Ultra-Wideband Device Power Optimization

Abstract

An ultra-wideband (UWB) wireless communication system includes: a first wireless device; a second wireless device participating in a first ranging sequence with the first wireless device; and a transmission channel located between the first and second wireless devices for transmitting data of the first ranging sequence. At least one of the first wireless device or the second wireless device generates at least one channel impulse response (CIR) and determines whether the transmission channel includes a line-of-sight channel based on the at least one CIR. In response to determining that the transmission channel includes the line-of-sight channel, a dedicated processor reduces a current performance level of at least one of the first and second wireless devices during a second ranging sequence.

Description

Technical Field

[0001] The present disclosure relates generally to ultra-wideband (UWB) ranging technology, and more particularly to systems and methods for channel-dependent power optimization of UWB ranging devices. Background Art

[0002] Ultra-wideband (UWB) technology is implemented in wireless electronic communication transceivers because it has superior positioning accuracy and high data throughput compared to other wireless technologies, especially compared to wireless technologies including Internet of Things (IoT) devices. One application includes implementing a UWB computer chip in a key fob, smartphone, or other remote electronic device to remotely digitally access and control the computer processor of the vehicle through one or more antenna anchors installed in the vehicle to lock or unlock the vehicle's doors or achieve other remote functions. Summary of the invention

[0003] According to one aspect of the present invention, there is provided an ultra-wideband (UWB) wireless communication system, comprising:

[0004] a first wireless device;

[0005] a second wireless device that participates in a first ranging sequence with the first wireless device; and

[0006] a transmission channel located between the first and second wireless devices and used to transmit data of the first ranging sequence, wherein at least one of the first wireless device or the second wireless device generates at least one channel impulse response (CIR), and determines whether the transmission channel includes a line-of-sight channel according to the at least one CIR; and

[0007] A dedicated processor is provided to reduce a current performance level of at least one of the first and second wireless devices during a second ranging sequence in response to determining that the transmission channel includes the line-of-sight channel.

[0008] According to one or more embodiments, the first wireless device is a UWB ranging initiating device of a key fob, and the second wireless device is a UWB responding device of an antenna anchor.

[0009] According to one or more embodiments, the dedicated processor includes a channel detection processor that establishes a leading edge of the at least one CIR measured at the location of the second wireless device.

[0010] According to one or more embodiments, the line-of-sight channel is identified by matching the leading edge of the at least one CIR with a cross-correlation function calculated according to the IEEE 802.15.4a standard.

[0011] According to one or more embodiments, the dedicated processor reduces the current performance level of the first wireless device in the second ranging sequence by reducing the quality of the estimate of the at least one CIR, the power supply voltage, the number of preamble symbols used to establish a correlation result, the analog-to-digital converter (ADC) sampling rate, the number of ADC bits, or a combination thereof.

[0012] According to one or more embodiments, each of the first and second wireless devices processes the UWB signal provided by the transmission channel to calculate the time of arrival (TOA) of the signal, which is in turn used by the first wireless device to determine the flight time and range between the first and second wireless devices.

[0013] According to one or more embodiments, the first and second wireless devices determine one of: determining a noise power level of the at least one CIR within a noise range, determining a detection threshold based on the noise power level, and determining the TOA based on an index at which the at least one CIR exceeds the detection threshold.

[0014] According to one or more embodiments, the first wireless device includes one or more analog circuits, oscillator drivers, and filters, and wherein in response to determining that the transmission channel includes the line-of-sight channel, the dedicated processor reduces the current performance level of the one or more analog circuits, oscillator drivers, and filters during the second ranging sequence.

[0015] According to one or more embodiments, the second wireless device includes a plurality of UWB ranging devices each communicating with the first wireless device, and wherein the UWB wireless communication system further includes a central processing unit that controls the plurality of UWB ranging devices to optimize power consumption of the combination of the plurality of UWB ranging devices of the first wireless device and the second wireless device.

[0016] According to one or more embodiments, a channel quality indicator is determined based on the at least one CIR, wherein the line-of-sight channel is determined based on the channel quality indicator.

[0017] According to a second aspect of the present invention, there is provided an ultra-wideband (UWB) wireless transceiver, comprising:

[0018] transceiver circuitry and associated antennas that detect and quantize UWB signals;

[0019] a ranging processor that generates at least one channel impulse response (CIR) based on the UWB signal;

[0020] a signal detector that determines an estimated time of arrival (TOA) based on the CIR;

[0021] a channel detection algorithm processor, the channel detection algorithm processor determining a line-of-sight channel between the UWB wireless transceiver and another UWB wireless transceiver based on the CIR; and

[0022] A device controller, in response to determining that the transmission channel includes the line-of-sight channel, reduces a current performance level of at least one of the UWB wireless transceivers.

[0023] According to one or more embodiments, the first wireless device is a UWB ranging initiating device of a key fob.

[0024] According to one or more embodiments, the UWB wireless transceiver additionally includes a channel detection processor that establishes a leading edge of the at least one CIR measured at the location of the second wireless device.

[0025] According to one or more embodiments, the line-of-sight channel is identified by matching the leading edge of the at least one CIR with a cross-correlation function calculated according to the IEEE 802.15.4a standard.

[0026] According to one or more embodiments, the dedicated processor reduces the current performance level of the first wireless device in the second ranging sequence by reducing the quality of the estimate of the at least one CIR, the power supply voltage, the number of preamble symbols used to establish a correlation result, the analog-to-digital converter (ADC) sampling rate, the number of ADC bits, or a combination thereof.

[0027] According to one or more embodiments, the UWB wireless transceiver further includes one or more analog circuits, oscillator drivers, and filters, and wherein in response to determining that the transmission channel includes the line-of-sight channel, the device controller reduces a current performance level of the one or more analog circuits, oscillator drivers, and filters during the second ranging sequence.

[0028] According to one or more embodiments, a channel quality indicator is determined based on the at least one CIR, wherein the line-of-sight channel is determined based on the channel quality indicator.

[0029] According to another aspect of the present invention, there is provided a method for controlling power consumption of an ultra-wideband (UWB) device, comprising:

[0030] outputting a first electronic message from the first wireless device to the second wireless device;

[0031] storing, at the first wireless device, a first timestamp of transmitting the first electronic message;

[0032] determining, at the second wireless device, a first channel impulse response (CIR) and a time of arrival of the first electronic message;

[0033] storing, at the second wireless device, a second timestamp of transmitting the first electronic message corresponding to the arrival time of the first electronic message;

[0034] outputting, from the second wireless device to the first wireless device, a second electronic message including the second timestamp and a third timestamp of transmitting the second electronic message;

[0035] determining, at the first wireless device, a second channel impulse response (CIR) and a time of arrival of the second electronic message;

[0036] detecting whether a line-of-sight channel exists between the first and second wireless devices based on the CIR of the second electronic message; and

[0037] In response to detecting the line-of-sight channel, reducing a current performance level of the first wireless device during a subsequent ranging sequence.

[0038] According to one or more embodiments, the method further comprises,

[0039] determining a fourth timestamp corresponding to an arrival time of the second electronic message; and

[0040] A time of flight and a range between the first and second wireless devices are determined based on the first, second, third and fourth timestamps.

[0041] According to one or more embodiments, the line-of-sight channel is identified by establishing a leading edge of the second CIR and matching the leading edge of the second CIR with a cross-correlation function. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The present invention is illustrated by way of example and is not limited in the accompanying drawings, in which like reference numerals indicate like elements. The elements in the drawings are illustrated for simplicity and clarity and are not necessarily drawn to scale.

[0043] Figure 1 is a block diagram of a UWB communication system according to some embodiments.

[0044] Figure 2 is a flow chart illustrating a method for optimizing power consumption of a UWB ranging initiating device according to some embodiments.

[0045] Figure 3is a graph showing measured channel impulse responses (CIRs) for two line-of-sight (LOS) channels, including data for performing time-of-arrival (ToA) calculations between a UWB initiating device and a UWB responding device, according to some embodiments.

[0046] Figure 4 is a graph illustrating a cross-correlation function for two line-of-sight (LOS) channels calculated in accordance with the IEEE 802.15.4a standard, according to some embodiments.

[0047] Figure 5 is a flow chart illustrating a method for performing ToA calculations between a UWB initiating device and a UWB responding device according to some embodiments.

[0048] Figure 6 An application of a UWB communication system implemented for an automobile according to another example embodiment is shown.

[0049] Figure 7 is a flow chart illustrating a method for optimizing power consumption of a system including multiple UWB ranging devices according to some embodiments. DETAILED DESCRIPTION

[0050] In order to take advantage of the advantages of positioning accuracy and high data throughput compared to other wireless technologies, UWB transceivers or transceivers compliant with the IEEE 802.15.4 system typically transmit 500MHz or 1GHz pulses to enable the determination of time of flight (ToF) or related signal strength measurements, which in turn can accurately estimate the distance between UWB transceivers. To this end, UWB transceivers are typically operated according to a fixed configuration for a specific pre-programmed application in a manner that produces the best possible performance by the UWB device participating in the ranging operation including measuring the distance between the UWB transceivers, thereby obtaining the position of the initiating transceiver to the responding transceiver with the best possible ranging accuracy.

[0051] However, depending on the fixed configuration of the transceiver in the UWB system, achieving high-precision ranging potential requires considerable power consumption, which may shorten the battery life.

[0052] In short, embodiments of the inventive concept adapt the performance of a UWB device of an electronic switch to measured channel conditions, thereby optimizing power consumption during device operation. Preferred applications include implementing power reduction techniques in ranging operations performed between a user's key fob, smartphone or other mobile electronic device and a car anchor in a manner that allows electronic communications to be performed between these devices in a manner that reduces the power requirements of the key fob battery or other power source.

[0053] In some embodiments, an ultra-wideband (UWB) wireless communication system includes a first wireless device (also referred to as a ranging initiating device) such as the key fob described above and a second wireless device (also referred to as a responding device) such as the car anchor described above, the first and second wireless devices participating in a plurality of ranging sequences via a transmission channel formed between the transmission channels between the first and second wireless devices. The ranging sequence may include a message including a UWB preamble output from the ranging initiating device to the responding device. In doing so, the ranging initiating device stores a first timestamp of the transmission. The responding device receives the message and processes the preamble to determine a channel impulse response (CIR) and a second timestamp, or determines a time of arrival (ToA) based on the CIR. After a predetermined time or a third timestamp, the responding device outputs a message including the second and third timestamps to the ranging initiating device. The ranging initiating device receives the message and determines a CIR estimate and ToA, or a fourth timestamp. The ranging initiating device also calculates a time of flight (ToF) and a range from the first to the fourth timestamps. Finally, the ranging initiating device determines whether line of sight (LOS) is detected based on the CIR estimate. If LOS is detected, the ranging device reduces its own device performance for subsequent ranging sequences.

[0054] Figure 1 1 is a block diagram of a UWB communication system 10 according to some embodiments. In some embodiments, the UWB communication system 10 complies with the IEEE 802.15.4 technical standard, the contents of which are incorporated herein by reference in their entirety. As shown, the ranging initiating device 102 and the responding device 104 exchange data via one or more transmission channels 110, collectively referred to as communication paths or links.

[0055] The ranging initiating device 102 includes a UWB wireless transceiver, etc. Therefore, the ranging initiating device 102 may also be referred to as a first UWB wireless transceiver, and may constitute a part of a user wireless UWB device together with an omnidirectional antenna 121 and a corresponding processor, for transmitting data using a technique that causes radio energy to spread over the UWB frequency band of a transmission channel 110. In some embodiments, the ranging initiating device 102 and / or the receiving device 104 include a transceiver circuit system and an associated antenna 121 that detects and quantifies UWB signals. In some embodiments, the first UWB wireless transceiver 102 operates as a ranging initiator, and may therefore be incorporated into various wireless applications, such as a key card or other secure hardware device for controlling and protecting access to a computer system of other mobile devices.

[0056] The ranging initiating device 102 includes a power source such as a button battery. As described above, embodiments of the inventive concept improve the expected life of the battery by performing channel-dependent power optimization techniques, and in doing so, reduce the current consumption of the ranging initiating device 102, particularly when a LOS channel is detected as part of electronic communication between the ranging initiating device 102 and the responding device 104.

[0057] The responding device 104 also includes a UWB wireless transceiver, etc. Therefore, the responding device 104 may also be referred to as a second UWB wireless transceiver 104, which includes an antenna anchor or related device for detecting UWB pulses transmitted by the first UWB wireless transceiver 102 and forwarding the pulses to a central processing unit (CPU) or other position detection system for calculating the position of the first UWB wireless transceiver 102. As part of the ranging operation, the signals exchanged with the ranging initiating device 102 and output via the transmission channel 110 include data packet preamble data, etc., exchanged as part of the ranging operation for generating a time of flight (ToF) estimate value, so as to accurately provide spatial awareness and relative positioning between the UWB devices 102, 104.

[0058] In order to detect, demodulate and / or decode the signal received from the first UWB wireless transceiver 102, the second UWB wireless transceiver 104 includes an antenna 121. In some embodiments, the first UWB wireless transceiver 102 and / or the second UWB wireless transceiver 104 include a transmitter and a receiver, and exchange data in a wireless manner via the antenna 121. Although only a single antenna 121 is shown, the wireless device (the first UWB wireless transceiver 102 and / or the second UWB wireless transceiver 104) may include multiple transmitters, multiple receivers, multiple transceivers and / or multiple antennas. The antenna 121 may communicate with a signal detector 144, etc., which is used to detect and quantify the signal received by the transceiver 104, for example, energy level, power spectral density, etc. In some embodiments, the first and second wireless transceivers 102, 104 are both part of a wireless device that includes one or more hardware processors for controlling the operation of the transceiver circuit systems and associated antennas 121 and memory devices for storing program codes that are executed by the processing units to perform the processing required to control the transceivers 102, 104.

[0059] In addition to the antenna 121, the ranging initiating device 102 may include, but is not limited to, a ranging processor 122, a signal detector 124, a channel detection algorithm 128, a device controller 130, and a timestamp storage device 132, which may be part of one or more hardware processors, software, or a combination thereof. The device controller 130, preferably at least a part of the ranging initiating device 102, reduces or otherwise changes or optimizes the performance of the device to reduce power consumption when a LOS channel is detected in the transmission between the transceivers of the ranging initiating device 102 and the responding device 104. The responding device 104 may include components similar to those of the ranging initiating device 102, for example, a ranging processor 142, a signal detector 144, and a timestamp storage device 146.

[0060] The signal detector 124 detects and quantifies the received signal, e.g., energy level, power spectral density, etc. The ranging processor 122 estimates the time when the signal is received via the transmission channel 110. In response to receiving a data signal including a preamble, for example, at the beginning of a data packet including relevant data for synchronizing the UWB devices 102, 104, the ranging processor 122 generates a CIR, which is used to generate a time stamp including a ToA estimate. The ToA timestamps stored by the two devices 102, 104 at the storage device 132, 146 are used to estimate the flight time as part of the ranging operation, which may include, but is not limited to, calculating the round trip time of the challenge / response data packet or other related calculations.

[0061] The channel detection algorithm 128 communicates with the ranging processor 122 and the signal detector 124 to determine the channel type for electronic communications between the UWB transceivers 102, 104. Specifically, the channel detection algorithm 128 can distinguish between LOS channels and NLOS channels, which is relevant to obtaining an accurate estimate of system performance according to the IEEE 802.15.4a channel model.

[0062] Specifically, according to embodiments of the present inventive concept, it is important for the channel detection algorithm 128 to detect the LOS channel to optimize power consumption. In many ranging applications, a LOS condition occurs when there is a direct clear path between the ranging initiating device 102 and the responding device 104. Figure 1 As shown in the example in FIG. 1 , a car is parked in an open area and a user approaches the car with a key fob 102 . At this time, direct electronic communication is established via a transmission channel 110 between the ranging initiating device 102 (eg, the key fob) and the responding device 104 (eg, the UWB anchor of the car).

[0063] The device controller 130 is constructed and arranged to reduce the performance of the UWB transceiver 102, for example, to perform Figure 2 Method 200 is described.

[0064] Figure 3 A diagram 300 of such a LOS condition is shown. Here, two CIRs are measured at two different locations of the ranging initiating device 102 relative to the responding device 104 of the car. The strong peaks A, B of the measured CIRs 301, 302 correspond to the direct (LOS) path, i.e., almost no reflections occur. The leading edge 312 of the CIRs 301, 302 is the edge extending from the noise range 308, which is the signal region that appears after the first path 310 detected by the signal detector 124 of the responding device 104 and before the region of interest where the peaks A, B are located. The detected first path 310 is processed as a reference to generate a timestamp for calculating the distance between the UWB wireless transceivers 102, 104.

[0065] Reference again Figure 3 As shown in the graph 300, it is reiterated that, in addition to having different maximum peaks (A, B), the two CIRs 301, 302 have the same leading edge 312 or similar shape, which determines that the detected channel is the LOS channel required for optimizing power consumption according to an embodiment of the inventive concept. Specifically, the presence of the LOS channel allows subsequent ranging sequences between UWB transceivers to be performed by introducing more noise into the noise range of the measured CIR and / or processing less accurate or worse quality CIR estimates than signals generated according to a fixed configuration that produces optimal performance for the UWB wireless device. Therefore, despite the presence of additional noise or less accurate CIR estimates, power can still be reduced in ranging operations (e.g., subsequent distance measurements) when a LOS channel is detected.

[0066] Figure 2 is a flow chart illustrating a method 200 for optimizing power consumption of a UWB ranging device according to some embodiments. In describing the method 200, reference is made to Figure 1 Therefore, some or all steps of method 200 may be performed by Figure 1 The elements of the UWB communication system 10 are implemented.

[0067] In some embodiments, method 200 is initiated by a bootstrap process performed by an apparatus, i.e., initiating device 102, responding device 104, or other device participating in a UWB ranging operation. For purposes of describing method 200, reference is made to initiating device 102, although method 200 is equally applicable to responding device 104. For example, reference Figure 1, a boot routine may be stored in a memory of the initiator device 102, but is not limited thereto, so that a processor of the initiator device 102 may execute the stored routine, which may include, for example, a sequence of instructions to clear a cache of the device 102 and bring the device 102 into an operational state.

[0068] At block 202, the ranging initiating device 102 or the first UWB transceiver is preconfigured (e.g., preprogrammed by a software program) to full device performance in a manner that produces the best possible performance through the UWB device. For example, the initiating device 102 may be parameterized, for example, in accordance with the IEEE 802.15.4 standard, to allow the initiating device 102 and the responding device 104 to communicate. For example, communication may occur in channel 5 (approximately 6.5 GHz) with a bandwidth of 500 MHz and root raised cosine pulses. Device-level parameters may include, but are not limited to, analog-to-digital converter (ADC) sampling rate, power supply voltage, etc. Other parameters may include, but are not limited to, channel bandwidth, wavelength, frequency, pulses, and / or other parameters that affect power requirements and consumption and thus affect device 102 performance. Generally speaking, the best possible performance of the initiating device 102 requires greater power consumption, increases the load on the device battery, and shortens the battery life.

[0069] At block 204 , a ranging operation is performed, such as making distance measurements between the ranging initiating device 102 and the responding device 104 for positioning and location tracking applications, etc.

[0070] At decision block 206, the channel detection algorithm 128 determines the channel type included in the transmission channel according to the CIR, such as NLOS and / or LOS channels. LOS signal propagation has different characteristics from NLOS signal propagation, resulting in different ToA measurement results. Therefore, for UWB positioning tracking applications, it is very important to identify the channel type.

[0071] If the result at decision block 206 is that a LOS channel is detected, the method 200 proceeds to block 208 where the device controller 130 reduces the device performance for the next ranging sequence. This can reduce power consumption. Otherwise, if it is determined that the channel is not a LOS channel and / or if the current channel begins to deteriorate, the method 200 returns to block 202 where the ranging operation continues with full device performance.

[0072] Reference again Figure 3 As described above, the ToA timestamp may be determined based on the same leading edge of two measured CIRs of two different LOS channels or different locations of the first UWB wireless transceiver 102 relative to the second UWB wireless transceiver 104. Figure 4 As shown in the diagram 400 of the power optimization algorithm, the frontier 412 (with Figure 3 312 shown in FIG. 3 ) and used as an algorithm for power optimization according to some embodiments of the present inventive concept.

[0073] Figure 5 Shown for Figure 4 The power optimization algorithm in the graph 400 depicts a flow chart of a method 500 for performing ToA calculations. Therefore, when describing the method 500, reference is made to Figure 4 .

[0074] At block 502, a noise power measurement 430 is calculated based on the CIR estimates 401, 402 for the first LOS channel and the second LOS channel, respectively. In some embodiments, the initiating device 102 and the responding device 104 each perform a noise power calculation on their respective devices to subsequently determine a detection threshold as a basis for calculating a timestamp or ToA. Figure 4 As shown, noise power 430 is calculated based on CIR samples 401, 402 that are within the noise range 408 or the region before the useful portion of the CIR.

[0075] At block 504, a detection threshold 440 is calculated by multiplying the noise power 430 calculated at block 504 by a scaling factor. Thus, the detection threshold 440 may be referred to as a scaled noise power threshold.

[0076] At block 506, a threshold, or time, index, or minimum index at which the CIR 401, 402 exceeds the threshold 440 is determined. In some embodiments, one unit of the index corresponds to a sampling period of the ADC of the device, where the sampling period is 1 ns = 1 / (1 GHz). Figure 4 As shown, the first index exceeds the threshold (CIR index = 750) to provide a coarse resolution.

[0077] At block 508, a ToA timestamp is established. An interpolation step is performed between the coarse resolution determined in block 506 (e.g., 750) and the next smallest index unit (e.g., 749). Thus, a fractional index that crosses a threshold, such as 749.5, may be determined, thereby increasing the resolution.

[0078] Reference again Figure 4 As shown in the diagram 400, in some embodiments, the cross-correlation function 420 is calculated by matching the leading edges in the measured CIRs 401, 402 according to the IEEE 802.15.4a standard, specifically, using the following equation:

[0079]

[0080] Where p(t) is the transmit / receive pulse, r(t) is the standard reference pulse, and Er and Ep are the corresponding pulse energies. The reference pulse is a root raised cosine pulse defined by,

[0081]

[0082] Among them, T p is the pulse width and β is the attenuation factor. Based on the chip measurement in LOS, the transmit / receive pulse (envelope) is determined as

[0083] p(t)=A cos 2 (π / T t)-T / 2 <t<T / 2

[0084] Where T is the pulse width and A is the amplitude. From the figure, it can be seen that in the LOS channel, the leading edge has a predefined shape given by the cross-correlation function that can be used in the power optimization algorithm.

[0085] Reference again Figure 2-5 If the noise power 430 increases, the calculations performed in block 504 allow the scaling factor used to calculate the detection threshold to be reduced to achieve the same or similar detection threshold, thereby achieving the same ranging accuracy.

[0086] Similarly, since the leading edge in the LOS channels 401, 402 is determined by a known cross-correlation function, the function can be used in a TOA algorithm even with the added noise power 430.

[0087] In some embodiments, the additional noise is allowed so that the power consumption required by the RF analog circuits or electronic components of the UWB transceiver 102 (eg, phase-locked loop circuits, local oscillator drivers, anti-aliasing filters, etc.) can be reduced.

[0088] As described above, another method for reducing power is to deal with CIR estimates that are less accurate or worse than the quality of signals generated according to a fixed configuration that produces the best possible performance for the UWB wireless device. In some embodiments, the CIR is estimated based on the correlation results between the transmit / receive pulses on the preamble symbols and the reference pulses. Since the transmit / receive pulses may be drowned in the noise under harsh channel conditions, it is necessary to average multiple preamble symbols to improve the signal-to-noise ratio. However, in the LOS channel, the pulses are already strong relative to the noise, so the number of preamble symbols used for averaging can be reduced during operation to save power consumption. Similarly, the number of samples used for correlation used to establish the correlator length, etc. can also be reduced. In some embodiments, other methods for reducing the power of the UWB transceiver may include reducing the ADC sampling rate, the number of ADC bits, or related ADC features.

[0089] about Figure 2-5 The foregoing embodiments shown and described relate to power consumption at the device or computer chip level. However, other embodiments may accommodate system-level configurations, for example, where multiple UWB ranging devices are operating simultaneously (e.g., 3D localization of objects), system-level power optimization may also be performed.

[0090] refer to Figure 6 , the key fob 102 or related UWB device communicates with a plurality of UWB anchor devices 604A-C (collectively referred to as 604) located in various areas of the vehicle (such as the bumper, roof, dashboard, etc.). The UWB anchor device 604 can be controlled by a CPU 610, which can be located at the same location on the vehicle as the anchor device 604, or can be located at a different location and wirelessly communicate with the anchor device 604 and / or the key fob 102.

[0091] Figure 7 is a flow chart illustrating a method 700 for optimizing power consumption of a system including multiple UWB ranging devices according to some embodiments. In describing the method 700, reference may be made to Figure 6 For example, part or all of method 700 may be performed by one or more components such as Figure 6 A special processor such as the CPU 610 and / or an example Figure 1 and 6 The invention is executed by a device controller of a UWB ranging device such as the key fob 102 shown.

[0092] At block 702, an initiation strategy for ranging between the key fob 102 and one or more UWB anchor devices 604 is selected by the CPU 610. The initiation strategy may be implemented as an electronic configuration file stored in a computer memory and executed by a hardware processor of the UWB ranging device. The initiation strategy may be selected based on one or more predetermined parameters, including but not limited to: the number of UWB devices configured for fine ranging operation, the number of ranging measurements within a given time interval, a default device performance level such as configured to 100% performance. Here, the UWB ranging device, such as the anchor device 604 and / or the key fob 102, may operate at its limits (thus, 100% performance) within the design specifications: processing analog signals at the lowest noise contribution and least signal distortion and at the highest supply voltage, processing digital signals at the highest clock frequency using all available bits.

[0093] Examples of metrics to establish such performance limits may include, but are not limited to: clock / sampling frequency of the ADC, number of bits used for processing (eg, ADC bits or correlator bits), supply voltage to determine noise performance, and the like.

[0094] Reference Figure 6, whether the launch strategy can be configured as anchor 604 depends on whether the key fob 102 is within a predetermined range from the car, such as the Thatcham area, ie 2m from the car.

[0095] At block 704 , a first ranging sequence is performed using at least two ranging devices according to the initiation strategy at block 702 .

[0096] At block 706, after performing the first ranging sequence, the corresponding CIR is estimated, and at block 708, a set of channel quality indicators (CQIs) are calculated. In some embodiments, both the key fob 102 and the car anchor 604 perform the CQI calculations. In some embodiments, the car anchor 604 performs this calculation. In some embodiments, the CPU 610 performs this calculation. For example, Figure 6 As shown, CIR1 to CIR2 are calculated for data exchange between the key fob 102 and the UWB anchor points 604A-C, respectively. N In some embodiments, the CQI is calculated to determine the magnitude of the peak in the CIR and the difference between the peak and the index of the detected first path. On the other hand, a lower CQI value generally indicates a poor channel. For example, Figure 3 As shown, the LOS channel is identified as having a high peak value and a small exponential difference.

[0097] Thus, in decision block 710, the calculated CQI value indicative of the channel condition may be compared to a test condition. The threshold may be application specific. The test condition may be any of the examples provided herein. Other test conditions may include a threshold at the measured leading edge (e.g., Figure 4 412, 413) and the desired leading edge (e.g. corresponding to Figure 4 The maximum difference in the range of index values ​​between the correlation function curve 420 in FIG. 4 is lower than a certain value. For example, Figure 3 The LOS peak value A shown can be used as a threshold. Figure 3 The peak A in the figure is smaller than the peak A in the figure. Figure 3 The indicated index is compared to a larger index, and / or produces an indicative ratio curve Figure 3300, the method 700 proceeds to block 712, where the initiation policy in block 702 is applied to reduce the device performance of at least two devices participating in the first ranging sequence of step 704. Here, the CPU 610 selects a policy or modifies the current policy for a subsequent ranging sequence (e.g., a second ranging sequence after the first ranging sequence in block 704) with the goal of optimizing the power of the key fob 102 or other UWB ranging initiating device and / or the associated anchor point 604 participating in the data exchange during the first ranging sequence. For example, the policy may be applied to reduce the number of measurements, to configure or reconfigure to include a smaller number of UWB anchors 604 in a subsequent ranging sequence, to reduce the device performance of the active anchor, and / or to reduce the demand for battery power or other power. Therefore, the method 700 returns to block 704, where one or more subsequent ranging sequences are performed with a new policy or an adapted policy corresponding to the reduced performance level.

[0098] In contrast, if at decision block 710, the calculated CQI value does not satisfy or meets the test condition, or is less than the threshold, the method 700 proceeds to block 714, where the performance of at least two devices participating in the first ranging sequence is improved, and the method 700 returns to block 704, where one or more subsequent ranging sequences are performed with a new strategy or an adapted strategy corresponding to the improved performance level.

[0099] It should be understood that the disclosed embodiments include at least the following. In one embodiment, an ultra-wideband (UWB) wireless communication system includes: a first wireless device; a second wireless device, the second wireless device participating in a first ranging sequence with the first wireless device; and a transmission channel, the transmission channel is located between the first and second wireless devices, and is used to transmit data of the first ranging sequence, at least one of the first wireless device or the second wireless device generates at least one channel impulse response (CIR), and determines whether the transmission channel includes a line-of-sight channel based on the at least one CIR; and a dedicated processor, in response to determining that the transmission channel includes the line-of-sight channel, the dedicated processor reduces a current performance level of at least one of the first and second wireless devices during a second ranging sequence.

[0100] An alternative embodiment of the UWB wireless communication system includes one or any combination of the following features. The first wireless device is a UWB ranging initiating device of a key fob, and the second wireless device is a UWB responding device of an antenna anchor. The dedicated processor includes a channel detection processor that establishes a leading edge of the at least one CIR measured at the location of the second wireless device. The line-of-sight channel is identified by matching the leading edge of the at least one CIR with a cross-correlation function calculated according to the IEEE 802.15.4a standard. The dedicated processor reduces the current performance level of the first wireless device in the second ranging sequence by reducing the quality of the estimate of the at least one CIR, the power supply voltage, the number of preamble symbols used to establish the correlation result, the analog-to-digital converter (ADC) sampling rate, the number of ADC bits, or a combination thereof. Each of the first and second wireless devices processes the UWB signal provided by the transmission channel to calculate the time of arrival (TOA) of the signal, which is in turn used by the first wireless device to determine the flight time and range between the first and second wireless devices. The first and second wireless devices determine one of: determining a noise power level of the at least one CIR within a noise range, determining a detection threshold based on the noise power level, and determining the TOA based on an index by which the at least one CIR exceeds the detection threshold. The first wireless device includes one or more analog circuits, an oscillator driver, and a filter, and wherein in response to determining that the transmission channel includes the line-of-sight channel, the dedicated processor reduces the current performance level of the one or more analog circuits, oscillator driver, and filter during the second ranging sequence. A channel quality indicator is determined based on the at least one CIR, wherein the line-of-sight channel is determined based on the channel quality indicator.

[0101] In another embodiment, an ultra-wideband (UWB) wireless transceiver includes a transceiver circuit and an associated antenna, wherein the transceiver circuit system and the associated antenna detect and quantize UWB signals; a ranging processor, which generates at least one channel impulse response (CIR) based on the UWB signal; a signal detector, which determines an estimated time of arrival (TOA) based on the CIR; a channel detection algorithm processor, which determines a line-of-sight channel between the UWB wireless transceiver and another UWB wireless transceiver based on the CIR; and a device controller, which, in response to determining that the transmission channel includes the line-of-sight channel, reduces a current performance level of at least one of the UWB wireless transceivers.

[0102] An alternative embodiment of the ultra-wideband (UWB) wireless transceiver includes one or any combination of the following features. The first wireless device is a UWB ranging initiating device of a key fob. The transceiver also includes a channel detection processor that establishes a leading edge of the at least one CIR measured at the location of the second wireless device. The line-of-sight channel is identified by matching the leading edge of the at least one CIR with a cross-correlation function calculated according to the IEEE 802.15.4a standard. The dedicated processor reduces the current performance level of the first wireless device in the second ranging sequence by reducing the quality of the estimate of the at least one CIR, the power supply voltage, the number of preamble symbols used to establish the correlation result, the analog-to-digital converter (ADC) sampling rate, the number of ADC bits, or a combination thereof. The UWB wireless transceiver also includes one or more analog circuits, an oscillator driver, and a filter, and in response to determining that the transmission channel includes the line-of-sight channel, the device controller reduces the current performance level of the one or more analog circuits, the oscillator driver, and the filter during the second ranging sequence.

[0103] In another embodiment, a method for controlling power consumption of an ultra-wideband (UWB) device includes outputting a first electronic message from a first wireless device to a second wireless device; storing a first timestamp for transmitting the first electronic message at the first wireless device; determining a first channel impulse response (CIR) and an arrival time of the first electronic message at the second wireless device; storing a second timestamp for transmitting the first electronic message corresponding to the arrival time of the first electronic message at the second wireless device; outputting a second electronic message from the second wireless device to the first wireless device, the second electronic message including the second timestamp and a third timestamp for transmitting the second electronic message; determining a second channel impulse response (CIR) and an arrival time of the second electronic message at the first wireless device; detecting whether a line-of-sight channel exists between the first and second devices based on the CIR of the second electronic message; and in response to detecting the line-of-sight channel, reducing a current performance level of the first wireless device during a subsequent ranging sequence.

[0104] Alternative embodiments of the method include one or any combination of the following features. The method further includes determining a fourth timestamp corresponding to a time of arrival of the second electronic message; and determining a time of flight and a range between the first and second wireless devices based on the first, second, third, and fourth timestamps. The line-of-sight channel is identified by establishing a leading edge of the second CIR and matching the leading edge of the second CIR with a cross-correlation function.

[0105] Although the present invention is described herein with reference to specific embodiments, various modifications and changes may be made without departing from the scope of the present invention as set forth in the appended claims. Therefore, the description and drawings should be regarded as illustrative rather than restrictive, and all such modifications are intended to be included within the scope of the present invention. Any benefits, advantages, or solutions to problems described herein with respect to specific embodiments should not be construed as key, required, or essential features or elements of any or all claims.

[0106] Unless otherwise stated, terms such as "first," "second," and the like are used to arbitrarily distinguish between the elements such terms describe. Therefore, these terms are not necessarily intended to indicate temporal priority or other priority of such elements.

Claims

1. An ultra-wideband (UWB) wireless communication system, characterized in that: include: a first wireless device; a second wireless device, the second wireless device participating in a first ranging sequence with the first wireless device; as well as a transmission channel located between the first and second wireless devices and used to transmit data of the first ranging sequence, wherein at least one of the first wireless device or the second wireless device generates at least one channel impulse response (CIR), and determines whether the transmission channel includes a line-of-sight channel according to the at least one CIR; as well as a dedicated processor that, in response to determining that the transmission channel includes the line-of-sight channel, reduces a current performance level in the first wireless device during a second ranging sequence by reducing a quality of an estimate of the at least one CIR, a power supply voltage, a number of preamble symbols used to establish a correlation result, an analog-to-digital converter (ADC) sampling rate, a number of ADC bits, or a combination thereof.

2. The UWB wireless communication system according to claim 1, characterized in that: The first wireless device is a UWB ranging initiating device of a key fob, and the second wireless device is a UWB responding device of an antenna anchor.

3. The UWB wireless communication system according to claim 1, characterized in that: The dedicated processor includes a channel detection processor that establishes a leading edge of the at least one CIR measured at the location of the second wireless device.

4. The UWB wireless communication system according to claim 3, characterized in that: The line-of-sight channel is identified by matching the leading edge of the at least one CIR with a cross-correlation function calculated according to the IEEE 802.15.4a standard.

5. The UWB wireless communication system according to claim 1, characterized in that: Each of the first and second wireless devices processes the UWB signal provided by the transmission channel to calculate a time of arrival (TOA) of the signal, which is in turn used by the first wireless device to determine a time of flight and range between the first and second wireless devices.

6. The UWB wireless communication system according to claim 5, characterized in that The first and second wireless devices determine one of: determining a noise power level of the at least one CIR within a noise range, determining a detection threshold based on the noise power level, and determining the TOA based on an index by which the at least one CIR exceeds the detection threshold.

7. The UWB wireless communication system according to claim 6, characterized in that: The first wireless device comprises one or more analog circuits, oscillator drivers, and filters, and wherein in response to determining that the transmission channel comprises the line-of-sight channel, the dedicated processor reduces the current performance level of the one or more analog circuits, oscillator drivers, and filters during the second ranging sequence.

8. An ultra-wideband (UWB) wireless transceiver, characterized in that: include: transceiver circuitry and associated antennas that detect and quantize UWB signals; a ranging processor that generates at least one channel impulse response (CIR) based on the UWB signal; a signal detector that determines an estimated time of arrival (TOA) based on the CIR; a channel detection algorithm processor, the channel detection algorithm processor determining a line-of-sight channel between the UWB wireless transceiver and another UWB wireless transceiver based on the CIR; as well as a device controller that, in response to determining that the transmission channel includes the line-of-sight channel, reduces a current performance level in the UWB wireless transceiver in a second ranging sequence by reducing a quality of an estimate of the at least one CIR, a power supply voltage, a number of preamble symbols used to establish a correlation result, an analog-to-digital converter (ADC) sampling rate, a number of ADC bits, or a combination thereof.

9. A method for controlling power consumption of an ultra-wideband (UWB) device, characterized in that: include: outputting a first electronic message from the first wireless device to the second wireless device; storing, at the first wireless device, a first timestamp of transmitting the first electronic message; determining, at the second wireless device, a first channel impulse response (CIR) and a time of arrival of the first electronic message; storing, at the second wireless device, a second timestamp of transmitting the first electronic message corresponding to the arrival time of the first electronic message; outputting, from the second wireless device to the first wireless device, a second electronic message including the second timestamp and a third timestamp of transmitting the second electronic message; determining, at the first wireless device, a second channel impulse response (CIR) and a time of arrival of the second electronic message; detecting whether there is a line-of-sight channel between the first and second wireless devices based on the CIR of the second electronic message; as well as In response to detecting the line-of-sight channel, reducing the current performance level of the first wireless device during a subsequent ranging sequence by reducing the quality of the estimate of the at least one CIR, the power supply voltage, the number of preamble symbols used to establish a correlation result, the analog-to-digital converter (ADC) sampling rate, the number of ADC bits, or a combination thereof.

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