interface outputs a control signal to the wireless monitor. Some variations of the input device may include at least one switch configured to generate a control signal. For example, the input device may include a touch surface for a user to provide input corresponding to the control signal (e.g., a finger contacting the touch surface). An input device including a touch surface may be configured to detect contact and movement on the touch surface using any of a variety of touch sensitivity technologies, including capacitive, resistive, infrared, optical imaging, dispersive signal, acoustic pulse recognition, and surface acoustic wave technology. In variations of the input device including at least one switch, the switch may include, for example, at least one of a button (e.g., a hard key, a soft key), a touch surface, a keyboard, an analog stick (e.g., a joystick), a directional pad, a mouse, a trackball, a jog dial, a stepper switch, a rocker switch, a pointer device (e.g., a stylus), a motion sensor, an image sensor, and a microphone. The motion sensor may receive user movement data from the optical sensor and classify user gestures as control signals. The microphone may receive audio data and recognize user speech as control signals.

[0158] A haptic device may be incorporated into one or more of the input and output devices to provide additional sensory output (e.g., force feedback) to the user. For example, the haptic device may generate a tactile response (e.g., vibration) to confirm a user input to an input device (e.g., a touch surface). As another example, tactile feedback may notify the user that an input has been overridden by an external wireless device.

[0159] a. Subarray

[0160] A subarray may generally refer to any subset of a plurality of transducer elements of a wireless device. In some variations, a subarray may comprise one or more of: a group of adjacent transducer elements, a group of alternating transducer elements (e.g., every two elements), a group of every 'nth' transducer element, or any subset of the transducer elements of a transducer array. For example, a subarray may comprise a group of transducer elements selected for efficiently delivering wireless power to a wireless implantable device based on a feedback signal, as described in detail herein. In some variations, a subarray may comprise a single transducer element of an external wireless device. In some variations, a subarray may comprise all transducer elements of an external wireless device.

[0161] In some variations, a subarray may comprise a set of non-overlapping transducer elements. For example, an external wireless device may comprise a linear 1D array having elements labeled 1, 2, 3, etc., where the subarrays may consist of elements numbered 1-8, 9-16, 17-24, etc. In some variations, a subarray may comprise a set of overlapping transducer elements. For example, for the example of a linear 1D array, the subarrays may consist of elements numbered 1-8, 2-9, 3-10, etc. In some variations, the subarrays may have different sizes. For example, different subarrays of the same external wireless device may comprise one or more of: different numbers of transducer elements (e.g., some subarrays may comprise 4 transducer elements, some subarrays may comprise 16 transducer elements), transducer elements of different sizes, combinations thereof, etc. In some variations, the selection of transducer elements for a predetermined subarray of the external wireless device may be based on feedback signal data, as described in detail herein.

[0162] b. Transducer configuration

[0163] A transducer configuration (e.g., a transducer array configuration, a configuration of a transducer array) may generally refer to one or more transducer elements of a wireless device that are configured to exchange one or more of wireless power, data, commands, and signals with another wireless device. A transducer configuration may also refer to the parameters and settings of one or more transducer elements (e.g., one or more transducer elements of a transducer array) that are configured to transmit signals (e.g., the frequency, amplitude, phase, time delay, duration, etc., at which one or more transducer elements may be configured to transmit signals) and / or the parameters and settings of one or more transducer elements (e.g., one or more transducer elements of a transducer array) that are configured to receive signals (e.g., the phase shift, time delay, gain, etc., at which one or more transducer elements may be configured to receive signals). In some variations, a transducer configuration may be selected by a processor of a wireless device (e.g., an external wireless device) based on feedback signals received from another wireless device (e.g., a wireless implantable device).

[0164] In some variations, a transducer configuration configured to transmit wireless signals to a wireless device may be referred to as a transmitting transducer configuration (TTC). In some variations, a transducer configuration configured to receive wireless signals from a wireless device may be referred to as a receiving transducer configuration (RTC). In some variations, a transducer configuration selected by a processor of a wireless device based on feedback signals received from another wireless device may be referred to as an optimal transducer configuration (OTC), which may be an improvement over a default transducer configuration, but is not necessarily the most optimal transducer configuration. In some variations, a set of transducer elements of a wireless device that may be selectively configured to power a wireless implantable device and / or transmit other downlink signals to the wireless implantable device, along with drive signals for each of these transducer elements, may be collectively referred to as a subarray powering snapshot. In some variations, a group of transducer elements of a wireless device configured to receive an uplink signal (e.g., data) from a wireless implantable device, along with parameters associated with receiving the signal or conditioning the received signal (such as gain, phase shift, delay, filtering, time window, etc., used to receive the signal), may be collectively referred to as a subarray uplink data snapshot.

[0165] c. User prompts

[0166] A user prompt (also referred to as user feedback) may generally refer to one or more instructions, notifications, recommendations, alerts, etc., provided by a wireless device to a user. User prompts may be used for a variety of purposes, including, but not limited to: conveying data regarding the state of charge (SoC) and / or depth of discharge (DoD) of an energy storage device of a wireless implantable device and / or a battery of an external wireless device, requesting a user to recharge a battery, conveying data regarding a data transfer and / or wireless signal exchange between two wireless devices (e.g., a percentage of data transfer completion), requesting a user to manually adjust or reposition the wireless device on the patient's body, combinations thereof, etc. In some variations, the user prompt may include one or more of the following: feedback signal data (e.g., apodization of one or more transducer elements of a transducer array), link scan signal data, transducer array configuration, characteristics of a first data signal, characteristics of a second data signal, characteristics of a combined data signal, characteristics of a delayed and summed data signal, decoded data bits, characteristics of a predistorted data signal, characteristics of a test signal, combinations thereof, etc. In some variations, the user prompt may be provided using one or more of a visual instruction, an audio instruction, a vibration, a notification (e.g., an alert on a phone, computer, etc., a push notification, an email, etc.), combinations thereof, etc. Variations of communication devices, user interfaces, input devices, output devices, etc., as described herein, may be used to provide the user prompt.

[0167] In some variations, the user prompt (e.g., visual instruction) may include one or more of the following: an image, photograph, or stylized representation (e.g., schematic, cartoon, diagram) of the patient's chest (e.g., showing one or more of the chest, arm, neck, or head); a current device configuration (e.g., position, angle, tilt, etc.) of the wireless device; a target device configuration (e.g., position, angle, rotation, tilt, etc.) of the wireless device; a map showing the current / target position; instructions displayed in text form (e.g., a sentence instructing the user to move the wireless device toward the patient's left arm, right arm, head, etc.; a number or percentage representing the power received by the wireless device, the battery's SoC and / or DoD, etc.); an arrow instructing the user to move, rotate, and / or adjust the wireless device; an LED (e.g., solid, flashing); combinations thereof; etc. For example, in some variations, the current position of the wireless device and the target position may be superimposed on an image of the chest. The user may be instructed to move the wireless device until the wireless device reaches the target position.

[0168] In some embodiments, the audio instructions may include one or more of: a voice command (e.g., requesting the user to move the wireless device toward the patient's left arm, requesting the user to recharge the battery of the wireless device, notifying the user that data transfer between two wireless devices is complete), a beep, an alarm, a combination thereof, etc.

[0169] d. Network

[0170] In some variations, the systems, devices, and methods described herein can communicate with other wireless devices via, for example, one or more networks, each of which can be any type of network (e.g., a wired network, a wireless network). Communications can be encrypted or unencrypted. A wireless network can refer to any type of digital network that is not connected by any type of cable. Examples of wireless communications in a wireless network include, but are not limited to, cellular, radio, satellite, and microwave communications. However, a wireless network can be connected to a wired network to connect to the Internet, other carrier voice and data networks, business networks, and personal networks. Wired networks are typically delivered via copper twisted pair, coaxial cable, and / or fiber optic cable. There are many different types of wired networks, including wide area networks (WANs), metropolitan area networks (MANs), local area networks (LANs), internet area networks (IANs), campus area networks (CANs), global area networks (GANs) (such as the Internet), and virtual private networks (VPNs). Hereinafter, a network refers to any combination of wireless, wired, public, and private data networks, which are typically interconnected via the Internet to provide a unified networking and information access system.

[0171] Cellular communications may include technologies such as GSM, PCS, CDMA or GPRS, W-CDMA, EDGE or CDMA 2000, LTE, WiMAX, and 5G networking standards. Some wireless network deployments combine networks from multiple cellular networks or use a mix of cellular, Wi-Fi, and satellite communications. In some variations, the network can be used to remotely process any data or information used by the wireless system described herein. For example, a processor that can process any data or information related to the wireless system can be located in the same housing as the wireless implantable device and / or in the same housing as the external wireless device, in a separate housing in the same room or building as the wireless implantable device, in a location remote from the wireless implantable device and the external wireless device (e.g., a different building, city, country), or any combination thereof. The processing of data or information related to the wireless system can be performed in real time as the data (e.g., feedback signal data, physiological data) is received or recorded, or the processing can be performed at a different time.

[0172] E. Wireless signal

[0173] As used herein, a wireless signal may generally refer to any wireless signal exchanged between two devices, such as a wireless implantable device and an external wireless device. In some variations, a wireless signal may include one or more of the following: wireless power or power signal, downlink data signal, downlink command, interrogation signal, feedback signal, link scan signal, uplink data signal, uplink command, reflected signal, backscattered signal, etc.

[0174] a. Feedback signal

[0175] A feedback signal may generally refer to any signal received by a wireless device (e.g., an external wireless device) from another wireless device (e.g., a wireless implantable device). In some variations, a feedback signal may be generated in response to another signal (e.g., an interrogation signal). In some variations, a wireless device (e.g., a wireless implantable device) may be configured to transmit one or more feedback signals without interrogation by another wireless device. For example, a wireless implantable device may be configured to periodically transmit a feedback signal, which in some variations may also be referred to as a beacon signal.

[0176] In some variations, the feedback signal may be generated using one or more of mechanical waves (e.g., ultrasound, sound waves, vibration waves), magnetic fields (e.g., induced magnetic fields), electric fields (e.g., capacitive electric fields), electromagnetic waves (e.g., RF waves, light waves), current coupling, surface waves, and the like. In some variations, the feedback signal may be generated in the form of a continuous wave (CW) signal or a pulsed wave (PW) signal. In some variations, the feedback signal may be generated using any known digital or analog modulation technique, such as ASK, FSK, PSK, AM, FM, PM, pulse modulation, PAM, PIMD, PPM, PCM, PDM, and the like. In some variations, the ultrasonic feedback signal may include a carrier frequency between approximately 20 kHz and approximately 20 MHz. In some variations, the ultrasonic feedback signal pulses may include a pulse duration between approximately 1 μs and approximately 1 ms.

[0177] In some variations, the feedback signal may comprise one or more pulses. For example, the wireless implantable device may be configured to transmit a single ultrasonic pulse as the feedback signal (e.g., comprising one or more cycles of a carrier frequency), or it may periodically transmit multiple ultrasonic pulses. Such ultrasonic pulses may be used by the external wireless device to triangulate or locate the wireless implantable device and / or to estimate the link gain between the external wireless device and the wireless implantable device, as described in more detail herein. In some variations, the feedback signal may comprise multiple cycles of the carrier frequency. For example, the duration of the feedback signal may be greater than approximately 5 cycles of the carrier frequency of the feedback signal. In some variations, the feedback signal may comprise a pulse signal. In some variations, the pulse signal may comprise one or more of the following: a rectangular pulse, a Dirac pulse, a sinusoidal pulse, a triangular pulse, a trapezoidal pulse, a raised cosine pulse, a sinc pulse, a Gaussian pulse, one or more cycles of the carrier frequency of the pulse signal, combinations thereof, etc. In some variations, the pulse signal may comprise a sinusoidal cycle of the carrier frequency. In some variations, the pulse signal may include one or more of a 2-level square wave, a 3-level square wave, a 5-level square wave, a multi-level square wave, combinations thereof, etc. In some variations, the feedback signal may be generated by a multi-level pulser circuit (e.g., a 3-level pulser) of the first device.

[0178] In some variations, the feedback signal may include data encoded using a modulation technique (e.g., digital modulation). For example, in some variations, the wireless implantable device may encode one or more of the following into the feedback signal, including but not limited to: the power or voltage received by one or more transducers of the wireless implantable device (e.g., after digitization of the power or voltage), the battery and / or capacitor voltage of the wireless implantable device, the energy state of the wireless implantable device, the energy stored on the power source (e.g., battery, capacitor) of the wireless implantable device, the battery charging current, the DC voltage generated by the power circuit of the wireless implantable device, the time duration corresponding to the wireless power signal received by the wireless implantable device, the time duration corresponding to the charging of the energy storage device of the wireless implantable device, combinations thereof, and the like. As another example, in some variations, the wireless implantable device may encode a unique identification (ID) number or code into the feedback signal. In some variations, the feedback signal may encode a time delay. For example, in some variations, the feedback signal may encode the time delay (e.g., after digitization) between receiving the interrogation and / or power signal from the external wireless device and sending the feedback signal to the external wireless device.

[0179] In some variations, the feedback signal may include one or more of a reflection signal and a backscattered signal. These signals may be generated when an interrogation signal, or any other signal transmitted by an external wireless device, reflects or backscatters off one or more wireless implantable devices and / or one or more tissue structures (such as a rib, a lung, a boundary between two tissue types, etc.). Reflections from the wireless implantable device may include one or more reflections from one or more of: a housing, coating, or packaging of the wireless implantable device; a wireless implantable device transducer (e.g., an ultrasound transducer); a surface (e.g., front, back, side, exterior, interior) of the wireless implantable device; any portion of the wireless implantable device; combinations thereof; and the like. In some variations, the reflection signal may include an ultrasound reflection signal generated when an ultrasound signal transmitted by a subarray of the external wireless device reflects into the tissue.

[0180] b. Link scan signal

[0181] A link scan signal may generally refer to any signal transmitted over a wireless link that can be processed to determine characteristics of the wireless link. A link scan signal may be transmitted by any device in a wireless system. For example, a link scan signal may be transmitted by one or more of a wireless implantable device and an external wireless device. For example, a link scan signal may be a pulse signal transmitted by the wireless implantable device and received by the external wireless device. A processor in the external wireless device may be configured to process the received pulse signal to determine a pulse response of the wireless link or system.

[0182] In some variations, the link scan signal may include parameters or characteristics similar to those described for the feedback signal (e.g., signal modality, type, modulation, etc.). In some variations, the link scan signal may be generated using one or more of mechanical waves (e.g., ultrasonic waves, sound waves, vibration waves), magnetic fields (e.g., induced magnetic fields), electric fields (e.g., capacitive electric fields), electromagnetic waves (e.g., RF waves, light waves), current coupling, surface waves, etc. In some variations, the link scan signal may include one or more of the following: a pulse signal, a pulse signal, a feedback signal, a predetermined digital code, and a continuous wave signal. In some variations, the pulse signal may include one or more of the following: a rectangular pulse, a Dirac pulse, a sinusoidal pulse, a triangular pulse, a trapezoidal pulse, a raised cosine pulse, a sinc pulse, a Gaussian pulse, one or more cycles of a carrier frequency of the pulse signal, combinations thereof, etc. In some variations, the pulse signal may include a sinusoidal cycle of the carrier frequency. In some variations, the pulse signal may comprise one or more of a 2-level square wave, a 3-level square wave, a 5-level square wave, a multi-level square wave, combinations thereof, etc. In some variations, the link scan signal may be generated by a multi-level pulser circuit (e.g., a 3-level pulser) of the first device. In some variations, the ultrasound link scan signal may comprise a carrier frequency between approximately 20 kHz and approximately 20 MHz.

[0183] In some variations, the link scan signal may comprise data encoded using a modulation technique (e.g., digital modulation). In some variations, the link scan signal may comprise one or more of a reflected signal and a backscattered signal. For example, the link scan signal may comprise a reflected signal from the wireless implantable device that corresponds to a signal transmitted into tissue by an external wireless device.

[0184] c.Data signal

[0185] A data signal generally refers to any signal used for data communication and transmitted over a wireless link. A data signal may be transmitted by any device in a wireless system. For example, a data signal may be transmitted by one or more of a wireless implantable device and an external wireless device. A data signal may include one or more of an uplink data signal and a downlink data signal. An uplink data signal may refer to a data signal transmitted from the wireless implantable device to the external wireless device. A downlink data signal may refer to a data signal transmitted from the external wireless device to the wireless implantable device.

[0186] In some variations, the data signal may include parameters or characteristics similar to those described for the feedback signal (e.g., signal modality, type, modulation, etc.). In some variations, the data signal may be generated using one or more of mechanical waves (e.g., ultrasonic waves, sound waves, vibration waves), magnetic fields (e.g., induced magnetic fields), electric fields (e.g., capacitive electric fields), electromagnetic waves (e.g., RF waves, light waves), current coupling, surface waves, etc. In some variations, the data signal may be generated in the form of a continuous wave (CW) signal or a pulsed wave (PW) signal. In some variations, the data signal may include one or more of digital data and analog data. In some variations, the data signal may be generated using any known digital or analog modulation technique, such as ASK, FSK, PSK, AM, FM, PM, pulse modulation, PAM, PIMD, PPM, PCM, PDM, etc. In some variations, the ultrasonic data signal may include a carrier frequency between approximately 20 kHz and approximately 20 MHz. In some variations, a data bit of a data signal (e.g., an ultrasound data signal) may comprise a pulse duration (or bit duration) between about 1 μs and about 1 ms. In some variations, the data signal may comprise one or more of a reflected signal and a backscattered signal. For example, the data signal may comprise backscattered communication.

[0187] In some embodiments, the data signal may encode one or more of: physiological parameters (e.g., information about physiological parameters sensed by the wireless implantable device), parameters of the wireless device (e.g., the voltage of the energy storage device of the wireless implantable device, the frequency of the wireless device, the ID of the wireless device, etc.), parameters of the wireless link (e.g., link gain), data generated by a processor of the wireless device (e.g., feedback signal data), data generated by a user (e.g., user commands), wireless commands or instructions, combinations thereof, etc.

[0188] II. Methods

[0189] Methods for exchanging wireless signals in a wireless system using any of the systems and devices described herein are described herein. Generally speaking, a wireless system or device can implement one or more of the methods described herein, or any subset of one or more of the methods described herein, or a combination of the methods or subsets thereof. One or more of the methods described herein, or steps therein, can be applied to a variety of wireless implantable devices and / or wireless monitors.

[0190] Wireless signals exchanged in wireless systems that include heterogeneous media (e.g., ribs, lungs, muscles, etc.) may experience reflections from various objects or structures in the media. Due to multipath interference, such reflections may cause unwanted destructive and / or constructive interference to the wireless signals. This document provides solutions for mitigating and / or addressing the effects of multipath interference to efficiently and / or reliably deliver wireless signals (e.g., power, data, commands, etc.) in wireless systems.

[0191] In some variations, exchanging wireless signals in a wireless system may be facilitated by sending a feedback signal from a first device of the wireless system to a second device of the wireless system. In some variations, a method of exchanging wireless signals in a wireless system may include one or more of the following steps, including but not limited to: sending a feedback signal from the first device of the wireless system to the second device of the wireless system for a first duration; receiving the feedback signal for a second duration using one or more transducer elements of a transducer array of the second device; processing, using a processor of the second device, the feedback signal received using the one or more transducer elements of the transducer array for the second duration to generate feedback signal data; determining, using the processor of the second device, a transducer array configuration of the second device based at least in part on the feedback signal data; and exchanging one or more wireless signals with the first device using the transducer array configuration of the second device.

[0192] In some embodiments, a method for exchanging wireless signals in a wireless system may include one or more of the following steps, including but not limited to: sending a feedback signal from a first device of the wireless system to a second device of the wireless system; receiving the feedback signal using a first transducer array of the second device; extracting one or more portions of the received feedback signal received by one or more transducer elements of the first transducer array of the second device using a processor of the second device; processing the extracted one or more portions of the received feedback signal using the processor of the second device to generate feedback signal data; determining a second transducer array configuration of the second device based at least in part on the feedback signal data; and exchanging one or more wireless signals with the first device using the second transducer array configuration of the second device.

[0193] In some variations, exchanging wireless signals in a wireless system may be facilitated by sending a link scan signal from a first device of the wireless system to a second device of the wireless system. In some variations, a method of exchanging wireless signals in a wireless system may include one or more of the following steps, including but not limited to: sending a link scan signal from a first device of the wireless system to a second device of the wireless system; receiving the link scan signal using a first transducer array of the second device; processing, using a processor of the second device, the received link scan signal received by one or more transducer elements of the first transducer array of the second device to generate link scan signal data; determining a second transducer array configuration of the second device based at least in part on the link scan signal data; and exchanging one or more wireless signals with the first device using the second transducer array configuration of the second device.

[0194] In some variations, exchanging wireless signals in a wireless system may be facilitated by sending a link scan signal and a feedback signal from a first device of the wireless system to a second device of the wireless system. In some variations, a method of exchanging wireless signals in a wireless system may include one or more of the following steps, including but not limited to: sending a link scan signal and a feedback signal from a first device of the wireless system to a second device of the wireless system; receiving the link scan signal and the feedback signal using a first transducer array of the second device; extracting, using a processor of the second device, the received link scan signal and the received feedback signal received by one or more transducer elements of the first transducer array of the second device to generate feedback signal data; determining a configuration of a second transducer array of the second device based at least in part on the feedback signal data; and exchanging one or more wireless signals with the first device using the configuration of the second transducer array of the second device.

[0195] Also described herein are methods for exchanging wireless signals based on defocusing acoustic beams. Also described herein are methods for closed-loop powering to achieve the necessary voltage and / or power level at a first device when transmitting wireless power from a second device to the first device.

[0196] Also described herein is a method for wireless data communication between two or more devices in a wireless system. In some variations, the wireless data communication between the two wireless devices may utilize a link scan signal. In some variations, a method for decoding a data signal in a wireless system may include steps including, but not limited to: transmitting a link scan signal and a first data signal from a first device in the wireless system to a second device in the wireless system; receiving the link scan signal and the first data signal using one or more transducer elements of the second device; processing the received link scan signal and the received first data signal using a processor of the second device to generate a second data signal; and decoding the first data signal based at least in part on the second data signal.

[0197] In some variations, wireless data communication between a first device and a second device of a wireless system may utilize selection of one or more transducer elements of the second device. In some variations, a method for decoding a data signal in a wireless system may include steps including, but not limited to: transmitting a link scan signal and a first data signal from a first device of the wireless system to a second device of the wireless system; receiving the link scan signal and the first data signal using one or more transducer elements of the second device; processing one or more of the received link scan signal and the received first data signal using a processor of the second device to select one or more transducer elements of the second device; and decoding the first data signal based at least in part on the selected one or more transducer elements of the second device.

[0198] In some variations, wireless data communication between two wireless devices may utilize a predistorted data signal. In some variations, a method for decoding a signal in a wireless system may include steps including, but not limited to: transmitting a link scan signal from a first device of the wireless system to a second device of the wireless system; receiving the link scan signal using one or more transducer elements of the second device; processing the received link scan signal using a processor of the second device to generate link scan signal data; generating a predistorted data signal based on the link scan signal data using the processor of the second device; transmitting the predistorted data signal from the second device to the first device; receiving the predistorted data signal using one or more transducer elements of the first device; and processing the received predistorted data signal using the processor of the first device to generate decoded data.

[0199] Also described herein is a method of calibrating a wireless system. In some variations, a method of calibrating a wireless system may include steps including, but not limited to: sending one or more test signals comprising one or more carrier frequencies from a first device of the wireless system to a second device of the wireless system; receiving the one or more test signals using the second device; processing the one or more received test signals using a processor of the second device to generate test signal data; determining, using the processor of the second device, one or more selected carrier frequencies based at least in part on the test signal data; sending one or more wireless commands from the second device to the first device comprising information corresponding to the one or more selected carrier frequencies; and storing the information corresponding to the one or more selected carrier frequencies in a memory of the first device.

[0200] In some variations, exchanging wireless signals in a wireless system may be facilitated by one or more predetermined transmit voltage levels. In some variations, a method of exchanging wireless signals in a wireless system may include steps including, but not limited to: transmitting a feedback signal from a first device of the wireless system to a second device of the wireless system; receiving the feedback signal using one or more transducer elements of a transducer array of the second device; processing, using a processor of the second device, the feedback signal received using the one or more transducer elements of the transducer array to generate feedback signal data; determining, using the processor of the second device, a transducer array configuration of the second device based at least in part on the feedback signal data and one or more predetermined transmit voltage levels of a supply of the second device; and exchanging one or more wireless signals with the first device using the transducer array configuration of the second device.

[0201] In some variations, exchanging wireless signals in a wireless system may be facilitated by one or more transmitter circuits. In some variations, a method for exchanging wireless signals in a wireless system may include steps including, but not limited to: transmitting a feedback signal from a first device of the wireless system to a second device of the wireless system; receiving the feedback signal using one or more transducer elements of a transducer array of the second device; processing, using a processor of the second device, the feedback signal received using the one or more transducer elements of the transducer array to generate feedback signal data; determining, using the processor of the second device, transmitter circuit data corresponding to one or more transmitter circuits of the second device based at least in part on the feedback signal data, the one or more transmitter circuits being configured to apply a transmit signal to the one or more transducer elements of the transducer array; determining, using the processor of the second device, a transducer array configuration of the second device based at least in part on the feedback signal data and the transmitter circuit data; and exchanging one or more wireless signals with the first device using the transducer array configuration of the second device.

[0202] A. Exchange wireless signals with wireless devices

[0203] In some embodiments, beamforming may be performed in a wireless system to establish a reliable and / or efficient wireless link between two or more wireless devices. In some embodiments, a wireless signal (such as a feedback signal) wirelessly propagated from a first device of the wireless system may be received by a second device of the wireless system. Such received signal may be processed by a processor of the second device to determine a transducer configuration of the second device for exchanging wireless signals with the first device. For example, the transducer configuration may include a set of elements of a transducer array of the second device for transmitting wireless power to the first device and their corresponding signal strengths and delays or phases. Determining such a transducer configuration may be challenging in a wireless link or system that experiences multipath interference due to reflections of wireless signals propagating in the wireless link from heterogeneous media and structures. For example, an ultrasound signal propagating in a chest cavity may experience multipath interference due to reflections and / or scattering of ultrasound waves from ribs, lungs, and / or other tissue boundaries. Because conventional ultrasound beamforming techniques may not account for multipath interference, using such techniques to deliver wireless power or energy to a wireless implantable device may result in a reduction in the total power or energy delivered due to destructive interference of ultrasound waves reaching the wireless implantable device from one or more reflectors in the medium. This paper provides a solution to overcome this challenge.

[0204] a. Exchange wireless signals based on feedback signals

[0205] In some variations, wireless devices in a wireless system may exchange wireless signals based on a feedback signal propagated from a first device of the wireless system to a second device of the wireless system.

[0206] Figure 3 The present invention is a flowchart generally describing a variation of a method (300) for exchanging wireless signals with a device based on a feedback signal. In some variations, determining a transducer array configuration of the second device based at least in part on feedback signal data (e.g., characterizing a wireless link between the first and second devices) may allow the second device to transmit a focused wireless signal (e.g., ultrasound) to generate a reliable and / or efficient wireless link between the second and first devices. The method (300) may include the following steps: transmitting a feedback signal from a first device of a wireless system to a second device of the wireless system for a first duration (302); receiving the feedback signal for a second duration (304) using one or more transducer elements of a transducer array of the second device; processing the feedback signal received by the one or more transducer elements of the transducer array within the second duration to generate feedback signal data (306) using a processor of the second device; determining a transducer array configuration of the second device based at least in part on the feedback signal data (308) using the processor of the second device; and exchanging one or more wireless signals with the first device using the transducer array configuration of the second device (310).

[0207] In some variations, the feedback signal may comprise one or more analog pulses. In some variations, processing the feedback signal may comprise extracting analog characteristics of the feedback signal, such as one or more of the following: amplitude, phase, time delay, arrival time, duration, number of cycles, frequency, power, energy, combinations thereof, and the like.

[0208] In some variations, the received feedback signal may be processed on a subset of the transducer elements (e.g., some or all of the transducer elements) on which the feedback signal is received. In some variations, the transducer elements selected to process the received feedback signal may be predetermined. In some variations, the transducer elements selected to process the received feedback signal may be selected based on one or more characteristics of one or more received feedback signals, one or more of other signals in the wireless system, characteristics of the transducer elements, combinations thereof, or the like. For example, the transducer elements selected to process the received feedback signal may be selected based on: the signal strength of the received feedback signal, the signal-to-noise ratio of the received feedback signal, the energy of the received feedback signal in one or more frequency bands, a predetermined apodization of the transducer elements, a moving average of the feedback signal amplitude, the signal strength of the interference source, the signal strength of the multipath interference, and the multipath time. Apodization may be a relative amplitude weighting applied to different transducer elements of a transducer array for transmitting and / or receiving wireless signals. For example, a transducer element having an apodization value of 0.7 may be configured to transmit a signal at approximately 70% of the amplitude, or equivalently, at approximately 49% of the power level, relative to a transducer element having an apodization value of 1.0. In some variations, multipath time may refer to a duration of time within which multipath reflections or multipath interference in a wireless link may dissipate to below a predetermined threshold (e.g., a predetermined power level).

[0209] In some variations, the second duration may be greater than the first duration. In some variations, the second duration may be predetermined based on one or more of: multipath propagation in the wireless link, multipath time, signal attenuation in the medium, propagation speed of the wireless signal in the medium, system calibration by sending a signal through the system and measuring the time required for the multipath echo to dissipate, a combination thereof, or the like. In some variations, the second duration may be determined by a processor of the second device based on characteristics of the received feedback signal (e.g., by measuring the time required for the multipath echo in the received feedback signal to dissipate). In some variations, the second duration of the received feedback signal may be less than the first duration of the transmitted feedback signal. For example, the transmitted feedback signal may include a pulse signal comprising multiple cycles of a carrier frequency, and the second duration of the received feedback signal may include a portion of the pulse signal comprising one or more cycles having a stable signal amplitude (e.g., an amplitude at which the multipath echo has dissipated).

[0210] In some variations, the method (300) may include detecting the onset (e.g., rising edge, arrival time) of a feedback signal received on one or more transducer elements of a transducer array using one or more of: envelope detection, predetermined timing, coherent detection (e.g., using mixing), comparison of the received feedback signal amplitude to a threshold level, combinations thereof, etc. In some variations, onset detection may include using one or more of: envelope detection, predetermined timing (e.g., based on a time at which a first device may transmit a feedback signal and a signal propagation delay from the first device to the second device), coherent detection, and comparison of the received feedback signal amplitude to a threshold level (e.g., a predetermined threshold).

[0211] In some variations, the feedback signal data may include one or more of the following: absolute amplitude or magnitude, relative amplitude or magnitude, absolute signal strength, relative signal strength, energy of the signal in one or more frequency bands, apodization, absolute phase, relative phase, absolute time delay, relative time delay, absolute arrival time, relative arrival time, frequency, time duration, number of cycles, absolute signal-to-noise ratio, relative signal-to-noise ratio, combinations thereof, etc., of the feedback signal received by one or more transducer elements of the transducer array during the second duration. For example, in some variations, the arrival time of the feedback signal received at one or more transducer elements may include detecting the absolute timing of a rising edge of the received feedback signal, or the timing of a rising edge of the received feedback signal relative to a reference transducer element. In some variations, the reference transducer element may be determined based on one or more of the following: amplitude, energy, signal-to-noise ratio or signal-to-interference ratio of the received feedback signal, apodization of the transducer element, combinations thereof, etc. For example, the reference transducer element may be the transducer element that receives the strongest amplitude or SNR of the feedback signal.

[0212] In some variations, the transducer array configuration may include one or more of the following: selection of transducer elements, apodization applied to one or more transducer elements of the transducer array for transmitting a wireless signal to the first device, signal strength, voltage level, current level, pulse width, pulse width modulation, duty cycle of the signal, phase, time delay, frequency, transmission duration, combinations thereof, etc. In some variations, the transmitted wireless signal may include one or more of the following: power, data, commands, one or more other signals (e.g., pulses), combinations thereof, etc. In some variations, the second device may include one or more pulser circuits for driving one or more transducer elements of the transducer array for transmitting the wireless signal. In some variations, the output or transmit signal of the pulser circuit may include one or more signal levels (e.g., a 2-level pulser output or square wave, a 3-level pulser output, a 5-level pulser output, combinations thereof, etc.). In some variations, a multi-level pulser output may include a pulse width or duty cycle that can be modulated (e.g., pulse width modulation) to modulate the transmit power.

[0213] In some variations, the transmit duration of a wireless signal sent from a second device to a first device may be determined by a processor of the second device based on monitoring feedback signal data (e.g., link efficiency, apodization, phase, and / or delay) corresponding to feedback signals received by transducer elements of a transducer array of the second device. For example, if the feedback signal data does not change significantly over time, the second device may be configured to transmit the wireless signal with a longer transmit duration. In some variations, a long transmit duration may allow an increase in the duty cycle of the wireless power (e.g., the duration of a burst in which the wireless power is on relative to the total repetition interval), thereby allowing the energy source (e.g., a capacitor, a battery) of the first device to be charged faster. In some variations, the processor of the second device may be configured to periodically monitor the feedback signal data over time and dynamically adjust the transmit duration of the wireless signal sent from the second device to the first device based on the feedback signal data (e.g., the rate of change of apodization or phase corresponding to the feedback signal received by the transducer elements).

[0214] In some variations, it may be desirable to achieve one or more of the following: efficient and / or rapid charging of a first device from a second device using one or more wireless power signals, and operation or heating below a safe strength level due to the wireless power signals within the body. In some variations, closed-loop powering may be employed to achieve a target power level at a first device (e.g., a wireless implantable device). In some variations, a first device may be configured to send or communicate feedback regarding one or more of a power level, voltage level, or current level received or generated by the first device in response to a first wireless power signal received from a second device. However, in some systems where the first device may move relative to the second device over time or where there may be other link changes over time, feedback regarding the power level, voltage level, or current level may be insufficient to achieve reliable wireless powering or charging of the first device. Solutions to overcome this challenge are provided herein.

[0215] In some variations, a first device receiving a wireless power signal from a second device may be configured to determine or measure a first duration, the first duration comprising one or more of: a duration corresponding to the wireless power signal received by the first device, a duration corresponding to charging of an energy storage device of the first device (e.g., a duration during which the energy storage device of the first device is charged while receiving the wireless power signal), combinations thereof, or the like. In some variations, the first duration may comprise a duration during which a predetermined condition may be satisfied. In some variations, the predetermined condition may comprise checking whether one or more of the following is above or below a predetermined threshold (e.g., using a processor of the first device), including but not limited to: a wireless power level or energy level received by the first device, a voltage generated by the first device in response to the received wireless power signal (e.g., an output voltage of a rectifier, an AC-DC converter circuit, a DC-DC converter circuit, a charging circuit, a power management circuit, etc.), a current generated by the first device in response to the received wireless power signal (e.g., a load current of a rectifier circuit, a current in a clamping circuit, a charging current of the energy storage device of the first device, etc.), combinations thereof, or the like. In some variations, the first duration may be digitized by the first device (e.g., using a timer circuit, a time-to-digital converter circuit, etc.). In some variations, information about the first duration may be sent by the first device to the second device in the form of a feedback signal and / or a wireless data signal (e.g., the digitized duration may be sent in the form of OOK data bits). In some variations, the second device may be configured to receive (e.g., using one or more transducer elements of a transducer array) and process (e.g., using a processor of the second device) the feedback signal and / or the wireless data signal to generate feedback signal data (e.g., the feedback signal data may include information about the first duration), and determine the second duration based at least in part on the feedback signal data. In some variations, the second device may be configured to exchange one or more wireless signals with the first device based on the second duration (e.g., sending a wireless power signal to the first device for a duration equal to the second duration). In some variations, the second duration may be substantially equal to the first duration. In some variations, the second duration may be greater than the first duration. For example, if the first duration is substantially equal to the duration of the wireless power signal transmitted by the second device, this may indicate that the energy storage device of the first device is capable of charging within the entire duration of the wireless power signal, and a longer wireless power signal duration may be beneficial for faster charging of the energy storage device of the first device. In some variations, the second device may be configured to adjust (e.g., increase or decrease) the transmission duration of the next one or more wireless signals (e.g., wireless power signals, wireless data signals, etc.) transmitted by the second device to the first device based on the feedback signal data. In some variations, the second device may be configured to dynamically adjust its transmission duration based on feedback from the first device.For example, feedback from the first device may include a digitized duration of the received power signal received by the first device during which the output voltage of the rectifier circuit of the first device may be above a predetermined threshold voltage level (e.g., 3V, 4V, etc.). This may facilitate optimizing (or increasing) or adjusting the duty cycle of the wireless power (the duty cycle may be calculated as the duration of the power signal available to charge the first device divided by the repetition interval of the wireless power signal transmitted by the second device). For example, such an approach may allow for maximizing (or increasing) the charging rate of one or more energy storage devices of the first device and / or minimizing (or reducing) the time required to charge one or more energy storage devices of the first device.

[0216] In some variations, a system configured to exchange wireless power or data may include: a first device, the first device including a first transducer, a first processor, and an energy storage device, wherein the first transducer may be configured to receive a first wireless power signal from a second device, the energy storage device may be configured to charge based on the received first wireless power signal, the first processor may be configured to determine a charging duration corresponding to one or more predetermined conditions, and the first device may be configured to send a feedback signal based on the charging duration, wherein the second device may include a second transducer and a second processor, wherein the second transducer may be configured to receive the feedback signal, the second processor may be configured to process the feedback signal to generate feedback signal data and determine a transducer configuration based at least in part on the feedback signal data, and the second device may be configured to send a second wireless power signal to the first device based on the transducer configuration.

[0217] In some variations, the charging duration may include one or more of: a duration associated with the first wireless power signal, a duration associated with a signal generated by the first device in response to the first wireless power signal, a duration associated with charging of an energy storage device of the first device, combinations thereof, and the like. For example, the charging duration may include the duration of time that a voltage level on a capacitor of the first device (e.g., an output capacitor of a rectifier circuit) is above a predetermined threshold. For example, the voltage level on the capacitor may increase based on power recovery of the first wireless power signal by the rectifier circuit. In some variations, the voltage level on the capacitor may exceed the predetermined threshold even after the first wireless power signal has dissipated (e.g., for relatively large capacitances). In some variations, the charging duration may be greater than the duration of the first wireless power signal. In some variations, the charging duration may be less than the duration of the first wireless power signal (e.g., if the first device moves significantly during the duration of the first wireless power signal, the first device may receive a power level that decreases over time, causing the voltage level on the capacitor to drop below the predetermined threshold).

[0218] In some embodiments, the predetermined condition may include one or more of the following: an absolute or relative time duration corresponding to the received first wireless power signal, an absolute or relative time duration corresponding to a voltage generated by the first device in response to the received first wireless power signal, an absolute or relative time duration corresponding to a current generated by the first device in response to the received first wireless power signal, an absolute or relative power level corresponding to the received first wireless power signal, an absolute or relative energy level corresponding to the received first wireless power signal, an absolute or relative voltage level generated by the first device in response to the received first wireless power signal, and an absolute or relative current level generated by the first device in response to the received first wireless power signal.

[0219] Figure 23 The present invention is a flowchart generally describing a variation of a method (2300) for exchanging wireless signals with a device based on a charging duration. The method (2300) may include the following steps: receiving a first wireless power signal at a first transducer of a first device of a wireless system from a second device of a wireless system, wherein the first device may include an energy storage device and a first processor, and the second device may include a second transducer and a second processor (2302); charging the energy storage device based on the received first wireless power signal (2304); determining, using the first processor, a charging duration corresponding to one or more predetermined conditions (2306); sending a feedback signal from the first device to the second device based on the charging duration (2308); receiving the feedback signal using the second transducer (2310); processing the feedback signal using the second processor to generate feedback signal data (2312); determining, using the second processor, a transducer configuration based at least in part on the feedback signal data (2314); and sending a second wireless power signal from the second device to the first device based on the transducer configuration (2316).

[0220] In some embodiments, the predetermined condition may include one or more of the following: an absolute or relative time duration corresponding to the received first wireless power signal, an absolute or relative time duration corresponding to a voltage generated by the first device in response to the received first wireless power signal, an absolute or relative time duration corresponding to a current generated by the first device in response to the received first wireless power signal, an absolute or relative power level corresponding to the received first wireless power signal, an absolute or relative energy level corresponding to the received first wireless power signal, an absolute or relative voltage level generated by the first device in response to the received first wireless power signal, and an absolute or relative current level generated by the first device in response to the received first wireless power signal.

[0221] In some variations, the method may include: digitizing the charging duration using a first processor. For example, in some variations, the first processor may include a timer circuit and an analog-to-digital converter to determine the digital bits representing the charging duration. In some variations, the method may include: encoding or modulating the feedback signal using the first processor using one or more of a digital representation of the charging duration (e.g., using OOK modulation) and an analog representation of the charging duration. In some variations, the feedback from the first device regarding the charging duration may include as part of one or more of a feedback signal, a data signal, an uplink data signal, a combination thereof, or the like.

[0222] In some variations, the feedback signal data may include one or more of the following: a digital representation of charging duration, an analog representation of charging duration, an absolute amplitude or magnitude of the feedback signal received by the second transducer, a relative amplitude or magnitude, an absolute signal strength, a relative signal strength, energy of the signal in one or more frequency bands, apodization, absolute phase, relative phase, absolute time delay, relative time delay, absolute time of arrival, relative time of arrival, frequency, time duration, number of cycles, absolute signal-to-noise ratio, and relative signal-to-noise ratio. In some variations, the feedback signal data may include one or more of the following: a mean, median, mode, variance, standard deviation, minimum, maximum, percentile, histogram, statistical distribution, frequency, and probability of one or more charging durations corresponding to one or more first wireless power signals received by the first transducer from the second device.

[0223] In some variations, the transducer configuration may include one or more of the following: an absolute or relative duration of the second wireless power signal, one or more absolute or relative power levels of the second wireless power signal (e.g., increasing power levels over the duration or burst duration of the second wireless power signal), one or more absolute or relative amplitudes of the second wireless power signal, an absolute or relative pulse repetition frequency (PRF) or duty cycle of the powering of the second wireless power signal, and an absolute or relative frequency of the second wireless power signal. For example, the second processor may be configured to adjust or adapt the transmit duration of the second wireless power signal based on feedback regarding the duration of one or more previously transmitted wireless power signals that successfully charged the energy storage device of the first device. In some variations, the second processor may be configured to adapt, adjust, or ramp the transmit power level corresponding to the second wireless power signal over time. For example, if the intensity or power level of the first wireless power signal received by the first device decays over time, the second processor may be configured to increase the transmit power level of the second wireless power signal over time so that the first device receives a substantially uniform intensity or power level over time (or an intensity or power level that varies relatively little over time). For example, in some variations, the PRF of the second wireless power signal may be adjusted to meet an intensity limit (e.g., a time-averaged intensity limit) or a heating limit within the body.

[0224] In some variations, the second processor may be configured to process multiple feedback signals received from the first device (e.g., one or more feedback signals may encode information about the charging duration). In some variations, the second processor may be configured to determine the transmission duration and / or power level of the second wireless power signal based on the multiple feedback signals received from the first device (e.g., by calculating an average of the charging durations corresponding to the multiple first wireless power signals received by the first device and transmitting the second wireless power signal with a transmission duration that may be substantially equal to the average). In some variations, the second device may include a memory to store feedback signal data (e.g., storing the charging durations corresponding to the multiple first wireless power signals).

[0225] In some variations, the duration of the second wireless power signal may be configured to be substantially equal to or greater than the charging duration. In some variations, the duration of the second wireless power signal may be configured to be substantially equal to or greater than one or more of the following: the mean of one or more charging durations, the median of one or more charging durations, the mode of one or more charging durations, and a value corresponding to one or more charging durations, the one or more charging durations corresponding to one or more first wireless power signals received by the first transducer from the second device. For example, in some variations, the duration of the second wireless power signal may be configured to be substantially equal to or greater than the sum of the mean and one or more standard deviations of the distribution of the one or more charging durations (e.g., the mean and standard deviation of a Gaussian distribution). This approach may be advantageous for wireless links that vary over time, allowing the optimal transmission duration of the second wireless signal to be empirically determined based on the charging duration corresponding to one or more previous first wireless signals.

[0226] In some variations, the second transducer may comprise one or more transducer arrays comprising one or more transducer elements. In some variations, the transducer configuration may comprise one or more of: a selected set of transducer elements, apodization applied to the one or more transducer elements for transmitting one or more wireless power signals to the first device, signal strength, voltage level, current level, pulse width, pulse repetition rate, pulse width modulation, duty cycle, phase, time delay, frequency, and transmission duration.

[0227] In some variations, the first device may comprise an implantable medical device, and the second device may comprise an external wireless device configured to be physically separate from the first device. In some variations, the first wireless power signal and the second wireless power signal may comprise ultrasonic or acoustic signals.

[0228] In some variations, the transducer array configuration may include a set of parameters (e.g., transducer element phase) based on a parameter (e.g., phase) of the feedback signal. For example, the phase applied to one or more transducer elements of the transducer array for transmitting a wireless signal to the first device may be based on one or more of the following: the relative phase of the feedback signal received at the predetermined frequency within the second duration, and the arrival time of the feedback signal received on the one or more transducer elements. Additionally or alternatively, the time delay applied to one or more transducer elements of the transducer array for transmitting a wireless signal to the first device may be based on one or more of the following: the relative phase of the feedback signal received at the predetermined frequency within the second duration, and the arrival time of the feedback signal received on the one or more transducer elements. In some variations, the predetermined frequency may include one or more of the following: a carrier frequency of the feedback signal, a harmonic of the carrier frequency, a subharmonic of the carrier frequency, another frequency in the frequency band of the received feedback signal, a combination thereof, or the like. In some variations, the time delay applied to the transducer element may comprise the sum of: a relative arrival time of the feedback signal (e.g., relative to a reference transducer element), the relative arrival time rounded to a period of the carrier frequency of the feedback signal; and a time delay or phase corresponding to a relative phase of the received feedback signal received at the carrier frequency of the feedback signal within a second duration (e.g., relative to the reference transducer element). For example, this may facilitate aligning rising and / or falling edges of a wireless signal (e.g., an ultrasonic pressure wave), as well as aligning the steady-state phase of a wireless signal received by a transducer element of a first device from a different transducer element of a second device. In some variations, aligning rising and / or falling edges may allow for shortening the bit duration of OOK-modulated downlink data bits transmitted by a second device (e.g., an external device) to a first device (e.g., an implantable medical device), thereby allowing for higher data rates and faster data communication. In some variations, the relative phase of the feedback signal received at the predetermined frequency during the second duration may be the relative phase of a portion of the feedback signal having a stable amplitude (e.g., an amplitude within approximately 5% of a steady-state value of the feedback signal after multipath reflections have dissipated below a predetermined threshold). In some variations, the transmit phase or time delay may be applied using one or more of: multiple clock cycles, a delay line, a digitally controlled phase or time delay, an analog phase or time delay, a combination thereof, etc. In some variations, the transmit phase may be wrapped (e.g., constrained to [0, 2π) or [-π, π) radians). In some variations, the transmit phase may be unwrapped.

[0229] In some variations, the processor of the second device may be configured to select one or more transducer elements of the transducer array of the second device for sending wireless data or wireless commands to the first device based on one or more of the signal strength of the multipath interference of the feedback signal received by the transducer elements of the transducer array, the signal-to-interference ratio (SIR), the signal-to-noise-interference ratio (SNIR), a combination thereof, etc. For example, the processor may be configured to select a transducer element with low multipath interference or high SNIR of the feedback signal for sending wireless data or wireless commands to the first device. This can promote high-fidelity data or command signals and / or higher downlink data rates at the first device and allow reliable detection of data or commands at the first device. In some variations, the processor of the second device may be configured to select one or more transducer elements of the transducer array of the second device for sending wireless power to the first device based on one or more of the signal strength of the feedback signal received by the transducer elements of the transducer array (e.g., the link efficiency corresponding to the received feedback signal). This can provide high power transfer link efficiency, thereby allowing faster wireless charging of the energy source of the first device.

[0230] In some variations, the received feedback signal may comprise a time duration having a stable amplitude. In some variations, the first duration of the transmitted feedback signal may be greater than the multipath time of the wireless link (e.g., to allow multipath reflections to dissipate, thereby producing a stable amplitude of the received feedback signal). In some variations, the first duration of the transmitted feedback signal may be greater than approximately 5 periods of the carrier frequency of the feedback signal. In some variations, the feedback signal may comprise one or more of a pulsed signal and a pulsed signal. In some variations, the pulsed signal may comprise one or more of a rectangular pulse, a Dirac pulse, a sine pulse, a triangular pulse, a trapezoidal pulse, a raised cosine pulse, a sinc pulse, a Gaussian pulse, one or more periods of the carrier frequency of the pulsed signal, combinations thereof, and the like.

[0231] In some variations, processing the feedback signal or determining the transducer array configuration of the second device may include one or more of the following: time domain analysis, frequency domain analysis, interpolation analysis, combinations thereof, etc. In some variations, the time domain analysis may include one or more of cross-correlation and time reversal. For example, a feedback signal received on a transducer element (or a portion of the feedback signal with a stable amplitude) may be cross-correlated with a feedback signal received on another transducer element (or a portion of the feedback signal with a stable amplitude) to determine their relative phase difference or time delay. In some variations, the relative phase difference or time delay may be reversed and applied to the transducer element for use in sending a wireless signal to the first device (e.g., to achieve focusing of a power or continuous wave signal at the transducer of the first device).

[0232] In some variations, frequency domain analysis may include computing one or more of a Fourier transform, a discrete Fourier transform (DFT), a discrete-time Fourier transform (DTFT), combinations thereof, and the like at one or more predetermined frequencies. In some variations, computing one or more of a Fourier transform, a discrete Fourier transform (DFT), and a discrete-time Fourier transform (DTFT) at one or more predetermined frequencies may include using one or more of a fast Fourier transform (FFT) algorithm, a Goertzel algorithm, combinations thereof, and the like. In some variations, applying the Goertzel algorithm at one or more predetermined frequencies may be computationally more efficient than determining a Fourier transform or DFT over a wide frequency band. In some variations, the one or more predetermined frequencies may be based on one or more feedback signal frequencies (e.g., a carrier frequency of the feedback signal). In some variations, determining the one or more predetermined frequencies may be based on one or more of a time domain analysis and a frequency domain analysis of feedback signals received by one or more transducer elements of the transducer array during one or more of the first duration, the second duration, and the third duration. For example, the third duration may include one or more cycles of the carrier frequency of the received feedback signal. In some variations, the start (e.g., rising edge) of a feedback signal pulse received on one or more transducer elements may be detected, and the third duration may be determined based on one or more of a start time (e.g., timing of the rising edge of the feedback signal pulse) and a predetermined pulse width of the feedback signal. For example, the third duration may begin at the start time or at a fixed time offset after the start time (e.g., one or more cycles of the carrier frequency after the start time) and end after one or more cycles of the carrier frequency of the received feedback signal (e.g., 5 cycles).

[0233] In some variations, the interpolation analysis may include interpolating one or more of the feedback signal data and the transducer array configuration from one or more transducer elements to one or more other transducer elements (e.g., adjacent transducer elements). For example, such interpolation analysis may be based on one or more interpolation techniques, such as spline interpolation, linear interpolation, cubic interpolation, combinations thereof, etc. In some variations, the interpolation may be performed using predetermined spatial positions of the transducer elements (e.g., calculating the transmit phase based on the difference in path lengths of the feedback signal propagating from the first device to different transducer elements of the second device). In some variations, the interpolation may allow the wireless signal to be transmitted on one or more transducer elements that are not configured to receive the feedback signal or process the received feedback signal.

[0234] In some variations, determining the transducer array configuration of the second device may include determining one or more of a link efficiency and a transmit power for transmitting wireless signals to the first device using at least one of the feedback signal data and a predetermined power of the transmitted feedback signal. For example, the closed-loop powering method described herein may be used to determine one or more of a link efficiency (e.g., uplink and / or downlink link efficiency) and a transmit power for transmitting wireless signals from the second device to the first device.

[0235] In some variations, one or more wireless signals exchanged with the first device may include one or more frequencies that are the same as or different from one or more frequencies of the feedback signal. For example, the feedback signal may include a carrier frequency f1, and the received feedback signal may be subjected to frequency domain analysis to generate feedback signal data (e.g., the amplitude, phase, etc. of the received feedback signal) at a frequency f2, where f1 may not be equal to f2. In some variations, the feedback signal data may be generated at frequency f1 and / or frequency f2, and the transducer array configuration (e.g., transmit phase or time delay, apodization, transmit signal strength, transmit signal pulse width, etc.) may be determined at frequency f2 (e.g., by scaling the amplitude and phase at frequency f1 to frequency f2), where f1 may not be equal to f2 (e.g., f2 may be a harmonic of f1, a subharmonic of f1, or an arbitrary frequency relative to f1).

[0236] In some variations, the transducer element configured to receive the feedback signal and the transducer array configuration used to exchange wireless signals with the first device may include one or more common transducer elements. In some variations, the transducer element used to receive the feedback signal and the transducer array configuration used to exchange wireless signals with the first device may include different transducer elements. In some variations, if one or more transducer elements used to exchange wireless signals with the first device have not been used to receive or process the feedback signal, the configuration of the one or more transducer elements may be determined using interpolation (e.g., based on adjacent transducer elements).

[0237] In some variations, the first device may comprise an implantable medical device, and the second device may comprise an external wireless device configured to be physically separate from the first device. In some variations, the first device may comprise an external wireless device, and the second device may comprise an implantable medical device configured to be physically separate from the first device.

[0238] In some variations, the method (300) may include sending a feedback signal or multiple feedback signals from the first device at one or more predetermined repetition intervals. In some variations, the predetermined repetition interval may correspond to a time duration during which the wireless link may be quasi-static (e.g., a time duration during which the link efficiency may vary by less than about 3 dB) or a time duration during which the first device may be relatively stationary relative to the first device. In some variations, the first duration of the sent feedback signal may be the same or different in different repetition intervals. In some variations, the second duration of the received feedback signal may be the same or different in different repetition intervals. In some variations, the method (300) may include sending a wireless command from the second device to the first device, and sending a feedback signal from the first device to the second device in response to receiving the wireless command. In some variations, the wireless command may include one or more of the following: a wireless signal, a pulse signal, a plurality of pulse signals, a signal with encoded data bits (e.g., using on-off keying (OOK) modulation), a combination thereof, etc. In some variations, the feedback signal sent may include a reflected signal or backscattered signal in response to a wireless signal sent by the second device to the first device. In some variations, the feedback signal sent may include one or more of the following: an ultrasonic signal, an acoustic signal, a vibration signal, a radio frequency signal, an electromagnetic signal, a magnetic signal, an electrical signal, an optical signal, a combination thereof, etc. In some variations, the feedback signal sent may be an ultrasonic signal or an acoustic signal having a carrier frequency between about 20 kHz and about 20 MHz. In some variations, the first duration of the feedback signal sent may be between about 1 μs and 1 ms (e.g., a pulse signal including one or more cycles of the carrier frequency). In some variations, the second duration of the received feedback signal may be between about 1 μs and 100 ms (e.g., may be 500 μs to capture multipath reflections of the sent feedback signal pulses).

[0239] In some variations, the method (300) may include sending one or more data signals from the first device to the second device. In some variations, the method (300) may also include selecting one or more transducer elements (e.g., some or all transducer elements) of a transducer array of the second device for processing the one or more data signals using a processor of the second device. In some variations, selecting the one or more transducer elements of the transducer array of the second device may be based on one or more of: signal strength of a received feedback signal, a signal-to-noise ratio of the received feedback signal, energy of the received feedback signal in one or more frequency bands, apodization of the transducer elements, a moving average of the feedback signal amplitude, signal strength of an interference source, signal strength of multipath interference, multipath time, combinations thereof, etc. In some variations, the method (300) may include sending one or more data signals from the second device to the first device.

[0240] Figure 4 A timing diagram (400) illustrates an exemplary variation of a feedback signal used in a method for exchanging wireless signals with a wireless device. As shown, a feedback signal (402) transmitted from a first device (e.g., a wireless implantable device) may include a first duration (404). The transmitted feedback signal (402) may be subject to multipath interference when wirelessly propagating through a medium (e.g., a heterogeneous tissue structure) between the first device and the second device. Also shown is a feedback signal (406) received by a transducer element during a second duration (408). Due to multipath interference in the wireless link, the feedback signal (406) received during the second duration (408) may include multipath reflections (410). In some variations, the second duration (408) may be greater than the time duration required for the multipath reflections (410) or echoes to dissipate (e.g., the time duration required for the intensity of the multipath reflections to dissipate to a certain level (e.g., 30 dB), to dissipate to below the intensity of the first received feedback signal pulse, or to dissipate to below a predetermined threshold level). The processor of the second device may be configured to process the received feedback signal (406) in the frequency domain. For example, the processor may be configured to calculate one or more of the amplitude (412) and phase (414) of the Fourier transform of the received feedback signal (406) using one or more of an FFT algorithm and a Goertzel algorithm at one or more predetermined frequencies within a second duration (or within a third duration obtained by zero-padding the received feedback signal). In some variations, the processor may be configured to generate feedback signal data comprising the received feedback signal (406) at one or more predetermined frequencies (such as Figure 4 One or more of an amplitude value Mag0 (416) and a phase value Phase0 (418) at a carrier frequency of the transmitted feedback signal (denoted by f0 in FIG). As an example, feedback signal data corresponding to the received feedback signals of three transducer elements of the transducer array may include an amplitude of [85.8, 61.5, 32.0] in arbitrary units and a phase of [19.3, -89.6, 72.5] in degrees. Based on the feedback signal data, the processor may determine a transducer array configuration for transmitting a wireless signal to the first device on the three transducer elements, the transducer array configuration including an apodization or transmit signal strength of [1.00, 0.72, 0.37] in arbitrary units and a transmit phase of [0, -108.9, 53.2] degrees. The apodization may be calculated by normalizing the amplitude to a maximum amplitude. The transmit phase may be calculated as a phase difference relative to a reference transducer element.

[0241] Figure 5The present invention is a flowchart generally describing a variation of a method (500) for exchanging wireless signals with a device based on a feedback signal. The method (500) may include the following steps: sending a feedback signal (502) from a first device of a wireless system to a second device of the wireless system; receiving the feedback signal (504) using a first transducer array of the second device; extracting one or more portions of the received feedback signal received by one or more transducer elements of the first transducer array of the second device using a processor of the second device (506); processing the extracted one or more portions of the received feedback signal using the processor of the second device to generate feedback signal data (508); determining a second transducer array configuration of the second device based at least in part on the feedback signal data (510); and exchanging one or more wireless signals (512) with the first device using the second transducer array configuration of the second device. The feedback signals, transducer arrays, processors, transducer array configurations, feedback signal data, and wireless signals described herein are applicable to any of the methods described herein. In some variations, the duration of the extracted one or more portions of the received feedback signal may be less than the duration of the received feedback signal.

[0242] Figure 6A timing diagram (600) illustrates an exemplary variation of a feedback signal used in a method for exchanging wireless signals with a wireless device. As shown, a feedback signal (602) transmitted from a first device (e.g., a wireless implantable device) may be subject to multipath interference in a wireless link, such that a feedback signal (604) received by a second device (e.g., an external wireless device) may include varying amplitude levels. In some variations, extracting one or more portions of the received feedback signal (604) may include searching for one or more regions (606) of the received feedback signal waveform having stable amplitudes. In some variations, such regions (606) of the received feedback signal may correspond to a duration during which all major reflections of the feedback signal in the wireless link may be in a stable state. In some variations, such regions (606) of the received feedback signal may occur after the second device receives the last major reflection of the feedback signal. In some variations, the duration of the transmitted feedback signal (602) may be greater than approximately five cycles of the carrier frequency of the feedback signal. Such a long duration of the feedback signal may allow the amplitude of the received feedback signal to stabilize to account for constructive and / or destructive interference from reflections of the feedback signal in the wireless link. In some variations, the duration of the transmitted feedback signal (602) may be selected based on the expected location of reflectors in the wireless link (e.g., ribs, lungs, tissue boundaries, etc.) relative to the location of the first device and the location of the second device. For example, in some variations, if reflections in the wireless link are expected to stabilize within approximately 100 microseconds (e.g., the signal amplitude stabilizes within 5% or 1%, etc.), the duration of the feedback signal may be selected to be approximately 100 microseconds or longer. In some variations, the duration of the transmitted feedback signal (602) may be selected based on the multipath time of the link (e.g., the time delay between the arrival time of a direct line of sight signal or a first reflection and the arrival time of a last reflection of a signal propagating from a first device of the wireless system to a second device). In some variations, extracting a portion of the received feedback signal may include detecting one or more regions of the received feedback signal waveform where the envelope of the received feedback signal may not change by more than a predetermined percentage (eg, no more than ±5%).

[0243] Optionally, in some variations, the method (500) may include: detecting one or more of a rising edge and a falling edge of the received feedback signal before extracting one or more portions of the received feedback signal. For example, a rising edge of the received feedback signal may be detected, the timing of the occurrence of the rising edge may be determined, and a region of the received feedback signal starting from a certain time may be extracted, the time may be a predetermined duration after the timing of the occurrence of the rising edge. Such a predetermined duration may be based on the multipath time of the wireless link or the time required for reflections in the link to stabilize. In some variations, the detection of the rising edge and / or falling edge of the received feedback signal may be performed by comparing the amplitude envelope and / or energy of the received feedback signal with a predetermined threshold. In some variations, such comparison with the predetermined threshold may be performed in the time domain and / or the frequency domain (e.g., after calculating the Fourier transform or short-time Fourier transform of the received feedback signal). In some variations, a sliding window or a filter or a matched filter may be applied to the received feedback signal to detect the rising edge and / or the falling edge. In some variations, the average amplitude envelope and / or average energy of the received feedback signal averaged over a predetermined duration may be compared to a predetermined threshold to detect a rising edge and / or a falling edge of the received feedback signal. For example, the received feedback signal may be digitized, and a rising edge may be detected by examining when a predetermined number of consecutive samples of the amplitude envelope of the received feedback signal cross a predetermined threshold.

[0244] In some variations, the first transducer array (e.g., an ultrasound array) of the second device may include a plurality of transducer elements (e.g., ultrasound transducer elements). In some variations, one or more portions of the received feedback signal may be extracted for feedback signals received by a subset of the elements of the first transducer array. For example, transducer elements that may not receive sufficient signal strength of the received feedback signal (e.g., due to ribs blocking the signal) may be omitted from further processing in order to save computing resources. In some variations, extracting one or more portions of the received feedback signal may be performed only for one or more transducer elements of the first transducer array that have the highest signal strength or signal-to-noise ratio (SNR) of the received feedback signal or a signal strength or SNR above a predetermined threshold. In some variations, extracting one or more portions of the received feedback signal may be performed only for one or more transducer elements of the first transducer array that have the highest link gain (or efficiency) with the first device or a link gain (or efficiency) with the first device that is above a predetermined threshold. In some variations, extracting one or more portions of the received feedback signal may be performed only for one or more predetermined transducer elements of the first transducer array of the second device.

[0245] In some variations, the method (500) may further include: digitizing the received feedback signal before extracting one or more portions of the feedback signal received by one or more transducer elements of the first transducer array. In some variations, the method (500) may further include: detecting a rising edge of the received feedback signal using analog signal processing before digitizing the feedback signal received by the one or more transducer elements of the first transducer array. For example, such analog signal processing may include one or more of: envelope detection (e.g., using an envelope detector circuit), integration (e.g., using a wait timer circuit based on charge integration), comparison with a predetermined threshold (e.g., using a comparator and a reference generator circuit), combinations thereof, etc. In some variations, extracting the one or more portions of the received feedback signal is performed using one or more of digital signal processing, analog signal processing, combinations thereof, etc.

[0246] In some variations, the feedback signal data may include one or more of the following: absolute amplitude or magnitude, relative amplitude or magnitude, absolute signal strength, relative signal strength, energy of the signal in one or more frequency bands, apodization, absolute phase, relative phase, absolute time delay, relative time delay, absolute arrival time, relative arrival time, frequency, time duration, number of cycles, absolute signal-to-noise ratio, relative signal-to-noise ratio, combinations thereof, etc. of the feedback signal received by one or more transducer elements of the first transducer array of the second device. In some variations, the relative amplitude, signal strength, phase, and / or time delay of a given transducer element may be relative to another transducer element of the second device. In some variations, determining the configuration of the second transducer array of the second device may include determining one or more of the amplitude, signal strength, phase, time delay, frequency, time duration, number of cycles, combinations thereof, etc. for transmitting wireless signals via one or more transducer elements of the second transducer array. In some variations, determining one or more of the amplitude, signal strength, phase, time delay, frequency, time duration, number of cycles, combinations thereof, etc., for transmitting a wireless signal via one or more transducer elements of a second transducer array may comprise performing one or more of cross-correlation, time reversal, frequency domain analysis (e.g., using one or more of an FFT and a Goertzel algorithm to compute one or more of a Fourier transform, a DFT, a DTFT), interpolation analysis (e.g., based on adjacent transducer elements), combinations thereof, etc. In some variations, time reversal may comprise reversing the time delay or phase of a received feedback signal received by one or more transducer elements of a transducer array of the second device from the first device in order to transmit the wireless signal to the first device. In some variations, time reversal may cause the ultrasound beam to be focused at the first device, which may facilitate efficient delivery of wireless power to the first device (e.g., a wireless implantable device).

[0247] In some variations, cross-correlation as described herein may include calculating a sliding dot product of at least two received feedback signals received by at least two transducer elements of a first transducer array of a second device. In some variations, cross-correlation may be performed to determine a relative time delay, lag, or phase difference between the at least two received feedback signals. In some variations, the relative time delay, lag, or phase difference between the at least two received feedback signals may be reversed when a wireless signal (e.g., power) is transmitted from the second device to the first device. In some variations, the feedback signal received on one or more transducer elements of the first transducer array may be cross-correlated with the received feedback signal having the highest signal strength or amplitude, SNR, and / or link gain. In some variations, the received and digitized feedback signals may be resampled (e.g., using upsampling, interpolation, expansion, etc.) prior to cross-correlation in order to change (e.g., increase) the resolution of the relative time delay, lag, and / or phase difference calculated using cross-correlation. In some variations, one or more received feedback signals may be normalized (e.g., the amplitude of the signal is scaled to set its maximum value to 1) prior to cross-correlation. In some variations, to reduce computation, cross-correlation between two or more received feedback signals may be performed with a maximum lag (or time shift) based on the time period of the received feedback signals. For example, the maximum lag for cross-correlation may be set to one time period of the carrier frequency of the feedback signals.

[0248] In some variations, determining one or more of the amplitude and signal strength of a wireless signal transmitted by one or more transducer elements of the second transducer array may include one or more of: envelope detection, energy detection in a predetermined frequency band (e.g., a bandwidth centered around the carrier frequency of the transmitted feedback signal), comparing relative signal strengths received at different transducer elements of the first transducer array, combinations thereof, etc. Such signal processing for determining the transmit amplitude or signal strength may be performed on one or more extracted portions of the received feedback signal. Relative transmit signal strengths calculated based on determining relative amplitudes of stable regions of the received feedback signal may be beneficial for efficiently powering the first device from the second device.

[0249] In some embodiments, determining one or more of an amplitude, signal strength, phase, and delay for transmitting a wireless signal through one or more transducer elements of a second transducer array may further comprise interpolating one or more of the amplitude, signal strength, phase, and delay based on the relative spatial positions of the transducer elements of the first and second transducer arrays. For example, the first transducer array may comprise alternating transducer elements of a one-dimensional second transducer array comprising a plurality of equally spaced transducer elements. In such a case, one or more of the amplitude, signal strength, phase, and delay determined for the elements of the first transducer array may be interpolated (e.g., using spline interpolation, linear interpolation, etc.) to determine one or more of the amplitude, signal strength, phase, and delay for one or more transducer elements of the second transducer array. In some embodiments, the phase may be unwrapped prior to interpolation to obtain a continuous phase signal that is not constrained to its principal values ​​of (-π, π] or [0, 2π) radians. In some variations, determining the configuration of the second transducer array may further include a method of closed-loop powering, as described herein.

[0250] In some variations, the first device may comprise an implantable medical device, and the second device may comprise an external wireless device configured to be physically separated from the first device. In some variations, the first transducer array and the second transducer array may comprise one or more common transducer elements (e.g., the same set of transducer elements). In some variations, the first transducer array may comprise a subset of the second transducer array. In some variations, the first transducer array and the second transducer array may comprise different transducer elements. In some variations, the first transducer array and the second transducer array may each comprise an acoustic (e.g., ultrasonic) transducer array.

[0251] Figure 7 A cross-sectional schematic diagram illustrating variations of ultrasound beams and transmit signal strengths for an ultrasonic transducer array (700). Relative transmit signal strengths or apodization of transducer elements (722) of a transducer array (720) of a second device (714) are shown. Apodization can be a relative amplitude weighting applied to different transducer elements of a transducer array. Relative transmit signal strengths and corresponding transmit delays (not shown) can be calculated using any of the methods described above. This transducer configuration of the second transducer array (720) can produce an ultrasound beam (742) that can be focused at the location of a wireless implantable device (710) implanted in chest tissue (770) including a rib cage or rib (772).

[0252] b. Exchange wireless signals based on link scanning signals

[0253] In some variations, sending a feedback signal with a long duration (e.g., greater than about 5 cycles of the carrier frequency of the feedback signal) may not be desirable. For example, due to the limited energy budget of the wireless implantable device, it may be desirable to avoid sending long-duration feedback signals from the wireless implantable device (e.g., the miniature implantable device may not have sufficient stored energy, or it may be advantageous to utilize its stored energy for other operations such as sensing or stimulation). This may be particularly challenging in wireless systems that experience multipath interference. For example, as discussed in the example above, in some variations, if the multipath time in the wireless system is about 100 microseconds, a feedback signal duration greater than or equal to about 100 microseconds may be required to allow the amplitude of the received feedback signal to stabilize. However, a battery-free wireless implantable device may not have enough energy to send such a long-duration feedback signal. Solutions to overcome this challenge are provided herein.

[0254] In some variations, the method of exchanging wireless signals may be based on link scanning signals, as described herein. Figure 8 The present invention is a flowchart generally describing a variation of a method (800) for exchanging wireless signals with a device based on a link scan signal. The method (800) may include the following steps: sending a link scan signal from a first device of a wireless system to a second device of the wireless system (802); receiving the link scan signal using a first transducer array of the second device (804); processing the received link scan signal received by one or more transducer elements of the first transducer array of the second device using a processor of the second device to generate link scan signal data (806); determining a configuration of a second transducer array of the second device based at least in part on the link scan signal data (808); and exchanging one or more wireless signals with the first device using the second transducer array configuration of the second device (810). The link scan signal, transducer array, processor, transducer array configuration, link scan signal data, and wireless signals described herein are applicable to any of the methods described herein.

[0255] In some variations, the link scan signal may comprise one or more of a pulsating signal, a pulse signal, combinations thereof, and the like. In some variations, the pulse signal may comprise one or more periods of a carrier frequency of the pulse signal. In some variations, the pulse signal may comprise one or more of a rectangular pulse, a Dirac pulse, a sine pulse, a triangular pulse, a trapezoidal pulse, a raised cosine pulse, a sinc pulse, a Gaussian pulse, one or more periods of a carrier frequency of the pulse signal, combinations thereof, and the like.

[0256] In some variations, processing the received link scan signal received by the transducer elements of the first transducer array may include determining a pulsation response of the wireless system. For example, if the transmitted link scan signal includes a pulsation signal, the received link scan signal may include the pulsation response of the wireless system. In some variations, the pulsation response of the wireless system may be determined based on the received link scan signal and the transmitted link scan signal. For example, the pulsation response of the wireless system may be determined by a processor of the second device by performing a deconvolution on the received link scan signal with a reference link scan signal (e.g., the transmitted link scan signal). In some variations, the Fourier transform of the received link scan signal may be divided by the Fourier transform of the transmitted link scan signal to determine the pulsation response of the wireless system.

[0257] In some variations, processing the received link scan signal may further include: performing convolution on a ripple response of the wireless system corresponding to one or more transducer elements of the first transducer array with one or more template signals. The template signal may be any signal generated and / or received by a processor of the second device. For example, the template signal may include a sinusoidal pulse or a rectangular pulse comprising one or more cycles of a carrier frequency. In some variations, the template signal may represent a transmitted feedback signal of the method (500) for exchanging wireless signals based on a feedback signal, or may be the same as the transmitted feedback signal. In some variations, the template signal may include a pulse signal. In some variations, the pulse signal may include one or more of the following: a rectangular pulse, a Dirac pulse, a sine pulse, a triangular pulse, a trapezoidal pulse, a raised cosine pulse, a sinc pulse, a Gaussian pulse, one or more cycles of a carrier frequency of the pulse signal, a combination thereof, etc. In some variations, the duration of the template signal may be greater than about 5 cycles of the carrier frequency of the template signal. In some variations, the same template signal may be used to process link scan signals received by different transducer elements of the first transducer array of the second device. In some variations, different template signals may be used to process link scan signals received by different transducer elements of the first transducer array of the second device. The considerations discussed herein for the duration of the feedback signal (e.g., a feedback signal duration greater than or equal to the multipath time of the wireless link) may also apply to the duration of the template signal.

[0258] In some variations, the link scan signal data may comprise the output signal of the convolution of the received link scan signal with the template signal, or any characteristic of the convolved output signal (e.g., amplitude, time delay, phase, frequency, etc.). In some variations, the link scan signal data may comprise one or more of the following: absolute amplitude, relative amplitude, absolute signal strength, relative signal strength, apodization, absolute phase, relative phase, absolute time delay, relative time delay, combinations thereof, etc. of the convolved output signal. In some variations, the relative amplitude, signal strength, phase, and / or time delay of a given transducer element may be relative to another transducer element of a second device.

[0259] Figure 9 A timing diagram (900) of an exemplary variation of signals used in a method for exchanging wireless signals using a link scan signal. As shown, in some variations, a transmitted link scan signal (902) transmitted by a first device of a wireless system may include a short-duration rectangular pulse that may approximate a Dirac pulse or a Dirac delta function. Such a link scan signal may be advantageous for measuring a pulsation response of a wireless system (e.g., to characterize a transfer function of a wireless link of the wireless system), an approximate pulsation response of a wireless system, or a scaled pulsation response of a wireless system. Also shown is a conceptual representation of a corresponding received link scan signal (904) received by a transducer element of a first transducer array of a second device of the wireless system. The received link scan signal (904) may include a carrier frequency and bandwidth based on a resonant frequency and bandwidth of one or more of a transducer of the first device and a transducer of the second device. In addition, due to multipath interference (reflections of the link scan signal received from one or more reflectors or scatterers in the wireless link), the received link scan signal (904) may include one or more pulse signals. Also shown is an example of a template signal (906) comprising multiple cycles of a carrier frequency. The received link scan signal (904) may be convolved with the template signal (906) by a processor of the second device to generate a convolved output signal (908). In some variations, the convolved output signal (908) may simulate the received feedback signal of the method (500) for exchanging wireless signals based on a feedback signal. In some variations, the convolved output signal (908) may be further processed using processing steps similar to those applied to the received feedback signal in the method (500) for exchanging wireless signals based on a feedback signal described herein.

[0260] In some variations, determining the configuration of the second transducer array of the second device may include determining one or more of an amplitude, signal strength, phase, time delay, combinations thereof, etc., for transmitting wireless signals via one or more transducer elements of the second transducer array. In some variations, determining one or more of an amplitude, signal strength, phase, and time delay for transmitting wireless signals via one or more transducer elements of the second transducer array may include performing one or more of a cross-correlation, a time reversal, combinations thereof, etc. The cross-correlation and time reversal steps described herein may also be applicable here.

[0261] In some variations, determining one or more of the amplitude, signal strength, phase, and time delay for transmitting a wireless signal via one or more transducer elements of the second transducer array may further comprise interpolating one or more of the amplitude, signal strength, phase, and time delay based on the relative spatial positions of the transducer elements of the first and second transducer arrays. In some variations, determining the configuration of the second transducer array may comprise a closed-loop powering method. The interpolation steps described herein may also be applicable here.

[0262] In some variations, the first device may comprise an implantable medical device, and the second device may comprise an external wireless device configured to be physically separated from the first device. In some variations, the first transducer array and the second transducer array may comprise one or more common transducer elements (e.g., the same set of transducer elements). In some variations, the first transducer array may comprise a subset of the second transducer array. In some variations, the first transducer array and the second transducer array may comprise different transducer elements. In some variations, the first transducer array and the second transducer array may each comprise an acoustic (e.g., ultrasonic) transducer array.

[0263] In some variations, the first transducer array (e.g., an ultrasound array) of the second device may include a plurality of transducer elements (e.g., ultrasound transducer elements). In some variations, processing the received link scan signal may be performed for link scan signals received by a subset of the elements of the first transducer array. For example, transducer elements that may not receive sufficient signal strength of the received link scan signal (e.g., due to ribs blocking the signal) may be omitted from further processing in order to save computing resources. In some variations, processing the received link scan signal may be performed only for one or more transducer elements of the first transducer array that may receive the highest signal strength or signal-to-noise ratio of the link scan signal, or a signal strength or SNR above a predetermined threshold. In some variations, processing the received link scan signal may be performed only for one or more transducer elements of the first transducer array that may have the highest link gain (or efficiency) with the first device, or a link gain (or efficiency) with the first device that is above a predetermined threshold. In some variations, processing the received link scan signal may be performed only for one or more predetermined transducer elements of the first transducer array of the second device.

[0264] c. Exchange wireless signals based on feedback signals and link scan signals

[0265] In some variations, a method of exchanging wireless signals may be based on feedback signals and link scan signals, as described herein. Figure 10 The present invention is a flowchart generally describing a variation of a method (1000) for exchanging wireless signals with a device based on feedback signals and link scan signals. The method (1000) may include the following steps: sending a link scan signal and a feedback signal from a first device of a wireless system to a second device of the wireless system (1002); receiving the link scan signal and the feedback signal using a first transducer array of the second device (1004); processing the received link scan signal and the received feedback signal received by one or more transducer elements of the first transducer array of the second device using a processor of the second device to generate feedback signal data (1006); determining a configuration of a second transducer array of the second device based at least in part on the feedback signal data (1008); and exchanging one or more wireless signals with the first device using the configuration of the second transducer array of the second device (1010). The feedback signals, transducer arrays, processors, transducer array configurations, feedback signal data, link scan signal data, and wireless signals described herein are applicable to any of the methods described herein.

[0266] In some variations, processing the received link scan signal and the received feedback signal may include: performing a deconvolution of the received feedback signal with the received link scan signal. In some variations, processing the received link scan signal received by the transducer elements of the first transducer array may include: determining a ripple response of the wireless system. In some variations, processing the received link scan signal and the received feedback signal may include: performing a deconvolution of the received feedback signal with the ripple response of the wireless system or a scaled ripple response of the wireless system. In some variations, the method (1000) may further include: extracting one or more portions of the deconvolved output signal using a processor of the second device. In some variations, extracting the one or more portions of the deconvolved output signal may include: finding one or more regions of the deconvolved output signal having a stable amplitude.

[0267] In some variations, determining the second transducer array configuration of the second device may include determining one or more of an amplitude, signal strength, phase, and time delay for transmitting wireless signals via one or more transducer elements of the second transducer array. In some variations, determining one or more of an amplitude, signal strength, phase, and time delay for transmitting wireless signals via one or more transducer elements of the second transducer array may include performing one or more of a cross-correlation and a time reversal. The cross-correlation and time reversal steps described herein may also be applicable here.

[0268] In some variations, determining one or more of the amplitude, signal strength, phase, and delay for transmitting a wireless signal via one or more transducer elements of the second transducer array may further comprise interpolating one or more of the amplitude, signal strength, phase, and delay based on the relative spatial positions of the transducer elements of the first and second transducer arrays. The interpolation steps described herein may also be applicable here. In some variations, determining the second transducer array configuration includes a closed-loop powering method.

[0269] In some variations, the first device may comprise an implantable medical device, and the second device may comprise an external wireless device configured to be physically separated from the first device. In some variations, the first transducer array and the second transducer array may comprise one or more common transducer elements (e.g., the same set of transducer elements). In some variations, the first transducer array may comprise a subset of the second transducer array. In some variations, the first transducer array and the second transducer array may comprise different transducer elements. In some variations, the first transducer array and the second transducer array may each comprise an acoustic (e.g., ultrasonic) transducer array.

[0270] In some variations, criteria similar to those described for the method (500) for exchanging wireless signals based on feedback signals and the method (800) for exchanging wireless signals based on link scan signals may be used to select certain transducer elements of the first transducer array for processing their corresponding feedback signals and link scan signals.

[0271] d. Exchange wireless signals based on defocusing

[0272] In some variations, if the first device exhibits excessive movement relative to the second device, the transducer array configuration of the second device determined using the above method may be insufficient for exchanging wireless signals with the first device. For example, a wireless implantable device implanted in the heart may move relative to a fixed external wireless device located on the patient's chest. In some cases, after transmitting a feedback signal and / or a link scan signal, the wireless implantable device may move to a different position relative to the external wireless device before the external wireless device processes the received feedback signal and / or the received link scan signal and sends power to the original position of the wireless implantable device. This may result in insufficient wireless power delivery to the wireless implantable device, thereby significantly limiting its functionality. This document provides a solution to overcome this challenge.

[0273] In some variations, a wireless beam (e.g., an ultrasound beam) may be intentionally defocused to facilitate exchanging wireless signals with a moving wireless implantable device. Defocusing the wireless signal beam may refer to one or more of: increasing the spot size of the wireless signal beam at one or more locations within a region (e.g., at one or more locations within the body), making the wireless signal beam less directional, reducing the strength of the wireless signal beam at one or more locations within the region, combinations thereof, and the like. For example, the wireless signal beam may be defocused to achieve a large wireless signal beam diameter near the location of the wireless implantable device, such that the wireless implantable device receives a relatively uniform strength of the wireless signal (or achieves relatively low variation in wireless signal strength) despite movement of the wireless implantable device. In some variations, defocusing the wireless signal beam may help accommodate the range of motion of a wireless implantable device (e.g., an intracardiac device that may move due to heartbeat or breathing) over a given time period, thereby enabling reliable and efficient wireless power (or charging) and wireless data communication between the wireless implantable device and an external device. In some variations, it may be desirable to defocus the wireless beam to reduce the intensity or power of the wireless signal in vivo to minimize tissue heating and / or operate at safe in vivo intensity or power levels.

[0274] In some variations, a method for exchanging wireless signals between a first device and a second device of a wireless system may include the above-described method based on one or more of a feedback signal and a link scan signal. A transducer array configuration of the second device may be determined, the transducer array configuration comprising one or more of: a set of transducer elements of the transducer array, signal strength, amplitude, apodization, time delay, phase, combinations thereof, and the like. Such parameters of the transducer configuration may be determined using techniques such as cross-correlation and / or time reversal as described herein. In some variations, the parameters of the transducer configuration may be further adjusted to defocus the beam.

[0275] In some variations, the aperture and / or apodization of the transducer array may be adjusted to defocus the beam. In some variations, a smaller sub-aperture or sub-array of the transducer array of the second device may be selected (e.g., by turning off other transducer elements of the array) for exchanging wireless signals with the first device because the smaller aperture may correspond to a wider beam diameter. For example, a sub-array (comprising a set of continuous transducer elements or a set of discontinuous transducer elements) may be selected by selecting transducer elements that receive a feedback signal strength greater than a predetermined threshold. In some variations, a sub-array may be selected by selecting transducer elements that have an apodization greater than a predetermined threshold (e.g., greater than about 0.5) (determined after processing the received feedback signal and / or the received link scan signal). In some variations, a sub-array may be selected by selecting transducer elements that are adjacent to or near the transducer element having the largest or smallest delay or phase.

[0276] In some variations, a plurality of feedback signals and / or link scan signals may be received from a first device corresponding to one or more positions of the first device relative to a second device. A processor of the second device may process the plurality of received feedback signals and / or received link scan signals to generate a plurality of apodization and / or delay profiles using one or more of cross-correlation, time reversal, combinations thereof, or the like. In some variations, a transducer array configuration of the second device for exchanging wireless signals with the first device may include a mean of the plurality of apodization and / or delay profiles. Such a mean apodization and / or delay profile may produce a wider beam diameter that covers the range of motion of the first device. In some variations, the delay profile selected for exchanging wireless signals with the first device may include a delay profile corresponding to a wireless implantable device location that has an apodization profile that is closest to (or most similar to) the mean apodization profile across the plurality of wireless implantable device locations.

[0277] In some variations, the phase and / or delay applied to the transducer elements of the transducer array may be adjusted to defocus the beam. In some variations, the curvature of the delay or phase distribution across the transducer array of the second device may be adjusted (e.g., increased or decreased) to shift the focus of the ultrasound beam to a position between the first and second devices, or beyond the first device and further from the second device. By doing so, a wider beam diameter may be achieved near the location of the first device (thereby covering the range of motion of the first device) than when the beam is focused directly at one of the locations of the first device. In some variations, (e.g., a processor of the second device) may add one or more of noise (e.g., Gaussian noise, white noise, etc.), variation, perturbation, combinations thereof, etc., to one or more of the phase and time delay (or relative phase and / or relative time delay) applied to one or more transducer elements of a transducer array of the second device for transmitting signals to the first device (e.g., the phase and / or time delays comprising the transducer array configuration of the second device) in order to achieve defocusing of a beam (e.g., an acoustic beam near the location of the first device). In some variations, adding noise, variation, and / or perturbation to the transmit phase and / or time delay applied to the transducer elements may allow for intentionally generating a small, incoherent wireless signal at a target location (e.g., the location of a wireless implantable device or its transducer), thereby expanding the spot size or beam diameter of the wireless signal.

[0278] In some variations, the frequency of the wireless signal transmitted by the transducer array of the second device may be adjusted to defocus the beam. In some variations, a low frequency may be chosen because a low frequency may result in a wider beam diameter due to a longer wavelength. In some variations, the second device may receive a feedback signal from the first device at a first frequency, but the second device may deliver power to the first device at a second frequency, where the second frequency may be lower than the first frequency. In some variations, the wireless signal may be sent to the first device at the second frequency using the same apodization and time delay calculated based on the feedback signal at the first frequency. Using the lower second frequency to deliver wireless power may result in a wider beam diameter and lower tissue losses, thereby allowing reliable power delivery to the first device despite movement of the first device relative to the second device.

[0279] e. Closed-loop power supply

[0280] A closed-loop powering method is described herein. In some variations, the closed-loop powering method can be used to achieve a required power level at a first device when transmitting wireless power from a second device to a first device in a wireless system. The absolute signal strength transmitted by transducer elements of a transducer array of the second device, or the total transmit power of the second device, can be determined based on the closed-loop powering method.

[0281] In some variations, the power of the feedback signal sent by the first device may be known and expressed as P TX,fb The power of the feedback signal received by the second device can be expressed as P RX,fb The processor of the second device may be configured to calculate the uplink link gain or the uplink link efficiency η uplink (i.e., the gain or efficiency of a signal propagating from a first device to a second device.) The uplink link efficiency can be given by the following equation:

[0282]

[0283] In some variants, the downlink link efficiency η downlink (ie, the gain or efficiency of the signal propagating from the second device to the first device) may be based on the measured uplink link efficiency η uplink In some variants, based on reciprocity in the wireless link, it may be determined that the downlink link efficiency is equal to or substantially equal to the uplink link efficiency. In some variants, the downlink link efficiency may be different from the uplink link efficiency (e.g., if the link gain includes one or more non-reciprocal gain components). The downlink link efficiency η downlink The target received power level (P) at the first device when wirelessly powering the first device from the second device can be calculated using the following equation: RX,power ) and the transmission power from the second device (P TX,power ) Related:

[0284]

[0285] Assuming that the downlink link efficiency of the reciprocal system is equal to the uplink link efficiency, the required transmit power level from the second device can be calculated as:

[0286]

[0287] In some variations, the total transmit power level of the transducer array of the second device may be selected to be greater than the value calculated using the above equation in order to maintain sufficient margin for link variations or deviations. Based on the calculated total transmit power level of the transducer array, the absolute transmit signal strengths of the individual transducer elements of the array may be determined based on the relative signal strengths of the transducer elements and the impedances of the transducer elements.

[0288] In some variations, the total transmit power level required at the second device may be determined based on feedback from the first device. For example, the first device may be configured to digitize the voltage or power level it receives and transmit this digitized voltage or power level to the second device via one or more feedback signals, where the second device may adjust (increase or decrease) its transmit power to achieve the required voltage or power level at the first device.

[0289] In some variations, the first device may comprise an implantable medical device and the second device may comprise an external wireless device configured to be positioned physically separate from the first device.

[0290] B. Decode wireless data signals

[0291] In some variations, wireless data communications in a wireless system may be subject to multipath interference due to reflections of wireless signals propagating in the wireless link from heterogeneous media and structures. Multipath interference may cause the waveform of the wireless data signal received by the receiving device of the wireless system to be corrupted. Decoding such wireless data signals using conventional techniques may result in undesirable bit errors. For example, a wireless implantable device implanted in the heart may sense physiological parameters (e.g., pressure), digitize them, and transmit the digitized physiological parameter data to an external wireless device via an ultrasound uplink data signal. The ultrasound uplink data signal may experience multipath interference due to reflections and / or scattering of ultrasound waves from the ribs, lungs, and / or other tissue boundaries. This may cause the waveform of the uplink data signal received by the external wireless device to be corrupted, thereby causing bit errors in the decoded physiological parameter data, which may lead to inadequate or inaccurate management of the patient's disease. This article provides a solution to overcome this challenge.

[0292] In some variations, wireless data communication between two wireless devices may utilize a link scanning signal. Figure 11 The present invention is a flowchart generally describing a variation of a method (1100) for decoding a data signal in a wireless system. The method (1100) may include the following steps: transmitting a link scan signal and a first data signal from a first device of the wireless system to a second device of the wireless system (1102); receiving the link scan signal and the first data signal using one or more transducer elements of the second device (1104); processing the received link scan signal and the received first data signal using a processor of the second device to generate a second data signal (1106); and decoding the first data signal based at least in part on the second data signal (1108). The link scan signal, data signals (first data signal, second data signal), transducer elements, and processors described herein are applicable to any of the methods described herein.

[0293] In some variations, the link scan signal may comprise one or more of the following: a feedback signal, a heartbeat signal, a pulse signal, a pulse signal representing a single data bit of the first data signal, a pulse signal representing multiple data bits of the first data signal, a header signal, a tail signal, a predetermined digital code, a continuous wave signal, multiple heartbeat signals, multiple pulse signals, combinations thereof, and the like. In some variations, the pulse signal may comprise one or more of the following: a rectangular pulse, a Dirac pulse, a sinusoidal pulse, a triangular pulse, a trapezoidal pulse, a raised cosine pulse, a sinc pulse, a Gaussian pulse, one or more cycles of a carrier frequency of a pulse signal, combinations thereof, and the like. In some variations, the link scan signal may comprise a portion of the first data signal. For example, the link scan signal may comprise one or more header portions and / or one or more tail portions of the first data signal. In some variations, there may be a time delay between the link scan signal and the first data signal (e.g., a time delay to capture multipath reflections of the heartbeat signal, feedback signal, or pulse signal). In some variations, there may be no time gap between the link scan signal and the first data signal (e.g., they may be continuous waveforms).

[0294] In some variations, the first data signal may include one or more of an uplink data signal and a downlink data signal. In some variations, the first data signal may include one or more of the following: on-off keying (OOK) modulation, amplitude shift keying (ASK) modulation, pulse position modulation (PPM), frequency shift keying (FSK) modulation, phase shift keying (PSK) modulation, quadrature amplitude modulation (QAM), combinations thereof, etc.

[0295] In some variations, processing the received link scan signal and / or the received first data signal received by one or more transducer elements and described in any of the methods herein may include one or more of the following: analog signal processing, digital signal processing, signal amplification, low-pass filtering (e.g., anti-aliasing filtering), digitization, deconvolution of the received data signal with the received link scan signal or the ripple response of the wireless system, bandpass filtering (e.g., to suppress out-of-band thermal noise and thereby improve the SNR), matched filtering (e.g., to detect bits, headers, trailers, etc. in the data signal), cross-correlation (e.g., to determine the relative lag or delay between two data signals so that they can be delayed and summed), autocorrelation, signal combining (e.g., to improve the SNR of the data signal), delaying and summing two or more data signals (e.g., to improve the SNR), digital demodulation (e.g., OOK demodulation), comparison with a predetermined threshold, combinations thereof, and the like.

[0296] In some embodiments, the link scan signal and the first data signal received by different transducer elements or channels of the second device may first be processed separately (e.g., using amplification, digitization, low-pass filtering, deconvolution, matched filtering, cross-correlation, combinations thereof, etc.) to generate a second data signal corresponding to each of the processed channels. One or more of the second data signals from different channels may then be combined with one another (e.g., using cross-correlation to determine relative lags, delaying and summing to combine the signals, combinations thereof, etc.), after which the data is decoded from the combined signal (e.g., by applying a matched filter to the combined signal and comparing the output envelope with a predetermined threshold to detect a '1' or '0' bit based on the comparison result). The reason for signal combining may be to improve the SNR and / or signal-to-interference ratio (SIR) in order to reduce the number of bit errors or bit error rate in the decoded data. In some embodiments, certain channels may be selected for signal combining rather than performing the signal combining operation on all processed channels. In some embodiments, the channels selected for signal combining may be channels for which the second data signal may have the highest SNR, the highest SIR, an SNR above a predetermined threshold, an SIR above a predetermined threshold, a correct value for the header bit of the data stream, a combination thereof, or the like.

[0297] In some embodiments, when generating a second data signal corresponding to each processed channel, data decoding may be performed on multiple second data signals rather than performing signal combination and then data decoding. In some embodiments, the final result of the decoded data bit may be determined based on the majority occurrence of the bit (for example, if the first decoded bit of the majority of the processed channels is '1', the first decoded bit may be designated as '1'). In some embodiments, the link scan signals received from multiple channels and the received first data signals may be combined before processing and generating the second data signal. For example, the link scan signals received from multiple channels or transducer elements of the transducer array of the second device and the received first data signals may be delayed and summed based on one or more of the following: a delay calculated using cross-correlation, a delay determined by processing the feedback signal, a delay determined or used in a previous iteration of the method for decoding a wireless data signal described herein, a delay determined or used in a previous iteration of the method for exchanging wireless signals described herein, a combination thereof, etc.

[0298] In some variations, the processor of the second device may be configured to detect the start (e.g., rising edge, arrival time) of one or more of the received link scan signal and the received first data signal. In some variations, the start detection may include using one or more of: envelope detection, predetermined timing (e.g., based on knowledge of the time at which the first device may send the link scan signal or the first data signal and a signal propagation delay from the first device to the second device), coherent detection, and comparing the received feedback signal amplitude to a threshold level (e.g., a predetermined threshold).

[0299] In some variations, processing the received link scan signal and the first data signal may include, before further processing, selecting one or more time durations of one or more of the received link scan signal and the received first data signal based on one or more of: predetermined timing, signal start detection, detection of one or more of a rising edge and a falling edge of the signal, detection of one or more of a header component and a tail component of the signal, and multipath time and frequency drift of the received first data signal. In some variations, the timing of a rising edge of one or more of the link scan signal (e.g., a feedback signal pulse) and the first data signal may be detected (e.g., using envelope detection and comparing the envelope to a predetermined threshold), and the durations for processing the link scan signal and the first data signal may be selected based on predetermined fixed time offsets before and after the timing of the rising edge. The fixed time offset before the timing of the rising edge may be determined based on a difference between a minimum propagation delay and a maximum propagation delay of the wireless signal between different transducer elements of the first device and the second device. The fixed time offset after the timing of the rising edge can be determined based on one or more of the following: the duration of the link scan signal sent by the first device, the duration of the first data signal sent by the first device, the duration of multipath interference (e.g., multipath time), and detection of the end of one or more of the link scan signal and the first data signal (e.g., a falling edge, a tail, etc.).

[0300] In some variations, one or more signals processed herein may be zero-padded prior to further processing (e.g., to conform to a predetermined number of samples for a digital processing operation such as an FFT calculation). For example, a signal may be zero-padded prior to deconvolution and / or convolution operations as described herein. In some variations, one or more signals processed herein may be filtered (e.g., using one or more of a bandpass filter, a lowpass filter, a highpass filter, an all-pass filter, a notch filter, and a bandstop filter). In some variations, one or more signals processed herein may undergo one or more of a conversion from the time domain to the frequency domain (e.g., using an FFT operation) and a conversion from the frequency domain to the time domain (e.g., using an inverse FFT operation) in order to perform processing in one or more of the frequency domain or the time domain. In some variations, one or more signals processed herein may be upsampled, downsampled, or resampled prior to further processing. For example, both signals may be upsampled (e.g., by increasing the sampling frequency of the signals using one or more interpolation techniques (such as spline interpolation)) prior to cross-correlation in order to obtain a finer temporal resolution of their relative lag or time delay. In some variations, one or more of the signals processed herein may be scaled or normalized prior to further processing. For example, both signals may be normalized (e.g., to span an amplitude range from -1 to +1) prior to cross-correlation or deconvolution.

[0301] In some variations, processing the received link scan signal may include determining a ripple response or a scaled ripple response of the wireless system. Determining the ripple response may characterize a transfer function of the wireless link, which may allow for accurate data decoding in the presence of multipath interference, as described herein. In some variations, the received link scan signal itself may represent the ripple response or a scaled ripple response of the wireless system (e.g., when the link scan signal may include a ripple signal). In some variations, the scaled ripple response of the wireless system may include the ripple response of the wireless system scaled by a predetermined factor, where the predetermined factor may have a value of 1 or a non-1 value.

[0302] In some embodiments, determining a scaled ripple response of a wireless system (e.g., a transfer function of the wireless system or wireless link) may include deconvolving a scaled received link scan signal (e.g., a feedback signal) with a scaled reference link scan signal (e.g., a reference feedback signal) using one or more of frequency domain (or Laplace domain) analysis and time domain analysis.

[0303] In some variations, the scaled signals described herein (e.g., a ripple response, a received feedback signal, a reference feedback signal, a received link scan signal, a reference link scan signal, a received first data signal, a second data signal, a combined data signal, combinations thereof, etc.) may include signals scaled by one or more of: the amplitude of the signal in the time domain, the amplitude of the signal at frequency, the energy of the signal in one or more frequency bands, a signal-to-noise ratio, apodization of the corresponding transducer element on which the signal is received, a predetermined scaling factor (e.g., a scaling factor having a value of 1 or non-1), a scaling factor used for normalization, combinations thereof, etc. In some variations, scaling (e.g., reducing the maximum amplitude of the signal) may be performed on the signal prior to an operation (e.g., multiplication or convolution with another signal) to avoid saturation of the amplitude of the resulting signal relative to an amplitude limit (e.g., the maximum number of bits in an FPGA register). In some variations, scaling the signals by their SNR values ​​prior to combining the signals may allow for the generation of a combined signal having a higher SNR than the combined signal obtained without scaling the signals.

[0304] In some variations, the scaled reference link scan signal may represent a link scan signal sent by the first device (i.e., before the link scan signal propagates through the wireless link). In some variations, the scaled reference link scan signal may include an idealized link scan signal (e.g., an ideal pulsation, an ideal rectangular pulse). In some variations, a method of decoding a data signal in a wireless system may include preloading (or storing) the scaled reference link scan signal (e.g., a scaled reference feedback signal) into a memory of the second device using one or more of a frequency domain representation and a time domain representation. For example, this may be possible in a system in which the link scan signal sent by the first device is known a priori to the second device (e.g., one or more of the frequency, duration, number of cycles, amplitude, phase, combinations thereof, etc. of the sent link scan signal may be known a priori).

[0305] In some variations, a method for decoding a data signal in a wireless system may include generating one or more of a frequency domain representation and a time domain representation of a scaled reference link scan signal (e.g., a scaled reference feedback signal) based on one or more characteristics of a received link scan signal and a received first data signal. In some variations, the characteristics of one or more of the received link scan signal and the received first data signal may include one or more of the following: frequency, duration, number of cycles, amplitude, phase, and arrival time. For example, a processor of the second device may be configured to detect (on one or more transducer elements) a carrier frequency of one or more of the received link scan signal and the received first data signal, and generate a pulse signal based on the detected carrier frequency and a predetermined number of cycles. This may be useful in a system in which the carrier frequency used for signal transmission by the first device may not be known a priori to the second device.

[0306] In some variations, deconvolution may be performed in one or more of the time domain and the Laplace domain or the frequency domain. For example, deconvolving a time domain signal a(t) with another time domain signal b(t) in the Laplace domain or the frequency domain may include converting the time domain signal to frequency domain signals (e.g., A(f) and B(f)) and computing the division A(f) / B(f). For example, the ripple response (IR) of the wireless system may be determined by dividing the FFT of the received feedback signal by the FFT of the reference (or transmitted) feedback signal. In some variations, one or more deconvolution operations described herein may additionally include one or more of regularization and adding a noise floor to avoid division by zero (or division by very small numbers) or to suppress artifacts in the deconvolved output.

[0307] In some embodiments, processing the received link scan signal and the received first data signal may include deconvolving the scaled received first data signal with one or more of the scaled ripple response and the scaled received link scan signal using one or more of frequency domain analysis and time domain analysis to generate the second data signal.

[0308] In some variations, processing the received link scan signal (e.g., a ripple signal, a feedback signal, a pulse signal) and the received first data signal may include deconvolving the scaled received first data signal with the scaled received link scan signal using one or more of frequency domain analysis and time domain analysis to generate the second data signal or a scaled version thereof. For example, the received link scan signal may represent a ripple response or an impulse response of the wireless system. In some variations, the link scan signal may include one or more of the following: a ripple signal, a feedback signal, a pulse signal, a pulse signal representing a single data bit of the first data signal (e.g., a pulse representing a '1' bit of OOK modulation), a pulse signal representing multiple data bits of the first data signal, multiple ripple signals, multiple pulse signals, combinations thereof, etc.

[0309] In some variations, deconvolution may be performed to achieve one or more of suppressing multipath interference and aligning the signals in time. In some variations, the second data signal may comprise one or more of: an output signal of the deconvolution (e.g., in the time domain, the frequency domain, or both), a pulsatile sequence, a pulse sequence, a combination thereof, etc.

[0310] Figure 12 A timing diagram (1200) illustrates a variation of signals that may be used in a method for decoding a data signal in a wireless system. A received link scan signal (1202) is illustrated, which may include one or more pulses due to multipath interference in a wireless link. Also illustrated is a received first data signal (1204) that uses OOK modulation, which may be corrupted or have a low signal-to-interference ratio (SIR) or SNR due to multipath interference. Decoding such a received first data signal (1204) using conventional OOK demodulation techniques may be challenging. In some variations, the received first data signal (1204) may be deconvolved using the received link scan signal (1202), which may represent a pulsating response of the wireless system. In some variations, the deconvolution may be performed in the time domain and / or the frequency domain. Figure 12 The deconvolved output signal or second data signal (1206) is also shown. When examining the received first data signal (1204) and second data signal (1206), it can be noted that deconvolution can help suppress or reduce multipath interference or improve the SIR or SNR of the data signal. Performing OOK demodulation on the second data signal (1206) can achieve accurate data recovery, as shown in FIG. Figure 12 In some variations, decoding may be performed using one or more of a coherent OOK demodulation technique (e.g., using frequency mixing), a non-coherent OOK demodulation technique (e.g., using envelope detection), a combination thereof, or the like.

[0311] Figure 13 A timing diagram (1300) illustrates a variation of signals that may be used in another method for decoding a data signal in a wireless system. A received link scan signal (1302) of a transducer element is shown. The received link scan signal may include received feedback signal pulses (e.g., including one or more cycles of a carrier frequency) and multipath reflections (1304) of the received feedback signal pulses due to multipath interference in the wireless link. Also illustrated is a received first data signal (1306) of the transducer element based on OOK modulation. Due to multipath interference, the received first data signal may be corrupted or have a low signal-to-interference ratio (SIR) or SNR. Decoding such a received first data signal (1306) of the transducer element using conventional OOK demodulation techniques may be challenging. In some variations, a pulsation response (1310) of the transducer element may be determined by deconvolving the link scan signal (1302) received at the transducer element with a reference link scan signal (1308). For example, the reference link scan signal (1308) may include one or more cycles of a carrier frequency representing the link scan signal transmitted by the first device. In some variations, the first data signal (1306) received at the transducer element may be deconvolved with the pulsation response (1310) for the transducer element to generate a second data signal (1314) for the transducer element or an output signal of the deconvolution operation to suppress or mitigate multipath interference present in the first data signal (1306) received at the transducer element. In some variations, the deconvolution operation described herein may be performed in one or more of a time domain and a frequency domain. In some variations, the second data signal (1314) for the transducer element may be further OOK demodulated to accurately decode the first data signal (e.g., using the same method as that for the link scan signal). Figure 14 operations similar to those described for the combined data signals in FIG.

[0312] In some variations, a method of decoding a data signal in a wireless system may include filtering one or more of a link scan signal, a first data signal, and a second data signal using one or more of a bandpass filter, a lowpass filter, a highpass filter, an all-pass filter, a notch filter, a bandstop filter, combinations thereof, etc. In some variations, filtering may allow for one or more of: reducing or suppressing thermal noise, reducing the strength of an interference source, suppressing an interference source, combinations thereof, etc.

[0313] In some variations, a method of combining the selected second data signals may be desirable to improve the resulting SNR or SIR, thereby reducing the probability of errors in decoding the data bits. In some variations, the method of decoding a data signal in a wireless system may further include selecting two or more of the second data signals for combining into a single data signal based on one or more of the following: a header check, a trailer check, relative strengths of the two or more second data signals, relative signal-to-noise ratios of the two or more second data signals, relative strengths of residual interference present in the two or more second data signals, cross-correlation values ​​between the two or more second data signals and a reference second data signal, combinations thereof, or the like. For example, the selected two or more second data signals may include two or more second data signals having correct header bits (e.g., when decoding the header bits and comparing them to predetermined header bits). Filtering the second data signals based on the header check may be a computationally efficient method of filtering the second data signals prior to combining to obtain a higher SNR or SIR for accurate bit decoding. In some variations, the second data signals or corresponding transducer elements of the second device may be classified or ranked based on one or more of the following: relative strength of the second data signal, relative signal-to-noise ratio of the second data signal, relative signal-to-interference ratio of the second data signal, relative strength of residual interference present in the second data signal, cross-correlation value of the second data signal with a reference second data signal, combinations thereof, etc. For example, second data signals with high rankings (e.g., high SNR or SIR) may be used for further processing (e.g., signal combining). In some variations, a reference second data signal may be determined based on one or more of the following: amplitude, energy, signal-to-noise ratio, or signal-to-interference ratio of the second data signal, amplitude, energy, signal-to-noise ratio, or signal-to-interference ratio of the corresponding first data signal, amplitude, energy, signal-to-noise ratio, or signal-to-interference ratio of the corresponding link scan signal, apodization of the corresponding transducer element on which the link scan signal or first data signal may be received, combinations thereof, etc. For example, the reference second data signal may be the second data signal with the highest SNR or SIR.

[0314] In some embodiments, processing the received link scan signal and the received first data signal may further include applying matched filtering to one or more output signals (or second data signals) of the deconvolution. For example, a matched filter comprising a sinusoidal pulse having a duration equal to the bit width may be applied to the deconvolution output signal (or second data signal) to determine a time reference for decoding and / or to designate a bit as a '1' or a '0'. In some embodiments, a matched filter corresponding to a header and / or tail of the data stream may be applied to the deconvolution output signal to detect the timing and / or presence of the header and / or tail in the data signal. In some embodiments, the first data signal may include a plurality of predetermined bits or words at headers, tails, and / or intermediate positions in the bit stream of the first data signal (e.g., to facilitate time synchronization or determination of bit positions when performing data bit decoding on a second device, which may be particularly useful for decoding long data streams comprising a large number of data bits).

[0315] In some embodiments, processing the received link scan signal and the received first data signal may further include combining the deconvolved two or more output signals (or second data signals) using one or more of cross-correlation, delay and sum, combinations thereof, and the like. The deconvolved two or more output signals may be generated by processing the link scan signal and the first data signal received by two or more transducer elements of the transducer array of the second device. Combining signals from different transducer elements in this manner may result in an improved SIR or SNR of the combined signal compared to the SIR or SNR of the individual signals, thereby allowing accurate data recovery or reducing the bit error rate (because the number or probability of bit errors may be inversely correlated with the SIR or SNR). In some embodiments, time gaps resulting from a delay of one signal relative to the other may be zero-filled. In some embodiments, a method for decoding a data signal in a wireless system may include combining two or more second data signals or scaled second data signals using one or more of summation, delay and sum, averaging, delay and average, combinations thereof, and the like to generate one or more combined data signals. In some variations, the signals to be combined may be sorted, ordered, or ranked (e.g., S1, S2, S3, etc.), and different delay-and-sum combinations may be calculated (e.g., S1+S2, S1+S2+S3, etc.). In some variations, such sorting, ordering, or ranking may be based on a cross-correlation value (or similarity) between the signal and a reference signal (e.g., a signal with the highest SNR or SIR). In some variations, the method for decoding a data signal in a wireless system may further include selecting a combined data signal (e.g., a delayed and summed combination of a second data signal) for decoding data bits based on one or more of the following: an amplitude of the combined data signal in the time domain, an amplitude of the combined data signal in frequency, an energy of the combined data signal in one or more frequency bands, a signal-to-noise ratio of the combined data signal, a combination thereof, etc. In some variations, the method may further include decoding the data bits based at least on the one or more combined data signals using one or more of: OOK demodulation, ASK demodulation, PPM demodulation, FSK demodulation, PSK demodulation, QAM demodulation, envelope detection, matched filtering, comparing the amplitude of the one or more combined data signals to a predetermined threshold, sampling the amplitude of the one or more combined data signals at a fixed time offset, combinations thereof, and the like.

[0316] Figure 14is a timing diagram of an exemplary variation of signals used in a method for decoding a data signal in a wireless system based on a combined data signal and matched filtering. Similar operations may be performed on one or more second data signals (such as one or more output signals of a deconvolution of one or more first data signals with one or more pulse responses) to decode the one or more first data signals, such as Figure 14 1. A combined data signal (1402) is shown, which may be the result of delaying and summing two or more second data signals (e.g., the output of deconvolution of a received first data signal with a pulse response). In some variations, the combined data signal (1402) may be convolved (e.g., in the time domain or frequency domain) with a head matched filter (1404) to generate a head convolution output (1406). In some variations, the head matched filter (1404) may include a reference OOK data signal (e.g., including one or more pulses) corresponding to a predetermined header bit (e.g., 11001) known to be present at the beginning of the first data signal. In some variations, an envelope (1408) of the head convolution output may be determined (e.g., by squaring the head convolution output and applying a low-pass filter, or using other envelope detection techniques). The envelope (1408) of the head convolution output may be compared to a head convolution threshold (1410) to determine a head position (1412), the head position including the timing of the first peak of the envelope (1408) of the head convolution output that crosses the head convolution threshold (1410). In some variations, the combined data signal (1402) may be convolved (e.g., in the time domain or the frequency domain) with a bit-matched filter (1414) to generate a bit-convolved output (1416). In some variations, the bit-matched filter (1414) may include a reference OOK data signal corresponding to a predetermined single '1' bit (e.g., including a single pulse). In some variations, the envelope (1418) of the bit-convolution output may be determined (e.g., by squaring the head convolution output and applying a low-pass filter, or using other envelope detection techniques). In some variations, the bit position (1422) may be determined based on one or more of the header position (1412), the number of header bits, a predetermined bit duration (i.e., the duration, number of cycles of a carrier frequency, or number of clock cycles corresponding to a '1' and / or '0' bit), combinations thereof, etc. Figure 14, as illustrated by the arrows in . For example, the position of the first bit may be determined based on the head position (1412), the number of head bits (e.g., 5), and the duration of the single bit, and the positions of the other bits may be determined based on a fixed timing offset from the position of the first bit corresponding to the duration of the single bit. In some variations, the value of the envelope (1418) of the bit convolution output at the bit position (1422) may be compared to the bit convolution threshold (1420) to decode each bit as a '1' (e.g., for envelope values ​​greater than the bit convolution threshold) or a '0' (e.g., for envelope values ​​less than the bit convolution threshold). In some variations, one or more of the head match filter (1404), the bit match filter (1414), the head convolution threshold (1410), and the bit convolution threshold (1420) may be predetermined and preloaded (e.g., stored) in a memory of the second device. In some variations, one or more of the header matched filter (1404) and the bit matched filter (1414) may be preloaded (e.g., stored) in a time domain representation and / or a frequency domain representation. In some variations, during execution of the method for decoding a data signal (e.g., upon detecting a carrier frequency of one or more of the link scan signal and the first data signal), a processor of the second device may calculate one or more of the header matched filter (1404), the bit matched filter (1414), the header convolution threshold (1410), and the bit convolution threshold (1420).

[0317] In some variations, a method for decoding a data signal in a wireless system may include decoding data bits corresponding to one or more second data signals (e.g., output signals of a deconvolution of a first data signal with a ripple response of the wireless system) using one or more of: OOK demodulation, ASK demodulation, PPM demodulation, FSK demodulation, PSK demodulation, QAM demodulation, envelope detection, matched filtering, comparing the amplitude of the one or more second data signals to a predetermined threshold, sampling the amplitude of the one or more second data signals at a fixed time offset, combinations thereof, etc. In some variations, the method may further include, before decoding the data bits, selecting the one or more second data signals based on: a header check, a trailer check, relative strength of the one or more second data signals, relative signal-to-noise ratio of the one or more second data signals, relative strength of residual interference present in the one or more second data signals, a cross-correlation value between the one or more second data signals and a reference second data signal, combinations thereof, etc. In some variations, the method may further include determining one or more of: a majority occurrence (or majority vote) of a bit value, a weighted majority occurrence of a bit value, a mean bit value, a weighted mean bit value among the decoded data bit values ​​corresponding to two or more second data signals, combinations thereof, and the like. In some variations, decoding the bits based on majority occurrences may be less computationally intensive than combining the second data signals to generate a plurality of combined signals, selecting the combined signal with the highest signal-to-noise ratio (SNR), and decoding the bits based on the combined signal with the highest SNR. In some variations, determining the weighted majority occurrence or the weighted mean bit value may include scaling the bit value by one or more of: an apodization of a transducer element on which the corresponding link scan signal or the corresponding first data signal is received, an amplitude, energy, signal-to-noise ratio, time delay, phase, and multipath time of one or more of the second data signal, the corresponding first data signal, the corresponding link scan signal, combinations thereof, and the like. For example, the average of the decoded '1' and '0' bit values ​​across transducer elements or channels may be calculated and compared to a predetermined threshold (eg, 0.5) to ultimately assign a '1' or '0' decoded bit value.

[0318] In some variations, a method for decoding a data signal in a wireless system may include reporting an error or an indication that a bit may not be reliably decoded. Such an error or indication may be generated based on one or more of: a header check, a trailer check, a bit error rate, a strength of a link scan signal, a signal-to-noise ratio of the link scan signal, a signal-to-interference ratio of the link scan signal, energy of the link scan signal in one or more frequency bands, a moving average of the link scan signal amplitude, a strength of a first data signal, a signal-to-noise ratio of the first data signal, a signal-to-interference ratio of the first data signal, energy of the first data signal in one or more frequency bands, a moving average of the first data signal amplitude, a strength of a second data signal, a signal-to-noise ratio of the second data signal, a signal-to-interference ratio of the second data signal, energy of the second data signal in one or more frequency bands, a moving average of the second data signal amplitude, a signal strength of an interferer, a signal strength of a multipath interferer, a multipath time, apodization of one or more transducer elements, a combination thereof, or the like.

[0319] In some variations, the first device may send one or more link scan signals before sending one or more first data signals. For example, in some variations, the first device may send multiple first data signals after sending a link scan signal. In some variations, the first device may send one or more first data signals before sending one or more link scan signals. In some variations, the first device may send one or more link scan signals both before and after sending one or more first data signals.

[0320] In some variations, a method for decoding a data signal in a wireless system may include: transmitting a first link scan signal, followed by a first data signal, and subsequently a second link scan signal from a first device of the wireless system to a second device of the wireless system; and receiving the first link scan signal, the first data signal, and the second link scan signal using one or more transducer elements of the second device. In some variations, the method may further include: decoding a first portion of the first data signal (e.g., a first half of the first data signal) using the first link scan signal, and decoding a second portion of the first data signal (e.g., a second half of the first data signal) using the second link scan signal, based on any of the methods for decoding a data signal as described herein. This may be advantageous for transmitting a first data signal comprising a long data bit stream, where the first link scan signal may be insufficient to reliably and accurately decode the entire data stream due to changes in multipath interference over time. In some variations, this may also facilitate decoding a first data signal that includes a change or drift in its carrier frequency (or frequency content) over time (e.g., caused by frequency drift and / or a long settling time of an oscillator circuit of a first device that may transmit one or more link scan signals and a data signal). For example, the frequency content or carrier frequency of the first link scan signal may be closer to the frequency content or carrier frequency of the first portion of the first data signal, thereby allowing the first portion of the first data signal to be accurately decoded using one or more methods for decoding wireless data signals as described herein.

[0321] In some variations, the first device may comprise an implantable medical device, the second device may comprise an external wireless device configured to be physically separate from the first device, and the first data signal may comprise an uplink data signal. In some variations, the first device may comprise an implantable medical device, the second device may comprise an implantable medical device configured to be physically separate from the first device, and the first data signal may comprise a downlink data signal.

[0322] In some variations, a method for decoding a data signal in a wireless system may further include: transmitting one or more of a link scanning signal and a first data signal from a first device in the wireless system to a second device in the wireless system at one or more predetermined repetition intervals. In some variations, this may allow for reliable data transfer between the first device (e.g., a wireless cardiovascular implantable device) and the second device (e.g., an external wireless device) in the presence of relative motion (e.g., due to heartbeat and breathing) between the first device and the second device. In some variations, the one or more predetermined repetition intervals may be determined based on the relative motion speed between the first device and the second device. In some variations, the predetermined repetition interval may correspond to a time duration during which the wireless link may be quasi-static (e.g., a time duration during which the link efficiency may vary by less than approximately 3 dB) or a time duration during which the first device may be stationary relative to the first device. In some variations, the first device may transmit one link scanning signal (e.g., one feedback signal pulse) corresponding to multiple first data signals (e.g., transmitting the link scanning signal including the feedback signal pulse before transmitting the multiple first data signals, etc.). In some variations, the first device may transmit multiple link scanning signals corresponding to a single first data signal (e.g., transmitting a link scanning signal including feedback signal pulses before and after transmitting the first data signal, etc.). In some variations, the method may further include: transmitting a wireless command from the second device to the first device, and transmitting a link scanning signal and a first data signal from the first device to the second device in response to the first device receiving the wireless command. In some variations, the wireless command may include one or more of the following: a wireless signal, a pulse signal, multiple pulse signals, a signal with encoded data bits (e.g., using OOK modulation), a combination thereof, etc. In some variations, one or more of the one or more transmitted link scanning signals and the one or more transmitted first data signals may include a reflected signal or a backscattered signal generated in response to receiving a wireless signal transmitted by the second device to the first device.

[0323] In some variations, one or more of the transmitted link scan signal and first data signal may include one or more of the following: ultrasonic signals, acoustic signals, vibration signals, radio frequency signals, electromagnetic signals, magnetic signals, electrical signals, optical signals, combinations thereof, etc.

[0324] Figure 15The present invention is a flowchart generally describing a variation of a method (1500) for decoding a data signal in a wireless system. The method may include the following steps: transmitting a link scan signal and a first data signal from a first device of the wireless system to a second device of the wireless system (1502); receiving the link scan signal and the first data signal using one or more transducer elements of the second device (1504); processing one or more of the received link scan signal and the received first data signal to select one or more transducer elements of the second device (1506); and decoding the first data signal based at least in part on the selected one or more transducer elements of the second device (1508). In some variations, the link scan signal may include one or more of the following: a feedback signal, a pulsating signal, a pulse signal, a pulse signal representing a single data bit of the first data signal, a pulse signal representing multiple data bits of the first data signal, a header signal, a tail signal, a predetermined digital code, a continuous wave signal, multiple pulsating signals, multiple pulse signals, combinations thereof, and the like. In some variations, selection of the one or more transducer elements of the second device may be based on one or more of: a header check, a tail check, a bit error rate, a relative strength of the link scan signal, a relative signal-to-noise ratio of the link scan signal, a relative signal-to-interference ratio of the link scan signal, energy of the link scan signal in one or more frequency bands, a moving average of the amplitude of the link scan signal, a relative strength of the first data signal, a relative signal-to-noise ratio of the first data signal, a relative signal-to-interference ratio of the first data signal, energy of the first data signal in one or more frequency bands, a moving average of the amplitude of the first data signal, signal strength of an interferer, signal strength of multipath interference, multipath time, apodization of the one or more transducer elements, combinations thereof, etc. In some variations, in selecting the one or more transducer elements of the second device, one or more operations described herein (e.g., signal combining, matched filtering, data decoding using OOK demodulation, bandpass filtering, combinations thereof, etc.) may be used to process the received link scan signal and the received first data signal received at the selected transducer elements.

[0325] In some variations, the bit duration of the data signal may be selected to allow multipath interference to settle (e.g., a bit duration that is greater than the multipath time in the wireless link). In some variations, a high frequency (e.g., higher than the frequency of the power signal) may be used for the data signal to mitigate the effects of multipath interference (e.g., due to higher signal attenuation in tissue at higher frequencies). In some variations, the first data signal may include pulse position modulation (PPM), and the link scan signal may be used for time synchronization (e.g., to detect the timing of the PPM pulses).

[0326] In some variations, the received first data signals may be combined using one or more of summing, delaying and summing, averaging, delaying and averaging, combinations thereof, and the like to generate one or more combined signals. This may be done to improve the SNR or SIR of the combined signal relative to the one or more first data signals. In some variations, a delay for delaying and summing or delaying and averaging may be calculated based on an arrival time of one or more of a link scan signal and a received first data signal received at one or more transducer elements of the second device. In some variations, envelope detection may be performed on one or more of the received link scan signal and the received first data signal, and the envelope may be compared to a predetermined threshold to detect a start, arrival time, or rising edge of the signal, which may be used to delay the signal before combining and summing the signals.

[0327] Figure 16 A flowchart illustrating yet another variation of a method (1600) for decoding a data signal in a wireless system. The method (1600) may include the following steps: transmitting a link scan signal (1602) from a first device of the wireless system to a second device of the wireless system; receiving the link scan signal using one or more transducer elements of the second device (1604); processing the received link scan signal using a processor of the second device to generate link scan signal data (1606); generating a predistorted data signal based on the link scan signal data using the processor of the second device (1608); transmitting the predistorted data signal (1610) from the second device to the first device; receiving the predistorted data signal using one or more transducer elements of the first device (1612); and processing the received predistorted data signal using the processor of the first device to generate decoded data (1614). The link scan signal, data signal, link scan signal data, transducer elements, and processors described herein are applicable to any of the methods described herein.

[0328] In some variations, the link scan signal may include a pulse signal, and generating the predistorted data signal may include performing a deconvolution of the data signal (e.g., an ideal OOK data waveform without any multipath interference) with the received link scan signal. In some variations, the link scan signal data may include a pulse response of the wireless system, and generating the predistorted data signal may include performing a deconvolution of the data signal (e.g., an ideal OOK data waveform without any multipath interference) with the pulse response of the wireless system. As the predistorted data signal travels from the second device to the first device, it may undergo convolution with the pulse response of the wireless system. As a result, the received predistorted data signal received by the first device may resemble the original data signal (i.e., an ideal OOK data waveform without any multipath interference), thereby mitigating any signal impairments due to multipath interference. In some variations, time reversal may be applied to one or more received link scan signals, and the resulting one or more time-reversed signals may be used to transmit one or more data signals to the first device, rather than generating and transmitting predistorted data signals.

[0329] In some variations, the first device may comprise an implantable medical device, the second device may comprise an external wireless device configured to be physically separate from the first device, and the predistorted data signal may comprise a downlink data signal. In some variations, the first device may comprise an external wireless device, the second device may comprise an implantable medical device configured to be physically separate from the first device, and the predistorted data signal may comprise an uplink data signal.

[0330] Figure 17 A flowchart illustrating yet another variation of a method (1700) for decoding a data signal in a wireless system. The method (1700) may include the following steps: transmitting a data signal from a first device of the wireless system to a second device of the wireless system (1702); receiving the data signal using a plurality of transducer elements of the second device (1704); applying a predetermined delay to one or more received data signals received using the plurality of transducer elements of the second device using a processor of the second device to generate a delayed data signal (1706); summing two or more delayed data signals using the processor of the second device to generate one or more delayed and summed data signals (1708); and decoding the data signal using the processor of the second device based at least in part on the one or more delayed and summed data signals (1710). The data signals, transducer elements, and processors described herein are applicable to any of the methods described herein.

[0331] In some variations, the method (1700) may further include: sending a feedback signal from the first device to the second device before sending the data signal; receiving the feedback signal using one or more transducer elements of the second device; processing the received feedback signal using a processor of the second device to generate feedback signal data; and calculating a predetermined delay based at least in part on the feedback signal data. In some variations, the method (1700) may further include: sending a link scan signal from the first device to the second device before sending the data signal; receiving the link scan signal using one or more transducer elements of the second device; processing the received link scan signal using a processor of the second device to generate link scan signal data; and calculating the predetermined delay based at least in part on the link scan signal data. The feedback signal, link scan signal, data signal, transducer element, processor, feedback signal data, and link scan signal data as described herein are applicable to any of the methods described herein.

[0332] In some variations, the first device may comprise an implantable medical device, the second device may comprise an external wireless device configured to be physically separate from the first device, and the data signal may comprise an uplink data signal. In some variations, the first device may comprise an external wireless device, the second device may comprise an implantable medical device configured to be physically separate from the first device, and the data signal may comprise a downlink data signal.

[0333] In some embodiments, the processor of the second device may be configured to select one or more transducer elements of the second device for further processing one or more of the link scan signal and the first data signal based on one or more characteristics of the link scan signal and the first data signal.

[0334] In some variations, when decoding the data signal, the processor of one or more of the second device and the first device of the wireless system may be configured to perform one or more of error detection, error correction, a combination thereof, etc. (e.g., using an error correction code or ECC, a cyclic redundancy check or CRC, etc.). In some variations, when detecting the data signal, the processor of one or more of the second device and the first device may be configured to generate one or more of an acknowledgement signal (ACK) and a negative acknowledgement signal (NACK). For example, the processor of the second device may be configured to generate an ACK signal when a zero bit error is detected in the decoded first data signal (e.g., after performing a cyclic redundancy check), and send the ACK signal to the first device using the transducer array configuration of the second device as described herein. The variations of the data signal as described herein may be applicable to one or more of the ACK signal and the NACK signal.

[0335] C. Calibrate the wireless system

[0336] In some embodiments, a wireless implantable device may include a transducer having a resonant frequency, and a wireless transmitter including an oscillator circuit having an oscillator frequency. In some embodiments, the oscillator frequency may vary significantly across different wireless implantable devices due to variations between devices (e.g., variations between chips due to variations in integrated circuit manufacturing processes). In some devices, the resonant frequency of the transducer of the wireless implantable device may not match the oscillator frequency due to its excessive variation, which may result in low output power of any uplink signal transmitted by the wireless implantable device. In such cases, it may be necessary to calibrate and / or adjust the oscillator frequency. However, conventional methods of calibrating the oscillator frequency by testing the wireless implantable device and / or its components on a bench may be time-consuming and / or expensive and may not take into account the overall wireless system performance. This article provides a solution to alleviate this challenge.

[0337] Figure 18 The present invention is a flowchart generally describing a variation of a method (1800) for calibrating a wireless system. The method (1800) may include the following steps: transmitting one or more test signals comprising one or more carrier frequencies from a first device of the wireless system to a second device of the wireless system (1802); receiving the one or more test signals using the second device (1804); processing the one or more received test signals using a processor of the second device to generate test signal data (1806); determining one or more selected carrier frequencies based at least in part on the test signal data using the processor of the second device (1808); transmitting one or more wireless commands comprising information corresponding to the one or more selected carrier frequencies from the second device to the first device (1810); and storing the information corresponding to the one or more selected carrier frequencies in a memory of the first device (1812). The test signal may be any signal transmitted from one device of the wireless system to another device of the wireless system to test one or more characteristics of a wireless link between the two devices. For example, the test signal may include a sinusoidal signal and / or a rectangular signal comprising one or more cycles of the carrier frequency of the test signal or one or more cycles of an oscillator frequency of a first device (e.g., a wireless implantable device). In some variations, the test signal data may include any characteristic of the test signal (eg, amplitude, signal strength, frequency, phase, etc.) and / or any characteristic of the wireless link (eg, link efficiency).

[0338] In some variations, the method (1800) may further include: transmitting, from the first device to the second device, a wireless signal comprising one or more selected carrier frequencies. In some variations, the transmitted wireless signal may include one or more of the following: a feedback signal, a link scan signal, an uplink data signal, a combination thereof, etc.

[0339] In some variations, determining the one or more selected carrier frequencies may include determining one or more carrier frequencies at which a parameter of the received test signal may have a value greater than a predetermined threshold. In some variations, the parameter of the received test signal may include one or more of the following: signal strength, signal amplitude, signal power, signal energy, signal-to-noise ratio, signal-to-interference ratio, link efficiency, link gain, combinations thereof, etc. In some variations, the memory of the first device may include one or more of non-volatile memory, volatile memory, combinations thereof, etc. In some variations, the non-volatile memory may be configured to permanently store information corresponding to the one or more selected carrier frequencies and / or to store information corresponding to the one or more selected carrier frequencies until the next calibration operation.

[0340] Figure 19A schematic block diagram of a wireless system (1900) configured for calibration is shown. The system (1900) may include a wireless device (1914) comprising a transducer (1920) and a processor (1930). The system may also include a wireless implantable device (1910) comprising a transducer (1920), a wireless transmitter (1960), a wireless receiver (1970), a processor (1930), and a memory (1980). In some variations, the processor (1930) of the wireless implantable device (1910) may be configured to control the wireless transmitter (1960) to transmit one or more test signals (1950) comprising one or more carrier frequencies through the transducer (1920) of the wireless implantable device (1910). The transducer (1920) of the wireless device (1914) may be configured to receive the one or more test signals (1950). The processor (1930) of the wireless device (1914) may be configured to process one or more received test signals (1950) to generate test signal data. In some variations, the processor (1930) of the wireless device (1914) may be further configured to determine one or more selected carrier frequencies based at least in part on the test signal data. The processor (1930) of the wireless device (1914) may be further configured to control the transducer (1920) of the wireless device (1914) to transmit one or more wireless commands to the wireless implantable device (1910) via one or more downlink signals (1940), wherein the one or more wireless commands may include information corresponding to the one or more selected carrier frequencies. The wireless receiver (1970) of the wireless implantable device (1910) may be configured to receive the one or more wireless commands via the transducer (1920). In some variations, the processor (1930) may be configured to store the information corresponding to the one or more selected carrier frequencies in a memory (1980) of the wireless implantable device (1910). Optionally, in some variations, the processor (1930) may be configured to control the wireless transmitter (1960) to transmit one or more wireless signals at one or more selected carrier frequencies.

[0341] D. Exchanging wireless signals based on one or more predetermined transmit voltage levels

[0342] In some variations, a first device and a second device of a wireless system may be configured to exchange wireless signals based on one or more predetermined transmit voltage levels of the second device. Any method for exchanging wireless signals may be used with any of the methods described herein (e.g., exchanging wireless signals based on feedback signals and / or link scan signals, exchanging wireless signals based on defocusing, closed-loop powering, decoding wireless data signals, calibrating wireless systems).

[0343] The closed loop powering method described herein includes calculating a transmit power level (P) from a second device based on one or more of the following: TX,power ): Power of the feedback signal sent by the first device (P TX,fb ), the power of the feedback signal received by the second device (P RX,fb ), the target received power level at the first device (P RX,power ) and uplink or downlink link efficiency. In addition, in some variations, the transmit power level may correspond to the transmit voltage level. For example, the transmit voltage level may be determined based on the required transmit power level and the impedance of one or more transducer elements used to transmit wireless power or wireless signals. In some variations, the required transmit power level or transmit voltage level may change over time due to changes in the link efficiency between the first device and the second device (for example, due to movement of the first device (such as an intracardiac implantable device) relative to the second device (such as an external wireless device)). However, in some cases, it may be impractical to configure the second device to have a variable or adjustable transmit voltage level because this may increase one or more of hardware complexity, device size, and cost. In addition, in some variations, bursts of variable transmit power levels may be required, and the transmit voltage level may not be adjusted quickly within the time period of the burst (for example, adjusting the transmit voltage level may require charging or discharging a large capacitor, which may take a long time). Conversely, in some variations, it may be advantageous to configure the second device to have one or more predetermined or fixed transmit voltage levels. Therefore, additional devices, systems, and methods may be desirable for reliably exchanging wireless signals between two or more devices of a wireless system based on the constraint of one or more predetermined transmit voltage levels.

[0344] Figure 20A schematic block diagram illustrates an exemplary variation of a wireless system (2000) configured to exchange wireless signals. In some variations, the system (2000) may include a first device (2010), such as a wireless implantable device, comprising at least a transducer (2020). In some variations, the system (2000) may also include a second device (2014), such as a wireless device, comprising a transducer (2020), a processor (2030), a transmitter circuit (2070), and a supply (2080). In some variations, the supply (2080) may include one or more of a power supply or source, a voltage supply or source, a current supply or source, and an energy supply or source. In some variations, the first device (2010) may be configured to transmit a feedback signal (2050), and the transducer (2020) of the second device (2014) may include a transducer array configured to receive the feedback signal at one or more transducer elements of the transducer array. In some variations, the supplying device (2080) may include one or more predetermined transmit voltage levels. In some variations, the processor (2030) of the second device (2014) may be configured to process the feedback signal (2050) received by the one or more transducer elements of the transducer array to generate feedback signal data, and determine a transducer array configuration based at least in part on the feedback signal data and the one or more predetermined transmit voltage levels of the supplying device (2080). Furthermore, the second device (2014) may be configured to exchange one or more wireless signals (2040) with the first device (2010) using the transducer array configuration.

[0345] Figure 21 The present invention is a flowchart generally describing a variation of a method (2100) for exchanging wireless signals with a device based on one or more predetermined transmit voltage levels. The method (2100) may include the following steps: transmitting a feedback signal from a first device of a wireless system to a second device of the wireless system (2102); receiving the feedback signal using one or more transducer elements of a transducer array of the second device (2104); processing the feedback signal received using the one or more transducer elements of the transducer array using a processor of the second device to generate feedback signal data (2106); determining, using the processor of the second device, a transducer array configuration of the second device based at least in part on the feedback signal data and one or more predetermined transmit voltage levels of a supply...

Claims

1. A system configured to exchange wireless power or data, comprising: a first device configured to send a feedback signal; as well as A second device comprising a transducer array, a processor, and a supply, wherein The transducer array is configured to receive the feedback signal on one or more transducer elements of the transducer array, said supply means comprising one or more predetermined transmission voltage levels, The processor is configured to process the feedback signal received by one or more transducer elements of the transducer array to generate feedback signal data, and determine a transducer array configuration based at least in part on the feedback signal data and the one or more predetermined transmit voltage levels of the supply device, and The second device is configured to exchange one or more wireless signals with the first device using the transducer array configuration.

2. The system of claim 1 , wherein the feedback signal data comprises one or more of the following: absolute amplitude or magnitude, relative amplitude or magnitude, absolute signal strength, relative signal strength, energy of the signal in one or more frequency bands, apodization, absolute phase, relative phase, absolute time delay, relative time delay, absolute arrival time, relative arrival time, frequency, time duration, number of cycles, absolute signal-to-noise ratio, and relative signal-to-noise ratio of the feedback signal received by one or more transducer elements of the transducer array.

3. The system of claim 1 , wherein the transducer array configuration comprises one or more of: a selected set of transducer elements, apodization applied to one or more transducer elements of the transducer array for transmitting wireless signals to the first device, signal strength, voltage level, current level, pulse width, pulse width modulation, duty cycle, phase, time delay, frequency, and transmit duration. 4 . The system of claim 1 , wherein the processor is further configured to determine a transmit apodization of the transducer elements of the transducer array.

5. The system of claim 4 , wherein the processor is further configured to select a set of transducer elements for the transducer array configuration based on one or more of: the transmit apodization of the transducer elements, the one or more predetermined transmit voltage levels of the supply, and one or more predetermined target signal strengths at the first device.

6. The system of claim 4, wherein the transmit apodization of the transducer elements is proportional to the relative signal strengths of the feedback signals received by the transducer elements of the transducer array in one or more frequency bands.

7. The system of claim 4, wherein the transmit apodization of two or more transducer elements is substantially equal.

8. The system of claim 1 , wherein the second device further comprises one or more transmitter circuits configured to apply a transmit signal to one or more transducer elements of the transducer array, and the processor is configured to determine transmitter circuit data corresponding to the one or more transmitter circuits based at least in part on the feedback signal data.

9. The system of claim 8, wherein the transmitter circuit data comprises one or more of: efficiency, power dissipation, energy dissipation, current dissipation, voltage drop, heat dissipation, temperature, temperature rise, input power, input energy, input current, input voltage, output power, output energy, output current, and output voltage of the one or more transmitter circuits.

10. The system of claim 8, wherein the processor is further configured to determine the transmit apodization of the transducer element based at least in part on the transmitter circuit data.

11. The system of claim 1 , wherein the supply device comprises a plurality of predetermined transmit voltage levels, the processor is further configured to select one or more predetermined transmit voltage levels based at least in part on the feedback signal data and the plurality of predetermined transmit voltage levels, and the transducer array configuration further comprises the selected one or more predetermined transmit voltage levels for exchanging one or more wireless signals with the first device.

12. The system of claim 1 , wherein the supply comprises a first predetermined transmit voltage level and a second predetermined transmit voltage level, and the transducer array configuration comprises the first predetermined transmit voltage level for transmitting wireless power and comprises the second predetermined transmit voltage level for transmitting one or more of wireless data and commands to the first device.

13. The system of claim 12, wherein the first predetermined transmit voltage level is greater than or substantially equal to the second predetermined transmit voltage level.

14. The system of claim 1, wherein the first device comprises an implantable medical device and the second device comprises an external wireless device configured to be physically separate from the first device.

15. The system of claim 1, wherein the first device comprises an external wireless device and the second device comprises an implantable medical device configured to be positioned physically separate from the first device.

16. The system of claim 1, wherein the second device is further configured to send a wireless command to the first device, and the first device is configured to send the feedback signal in response to receiving the wireless command.

17. The system of claim 1, wherein the first device is configured to transmit the feedback signal at one or more predetermined repetition intervals.

18. A method for exchanging wireless signals in a wireless system, comprising: sending a feedback signal from a first device of the wireless system to a second device of the wireless system; receiving the feedback signal using one or more transducer elements of a transducer array of the second device; processing, using a processor of the second device, the feedback signal received using one or more transducer elements of the transducer array to generate feedback signal data; determining, using the processor of the second device, a transducer array configuration of the second device based at least in part on the feedback signal data and one or more predetermined transmit voltage levels of a supply of the second device; as well as One or more wireless signals are exchanged with the first device using the transducer array configuration of the second device.

19. The method of claim 18, wherein the feedback signal data comprises one or more of the following: absolute amplitude or magnitude, relative amplitude or magnitude, absolute signal strength, relative signal strength, energy of the signal in one or more frequency bands, apodization, absolute phase, relative phase, absolute time delay, relative time delay, absolute arrival time, relative arrival time, frequency, time duration, number of cycles, absolute signal-to-noise ratio, and relative signal-to-noise ratio of the feedback signal received by one or more transducer elements of the transducer array.

20. The method of claim 18, wherein the transducer array configuration comprises one or more of: a selected set of transducer elements, apodization applied to one or more transducer elements of the transducer array for transmitting wireless signals to the first device, signal strength, voltage level, current level, pulse width, pulse width modulation, duty cycle, phase, time delay, frequency, and transmit duration.

21. The method of claim 18, further comprising: Transmit apodization of the transducer elements of the transducer array is determined using the processor of the second device.

22. The method of claim 21, further comprising: Using the processor of the second device, a set of transducer elements is selected for the transducer array configuration based on one or more of the transmit apodization of the transducer elements, the one or more predetermined transmit voltage levels of the supply, and one or more predetermined target signal strengths at the first device.

23. The method of claim 21, wherein the transmit apodization of the transducer elements is proportional to the relative signal strengths of the feedback signals received by the transducer elements of the transducer array in one or more frequency bands.

24. The method of claim 21, wherein the transmit apodization of two or more transducer elements is substantially equal.

25. The method of claim 18, further comprising: Using the processor of the second device, transmitter circuit data corresponding to one or more transmitter circuits of the second device is determined based at least in part on the feedback signal data, the one or more transmitter circuits being configured to apply a transmit signal to one or more transducer elements of the transducer array.

26. The method of claim 25, wherein the transmitter circuit data comprises one or more of: efficiency, power dissipation, energy dissipation, current dissipation, voltage drop, heat dissipation, temperature, temperature rise, input power, input energy, input current, input voltage, output power, output energy, output current, and output voltage of the one or more transmitter circuits.

27. The method of claim 25, further comprising: A transmit apodization of the transducer element is determined based at least in part on the transmitter circuit data.

28. The method of claim 18, further comprising: using the processor of the second device to select one or more predetermined transmit voltage levels of the supply device from a plurality of predetermined transmit voltage levels of the supply device based at least in part on the feedback signal data, and exchanging one or more wireless signals with the first device using the transducer array configuration including the selected one or more predetermined transmit voltage levels.

29. The method of claim 18, further comprising: Wireless power is transmitted to the first device using a first predetermined transmission voltage level of the supply means, and one or more of wireless data and commands are transmitted to the first device using a second predetermined transmission voltage level of the supply means.

30. The method of claim 29, wherein the first predetermined transmit voltage level is greater than or substantially equal to the second predetermined transmit voltage level.

31. The method of claim 18, wherein the first device comprises an implantable medical device and the second device comprises an external wireless device configured to be positioned physically separate from the first device.

32. The method of claim 18, wherein the first device comprises an external wireless device and the second device comprises an implantable medical device configured to be positioned physically separate from the first device.

33. The method of claim 18, further comprising: One or more wireless commands are sent from the second device to the first device, and one or more feedback signals are sent from the first device to the second device in response to receiving the one or more wireless commands.

34. The method of claim 18, further comprising: The feedback signal is sent from the first device at one or more predetermined repetition intervals.

35. A system configured to exchange wireless power or data, comprising: a first device configured to send a feedback signal; as well as a second device comprising a transducer array, a processor, and one or more transmitter circuits, wherein The transducer array is configured to receive the feedback signal on one or more transducer elements of the transducer array, The one or more transmitter circuits are configured to apply a transmit signal to one or more transducer elements of the transducer array, The processor is configured to: process the feedback signal received by one or more transducer elements of the transducer array to generate feedback signal data, determine transmitter circuit data corresponding to the one or more transmitter circuits based at least in part on the feedback signal data, and determine a transducer array configuration based at least in part on the feedback signal data and the transmitter circuit data, and The second device is configured to exchange one or more wireless signals with the first device using the transducer array configuration.

36. The system of claim 35 , wherein the feedback signal data comprises one or more of: absolute amplitude or magnitude, relative amplitude or magnitude, absolute signal strength, relative signal strength, energy of the signal in one or more frequency bands, apodization, absolute phase, relative phase, absolute time delay, relative time delay, absolute arrival time, relative arrival time, frequency, time duration, number of cycles, absolute signal-to-noise ratio, and relative signal-to-noise ratio of the feedback signal received by one or more transducer elements of the transducer array.

37. The system of claim 35, wherein the transmitter circuit data comprises one or more of: efficiency, power dissipation, energy dissipation, current dissipation, voltage drop, heat dissipation, temperature, temperature rise, input power, input energy, input current, input voltage, output power, output energy, output current, and output voltage of the one or more transmitter circuits.

38. The system of claim 35, wherein the transducer array configuration comprises one or more of: a selected set of transducer elements, apodization applied to one or more transducer elements of the transducer array for transmitting wireless signals to the first device, signal strength, voltage level, current level, pulse width, pulse width modulation, duty cycle, phase, time delay, frequency, and transmit duration.

39. The system of claim 35, wherein the processor is further configured to determine a transmit apodization of the transducer elements of the transducer array.

40. The system of claim 39, wherein the processor is further configured to select a set of transducer elements for the transducer array configuration based on one or more of: the transmit apodization of the transducer elements, the transmitter circuit data, and one or more predetermined target signal strengths at the first device.

41. The system of claim 40, wherein the transducer array configuration comprises one or more transmit voltage levels, and the processor is configured to determine the one or more transmit voltage levels based at least in part on a selected set of transducer elements of the transducer array configuration.

42. The system of claim 39, wherein the transmit apodization of the transducer elements is proportional to the relative signal strengths of the feedback signals received by the transducer elements of the transducer array in one or more frequency bands.

43. The system of claim 39, wherein the transmit apodization of two or more transducer elements is substantially equal.

44. The system of claim 35, wherein the first device comprises an implantable medical device and the second device comprises an external wireless device configured to be positioned physically separate from the first device.

45. The system of claim 35, wherein the first device comprises an external wireless device and the second device comprises an implantable medical device configured to be positioned physically separate from the first device.

46. ​​The system of claim 35, wherein the second device is further configured to send one or more wireless commands to the first device, and the first device is configured to send one or more feedback signals in response to receiving the one or more wireless commands.

47. The system of claim 35, wherein the first device is configured to transmit the feedback signal at one or more predetermined repetition intervals.

48. A method for exchanging wireless signals in a wireless system, comprising: sending a feedback signal from a first device of the wireless system to a second device of the wireless system; receiving the feedback signal using one or more transducer elements of a transducer array of the second device; processing, using a processor of the second device, the feedback signal received using one or more transducer elements of the transducer array to generate feedback signal data; determining, using the processor of the second device, transmitter circuit data corresponding to one or more transmitter circuits of the second device based at least in part on the feedback signal data, the one or more transmitter circuits configured to apply transmit signals to one or more transducer elements of the transducer array; determining, using the processor of the second device, a transducer array configuration of the second device based at least in part on the feedback signal data and the transmitter circuit data; as well as One or more wireless signals are exchanged with the first device using the transducer array configuration of the second device.

49. A method as claimed in claim 48, wherein the feedback signal data includes one or more of the following: absolute amplitude or magnitude, relative amplitude or magnitude, absolute signal strength, relative signal strength, energy of the signal in one or more frequency bands, toe-off, absolute phase, relative phase, absolute time delay, relative time delay, absolute arrival time, relative arrival time, frequency, time duration, number of cycles, absolute signal-to-noise ratio and relative signal-to-noise ratio of the feedback signal received by one or more transducer elements of the transducer array.

50. The method of claim 48, wherein the transmitter circuit data comprises one or more of: efficiency, power dissipation, energy dissipation, current dissipation, voltage drop, heat dissipation, temperature, temperature rise, input power, input energy, input current, input voltage, output power, output energy, output current, and output voltage of the one or more transmitter circuits.

51. The method of claim 48, wherein the transducer array configuration comprises one or more of: a selected set of transducer elements, apodization applied to one or more transducer elements of the transducer array for transmitting wireless signals to the first device, signal strength, voltage level, current level, pulse width, pulse width modulation, duty cycle, phase, time delay, frequency, and transmit duration.

52. The method of claim 48, further comprising: Transmit apodization of the transducer elements of the transducer array is determined using the processor of the second device.

53. The method of claim 52, further comprising: A set of transducer elements for the transducer array configuration is selected using the processor of the second device based on one or more of: the transmit apodization of the transducer elements, the transmitter circuit data, and one or more predetermined target signal strengths at the first device.

54. The method of claim 53, further comprising: One or more transmit voltage levels for the transducer array configuration are determined using the processor of the second device based at least in part on a selected set of transducer elements of the transducer array configuration.

55. The method of claim 52, wherein the transmit apodization of the transducer elements is proportional to the relative signal strengths of the feedback signals received by the transducer elements of the transducer array in one or more frequency bands.

56. The method of claim 52, wherein the transmit apodization of two or more transducer elements is substantially equal.

57. The method of claim 48, wherein the first device comprises an implantable medical device and the second device comprises an external wireless device configured to be positioned physically separate from the first device.

58. The method of claim 48, wherein the first device comprises an external wireless device and the second device comprises an implantable medical device configured to be positioned physically separate from the first device.

59. The method of claim 48, further comprising: A wireless command is sent from the second device to the first device, and the feedback signal is sent from the first device to the second device in response to receiving the wireless command.

60. The method of claim 48, further comprising: The feedback signal is sent from the first device at one or more predetermined repetition intervals.

61. A system configured to exchange wireless power or data, comprising: A first device comprising a first transducer, a first processor, and an energy storage device, wherein The first transducer is configured to receive a first wireless power signal from a second device, The energy storage device is configured to be charged based on the received first wireless power signal, The first processor is configured to determine a charging duration corresponding to one or more predetermined conditions, and The first device is configured to send a feedback signal based on the charging duration, wherein The second device includes a second transducer and a second processor, wherein the second transducer being configured to receive the feedback signal, The second processor is configured to process the feedback signal to generate feedback signal data and determine a transducer configuration based at least in part on the feedback signal data, and The second device is configured to transmit a second wireless power signal to the first device based on the transducer configuration.

62. A system as described in claim 61, wherein the predetermined condition includes one or more of the following: an absolute or relative time duration corresponding to the received first wireless power signal, an absolute or relative time duration corresponding to the voltage generated by the first device in response to the received first wireless power signal, an absolute or relative time duration corresponding to the current generated by the first device in response to the received first wireless power signal, an absolute or relative power level corresponding to the received first wireless power signal, an absolute or relative energy level corresponding to the received first wireless power signal, an absolute or relative voltage level generated by the first device in response to the received first wireless power signal, and an absolute or relative current level generated by the first device in response to the received first wireless power signal.

63. The system of claim 61, wherein the first processor is configured to digitize the charging duration.

64. The system of claim 61, wherein the feedback signal comprises one or more of a digital representation of the charging duration and an analog representation of the charging duration.

65. A system as described in claim 61, wherein the feedback signal data includes one or more of the following: a digital representation of the charging duration, an analog representation of the charging duration, an absolute amplitude or magnitude of the feedback signal received by the second transducer, a relative amplitude or magnitude, an absolute signal strength, a relative signal strength, the energy of the signal in one or more frequency bands, toe-off, absolute phase, relative phase, absolute time delay, relative time delay, absolute arrival time, relative arrival time, frequency, time duration, number of cycles, absolute signal-to-noise ratio, and relative signal-to-noise ratio.

66. A system as described in claim 61, wherein the feedback signal data includes one or more of the following: a mean, median, mode, variance, standard deviation, minimum, maximum, percentile, histogram, statistical distribution, frequency and probability of one or more charging durations corresponding to one or more first wireless power signals received by the first transducer from the second device.

67. A system as described in claim 61, wherein the transducer configuration includes one or more of the following: an absolute or relative duration of the second wireless power signal, one or more absolute or relative power levels of the second wireless power signal, one or more absolute or relative amplitudes of the second wireless power signal, an absolute or relative pulse repetition frequency of the second wireless power signal, and an absolute or relative frequency of the second wireless power signal.

68. The system of claim 61, wherein the duration of the second wireless power signal is configured to be substantially equal to or greater than the charging duration.

69. A system as described in claim 61, wherein the duration of the second wireless power signal is configured to be substantially equal to or greater than one or more of the following: a mean of one or more charging durations, a median of one or more charging durations, a mode of one or more charging durations, and a value corresponding to one or more charging durations, wherein the one or more charging durations correspond to the one or more first wireless power signals received by the first transducer from the second device.

70. The system of claim 61, wherein the second transducer comprises one or more transducer arrays comprising one or more transducer elements.

71. A system as described in claim 70, wherein the transducer configuration includes one or more of the following: a selected set of transducer elements, toe-cutting applied to the one or more transducer elements for transmitting one or more wireless power signals to the first device, signal strength, voltage level, current level, pulse width, pulse repetition rate, pulse width modulation, duty cycle, phase, time delay, frequency and transmission duration.

72. The system of claim 61, wherein the first device comprises an implantable medical device and the second device comprises an external wireless device configured to be physically separate from the first device.

73. The system of claim 61, wherein the first wireless power signal and the second wireless power signal comprise ultrasonic signals or acoustic signals.

74. A method for exchanging wireless signals in a wireless system, comprising: receiving a first wireless power signal at a first transducer of a first device of the wireless system from a second device of the wireless system, the first device comprising an energy storage device and a first processor, and the second device comprising a second transducer and a second processor; charging the energy storage device based on the received first wireless power signal; determining, using the first processor, a charging duration corresponding to one or more predetermined conditions; sending a feedback signal from the first device to the second device based on the charging duration; receiving the feedback signal using the second transducer; processing the feedback signal using the second processor to generate feedback signal data; determining, using the second processor, a transducer configuration based at least in part on the feedback signal data; and A second wireless power signal is sent from the second device to the first device based on the transducer configuration.

75. A method as claimed in claim 74, wherein the predetermined condition includes one or more of the following: an absolute or relative time duration corresponding to the received first wireless power signal, an absolute or relative time duration corresponding to the voltage generated by the first device in response to the received first wireless power signal, an absolute or relative time duration corresponding to the current generated by the first device in response to the received first wireless power signal, an absolute or relative power level corresponding to the received first wireless power signal, an absolute or relative energy level corresponding to the received first wireless power signal, an absolute or relative voltage level generated by the first device in response to the received first wireless power signal, and an absolute or relative current level generated by the first device in response to the received first wireless power signal.

76. The method of claim 74, further comprising: The charging duration is digitized using the first processor.

77. The method of claim 74, further comprising: The feedback signal is encoded or modulated using the first processor with one or more of a digital representation of the charging duration and an analog representation of the charging duration.

78. A method as claimed in claim 74, wherein the feedback signal data includes one or more of the following: a digital representation of the charging duration, an analog representation of the charging duration, an absolute amplitude or magnitude of the feedback signal received by the second transducer, a relative amplitude or magnitude, an absolute signal strength, a relative signal strength, the energy of the signal in one or more frequency bands, toe-off, absolute phase, relative phase, absolute time delay, relative time delay, absolute arrival time, relative arrival time, frequency, time duration, number of cycles, absolute signal-to-noise ratio and relative signal-to-noise ratio.

79. A method as claimed in claim 74, wherein the feedback signal data includes one or more of the following: a mean, median, mode, variance, standard deviation, minimum, maximum, percentile, histogram, statistical distribution, frequency and probability of one or more charging durations corresponding to one or more first wireless power signals received by the first transducer from the second device.

80. A method as claimed in claim 74, wherein the transducer configuration includes one or more of the following: an absolute or relative duration of the second wireless power signal, one or more absolute or relative power levels of the second wireless power signal, one or more absolute or relative amplitudes of the second wireless power signal, an absolute or relative pulse repetition frequency of the second wireless power signal, and an absolute or relative frequency of the second wireless power signal.

81. The method of claim 74, wherein the duration of the second wireless power signal is configured to be substantially equal to or greater than the charging duration.

82. A method as claimed in claim 74, wherein the duration of the second wireless power signal is configured to be substantially equal to or greater than one or more of the following: a mean of one or more charging durations, a median of one or more charging durations, a mode of one or more charging durations, and a value corresponding to one or more charging durations, wherein the one or more charging durations correspond to the one or more first wireless power signals received by the first transducer from the second device.

83. The method of claim 74, wherein the second transducer comprises one or more transducer arrays comprising one or more transducer elements.

84. A method as claimed in claim 83, wherein the transducer configuration includes one or more of the following: a selected set of transducer elements, toe-cutting applied to the one or more transducer elements for transmitting one or more wireless power signals to the first device, signal strength, voltage level, current level, pulse width, pulse repetition rate, pulse width modulation, duty cycle, phase, time delay, frequency and transmission duration.

85. The method of claim 74, wherein the first device comprises an implantable medical device and the second device comprises an external wireless device configured to be positioned physically separate from the first device.

86. The method of claim 74, wherein the first wireless power signal and the second wireless power signal comprise ultrasonic signals or acoustic signals.

87. A wireless implantable device comprising: a transducer configured to receive a wireless power signal, a power circuit coupled to the transducer and configured to recover at least a portion of the wireless power signal received by the transducer, an energy storage device coupled to the power circuit and configured to charge based on the portion of the wireless power signal recovered by the power circuit, and a processor coupled to one or more of the power circuit, the energy storage device, and the transducer, wherein The processor is configured to determine charging parameters corresponding to one or more predetermined conditions and adjust parameters of one or more of the power circuit, the energy storage device, and the transducer based at least in part on the charging parameters.

88. The apparatus of claim 87, wherein the power circuit comprises one or more of an AC-DC converter, a reconfigurable AC-DC converter, a rectifier, a reconfigurable rectifier, a DC-DC converter, a reconfigurable DC-DC converter, a linear regulator, a switching regulator, a switched capacitor voltage regulator, a boost converter, a buck converter, a switched capacitor DC-DC converter, a charging circuit, a battery charging circuit, a current source, a voltage source, a constant current (CC) charging circuit, a constant voltage (CV) charging circuit, a trickle charging circuit, a pulsed charging circuit, a current limiter circuit, and a voltage limiter circuit.

89. The device of claim 87, wherein the energy storage device comprises one or more of: a battery, a rechargeable battery, a capacitor, and an inductor.

90. A device as described in claim 87, wherein the charging parameters include one or more of the following: an absolute or relative time duration corresponding to the wireless power signal received by the transducer, an absolute or relative time duration of the voltage generated by the transducer in response to the received wireless power signal, an absolute or relative time duration of the current generated by the transducer in response to the received wireless power signal, an absolute or relative time duration corresponding to the wireless power signal recovered by the power circuit, an absolute or relative time duration of the voltage generated by the power circuit in response to the recovered wireless power signal, an absolute or relative time duration of the current generated by the power circuit in response to the recovered wireless power signal, an absolute or relative time duration corresponding to the charging of the energy storage device, and an absolute or relative charging rate of the energy storage device.

91. The device of claim 87, wherein the charging parameters include an absolute or relative voltage level corresponding to the energy storage device, an absolute or relative current level corresponding to the energy storage device, an absolute or relative power level corresponding to the energy storage device, an absolute or relative energy level corresponding to the energy storage device, an absolute or relative voltage level corresponding to the power circuit, an absolute or relative current level corresponding to the power circuit, an absolute or relative power level corresponding to the power circuit, an absolute or relative voltage level corresponding to the transducer, an absolute or relative current level corresponding to the transducer, and an absolute or relative power level corresponding to the transducer.

92. The device of claim 87, wherein the processor is configured to digitize the charging parameters.

93. The apparatus of claim 87, wherein the parameters of the power circuit adjusted by the processor include one or more of: a charging current level, a charging voltage level, a charging mode, a switching frequency of an AC-DC converter, a switching frequency of a DC-DC converter, a load current of an AC-DC converter, a load current of a DC-DC converter, a configuration of a matching network, and a signal applied to a switch coupled to the power circuit.

94. A device as described in claim 87, wherein the parameters of the energy storage device adjusted by the processor include one or more of the following: selection of capacitors, selection of batteries, number of capacitors, number of batteries, capacitance value, and signal applied to a switch coupled to the energy storage device.

95. The apparatus of claim 87, wherein the parameters of the transducer adjusted by the processor include one or more of: selection of a transducer element, an impedance coupled to the transducer, a matching network coupled to the transducer, and a signal applied to a switch coupled to the transducer.

96. The apparatus of claim 87, wherein the transducer comprises an acoustic transducer and the wireless power signal comprises an acoustic power signal.

97. The apparatus of claim 96, wherein the acoustic transducer comprises an ultrasonic transducer and the acoustic power signal comprises an ultrasonic power signal.

98. A method for charging a wireless implantable device, comprising: receiving a wireless power signal using a transducer of the wireless implantable device; recovering at least a portion of the received wireless power signal using a power circuit coupled to the transducer; charging an energy storage device coupled to the power circuit based on the recovered portion of the received wireless power signal; determining, using a processor coupled to one or more of the power circuit, the energy storage device, and the transducer, charging parameters corresponding to one or more predetermined conditions; and Parameters of one or more of the power circuit, the energy storage device, and the transducer are adjusted using the processor based at least in part on the charging parameters.

99. The method of claim 98, wherein the power circuit comprises one or more of an AC-DC converter, a reconfigurable AC-DC converter, a rectifier, a reconfigurable rectifier, a DC-DC converter, a reconfigurable DC-DC converter, a linear regulator, a switching regulator, a switched capacitor voltage regulator, a boost converter, a buck converter, a switched capacitor DC-DC converter, a charging circuit, a battery charging circuit, a current source, a voltage source, a constant current (CC) charging circuit, a constant voltage (CV) charging circuit, a trickle charging circuit, a pulsed charging circuit, a current limiter circuit, and a voltage limiter circuit.

100. The method of claim 98, wherein the energy storage device comprises one or more of: a battery, a rechargeable battery, a capacitor, and an inductor.

101. A method as claimed in claim 98, wherein the charging parameters include one or more of the following: an absolute or relative time duration corresponding to the wireless power signal received by the transducer, an absolute or relative time duration of the voltage generated by the transducer in response to the received wireless power signal, an absolute or relative time duration of the current generated by the transducer in response to the received wireless power signal, an absolute or relative time duration corresponding to the wireless power signal recovered by the power circuit, an absolute or relative time duration of the voltage generated by the power circuit in response to the recovered wireless power signal, an absolute or relative time duration of the current generated by the power circuit in response to the recovered wireless power signal, an absolute or relative time duration corresponding to the charging of the energy storage device, and an absolute or relative charging rate of the energy storage device.

102. A method as claimed in claim 98, wherein the charging parameters include an absolute or relative voltage level corresponding to the energy storage device, an absolute or relative current level corresponding to the energy storage device, an absolute or relative power level corresponding to the energy storage device, an absolute or relative energy level corresponding to the energy storage device, an absolute or relative voltage level corresponding to the power circuit, an absolute or relative current level corresponding to the power circuit, an absolute or relative power level corresponding to the power circuit, an absolute or relative voltage level corresponding to the transducer, an absolute or relative current level corresponding to the transducer, and an absolute or relative power level corresponding to the transducer.

103. The method of claim 98, wherein the processor is configured to digitize the charging parameters.

104. A method as claimed in claim 98, wherein the parameters of the power circuit adjusted by the processor include one or more of the following: charging current level, charging voltage level, charging mode, switching frequency of the AC-DC converter, switching frequency of the DC-DC converter, load current of the AC-DC converter, load current of the DC-DC converter, configuration of the matching network, and signal applied to the switch coupled to the power circuit.

105. A method as claimed in claim 98, wherein the parameters of the energy storage device adjusted by the processor include one or more of the following: selection of capacitors, selection of batteries, number of capacitors, number of batteries, capacitance value, and signal applied to a switch coupled to the energy storage device.

106. The method of claim 98, wherein the parameters of the transducer adjusted by the processor include one or more of: selection of a transducer element, an impedance coupled to the transducer, a matching network coupled to the transducer, and a signal applied to a switch coupled to the transducer.

107. The method of claim 98, wherein the transducer comprises an acoustic transducer and the wireless power signal comprises an acoustic power signal.

108. The method of claim 107, wherein the acoustic transducer comprises an ultrasonic transducer and the acoustic power signal comprises an ultrasonic power signal.

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