Communication system and method for wireless data transmission between an implant and an external device.

Abstract

A communication system 10 for wireless data transmission between an implantable medical device IMD 40 and an external device 60, and respective communication methods, aimed at increasing the lifetime of the IMD energy source, are disclosed. The communication system comprises a communication unit 62 and a processor 61. The IMD 40 is configured to monitor a body parameter of a patient and / or deliver a therapy signal to the patient, the IMD comprises a transceiver module configured to exchange data with a communication unit of the external device in an uplink direction from the transceiver module to the communication unit and in a downlink direction from the communication unit to the transceiver module. Further, respective computer program products and computer readable data carriers are described.

Description

[Technical Field]

[0001] The present invention relates to a communication system for wireless data transmission between an implantable medical device (IMD) and an external device, the IMD being configured to monitor the patient's health status and / or to deliver therapeutic signals to the patient. The external device is located at least partially outside the body. The present invention further relates to respective communication methods for wireless data transmission, respective computer program products, and respective computer-readable data carriers. [Background technology]

[0002] Active and passive implantable medical devices (IMDs, implants), such as pacemakers (with leads), BioMonitor, implantable leadless pacers (ILPs), implantable leadless pressure sensors (ILPSs), implantable cardiac defibrillators (ICDs), or Shockboxes, encompass sensors that collect physiological signals to monitor a patient's health status and transmit them as data to external devices (e.g., smartphones, computers, remote servers) using communication units. Data collected from these various sensors may include, but are not limited to, ECG, impedance, activity, posture, heart sounds, pressure, respiratory data, and other data. Active IMDs, such as pacemakers, ILPs, ICDs, or Shockboxes, can provide patients with therapeutic signals, such as electrical stimulation within the ventricles or atria.

[0003] Typically, such an IMD comprises a processor for data processing and a transceiver module configured to exchange messages bidirectionally with a communication unit of an external device, for example, when implanted in a patient's body. The communication unit of the external device, which is at least partially located outside the body, is configured to transmit data bidirectionally using the IMD's transceiver module. The communication unit generates messages and sends them to the IMD's transceiver module in the form of requests, for example, to receive data from the IMD regarding the patient's health status or IMD status, or to program it (to configure the IMD to apply appropriate therapy to the patient).

[0004] U.S. Patent Application Publication No. 2003 / 0009204(A1) describes a system and method for optimizing short-range and long-range telemetry communication between an implantable medical device and an external device such as an external programmer or remote monitor. According to the present invention, data is transmitted from the implantable device to the external device at either a faster or slower data transfer rate.

[0005] The document U.S. Patent Application Publication No. 2018 / 0152972(A1) describes a method and system for data transmission in which a communication link is initiated between an external device and an IMD. During a first connection interval, data packets are carried between the external device and the IMD, and connection criteria, including at least one of data throughput requirements, are monitored. Furthermore, the communication link is changed from a first connection interval to a second connection interval based on the connection criteria in order to extend the lifespan of the IMD, the second connection interval being longer than the first connection interval, and the change operation includes changing to the second connection interval when the data throughput requirements fall below a data threshold.

[0006] According to the above document, communication parameters must be considered to avoid improper depletion of the IMD battery. This is especially true in the case of telemetry communication between an IMD implanted in a patient's body and an external device. Such telemetry communication is often implemented as a short communication connection involving the exchange of several data packets, which are repeated at predefined, usually constant time intervals.

[0007] Typically, low link margins are used for telemetry communication between an IMD and external equipment. In such cases, high data transfer rates can cause communication loss, and potentially, high repetition rates lead to increased energy consumption. Since short-duration communication connections contain only a few data packets, the usual "negotiation" of the optimal data transfer rate between communication partners also increases energy consumption. The usual quality of service (QoS) methods for determining the overall performance of a data transmission service, which include requirements for all aspects of the connection such as service response time, loss, signal-to-noise ratio, crosstalk, echo, interrupts, frequency response, loudness level, etc., are not effective for short communications such as IMD-to-external equipment communication in the case of telemetry communication. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] U.S. Patent Application Publication No. 2003 / 0009204(A1) [Patent Document 2] U.S. Patent Application Publication No. 2018 / 0152972(A1) [Overview of the project] [Problems that the invention aims to solve]

[0009] Therefore, it is desirable to provide a communication system and method that does not deplete the IMD battery energy and to provide rapid results regarding at least one optimal communication parameter to extend its lifespan. [Means for solving the problem]

[0010] The above problems are solved by a communication system for wireless data transmission between an IMD and an external communication unit having the features of claim 1, by each communication method having the features of claim 8, by a computer program product having the features of claim 13, and by a computer-readable data carrier having the features of claim 14.

[0011] The above problems are solved, in particular, by a communication system for wireless data transmission between an IMD and an external device comprising a communication unit and a processor, wherein the IMD is configured to monitor the patient's physical parameters and / or to deliver therapeutic signals to the patient, the IMD comprises a transceiver module, the transceiver module is configured to exchange data with the communication unit of the external device in the uplink direction from the transceiver module to the communication unit and in the downlink direction from the communication unit to the transceiver module, the processor of the external device is configured to determine the signal strength of at least one data packet received by the communication unit and sent by the embedded transceiver module of the IMD at a predetermined initial data transfer rate, and to determine the noise level of the communication unit, the processor is further configured to determine the maximum possible uplink data transfer rate value for data transmission in the uplink direction and the maximum possible downlink data transfer rate value for data transmission in the downlink direction, based on the signal strength just determined of at least one data packet received by the communication unit from the transceiver module and the current noise level of the communication unit.

[0012] An IMD is an implantable medical device, such as an ILP, ILPS, or ICD, configured to monitor a patient's health status and / or to deliver therapeutic signals to the patient, as defined above. Other examples of IMDs that can realize the above subject are the IMDs mentioned above, SCS devices, drug delivery devices, or cochlear implants. An IMD can be implanted, at least partially, within the patient's body. After implantation, the IMD provides telemetry and communication with external devices.

[0013] The IMD comprises a processor for data processing and a transceiver module (e.g., an antenna) for sending and transmitting messages (i.e., communication signals) to and from a communication unit. The IMD's processor is electrically connected to the transceiver module, and the processor of the external device is electrically connected to the communication unit. Alternatively, the transceiver module or communication unit may be integrated into the IMD's processor or the external device's processor, respectively. The transceiver module and communication unit are configured to send signals / messages in the form of data packets to the other module / unit. Generally, such data packets are bit strings embedded in a system of syntactic and semantic rules defined in the communication protocol, which is represented in the respective algorithms and data structures. Messages received by the transceiver module are sent to the respective processor for data processing. Similarly, the processor generates the content of the signals / messages that are sent by the transceiver module or communication unit to their respective counterparts.

[0014] IMD memory modules may include any volatile medium, non-volatile medium, magnetic medium, or electrical medium, such as random access memory (RAM), read-only memory (ROM), non-volatile RAM (NVRAM), electrically-erasable programmable ROM (EEPROM), flash memory, or any other memory device.

[0015] The IMD may comprise further modules such as a power source (e.g., a battery), at least one sensor for retrieving physiological signals from the patient, and / or a signal generator for generating electrotherapy or electromagnetic therapy signals to provide therapy to the patient, for example. The transceiver module, memory module, power source, at least one sensor, and / or signal generator can be electrically connected to a processor. The components of the IMD can be housed in a hermetically sealed housing.

[0016] External devices are always located at least partially outside the body, especially in situations where the IMD is implanted in the patient's body. External devices may be computers, smartphones, servers, or similar computing devices equipped with communication units and processors. External devices may also be so-called patient remote devices (PRs) that can act as transceivers routing communication between the IMD and a remote monitoring server. PRs can give the patient or HCP the ability to modify the IMD's active therapy program, control its stimulation amplitude, turn stimulation on / off, and observe battery status. Thus, external devices can also function as external programmers for the IMD. The described functionality of external devices and the following methods can be realized through corresponding applications.

[0017] The communication unit is configured for bidirectional communication with the IMD's transceiver module and therefore includes a transceiver for messages (signals), such as an antenna.

[0018] For data / signal processing, each external device and IMD generally includes, or may include, a dedicated processor, which is considered a functional unit of the external device or IMD, that interprets and executes instructions, including instruction control units and arithmetic and logic units. The processor may include a microprocessor, controller, digital signal processor (DSP), application-specific integrated circuit (ASIC), field-programmable gate array (FPGA), discrete logic circuit, or any combination thereof. Alternatively or additionally, the processor may also be implemented using integrated dedicated hardware logic circuits, particularly in the case of IMDs, due to their small size and extremely limited power consumption. A processor may comprise multiple processing subunits.

[0019] Wireless communication between the communication unit and IMD's transceiver module includes communication via the air (without wiring) using electromagnetic waves, such as MedRadio / MICS / MEDS, EDGE, EV-DO, Flash-OFDM, GPRS, HSPA, LoRaWAN, RTT, UMTS, Narrowband IoT, Bluetooth, WLAN (WiFi), ZigBee, NFC, LTE, Wireless USB, Wibree (BLE), Ethernet® or WiMAX in the radio frequency domain, or IrDA or free-space optical communication (FSO) in the infrared or optical frequency domain. Therefore, each communication protocol or cooperative protocol (protocol suite) can be used, often having the same name (i.e., a system of rules implemented by hardware, software, or a combination thereof, that enables two or more entities of a communication system to transmit information via certain variations of physical quantities, defining rules, syntax, communication semantics and synchronization, and possible error recovery methods), and the TCP / IP protocol suite (e.g., IPv6, TCP, UDP, SMTP, HTTP / 2) can also be used, along with protocols such as TLS or SSL, IPX / SPX, X.25, AX.25, ebXML, AppleTalk, Bluetooth protocol (e.g., BR / EDR), Bluetooth 4.0 (BLE), ZigBee protocol, NFC protocol, IEEE 802.11 and 802.16 protocols, etc.). After implantation of the IMD, the communication path includes a path section within the tissue of the patient's body.

[0020] As shown above, communication between the communication unit and the transceiver module can use the MedRadio / MICS / MEDS specification. Medical Device Wireless Communication Service (MedRadio) is a specification and communication spectrum created for the U.S. Federal Communications Commission (FCC) for the communication needs of diagnostic and therapeutic IMD and wearable medical devices. The covered spectrum includes frequency bands in the 401 MHz to 406 MHz range, 413 MHz to 457 MHz range, and 2360 MHz to 2400 MHz range. The European Telecommunications Standards Institute (ETSI) has also created a specification and nearly identical spectrum, which is widely known as MICS / MEDS (Medical Data Service) in Europe and the rest of the world. The MICS band can be divided into 25 kHz channels, and IMD transceivers can use up to 300 kHz. In this case, data transfer rates of up to 800 kilobits / second are possible. The transmitted power output is extremely low, at 25 μW EIRP (-16 dBm) to avoid interference.

[0021] Therefore, communication modules and transceiver modules are equipped with hardware and software adapted to the communication techniques / protocols used.

[0022] In relation to the present invention, each processor is considered a functional unit of an IMD and external device that interprets and executes instructions, including an instruction control unit and arithmetic and logical units. A remote computer is a functional unit that can perform substantial calculations, including many arithmetic and logical operations, without human intervention, such as a personal mobile device (PMD), desktop computer, server computer, cluster / warehouse-scale computer, or embedded system.

[0023] The above communication system uses a predefined bit error rate (BER), for example, BER = 10. -5 Or BER=10 -3 The advantage is that the maximum possible uplink and downlink data transfer rates are determined solely based on determined values ​​from external equipment. There is no (additional) determination of any required values ​​within the IMD. Furthermore, the maximum possible uplink and downlink data transfer rates can be determined after the communication unit receives only one data packet from the IMD, thus the determination is extremely fast, resulting in reduced energy consumption of the IMD and thus a longer lifespan.

[0024] In one embodiment, the maximum possible uplink data transfer rate for data transmission in the uplink and downlink directions is 10 -3 The BER is taken into consideration.

[0025] The inventors have recognized that the maximum possible data transfer rate for a given BER and communication connection depends on the received carrier relative to the noise ratio measure. Therefore, the inventors determine the signal and interference levels received by the communication unit of an external device in order to receive a value relative to the maximum possible data transfer rate. Figure 2 shows the BER drawn against the normalized carrier-to-noise ratio measure, expressed as Eb / N0 (energy-to-noise-power-spectral density ratio per bit), for different types of bit error rate tests (BERT). From this graph, for example, FSK modulation and BER=10 -5 In contrast, if Eb / N0 > 14dB, it is possible to increase bandwidth and, consequently, data transfer speed.

[0026] The determination of the possible maximum uplink data transfer speed and the possible maximum downlink data transfer speed can further be based on the transceiver module used in the IMD. Each transceiver chip type achieves a specific sensitivity for each data transfer speed in relation to the thermal noise N. As an example, the following table (Table 1) lists the sensitivities for typical transceiver chips with respect to the data transfer speed. [Table 1]

[0027] Thus, in one embodiment, the possible maximum uplink data transfer speed values for data transmission in the uplink direction and the downlink direction take into account a predetermined type of IMD transceiver module.

[0028] The inventors assume that the signal strength C of one data packet received by the communication unit and sent by the transceiver module using a predefined initial data transfer speed E is C E = TX I + L (Equation 0) where TX I (in dBm) is the transmitter power output of the IMD's transceiver module and L is the total loss of the transmission path. Assuming further symmetry of the transmission path, the signal level C of a data packet received by the transceiver module and sent by the communication unit I is C I = TX E + L = C E + TX E - TX I (Equation I) where TX EL (in dBm) is the transmitter power output of the communication unit of the external device, and L is the (total) loss of the transmission path. The above formula is further based on the assumption that the same frequency is used for uplink data transmission and downlink data transmission, which is the case, for example, when the MICS band is used for data transmission. Thus, in one embodiment, the maximum possible uplink data transfer rate value for data transmission in the uplink and downlink directions takes into account a given frequency band for data transmission.

[0029] Signal strength C of at least one received data packet E After measurement, and from the contents of each data packet, TX I After the determination, the processor of the external device uses Equation I to determine the signal level C I TX will make the decision. E This is determined from external devices in relation to a predefined initial data transfer rate.

[0030] As shown above, a second important value in determining the maximum possible uplink data transfer rate for data transmission in the uplink direction and the maximum possible downlink data transfer rate for data transmission in the downlink direction is the current noise level received by the external equipment. This current noise level I E The noise level (in dBm) is determined by the processor of an external device as a moving arithmetic mean over a predetermined time period, for example, several seconds, using a predetermined bandwidth B (in Hz) for the transmission channel used. It is also possible to use a moving geometric mean or harmonic mean. Noise level I E This can be determined continuously, or at predetermined time intervals, every 5 to 20 minutes, over predetermined time intervals, for example, from 1 to 60 seconds. Current noise level I E This is the most recently determined noise level according to the method described above.

[0031] As shown in Figure 3, interference source I (in dBm units) 70 produces noise level I within the transceiver module of IMD40 at a distance x (in meters units). I It is generating I I is I I =ID x -D K It is calculated as, and here D x (in dB units) is the free path loss, D K This is the attenuation of the patient's tissue, and the tissue of patient 30 is part of the communication pathway. E D is the noise level (in dBm) generated by the interference source I in the external device 60 at a distance y (in meters), and it is assumed that the isotropic antenna has an antenna gain of 0 dBm. K is D x Based on the finding that it is longer compared to, and based on the assumption that interference sources are not usually placed closer than 25 cm from the IMD (x>0.25m), and that external equipment is usually placed within 2 m of the IMD (z<=2m), the following calculations are provided. I I =ID x -D K and I E =ID y D y / x =D y -D x =20*log 10 (y / x) y / x < (z+x) / x Therefore D y / x <20*log10((z+x) / x)=20*log 10 ((2m + 0.25m) / 0.25m) = 19 Therefore D y / x <19 Therefore, 19 is D y / x This is the upper limit. Therefore, noise level I I It can be calculated as follows: I I =I E -D K +19 (Formula II)

[0032] Equation II shows the interference I expected in IMD. I It provides a useful and sufficiently accurate ("sharp") value for [the subject].

[0033] This value is independent of the location of interference source I and can be determined without requiring actual measurement of interference within the IMD, as the measurement is performed only with external equipment, thus saving energy within the IMD.

[0034] Using this value for interference, the data transfer rate d in the downlink direction is calculated. DL It can be adjusted. In the case of telemetry using IMD, D K >>D y / x (=19), therefore I I < E It should be noted that this means interference within the IMD is much smaller than interference within external devices. This is because the data transfer rate is largely determined by interference. DL >d UL This suggests that they will have to choose that option.

[0035] The highest possible uplink data transfer rate value d for data transmission in the uplink direction. UL The determined value C E , I E Based on and N, the processor of the external device determines the data transfer rate in the uplink direction, and the communication unit of the external device transmits the received signal at this data transfer rate, according to a predefined BER (e.g., 10). -3 or 10 -5 ) can be decoded. Similarly, the highest possible downlink data transfer rate value d for data transmission in the downlink direction DL This is the calculated value C I , I I Based on and N, the external device's processor determines the data transfer rate in the downlink direction, and the IMD transceiver module receives the signal at this data transfer rate, predefined BER (e.g., 10).​-3 or 10 -5 ) can be decoded. N is the thermal noise floor in the communication unit or transceiver module, and Boltzmann constant k B From the values ​​(in J / K), bandwidth B (in Hz), and temperature T (in °K), N = 10 * log 10 It can be derived from (kB*T*B)+30.

[0036] Parameters N, TX E , D K And B is known for each specific communication channel and the specific bandwidth used.

[0037] For example, in the case of the MICS bandwidth (402Hz to 405Hz), the following parameters can be assumed. T XE (dBm units) = -16; D K (dB units) = 31.5; B (Hz units) = 00,000; N (dBm units) = -119

[0038] These values ​​are close to the parameters determined by study ITU-SA-1346 (see Table 2 below). [Table 2]

[0039] Since the sensitivity of the transceiver chips listed in Table 1 is provided in terms of thermal noise N, these values ​​must be matched by I / N (in dB) with respect to the noise level of the interference source I. Furthermore, TX I TX E , C E , I E Regarding this, tolerance values ​​must be considered, and these tolerance values ​​are determined to be approximately 6 dB for use in IMD and external device signal transmission paths. Therefore, the sensitivities listed in Table 1 must be reduced by the following value Δ. Δ I =full(I I / N,0)+6=max(I I+125.6) (Formula IIIa) Δ E = max(I E / N, 0)+6 = max(I E +125.6) (Formula IIIb)

[0040] From Formulas IIIa and IIIb, C Ieff (in dBm units)= C I - Δ I (Formula IVa) C Eeff (in dBm units)= C E - Δ E (Formula IVb) is obtained.

[0041] Next, based on C Eeff stored in Table 1 (stored in the processor or the connected data memory) by the processor, the maximum possible uplink data transfer speed value d UL for data transmission in the uplink direction can be derived, and based on C Ieff from Table 1, the maximum possible downlink data transfer speed value d DL for data transmission in the downlink direction can be derived. Therefore, the maximum possible uplink data transfer speed value d UL and the maximum possible downlink data transfer speed value d DL are determined by the processor of the external device using the signal strength C E determined immediately before one data packet or several data packets received by the communication unit within a predefined time period that ended immediately before, and the determined current noise level I E of the communication unit. All other parameters and assumptions are generally known or are automatically provided to the communication unit (TX from the content of the first data packet I ). Therefore, measurement by the transceiver module of the IMD is not required.

[0042] In one embodiment, the communication unit of the external device is the determined maximum possible uplink data transfer speed value dUL and the highest possible downlink data transfer rate value d DL The IMD is further configured to transmit to the transceiver module, and the IMD is then configured to set the uplink and downlink data transfer rates available to the transceiver module to the data transfer rate values ​​received from the communication unit. The communication unit, following the receipt of the first data packet, uses the second data packet to set these data transfer rate values ​​d UL and d DL This can be sent to the IMD transceiver module.

[0043] In one embodiment, the external device is configured to set the uplink and downlink data transfer rates available to the communication unit to these values, after sending, for example, the determined maximum possible uplink data transfer rate and the maximum possible downlink data transfer rate to the transceiver module using a second data packet.

[0044] In one embodiment, the processor of the external device is configured to determine the signal loss L in the uplink and downlink data transmissions, and the signal loss L can be determined by the processor of the external device based on equation 0 above. IMD TX I The transmitter power output of the transceiver module is received by the IMD's transmitted data signal, which is received by an external device. I The information regarding this is contained within the data signal. Therefore, L=C E -TX I And here the signal level C E This is determined by the communication unit, as explained above.

[0045] In another embodiment, the noise level I of the communication unit over a predetermined longer period of time (e.g., several days or several weeks) E (in dBm units) can be observed, thereby determining the noise level during this time period.E (in dBm) is the noise level of other subsections I E At least one subsection that is typically higher than (in dBm) can be identified. For this purpose, the noise level is monitored continuously over a given time period or at predetermined time intervals. Then, a pattern is identified and each subsection of the given time period is determined. Noise level I E If it is detected that at least one subsection is always higher than the noise level, the time specifications of such subsection are sent to the IMD by the communication unit in order to avoid this at least one subsection for telemetry communication. This is because telemetry communication is performed at a noise level of I E This means that it is preferable to provide it outside the higher, determined subsection.

[0046] The above problems are further solved, for example, by a communication method (which is a computer implementation) for wireless data transmission between an IMD and an external device equipped with a communication unit and a processor, wherein the IMD, after being implanted in the patient's body, monitors the patient's physical parameters and / or delivers therapeutic signals to the patient, the IMD comprises a transceiver module, the transceiver module exchanges data with the communication unit of the external device in the uplink direction from the transceiver module to the communication unit and in the downlink direction from the communication unit to the transceiver module, and the steps include the following: The processor of the external device determines the signal strength of at least one data packet received by the communication unit and sent at a predetermined initial data transfer rate by the embedded IMD transceiver module. • The processor of the external device determines the noise level of the communication unit. The processor determines the highest possible uplink data transfer rate value d for uplink data transmission, based on the signal strength of at least one data packet received by the communication unit from the transceiver module, and the current noise level of the communication unit. UL , and the highest possible downlink data transfer rate value d for downlink data transmission DL To decide.

[0047] More specifically, the method includes the following steps, and many of the features of the method have already been described above in relation to the communication system. Therefore, the above description also applies to the communication method.

[0048] First, at least one first data packet is sent by the IMD transceiver module to the communication unit of the external device at a predetermined initial data transfer rate, and information regarding the transmit power output of the transceiver module is provided in the contents of at least one first data packet. Furthermore, the communication unit of the external device receives the signal strength C of at least one first data packet. E Determine the signal strength (in dBm). If two or more single data packets are used, the signal strength C E The signal strength C (in dBm) is determined by the communication unit or processor of the external device as the average (i.e., arithmetic mean) or median of at least two data packets. However, in most cases, only a single received data packet packed from the IMD is sufficient. Next, using Equation I, the signal strength C is determined by the processor of the external device. I (in dBm units) is determined, TX E This can be determined from the parameters of the communication unit of the external device, TX I It is derived from the contents of at least one data packet.

[0049] Furthermore, before, during, or after the above steps, the actual noise level of the communication unit is measured. EThe noise level (in dBm) is determined by the processor of an external device, for example, as a moving arithmetic mean. Alternatively, other methods can be used to determine the average of different detected noise level values. Noise level I E This can be determined continuously or at predetermined time intervals. Known decay of patient tissue D K For example, D K Based on =31.5dB, the noise level of the IMD transceiver is I I The (in dBm units) is determined by the processor of the external device using Equation II. As in the example above, D K If =31.5dB, I It can be calculated as follows: I I =I E -12.5

[0050] Subsequently, the processor of the external device uses equations IIIa and IIIb above to calculate Δ E and Δ I This is determined. In the next step, C as described in equations IVa and IVb. Eeff and C Ieff This is determined. Next, the processor C Eeff Based on Table 1 (stored in the processor or connected data memory), the maximum possible uplink data transfer rate value d for data transmission in the uplink direction is obtained. UL Determine C Ieff Based on Table 1, the maximum possible downlink data transfer rate value d for data transmission in the downlink direction is shown. DL This will be determined. Details of the above method and assumptions are explained in detail above.

[0051] In one embodiment, the maximum possible uplink data transfer rate for data transmission in the uplink and downlink directions is 10 -2 , 10 -3 or 10 -5The bit error rate (BER), and / or a predetermined type of IMD transceiver module for data transmission and / or a predetermined frequency band are taken into consideration. In principle, the method / system is applicable to all selected bit error rates (BER), and 10 -3 This is a useful example in a communication system with a regular link. Another useful example is in a communication system with a good link. -5 BER is the 10 in a communication system with a bad link. -2 This is the BER. Therefore, preferably 10 -1 and 10 -6 Between, particularly preferably 10 -2 and 10 -5 The BER between and is therefore selected.

[0052] In one embodiment of the method, the communication unit of the external device transmits the determined maximum possible uplink data transfer rate value and the maximum possible downlink data transfer rate value to the transceiver module of the IMD, and the IMD then sets the uplink data transfer rate and downlink data transfer rate available to the transceiver module to the data transfer rate value received from the communication unit.

[0053] In one embodiment of the method, the external device sets the uplink and downlink data transfer rates available to the communication unit to the determined maximum possible downlink and uplink data transfer rates, as shown above.

[0054] In one embodiment of the method, the processor of the external device determines the signal loss in the uplink and downlink data transmissions as described above.

[0055] The above methods are implemented, for example, as a combination of computer instructions and data definitions as specified above and below, enabling the execution of computational and control functions by computer hardware, or as a computer program (executed on communication devices and / or IMDs, specifically on their processors) which is a syntactic unit consisting of declarations and statements or instructions necessary for the functions, tasks, or problem solving specified above and below, and adhering to the rules of a particular programming language.

[0056] Furthermore, a computer program product is disclosed that, when executed by a processor, contains instructions causing that processor to perform the steps of the method defined above. A computer-readable data carrier for storing such a computer program product is therefore described.

[0057] Next, the present invention will be described in more detail with reference to the attached schematic diagrams. [Brief explanation of the drawing]

[0058] [Figure 1] This figure shows an example of a communication system comprising an implantable leadless pacemaker (ILP) and a communication unit, with the ILP shown within a cross-section of the patient's heart. [Figure 2] This graph shows the BER (in dB) of a typical receiver against the energy-to-noise-power-spectral density ratio (Eb / N0) per bit (in dB). [Figure 3] This figure shows the system and interference source I. [Modes for carrying out the invention]

[0059] Figure 1 shows an example communication system 10 and the heart 20 of a patient 30 (having a right ventricle 21 and a right atrium 22). System 10 includes an example leadless ventricular pacemaker device 40 (hereinafter, "ILP40") for the IMD and external device 60. The ILP40 can be configured to be implanted in the right ventricle 21 of the heart (as shown in Figure 1) and to perform pacing of this ventricle, sense intrinsic ventricular depolarization and impedance, and suppress ventricular pacing in response to detected ventricular depolarization. The ILP40 further includes a transceiver module for sending messages to and receiving signals from the communication unit 62 of the external device 60. The transceiver module includes, for example, a transceiver chip. The ILP40 may further include an accelerometer sensor to measure the patient's posture. The ILP40 comprises modules such as a processor, a data memory module, a signal generator unit for providing therapeutic signals (e.g., pacing signals), a measurement unit with an ECG measurement unit, and a DC impedance sensor. Furthermore, the ILP40 is equipped with a power supply, and the above modules are electrically connected to each other. The power supply may include a battery, for example, a rechargeable or non-rechargeable battery. The data memory module may include any of the memory types mentioned above.

[0060] External devices 60, such as smartphones, computers, or programmers, are located outside the body and are adapted to communicate bidirectionally with the ILP 40 using their communication unit 62. The external device 60, which may be a portable patient device, comprises a processor 61 and a communication unit 62 containing a transceiver chip for exchanging messages with the ILP 40's transceiver module in the form of data packets, with the processor 61 and communication unit 62 being electrically connected to each other. Bidirectional exchange of messages (data packets) with the ILP 40 is represented by the symbol of a double arrow 50 in Figure 1. Wireless communication between the ILP 40 and the external device 60 can be facilitated by electromagnetic waves in the radio frequency range, for example, using the RF band, for example, the MICS band in the range of 402 MHz to 405 MHz. For this purpose, the communication unit 62 and the ILP 40 each include a transceiver chip.

[0061] The bidirectional communication between the ILP 40 and the external device 60 includes, for example, long-range electromagnetic telemetry communication, in which only a few data packets, including, for example, arrhythmia information recorded in the ILP, are exchanged between the communication unit 62 of the external device 60 and the transceiver module of the ILP 40.

[0062] To extend the lifespan of the ILP40, communication must be conducted at the highest possible data transfer rate in both the uplink and downlink directions. The uplink direction is from the transceiver module of the ILP40 to the communication unit 62 of the external device 60, and the reverse direction is the downlink direction. In the first step, in any case, a single initial data packet P1 is sent by the transceiver module of the ILP40 to the communication unit 62 of the external device 60 via a predefined channel of the MICS bandwidth at a low data transfer rate, e.g., 4 kb / s, for decoding by the communication unit 62. Transmitter power output TX I This information is either known to the external device beforehand (i.e., this information is always the same for known types or grades of IMD) or provided in the contents of data packet P1, for example, TXI The signal strength C of this first data packet P1 is either =0 dBm or either =0 dBm. The communication unit 62 and / or processor 61 receives the signal strength C of this first data packet P1. E Determine, for example C E = -87 dBm, which is a typical value for IMD transceivers operating in the MICS band. Nearly 75% of MICS communications operate at higher signal strengths, while 25% operate at lower signal strengths.

[0063] Furthermore, the transmitter power output TX of the communication unit 62 E It is known that this is approximately -16 dBm, and therefore, according to equation I above, the signal strength of the transceiver module is calculated by the processor 61 as follows: C I =C E +TX E -TX I = -87dBm - 16dBm - 0dBm = -103dBm

[0064] Prior to the first step described above, noise level I E This is determined by the processor 61 of an external device over a time period of, for example, 5 seconds, and approximately I E This is -109 dBm. This is a typical value for home applications (approximately 10 dB relative to N, see Table 1). For use in a clinic, a value of approximately 20 dB relative to N can be measured.

[0065] Equation II further shows that the value DK (in dB) for this particular arrangement is 31.5, and therefore the noise level is I I =I E -D K +19=-109dBm-31.5dBm+19=-121.5dBm In this example, the patient's body 30 attenuates the interference, and therefore the noise level becomes negligible compared to the thermal noise N.

[0066] In the next step, the Δ value is determined by the processor 61 of the external device 60 based on equations IIIa and IIIb. Δ E =max(-109+125,6)=16 and Δ I =max(-121.5+125,6)=6

[0067] Therefore, the processor 61 of the external device 60 performs further calculations using equations IVa and IVb. C Eeff =-87-16=-103 C Ieff =-103-6=-109

[0068] Using Table 1, the maximum possible data transfer rate is calculated by processor 61, d UL =200kb / s and d DL =32kb / s. The contents of Table 1 are stored as a lookup table in the data memory of processor 61 or external device 60 connected to processor 61. For use in a clinic, I is about 20dB higher than thermal noise. E If we apply the same expression using C Eeff =-113 and C Ieff Note that we obtain = -116.5. In this case, using Table 1, the highest possible data transfer rate is determined by the processor 61, d UL =4kb / s and d DL = 4kb / s

[0069] The above-mentioned maximum possible data transfer rate for uplink and downlink communication is transmitted from the processor 61 of the external device 60 using a second (response) data packet P2 and sent by the communication unit 62 to the transceiver module of the ILP 40 (see Figure 1). After sending P2, the communication unit 62 transmits the above-mentioned determined maximum possible data transfer rate d for communication with the transceiver module. UL and d DLThe transceiver module switches to these new data transfer rates and operates at them when it receives data packet P2 and determines the highest possible data transfer rate.

Claims

1. A communication system (10) for wireless data transmission between an implantable medical device (IMD, 40) and an external device (60) comprising a communication unit (62) and a processor (61), wherein the system comprises the IMD (40) and the external device (60), the IMD (40) being configured to monitor the physical parameters of a patient (30) and / or to deliver therapeutic signals to the patient, the IMD comprising a transceiver module, the transceiver module being configured to exchange data with the communication unit of the external device in the uplink direction from the transceiver module to the communication unit and in the downlink direction from the communication unit to the transceiver module, and the processor of the external device being configured to measure the signal strength (C) of at least one data packet (P1) received by the communication unit and sent by the transceiver module of the embedded IMD at a predetermined initial data transfer rate. Ｅ ) is determined, and the noise level (I) of the communication unit is determined. Ｅ The processor is configured to determine the highest possible uplink data transfer rate value (d) for uplink data transmission, based on the signal strength of the at least one data packet received by the communication unit from the transceiver module and the current noise level of the communication unit. ＵＬ ), and the highest possible downlink data transfer rate value for data transmission in the downlink direction (d ＤＬ A communication system (10) further configured to determine the following.

2. The maximum possible uplink data transfer rate value for data transmission in the uplink and downlink directions is 10 －１ and 10 －６ The communication system according to claim 1, which takes into account the bit error rate (BER) between and

3. The communication system according to claim 1 or 2, wherein the maximum possible uplink data transfer rate value for data transmission in the uplink and downlink directions takes into account a predetermined type of IMD transceiver module.

4. The communication system according to claim 1 or 2, wherein the maximum possible uplink data transfer rate value for data transmission in the uplink and downlink directions takes into consideration a predetermined frequency band for data transmission.

5. The communication system according to claim 1 or 2, wherein the communication unit (62) of the external device (60) is further configured to transmit the determined maximum possible uplink data transfer rate value and the maximum possible downlink data transfer rate value to the transceiver module of the IMD (40), and the IMD is configured to set the uplink data transfer rate and the downlink data transfer rate that are then available for use by the transceiver module to the data transfer rate values ​​received from the communication unit.

6. The communication system according to claim 1 or 2, wherein the external device (60) is configured to set the uplink data transfer rate and the downlink data transfer rate that can then be used by the communication unit (62) to the determined maximum possible downlink data transfer rate value and the determined maximum possible uplink data transfer rate value.

7. The communication system according to claim 1 or 2, wherein the processor (61) of the external device (60) is configured to determine the signal loss (L) in the uplink and downlink data transmissions, and / or the processor of the external device is configured to observe the noise level of the communication unit (62) over a predetermined time period, thereby identifying a subsection within that time period in which the noise level is typically higher than that of other subsections.

8. A communication method for wireless data transmission between an implantable medical device (IMD, 40) and an external device (60) comprising a communication unit (62) and a processor (61), wherein the IMD (40), after being implanted in the body of a patient (30), monitors the patient's physical parameters and / or delivers therapeutic signals to the patient, the IMD comprises a transceiver module, and the transceiver module exchanges data with the communication unit of the external device in the uplink direction from the transceiver module to the communication unit and in the downlink direction from the communication unit to the transceiver module. - The processor of the external device determines the signal strength (C) of at least one data packet (P1) received by the communication unit and sent at a predetermined initial data transfer rate by the transceiver module of the embedded IMD. Ｅ ) and - The processor of the external device controls the noise level (I) of the communication unit. Ｅ ) and - The processor determines the highest possible uplink data transfer speed value (d ＵＬ ), and the highest possible downlink data transfer speed value (d ＤＬ ) for data transmission in the uplink direction and the downlink direction, respectively, based on the just determined signal strength of the at least one data packet received by the communication unit from the transceiver module and the current noise level of the communication unit A communication method that includes this.

9. The maximum possible uplink data transfer rate value for data transmission in the uplink and downlink directions is 10 －１ and 10 －６ The communication method according to claim 8, taking into consideration the bit error rate (BER) between and and / or a predetermined type of IMD transceiver module and / or a predetermined frequency band for data transmission.

10. The communication method according to claim 8 or 9, wherein the communication unit (62) of the external device (60) transmits the determined maximum possible uplink data transfer rate value and the maximum possible downlink data transfer rate value to the transceiver module of the IMD (40), and the IMD sets the uplink data transfer rate and the downlink data transfer rate that the transceiver module can then use to the transmitted data transfer rate value.

11. The communication method according to claim 8 or 9, wherein the external device (60) sets the uplink data transfer rate and the downlink data transfer rate that can then be used by the communication unit (62) to the determined maximum possible downlink data transfer rate value and the determined maximum possible uplink data transfer rate value.

12. The communication method according to claim 8 or 9, wherein the processor (61) of the external device (60) determines the signal loss (L) in the uplink and downlink data transmissions and / or observes the noise level of the communication unit (62) over a predetermined period of time, thereby identifying a subsection within that period in which the noise level is typically higher than that of other subsections.

13. A computer program product that, when executed by the processor (61) of the external device (60), includes instructions causing the processor to perform the steps of the method according to claim 8 or 9.

14. A computer-readable data carrier for storing the computer program product described in claim 13.

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