Wireless communication and sensing

Abstract

According to a first aspect, there is provided a radio device (R1) configured for wireless communication and bistatic or multistatic radar sensing, comprising a transceiver, a memory, and a processor coupled to the transceiver and the memory. The transceiver and the processor are configured to, after transmission over the wireless channel (102), obtain, via the transceiver, a baseband receive signal comprising an encoded message and a plurality of reference signals from a second radio device (R2). The transceiver and the processor are configured to calculate channel state information using a plurality of reference signals included in the baseband receive signal. The transceiver and the processor are configured to calculate an estimate of a transmitted signal originally transmitted by the second radio device using the channel state information and the received signal. The transceiver and the processor are configured to perform at least demodulation and channel decoding on the estimate of the transmitted signal, thereby obtaining an estimate of the message transmitted by the second radio device. The transceiver and the processor are configured to generate a reconstruction of the transmitted signal by performing baseband signal processing and reference signal insertion on the estimated message, wherein the baseband signal processing and reference signal insertion correspond to the baseband signal processing and reference signal insertion performed by the second radio device. The transceiver and the processor are configured to generate sensed channel data by combining the reconstructed and received signals of the transmitted signal.

Description

Technical Field

[0001] This application relates to radio equipment, associated methods, systems, and computer program products configured for wireless communication and bistatic or multistatic radar sensing. Background Technology

[0002] Bistatic channel sensing refers to a method of sensing a channel matrix from a remote location at a first radio device when a second radio device transmits a signal. For example, the first radio device can detect line-of-sight signals and multiple reflections caused by scatterers present in the physical radio environment. Multistatic channel sensing extends this method by providing multiple radio devices to sense when a second radio device has transmitted a signal. Through signal processing, the channel matrix defining the physical radio environment can be reconstructed. The channel matrix can be processed to enable, for example, at least the first radio device to locate one or more scatterers, objects, or other radio devices in the physical environment. The first radio device can, for example, use a channel matrix composed of bistatic or multistatic components to obtain position, velocity, acceleration, spatial envelope, and other attributes. Integrating communication and sensing advances bistatic and multistatic channel sensing by constructing a channel matrix used for bistatic or multistatic channel sensing using communication waveforms designed for general wireless communication standards used for data transfer. This allows data communication and physical channel sensing to coexist. However, such techniques can be further improved. Summary of the Invention

[0003] According to a first aspect, a first wireless device configured for wireless communication and bistatic or multistatic radar sensing is provided, comprising a transceiver, a memory, and a processor coupled to the transceiver and the memory. The transceiver and processor are configured to, after transmission over a wireless channel, obtain via the transceiver a baseband received signal comprising an coded message and a plurality of reference signals from a second wireless device. The transceiver and processor are configured to calculate channel state information using the plurality of reference signals included in the baseband received signal. The transceiver and processor are configured to calculate an estimate of a transmitted signal originally transmitted by the second wireless device using the channel state information and the received signal. The transceiver and processor are configured to perform at least demodulation and channel decoding on the estimate of the transmitted signal to obtain an estimate of the message transmitted by the second wireless device. The transceiver and processor are configured to generate a reconstruction of the transmitted signal by performing baseband signal processing and reference signal insertion on the estimated message, wherein the baseband signal processing and reference signal insertion correspond to baseband signal processing and reference signal insertion performed by the second wireless device. The transceiver and processor are configured to generate sensing channel data by combining the reconstructed transmitted signal with the received signal.

[0004] One effect is that reference signals (sometimes referred to as pilot symbols) can be used to facilitate channel sensing in integrated radio communication and sensing schemes. Therefore, sensing in integrated radio communication and sensing schemes can be performed without prior knowledge of the transmitted data. In some embodiments, the payload used for channel estimation (a portion of the channel resources used for the reference signal) can be reduced. In some cases, a radio device that is not the intended receiver of the transmitted message can still perform channel sensing using the signal carrying the transmitted message by decoding the message intended for the intended receiver and then performing signal processing to achieve channel sensing. In some cases, a radio device that is not the intended receiver of the transmitted message may be unable to decode (for the purpose of channel sensing) the message intended for the intended receiver. In this case, the radio device that is not the intended receiver of the transmitted message can signal to the original radio device responsible for transmitting the message to the intended receiver to request a retransmission. According to embodiments, sensing based on communication signals already established between the radio devices becomes feasible. Therefore, the sensing to occur can be achieved without modifying the transmitter. Integrated sensing at bistatic or multistatic radio devices can be achieved using widely available communication signals. Furthermore, according to the techniques described herein, bistatic or multistatic radio devices can be able to estimate the channel state more accurately. In this case, the density or structure of the reference signal (pilot symbol) can be simplified or compressed to allow more data to be transmitted. Therefore, the proposed method generally improves the quality of bistatic or multistatic sensing given the resources already present in the communication protocol used for CSI estimation. By applying feedback from the bistatic or multistatic radio to the transmitter, the bistatic or multistatic receiver can set the resources available for sensing (CSI estimation) with respect to the dynamic conditions of the channel or the number of objects, reflectors, or scatterers in the physical channel.

[0005] According to a second aspect, a computer-implemented method for wireless communication and bistatic or multistatic radar sensing is provided, comprising: After transmission through the wireless channel, a baseband received signal, including coded messages and multiple reference signals, is obtained from the second wireless device; Using channel state information and received signals, calculate an estimate of the transmitted signal originally transmitted by the second wireless device; The estimated signal is obtained using channel state information and the received signal; The estimation of the transmitted signal involves at least demodulation and channel decoding to obtain an estimate of the message transmitted by the second radio device; By estimating the message, baseband signal processing and reference signal insertion are performed to generate a reconstructed transmitted signal, wherein the baseband signal processing and reference signal insertion correspond to the baseband signal processing and reference signal insertion performed by the second radio device; and Sensing channel data is generated by combining the reconstructed transmitted signal and the received signal.

[0006] According to a third aspect, a fourth wireless device configured for wireless communication and bistatic or multistatic radar sensing is provided, comprising a transceiver, a memory, and a processor coupled to the transceiver and the memory. The transceiver and processor are configured to: receive a negative acknowledgment from a first wireless device via the transceiver, the negative acknowledgment indicating that radar sensing at the first wireless device using coded messages received by the first wireless device is impossible; calculate an updated reference signal scheme; and transmit additional signals to the first wireless device, the additional signals including additional coded messages and additional plurality of reference signals. The additional plurality of reference signals are defined according to the updated reference signal scheme.

[0007] According to a fourth aspect, a wireless communication system is provided, comprising: a first wireless device configured for wireless communication and bistatic or multistatic radar sensing according to one of the first aspects or embodiments thereof; and a second wireless device configured to transmit a signal to the first wireless device, wherein the signal includes an coded message and a plurality of reference signals.

[0008] According to the fifth aspect, a computer program product including machine-readable instructions is provided, which, when executed by a processor, cause the processor to perform the method according to the second aspect.

[0009] In addition, a machine-readable storage medium is provided on which a computer program product according to the fifth aspect is stored. Attached Figure Description

[0010] Exemplary embodiments are depicted in the figures, and these embodiments should not be construed as limiting the claims, and will be explained in more detail below. Where possible, similar reference numerals in different figures denote similar or analogous features.

[0011] Figure 1 A schematic diagram illustrates a system of wireless devices located in a physical environment.

[0012] Figure 2 The first wireless device is schematically illustrated.

[0013] Figure 3 The second wireless device is schematically illustrated.

[0014] Figure 4An example of a combined communication and sensing signal chain is illustrated schematically.

[0015] Figure 5 An OFDM resource block with a first reference signal mode is schematically illustrated.

[0016] Figure 6 An OFDM resource block with a second reference signal mode is schematically illustrated.

[0017] Figure 7 The diagram schematically illustrates the signaling between a first radio device and a second radio device for determining a failed sensing attempt.

[0018] Figure 8 The method according to the second aspect is illustrated schematically. Detailed Implementation

[0019] Figure 1 A schematic diagram illustrates a system of wireless devices located in a physical environment.

[0020] The physical environment 102 at a given time step includes, for example, a simple urban scenario, comprising urban residences 104, 106 and trees and vegetation 103, 108, 110, 112. In this scenario, a vehicle at location A, including a first radio device R1, is traveling toward location B. For example, a second radio device R2 is included in a base station. The second radio device R2 is communicatively coupled to a network controller N, which, in this example, may host a location tracking service. A third radio device R3 and a fourth radio device R4 are also included in a roadside unit, designed, for example, to transmit CAM messages to vehicles in physical environment 102.

[0021] In this context, sensing of the physical environment 102 can be provided to address a range of sensing use cases. A first radio device R1 inside the vehicle can detect spatial information regarding the range, location, and speed of other vehicles or obstacles on the road surrounding the vehicle, including the first radio device R1. This information can be used by the vehicle for purposes such as cruise control, parking guidance, or collision avoidance. Static radio devices, such as a third radio device R3 and a fourth radio device R4, can detect spatial information regarding traffic density or line-of-sight signal obstructions to other radio devices in the physical environment 102.

[0022] For example, in the case of bistatic sensing, a second radio device R2 transmits a communication signal to one of the other radio devices in the physical environment 102. A first radio device R1 performs signal processing to achieve bistatic sensing on the signal transmitted from R2, so as to sense one aspect of the physical environment 102 using the signal transmitted from R2. This can be extended to the case of multistatic sensing, where a third radio device R3 and a fourth radio device R4 perform signal processing to achieve multistatic sensing on the signal transmitted from R2. In this example, the first radio device R1, the third radio device R3, and the fourth radio device R4 are configured to obtain multistatic sensing signals from the corresponding other radio devices, so that each radio device can form a more comprehensive representation of the physical environment 102. In another example, each radio device R1, R3, R4 transmits data representing individual bistatic or multistatic sensing results to the network controller N via radio device R2. A location sensing service communicatively coupled to the network controller N can, for example, verify the individual bistatic or multistatic sensing results from radio devices R1, R3, R4. After verification (e.g., via sensor fusion), the location sensing service then provides a representation of the physical environment 102 to the user application layer of the software in the radios and / or vehicles present in the physical environment 102. This advantageously enables the location sensing service to construct a more comprehensive representation of the physical environment 102 than might be constructed using bistatic sensing results from only one radio.

[0023] Generally, for multistatic sensing to be performed, the communication signal generated by the transmitter should be known at the receiver side. This specification proposes using reference signals transmitted through various communication standards to facilitate bistatic or multistatic sensing.

[0024] The state of the physical environment 102 involves parameters that affect the radio channel quality factor in the environmental area where at least the first radio device R1 and the second radio device R2 are operating. The term "physical environment" can refer to a 3D function defining the presence of radio frequency blocking or reflecting materials. In an urban environment, the physical environment may be affected by: the deployment of buildings in the environment, their height, shape, density, and construction materials, their relationship to street boundaries, and the overall deployment of buildings or other RF signal reflectors (e.g., the presence of urban canyons). The response of RF signals to the physical environment may be affected by the presence and shape of trees and shrubs, and especially water bodies. The physical environment may be affected by weather, such as rainfall and the presence of water layers on buildings, which may result in propagation characteristics different from those experienced on a sunny day. The physical environment can be defined by the overall traffic density, and therefore by the time of day in which a sample of the physical environment is obtained. Furthermore, the presence of individual vehicles with difficult-to-handle or congestive shapes near the first and second radio devices may affect the physical environment. Those skilled in the art will appreciate that many other parameters and factors of the physical environment are of general significance in influencing the radio channel quality factor between radio devices. The definition of the "physical environment" by a 3D function is not important. For example, a 2D image of a road intersection can allow for geometric analysis or other inferences about whether radio communication between two wireless devices will be affected by obstructions.

[0025] Figure 2 The first wireless device R1 is schematically illustrated.

[0026] Figure 3 The second wireless device R2 is schematically illustrated.

[0027] According to the first aspect, a first radio device R1 configured for wireless communication and bistatic or multistatic radar sensing is provided, including a transceiver 14, a memory 12, and a processor 10 coupled to the transceiver 14 and the memory 12.

[0028] The transceiver and processor are configured to obtain, via transceiver 14, a baseband received signal Y comprising an coded message X and a plurality of reference signals P from the second radio device R2 after transmission through wireless channel 102. That is, the baseband received signal Y transmitted through wireless channel 102 is obtained by the transceiver and processor. The processor is configured to calculate channel state information using the plurality of reference signals included in the baseband received signal. The processor is configured to calculate an estimate of the transmitted signal originally transmitted by the second radio device R2 using the channel state information and the baseband received signal. The processor is configured to perform at least demodulation and channel decoding on the estimate of the transmitted signal to obtain an estimate of the message W' transmitted by the second radio device R2. The processor is configured to generate a reconstruction of the transmitted signal by performing baseband signal processing and reference signal insertion on the estimated message W'. The baseband signal processing and reference signal insertion correspond to the baseband signal processing and reference signal insertion performed by the second radio device R2. The processor is configured to generate sensed channel data H by combining the reconstructed transmitted signal and the received signal.

[0029] Those skilled in the art will appreciate that the first radio device R1 is described using exemplary terminology, and that many types of devices may include the first radio device R1. For example, transceiver 14 may be configured to communicate using one or any combination of C-V2X and NR-V2X for autonomous driving.

[0030] According to one example, transceiver 14 is configured to communicate in transmission modes including direct V2X, encompassing V2V, V2I, and V2P in the ITS 5.9 GHz spectrum. According to another example, transceiver 14 modes include mobile broadband systems and technologies such as fourth-generation wireless mobile communication technology (4G), such as LTE, LTE Advanced Systems, and Mobile WiMAX. According to yet another example, transceiver 14 modes include fifth-generation wireless mobile communication technology (5G), such as 5G NR. Transceiver 14 can, for example, coordinate radio communications from one or more radio systems operating at different frequencies, such as cellular frequencies (approximately 900 MHz), Wi-Fi frequencies (approximately 2.4 or 5 GHz), or millimeter-wave frequencies (such as 57-64 GHz).

[0031] In this specification, references to the “transmitting” radio device R2 and the “receiving” radio device R1 do not preclude the possibility that these particular radio devices cannot participate in full-duplex or half-duplex communication. The references to the “transmitting” and “receiving” radio devices conveniently illustrate the signal flow of the algorithms discussed in this application; however, the skilled reader will appreciate that the transceivers of the radio devices operate as full-duplex or half-duplex transceivers.

[0032] In some embodiments, at least one of the radio devices R1-R4 is a base station, such as a NodeB, eNB, access point (AP), new radio base station (NR BS), 5G NodeB (NB), or next-generation NodeB (gNB). In some embodiments, at least one of the radio devices R1-R4 is a user equipment (UE). In some examples, the UE is integrated into one or more non-autonomous, autonomous, or semi-autonomous vehicles, such as cars, buses, airplanes, bicycles, drones, ships, trams, trains, etc.

[0033] According to the example, processor 10 is a single processor or a chipset including multiple integrated circuits for performing the tasks of radio device R1. As some examples, processor 10 may include one or any combination of an application processor, digital signal processor (DSP), coprocessor, central processing unit (CPU). According to the example, memory 12 may include a non-transitory computer-readable medium for electronically storing data, such as EEPROM, RAM, or other electronically readable storage media.

[0034] Therefore, radio device R1 (and the other radio devices R2-R4 discussed herein) can utilize orthogonal frequency division multiplexing (OFDM) with a cyclic prefix (CP) on the uplink (UL) and downlink (DL). In one example, radio device R1 uses half-duplex operation, using time division duplex (TDD). Figure 3 The radio device R2 shown in the figure may have a similar or identical design to the radio device R1, and therefore a further description of the second radio device R2 will not be repeated here.

[0035] According to the example, the encoded message X and multiple reference signals P are transmitted in a Radio Resource Control (RRC) message, a Medium Access Control-Control Element (MAC-CE), a Downlink Control Message (DCI), or a Side Link Control Message (SCI). In some examples, the encoded message X and multiple reference signals P are transmitted on one of the Physical Side Link Shared Channel (PSSCH), Physical Downlink Control Channel (PDCCH), Physical Downlink Shared Channel (PDSCH), or Physical Side Link Control Channel (PSCCH).

[0036] Figure 4 An example of a combined communication and sensing signal chain is illustrated schematically. Those skilled in the art will understand that physical components such as RF signal filtering, up-conversion and down-conversion, and amplification are conventionally omitted.

[0037] In previous multi-base sensing methods, the receiver (in this case, radio device R1) needs knowledge about the data transmitted by the transmitter (in this case, radio device R2). If This indicates the symbol emitted from R2, and The symbol received at R1 is indicated, where It involves element-wise matrix multiplication. In a generalized sense, multibase sensing is the estimation of the sensing channel. In existing methods, when attempting to estimate at R1... At that time, radio device R1 had requested the original transmitted symbol from R2. In this scheme, radar sensing at radio device R1 is possible without the need for the original transmitted symbols from radio device R2. Prior knowledge.

[0038] In short, the receiving radio device R1 receives... A reference signal (sometimes called a pilot symbol) is used to estimate the channel state information (CSI). After estimating the CSI, the receiving radio device R1 decodes the transmitted message to obtain... Decoding the sent message to obtain... Afterwards, the receiving radio device R1 is able to reconfigure In other words, the receiving radio device R1 can be based on the original message. To reconstruct the baseband signal, just as it appeared at the transmitting radio R1 before the application of the inverse Fourier transform (IFFFT), without the original message. The knowledge. Then, the receiving radio device R1 uses Reconstruction to improve channel The estimate.

[0039] Therefore, it is recommended to use two types of CSI (Channel State Information) to provide a combined communication and sensing scheme. The first CSI is used to decode (equalize) the baseband received at the receiving radio device R1. Signal. When calculating the channel During estimation, a second CSI is applied. This is done when calculating the channel. The second CSI applied during estimation improves the accuracy of channel sensing.

[0040] This provides the operation of the channel sensing process for a general OFDM system. Technicians will understand that the transmitting radio device R2 can generate OFDM resource blocks according to many different formats specified in applicable standards.

[0041] Go to Figure 4 Baseband messages are obtained from higher layers of the protocol stack of the transmitting radio device (R2 in this example). The baseband channel encoder 42 will transmit the baseband message. This is converted into a channel-coded message as defined by the applicable communication standard. For example, the baseband channel encoder 42 can use a dictionary of size 2*N*R (where N is the number of bits in the baseband message and R is the code rate) to convert the baseband message into a channel-coded message. The code is encoded into codeword SN. The coding rate R for this channel is selected such that reliable communication between transmitting radio device R2 and receiving radio device R1 is possible. Reliable communication is achieved by decoding the original baseband message at receiving radio device R1 with an arbitrarily small bit error rate. The ability.

[0042] Baseband mapper 43 obtains baseband messages The channel-coded version. The channel-coded version of the baseband message is obtained using a mapping function. This is used for mapping. For example, the output of baseband mapper 43 is a vector containing a channel-coded version of the baseband message with multiple elements, where each element is an IQ vector or a complex number representing the amplitude and phase of the corresponding symbol. Baseband mapper 43 can map the baseband message according to relevant standards. The channel coding version is mapped to one of OOK, BPSK, QPSK, QAM 16, QAM64 or many other constellations.

[0043] Reference signal generator 44 obtains the symbol vector from baseband mapper 43 and adds the reference signal P (sometimes called pilot symbol) to the symbol vector. The reference signal is applied in a sequence defined by the reference signal scheme defined in the applicable standard. The technical reader will appreciate that the absolute values ​​of the reference signals, as well as their positions and densities in the time-frequency grid of the corresponding resource block, are generally variable and designed to adapt to channel conditions. The baseband signal includes its reference signal R1. Therefore, it can be used by receiving radio device R1 to receive baseband signals present at receiving radio device R1. Channel estimation and correction.

[0044] The baseband IFFT generator 45 is configured to apply the IFFT (Inverse Fast Fourier Transform) to the baseband signal. Thus, the baseband signal The frequency domain complex vector is transformed into a time domain signal. The baseband IFFT generator 45 also generates a cyclic prefix. For example, the cyclic prefix can be a copy of multiple time-domain samples of the IFFT(X) signal, wherein the number of time-domain samples is selected to minimize the impact of delay spread on the OFDM modulation scheme, and the size of the cyclic prefix is ​​typically specified in the relevant standard documents.

[0045] After the baseband IFFT generator 45 generates a time-domain signal, it undergoes up-conversion, filtering, and amplification operations, and the resulting radio frequency (RF) signal is transmitted via an antenna on channel H 46. Channel H 46 is a function of the physical environment 102 and exerts reflection, attenuation, and refraction effects on the RF signal during a process known as multipath fading. The presence of moving scatterers in the physical environment 102 further imposes Doppler effects on the RF signal. These are referred to as channel effects. The receiving radio device R2 includes an RF front-end configured to amplify, down-convert, and filter the RF signal received via channel H 46.

[0046] The baseband FFT generator 47 is configured to remove the cyclic prefix and perform an FFT (Fast Fourier Transform) to produce the received baseband signal. The frequency domain representation. In other words, based on the OFDM waveform, the receiving radio device R1 receives in the frequency domain. .

[0047] Based on OFDM waveforms, messages (data) and included reference signals (pilot symbols) can be represented as matrices. ,in , These represent the number of sub-channels and the number of OFDM symbols, respectively.

[0048] .

[0049] After passing through the channel After transmission, the reference signal (pilot symbol) contains channel effects, which need to be estimated by the receiving radio device R2 and then removed from the baseband signal received at the receiving radio device R2. For example, the reference signal includes a representation of the true channel behavior between the transmitting radio device R2 and the receiving radio device R1, assuming that the channel behavior is not abrupt between transmissions of the reference signal in a given resource block.

[0050] The estimated channel obtained from the channel estimation enables 2D interpolation of the frequencies and times of other subcarriers in the resource block received at the receiving radio device R1. Therefore, the channel behavior of all subcarriers and resource blocks can be obtained.

[0051] The channel estimator and correction process 48 are configured to perform correction or equalization using a reference signal obtained at the receiving radio device R1. The equalization or interpolation process using the received reference signal enables the baseband frequency symbols received at the receiving radio device R1 to compensate for or equalize most or all channel degradation. Therefore, by applying and interpolating the reference signal to the received baseband signal... The receiving radio device R1 estimates the Channel State Information (CSI) in the corresponding subcarrier of the OFDM block in the frequency domain. For example, the corresponding OFDM subcarriers can be divided by interpolation from the reference signal (pilot symbol).

[0052] After equalization (correction using channel state information), the received baseband signal is processed using demapper 49. Demapping is performed. Equalization is sufficient to allow the communication data to be decoded by channel decoder 50 (estimated codeword SN). Therefore, receiving radio device R1 can reliably reconstruct the data. Original message transmitted by transmitting radio device R2 .

[0053] This concludes the description of encoding, modulation, transmission, reception, demodulation, and decoding of communication data in an OFDM system. However, via the channel... The baseband signal transmitted and received at the receiving radio device R1 can also be used for bistatic or multistatic radar sensing. Advantageously, this means that the same channel resources reserved for communication can also be used for sensing the physical environment 102, and that no special measures are required or fewer are needed to achieve the coexistence of communication and channel sensing.

[0054] By estimating the message The baseband reconfigurator 51, fed to the receiving radio device 51, performs sensing at the receiving radio device R1. The purpose of the baseband reconfigurator 51 is to model the frequency domain baseband signal at the transmitting radio device R2 (before performing IFFT at the transmitting radio device R2). Therefore, the purpose of the baseband reconfigurator 51 is to regenerate the frequency domain vector. .

[0055] In order to reliably model the frequency domain baseband signal at the transmitting radio equipment, the estimated message Need to include the original message When a resource block is transmitted, the same reference signal transmitted within that resource block is combined. In some embodiments, the reference signal concatenated with the encoded original message in the reference signal generator 44 of the transmitting radio device R2 is defined by a reference signal scheme existing in telecommunications standards. For example, document 3GPP TS 36.211 V17.3.0 (2023-03) defines the reference signal sequence for the 5G standard.

[0056] In one embodiment, the baseband reconfigurator 51 included in the receiving radio device R1 includes a reference signal sequence tracker configured to follow or mimic the state of the reference signal generation process of the transmitting radio device R2. This ensures that during the sensing process, the correct reference signal and the estimated message from the baseband reconfigurator 51 are obtained. Cascaded.

[0057] In another embodiment, the reference signaling scheme can be designed, modified, negotiated, or changed during operation to adapt to channel conditions. In this case, the baseband reconfigurator 51 is configured to monitor the control channel of a protocol, such as a PUCCH or PDCCH channel, for example, to track reference signaling schemes that have been designed, modified, negotiated, or changed during operation among one or more radios present in the network. When the reference signaling scheme changes during operation, the baseband reconfigurator 51 maintains a stateful record of the reference signaling scheme, such that estimation messages used for channel sensing at each time step are... Cascade with the correct reference signal.

[0058] According to an embodiment, the processor 10 is configured to insert the same baseband processing and reference signal as that applied by the second radio device R2 into the estimated message when generating a reconstruction of the transmitted signal.

[0059] Assuming that the channel decoder 50, demapper 49, channel estimator, and correction process 48 provide quality guarantees, the estimated message... Compared with the original message They are the same or substantially the same. This provides optimal sensing accuracy. In other words, for optimal sensing accuracy, it is assumed that... The optimal accuracy here has broad implications relative to the final use of the sensed information. For example, it might mean the accuracy of the velocity, position, and size of the object shape envelope detected by multistatic or bistatic techniques. Regarding the estimated message... Compared with the original message In contrast, the accuracy of the sensing will decrease from its optimal state.

[0060] The reference signal is inserted into the estimated message from the baseband reconfigurator 51. In the reconstructed signal. Technicians will recognize that, depending on the usage environment, suboptimal sensing results may still be accurate enough for some applications. As will be discussed later, for example, some examples if the estimated message... If the error rate is so inaccurate that reliable decoding cannot be performed, the receiving radio device R1 is configured to feed back NACK to the transmitting radio device R2, so that retransmission can be scheduled and the modulation and coding from the transmitting radio device R2 can be tuned to improve the bit error rate.

[0061] Therefore, given the estimated message The baseband reconfigurator 51 re-inserts the correct reference signal (pilot symbol) at the time or interval when it transmits the resource block containing the corresponding original message.

[0062] The baseband reconfigurator 51 reconstructs the baseband signal The received signal vector is provided to the channel sensing process 52. The channel sensing process 52 obtains the received signal vector from the baseband FFT generator 47. In an embodiment, the channel sensing process 52 and / or the baseband FFT generator 47 may store the corresponding... Time and / or frequency index Multiple previous samples.

[0063] According to an embodiment, the processor 10 is configured to calculate a channel quality measurement between the first radio device R1 and the second communication device R2 when an estimate of the transmitted signal is obtained using channel state information and received signals. For example, the channel quality measurement is based on the bit error rate of channel decoding, or feedback received from another radio device in the network via a side-channel.

[0064] Channel sensing process 52 execution and Element-by-element combination. According to an embodiment, and Element-wise combinations are and The element-by-element partitioning of the corresponding elements.

[0065] Therefore, the channel sensing process 52 obtains a second channel estimate, which is much more accurate than the first channel estimate calculated by the channel estimator and correction process 48. The reason for the improved accuracy is in the received vector... and emission vector The second channel estimation is performed on all elements. Conversely, the first channel estimation performed by the channel estimator and correction process 48 is an interpolation of the original transmitted reference signal (pilot symbol). The accuracy of this interpolation decreases as the density of the transmitted reference signal decreases. The first channel estimation performed by the channel estimator and correction process 48 is tolerable for message decoding, but it leads to a suboptimal state when bistatic or multistatic sensing requires accurate channel knowledge.

[0066] According to an embodiment, processor 10 is configured to process sensing channel data H to obtain bistatic or multistatic radar characteristics of physical environment 102, including both first radio device R1 and second radio device R2. Those skilled in the art will appreciate that additional radio devices such as R3, R4 can also contribute to the channel measurements to enhance the accuracy of the overall multistatic radar characteristics of physical environment 102.

[0067] According to an embodiment, processor 10 is configured to process sensing channel data H to obtain characteristics of at least one scatterer 104 included in physical environment 102. For example, the characteristics of the scatterer may include the location of an object registered in an absolute coordinate system within physical environment 102, in which radio devices R1-R4 are also registered. The characteristics of the scatterer may include a characterization of the physical size of the scatterer and / or a classification of its shape. Sensing channel data H may be compared with a scattering characteristic library to classify one or more objects in physical environment 102 as one or more items in the scattering characteristic library. In this way, sensing channel data H may identify vehicles, cyclists, buses or trams, and fixed elements in the physical environment, such as buildings, vegetation, or road signs.

[0068] Figure 7 The diagram schematically illustrates the signaling between a first radio device and a second radio device for determining a failed sensing attempt.

[0069] According to an embodiment, the processor is configured to cause transceiver 14 to transmit a negative acknowledgment (NACK) to the second radio device R2 if the channel quality measurement is below a predefined threshold. The negative acknowledgment indicates that it is impossible to use the baseband received signal Y for radar sensing, and / or is used to request the retransmission of the coded message X and multiple reference signals P or different multiple reference signals.

[0070] The foregoing embodiments aim to address situations where a first radio device R1 (a sensing radio device) cannot reliably decode a message transmitted from a second radio device R2 (the second radio device implicitly communicates with another radio device R3, R4 in the physical environment). For example, the second radio device R2 generates a message W and transmits it to the first radio device R1 using a predetermined set of reference signals P. A channel quality measurement characterizing the channel between radio devices R1 and R2 is calculated at R1. If the channel quality measurement indicates that the quality of the reconstructed message W' and / or the reference signals P is insufficient for successful channel sensing (accurate to a predefined specification), the first radio device R1 transmits a negative acknowledgment (NACK) to the second radio device R2.

[0071] According to an embodiment, when the second radio device R2 receives a negative acknowledgment (NACK), the second radio device R2 retransmits the original message to the first radio device R1.

[0072] According to an embodiment, when the second radio device R2 receives a negative acknowledgment (NACK), the second radio device R2 retransmits the original message to the first radio device R1. The original message has an additional number of parity bits or a code with a different code rate, thereby making the reconstructed message W' more likely to be correctly received.

[0073] According to an embodiment, when the second radio device R2 receives a negative acknowledgment (NACK), the second radio device R2 changes the reference signal mode and retransmits the changed reference signal mode P' using the original message W.

[0074] According to an embodiment, the first radio device R1 is configured to transmit an ACK to the second radio device R2, thereby notifying the second radio device that W+P or W+P' transmits an ACK sufficient to make the estimation of the channel matrix H accurate to an accuracy useful for sensing purposes.

[0075] In current cellular communication methods, for example, considering the radio channel between base stations and user equipment, the design of modulation and coding schemes is optimized for communication purposes. Figure 1 In the given environment, radio device R2 may be intended to communicate with radio device R3, while radio devices R1 and R4 are performing multistatic sensing using communication signals from radio device R2. Therefore, modulation and coding schemes should be designed so that radio devices R1 and R4 can also decode messages intended for radio device R2, because, according to the techniques described in this specification, the improved (second) channel estimation for providing improved multistatic sensing at each of the respective radio devices R2-R4 requires the original message for sensing the corresponding channel matrix with improved accuracy. Therefore, even though radio device R3 is a dedicated receiver for receiving messages generated by R2, radio devices R1 and R4 should be configured to decode messages from R2.

[0076] According to an embodiment, the processor 10 is configured to transmit channel quality measurements and / or channel occupancy metrics to the network control entity N, and to receive updated format definitions of coded messages X and a plurality of reference signals P from the network control entity N.

[0077] For example, to improve the quality of channel sensing, the reference signal pattern can be designed to be optimized for a specific physical environment 102, or even parameterized to take into account time of day, traffic conditions, etc. The foregoing embodiments pertain to a scenario where a network operator provides location sensing as a service. Here, the transmitted signal, and especially the reference signal, should be designed to comply with channel sensing-specific design criteria. For example, the symbol duration, operating carrier frequency, and spectrum can be adjusted based on the physical environment 102 that needs to be sensed. The network control entity N is configured to monitor network density and coverage, assess service demand, and control the budget for optimizing the signal parameters and patterns used for location sensing.

[0078] According to an embodiment, processor 10 is configured to receive decoded versions of coded message X and / or multiple reference signals P from third radio device R3 when calculating an estimate of the transmitted signal. Processor 10 is configured to use the decoded versions of coded message X and / or multiple reference signals P to generate a reconstruction of the transmitted signal. In other words, third radio device R3 can relay the decoded versions of the coded message and / or reference signals received at radio device R3 to first radio device R1 to improve the quality of multibase estimation. Specifically, by using relayed data in channel reconstruction based on decoding and forwarding principles, radio devices located at the edge of the location service coverage area can benefit from improved accuracy.

[0079] According to an embodiment, processor 10 is configured to use sensed channel data H to detect changes in a physical environment 102 that includes at least a first wireless device R1 and a second wireless device R2. Processor 10 is also configured to use the detected changes in the physical environment to estimate changes in channel state information. Furthermore, processor 10 is configured to transmit feedback information to the second wireless device R2, which includes the estimated changes in the channel state information due to the detected changes in the physical environment.

[0080] According to an embodiment, the feedback information may also include one or more of the following: suggested changes to the reference signal scheme, subcarrier indexes of the OFDM symbol index or OFDM frame index.

[0081] Brief Reference Figure 4 The first radio device R1 may include a channel quality monitor 53, which is configured to track channel quality using the received reference symbol P'. The channel quality monitor 53 may pass the channel quality to a reference signal generator 54 in the second (transmitting) radio device R2. For example, the channel quality monitor 53 may pass the channel quality via a side-channel or a resource area reserved for channel quality feedback. The reference signal generator 54 is configured to update the reference signal based on the passed channel quality.

[0082] Therefore, the sensing capabilities of radio devices R1-R4 can be used to adjust the reference signal scheme based on the sensed channel data H.

[0083] Figure 5 An OFDM resource block with a first reference signal mode is schematically illustrated.

[0084] Figure 6 An OFDM resource block with a second reference signal mode is schematically illustrated.

[0085] According to the third aspect, a fourth radio device R4 is provided, which is configured for wireless communication and bistatic or multistatic radar sensing, including a transceiver, a memory, and a processor coupled to the transceiver and the memory.

[0086] The transceiver and processor are configured to: receive a negative acknowledgment from a first radio device R1 via the transceiver, the negative acknowledgment indicating that radar sensing at the first radio device using the coded message X received by the first radio device is impossible; calculate an updated reference signal scheme; and transmit additional signals to the first radio device, the additional signals including additional coded messages X' and additional reference signals P'. The additional reference signals P' are defined according to the updated reference signal scheme.

[0087] Reference Figure 7 In one embodiment, a fourth radio device R4, configured to transmit communication signals, can receive a negative acknowledgment (NACK) from a first radio device R1, configured to perform bistatic or multistatic radar sensing. This implies that the communication signals transmitted by the fourth radio device R4 cannot be used for channel sensing purposes at the first radio device R1. A strategy to address this problem is to change the reference signal mode at the fourth radio device R4.

[0088] The first reference signal mode 60 represents a time-frequency grid including message symbols 60W and reference signals (pilot symbols) 60P. The second reference signal mode 62 represents a time-frequency grid including message symbols 62W and reference signals (pilot symbols) 62P. The first reference signal mode 60P includes 16 symbols or resource blocks, while the second reference signal mode 62P includes 12 symbols or resource blocks. Reference signal modes with a large number of symbols or resource blocks may, for example, perform better under unfavorable channel conditions at the cost of reduced message communication efficiency. Conversely, reference signal modes with a smaller number of symbols or resource blocks may perform better under favorable conditions with the benefit of improved message communication efficiency.

[0089] Therefore, when a radio device (such as a fourth radio device R4) receives a negative acknowledgment from another radio device R1-R3 in system 100, in an embodiment, the fourth radio device R4 is configured to adjust the reference signal pattern such that the reference signal pattern occupies a larger proportion of resource blocks relative to message W. According to an embodiment, the fourth radio device R4 is configured to make the reference signal pattern denser. According to an embodiment, the fourth radio device R4 is configured to adjust the structure of the reference signal pattern in response to sensed channel conditions.

[0090] Figure 1 The system of radio devices R1-R4 included in physical environment 102 is schematically illustrated.

[0091] According to a fourth aspect, a radio system 100 is provided, comprising: a first radio device R1 configured for wireless communication and bistatic or multistatic radar sensing according to the first aspect or embodiments thereof; and a second radio device R2 configured to transmit a signal to the first radio device, wherein the signal includes an coded message X and a plurality of reference signals P.

[0092] According to an embodiment, the system also includes a fourth radio device R4 according to the third aspect or an embodiment thereof.

[0093] Figure 8 The method according to the second aspect is illustrated schematically.

[0094] According to a second aspect, a computer-implemented method 70 for wireless communication and bistatic or multistatic radar sensing is provided, comprising: After transmission through the wireless channel, a baseband received signal Y, including coded message X and multiple reference signals P, is obtained from the second wireless device; The estimated value of the transmitted signal originally transmitted by the second radio device is calculated using channel state information and received signal. The estimated signals of 73 were obtained using channel state information and received signals; The estimation of the transmitted signal involves at least 74 demodulation and channel decoding to obtain an estimate of the message W' transmitted by the second radio device; A reconstruction of the transmitted signal 75 is generated by performing baseband signal processing and reference signal insertion on the estimation of message W', wherein the baseband signal processing and reference signal insertion correspond to the baseband signal processing and reference signal insertion performed by the second radio device; and 76 sensing channel data H is generated by combining the reconstructed transmitted signal and the received signal.

[0095] According to the fifth aspect, a computer program product including machine-readable instructions is provided, which, when executed by a processor, cause the processor to perform the method according to the second aspect.

[0096] According to the sixth aspect, a computer-readable medium including instructions is provided, which, when executed by a processor, cause the processor 16 to perform the method of the second aspect.

[0097] The examples provided in the accompanying drawings and those described in the foregoing written description are intended to provide an understanding of the principles of this specification. They are not intended to limit the scope of the appended claims. This specification describes variations and modifications to the illustrated examples. Only preferred examples have been presented, and all changes, modifications, and further applications of these examples within the scope of this specification are intended to be protected.

Claims

1. A first wireless device (R1) configured for wireless communication and bistatic or multistatic radar sensing, comprising: - Transceiver (14); - Memory (12); as well as - A processor (10) coupled to the transceiver (14) and the memory (12), wherein the transceiver and the processor are configured to: After transmission through the wireless channel (102), a baseband received signal (Y) including coded messages (X) and multiple reference signals (P) is obtained from the second wireless device (R2) via the transceiver (14). Channel state information is calculated using the plurality of reference signals included in the baseband received signal; The channel state information and the baseband received signal are used to calculate an estimate of the transmitted signal originally transmitted by the second radio device (R2); The estimation of the transmitted signal is performed at least by demodulation and channel decoding to obtain an estimate (W') of the message transmitted by the second radio device (R2). A reconstruction of the transmitted signal is generated by performing baseband signal processing and reference signal insertion on the estimated message (W'), wherein the baseband signal processing and reference signal insertion correspond to the baseband signal processing and reference signal insertion performed by the second radio device (R2); as well as Sensing channel data (H) is generated by combining the reconstructed transmitted signal and the received signal.

2. The first wireless device (R1) according to claim 1. The processor (10) is configured to: The sensing channel data (H) is processed to obtain bistatic or multistatic radar characteristics of the physical environment including both the first radio device (R1) and the second radio device (R2).

3. The first wireless device (R1) according to claim 2. The processor (10) is configured to: The sensing channel data (H) is processed to obtain the characteristics of at least one scatterer (104) included in the physical environment (102).

4. The first wireless device (R1) according to any one of the preceding claims. The processor (10) is configured to insert the same baseband processing and reference signal applied to the estimated message as the baseband processing applied by the second radio device (R2) when generating the reconstruction of the transmitted signal.

5. The first wireless device (R1) according to any one of the preceding claims. The processor (10) is configured to, when obtaining the estimate of the transmitted signal using the channel state information and the received signal: Calculate the channel quality measurement between the first radio device (R1) and the second radio device (R2).

6. The first wireless device (R1) according to claim 5. in, If the channel quality measurement is below a predefined threshold, the processor is configured to cause the transceiver (14) to transmit a negative acknowledgment (NACK) to the second radio device (R2), the negative acknowledgment indicating that it is impossible to use the baseband received signal (Y) for radar sensing, and / or requesting retransmission of the coded message (X) and the plurality of reference signals (P) or different plurality of reference signals.

7. The first wireless device (R1) according to claim 5 or 6. The processor (10) is configured to: Transmit the channel quality measurement and / or channel occupancy metric to the network control entity (N); and The network control entity (N) receives the updated format definitions of the encoded message (X) and the plurality of reference signals (P).

8. The first wireless device (R1) according to any one of the preceding claims. in, The processor (10) is configured to, when calculating the estimate of the transmitted signal: Receive the decoded version of the encoded message (X) and / or the plurality of reference signals (P) from the third radio device (R3); as well as The reconstructed signal is generated using the encoded message (X) and / or the decoded version of the plurality of reference signals (P).

9. The first wireless device (R1) according to any one of the preceding claims. The processor (10) is configured to: Changes in the physical environment (102) including at least a first wireless device (R1) and a second wireless device (R2) are detected using the sensing channel data (H); The changes in the channel state information are estimated using the detected changes in the physical environment; and Feedback information is transmitted to the second radio device (R2), which includes the estimated changes in the channel state information due to the changes detected in the physical environment.

10. The first wireless device (R1) according to claim 9. The feedback information further includes one or more of the following: suggested changes to the reference signal scheme, subcarrier indexes of OFDM symbol indexes or OFDM frame indexes.

11. A fourth wireless device (R4) configured for wireless communication and bistatic or multistatic radar sensing, comprising: - Transceiver; - Memory; as well as - A processor coupled to the transceiver and the memory, wherein the transceiver and the processor are configured to: A negative acknowledgment is received from the first radio device (R1) via the transceiver, the negative acknowledgment indicating that it is impossible to use the coded message (X) received by the first radio device for radar sensing at the first radio device; Calculate the updated reference signal scheme; as well as Transmit additional signals to the first wireless device, the additional signals including additional coded messages (X') and additional reference signals (P'), wherein the additional reference signals (P') are defined according to the updated reference signal scheme.

12. A radio system (100), comprising: - The first wireless device (R1) according to any one of claims 1 to 10, configured for wireless communication and bistatic or multistatic radar sensing; and - A second radio device (R2) is configured to transmit signals to a first radio device, wherein the signals include coded messages (X) and a plurality of reference signals (P).

13. The radio system (100) according to claim 12, further comprising: - The fourth wireless device (R4) according to claim 11.

14. A computer-implemented method (70) for wireless communication and bistatic or multistatic radar sensing, comprising: After transmission through the wireless channel, a baseband received signal (Y) including coded message (X) and multiple reference signals (P) is obtained from the second wireless device (71). Using the channel state information and the received signal, (72) an estimate of the transmitted signal originally transmitted by the second radio device is calculated; The estimated signal (73) is obtained using the channel state information and the received signal; The estimated transmitted signal is subjected to at least (74) demodulation and channel decoding to obtain an estimate (W') of the message transmitted by the second radio device. A reconstruction of the transmitted signal (75) is generated by performing baseband signal processing and reference signal insertion on the estimated (W') of the message, wherein the baseband signal processing and reference signal insertion correspond to the baseband signal processing and reference signal insertion performed by the second radio device; as well as (76) Sensing channel data (H) is generated by combining the reconstructed transmitted signal and the received signal.

15. A computer program product comprising machine-readable instructions that, when executed by a processor, cause the processor to perform the method according to claim 14.

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