Sensing device, method by sensing device, and program

Abstract

A sensing device (20) includes a control unit (210) and a communication unit (220). The communication unit (220) receives a sensing signal from a sensing transmitter (10). The control unit (210) calculates a phase difference of a reference signal included in the sensing signal, demodulates data included in the sensing signal, estimates a phase difference of the demodulated data on the basis of the phase difference of the reference signal, generates a propagation matrix on the basis of the phase difference of the data, and detects a detection target on the basis of the propagation matrix.

Description

Sensing device, method using the sensing device, and program CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on and claims the benefit of priority from Japanese Patent Application No. 2024-070220, filed on April 24, 2024, the entire contents of which are incorporated herein by reference.

[0002] The present disclosure relates to a sensing device, a method using the sensing device, and a program, and more particularly to a sensing device, a method using the sensing device, and a program that improve the accuracy of detecting an object to be detected.

[0003] The Third Generation Partnership Project (3GPP (registered trademark)) has defined wireless communication specifications called 5G NR (Fifth Generation New Radio), and technological development of the wireless specifications is progressing.

[0004] Following 5G NR, 6G systems, the sixth generation of wireless communication specifications, are also being considered. For 6G systems, technical specifications for sensing solutions are being considered. Sensing solutions utilize the Doppler effect to detect targets by analyzing changes in the frequency spectrum of emitted radio waves (signals).

[0005] Non-Patent Document 1 discloses a technology for detecting a detection target using radio waves in an Orthogonal Frequency Division Multiplexing (OFDM) system.

[0006] Yi Geng, Cictmobile, China, 'A Novel Waveform Design for OFDM-Based Joint Sensing and Communication System', [online], January 9, 2020, [searched March 28, 2020], Internet <URL: https: / / arxiv.org / pdf / 2301.03347>

[0007] Non-Patent Document 1 describes a new waveform design in which symbols are arranged diagonally in a resource block consisting of frequency (subcarriers) and time (slots) in an OFDM system.

[0008] As described above, in order to perform the sensing process, changes in the frequency spectrum of radio waves emitted from a transmitter are analyzed. This change in the frequency spectrum is represented by a delay (phase difference) between the phase of the signal when it is transmitted by the transmitter and the phase of the signal when it is received by the device performing the sensing. In the sensing process, the target is detected based on this phase difference, but errors may occur in the detection. The technology described in Non-Patent Document 1 does not prevent such errors.

[0009] The present disclosure provides a technology that reduces the possibility of errors that may arise from the inability to calculate the phase difference of the above-mentioned data, and improves the accuracy of detecting a detection target.

[0010] In a first aspect of the present disclosure, a sensing device of the present disclosure is a sensing device including a control unit and a communication unit, wherein the communication unit is configured to receive a sensing signal from a sensing transmitter, and the control unit is configured to calculate a phase difference of a reference signal included in the sensing signal, demodulate data included in the sensing signal, estimate a phase difference of the demodulated data based on the phase difference of the reference signal, generate a propagation matrix based on the phase difference of the data, and detect a detection target based on the propagation matrix.

[0011] Furthermore, in a second aspect of the present disclosure, a method performed by a sensing device in the present disclosure is a method performed by a sensing device, and includes receiving a sensing signal from a sensing transmitter, calculating a phase difference of a reference signal included in the sensing signal, demodulating data included in the sensing signal, estimating a phase difference of the demodulated data based on the phase difference of the reference signal, generating a propagation matrix based on the phase difference of the data, and detecting a detection target based on the propagation matrix.

[0012] According to the above configuration, the phase difference of the data is estimated from the phase difference of the reference signal, so that it is possible to reduce the possibility of an error occurring due to an inability to calculate the phase difference of the data. Note that the above configuration may achieve other effects instead of or in addition to the above effect.

[0013] 1 is a diagram showing a sensing system according to a first embodiment. FIG. 1 is a block diagram showing a schematic hardware configuration of a sensing transmitter according to the first embodiment. FIG. 2 is a block diagram showing a schematic functional configuration of a sensing transmitter according to the first embodiment. FIG. 3 is a block diagram showing a schematic hardware configuration of a sensing receiver according to the first embodiment. FIG. 4 is a block diagram showing a schematic functional configuration of a sensing receiver according to the first embodiment. FIG. 5 is a block diagram showing a schematic logical function configuration of a sensing transmitter according to the first embodiment. FIG. 6 is a block diagram showing a schematic logical function configuration of a sensing device according to the first embodiment. FIG. 7 is a diagram showing an OFDM resource structure. FIG. 8 is a diagram showing waveforms of a sensing signal on the time axis and DFT frequency axis. FIG. 9 is a diagram showing an OFDM resource structure and a waveform of a corresponding sensing signal on the time axis. FIG. 10 is a diagram showing waveforms of an interpolated sensing signal on the time axis. FIG. 11 is a diagram showing waveforms of an interpolated sensing signal on the time axis and DFT frequency axis. FIG. 12 is a flowchart showing sensing processing according to the first embodiment. FIG. 13 is a diagram showing an OFDM resource structure according to the first embodiment. FIG. 14 is a flowchart showing sensing processing according to a second embodiment. FIG. 15 is a block diagram showing a schematic logical function configuration of a sensing device according to a third embodiment. FIG. 16 is a flowchart showing sensing processing according to the third embodiment. FIG. 17 is a block diagram showing a schematic logical function configuration of a sensing device according to a fourth embodiment. FIG. 18 is a flowchart showing sensing processing according to the fourth embodiment. 10 is a block diagram showing a schematic logical function configuration of a sensing device according to a fifth embodiment. FIG. 11 is a flowchart showing sensing processing according to the fifth embodiment. FIG. 12 is a diagram showing an OFDM resource structure in which CPs are arranged according to the fifth embodiment.

[0014] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In this specification and drawings, elements that can be similarly described will be designated by the same reference numerals, and redundant description may be omitted.

[0015] The embodiments described below are merely examples of configurations that can realize the present disclosure. Each of the following embodiments can be modified or changed as appropriate depending on the configuration of the device to which the present disclosure is applied and various conditions. Not all combinations of elements included in each of the following embodiments are necessarily essential for realizing the present disclosure, and some elements can be omitted as appropriate. Therefore, the scope of the present disclosure is not limited to the configurations described in each of the following embodiments. As long as there are no mutual contradictions, configurations that combine multiple configurations described in the following embodiments can also be adopted.

[0016] 1. First embodiment 1.1 Sensing system

[0017] In the first embodiment, a sensing channel and / or a sensing signal, which is defined separately from wireless communication, is used for radio waves used to perform sensing. Hereinafter, in this embodiment, a "sensing signal" is used to perform sensing. The sensing signal may be used interchangeably with the sensing channel.

[0018] In a first embodiment, sensing is performed by multiple devices. Such sensing performed by multiple devices is referred to as "cooperative sensing." Cooperative sensing may be used interchangeably with group sensing, collaborative sensing, bistatic sensing, and multistatic sensing.

[0019] In collaborative sensing, sensing is performed by at least a sensing transmitter that transmits a sensing signal for performing sensing and a sensing receiver that receives the sensing signal. Sensing involves receiving a sensing signal transmitted to an object to be detected, such as a person or an obstacle, and analyzing changes in the frequency spectrum of the sensing signal to detect the object. Hereinafter, an object detected by sensing will be referred to as a "detection target." Detection targets include people, animals, objects, etc.

[0020] The sensing signal transmitted by the sensing transmitter is reflected from the target and its frequency spectrum changes due to the Doppler effect. The sensing receiver receives the sensing signal and analyzes the change in the frequency spectrum of the sensing signal to detect the target.

[0021] 1 , the sensing system S according to the first embodiment includes one or more sensing transmitters 10 and one or more sensing receivers 20. The sensing receiver 20 may be referred to as a “sensing device” because it detects a detection target based on a sensing signal.

[0022] The sensing transmitter 10 transmits a sensing signal and a communication signal to the sensing receiver 20. As described above, a sensing signal is a signal used to perform sensing, whereas a communication signal is a signal used to convey predetermined information to the sensing receiver 20. A communication signal may be used interchangeably with a communication channel.

[0023] The sensing transmitter 10 may be a device that wirelessly communicates with the sensing receiver 20, and may be, for example, a user equipment (UE) that operates in accordance with the 3GPP 5G NR specification. The sensing transmitter 10 may also be a terminal device that complies with other older or newer 3GPP specifications.

[0024] The sensing transmitter 10 may be, for example, a mobile phone terminal such as a smartphone, a tablet terminal, a laptop PC, a communication module, a communication card, or an IoT device such as a surveillance camera or a robot. The sensing transmitter 10 may be a vehicle (e.g., a car, a train, etc.) or a device provided therein. The sensing transmitter 10 may be a transport vehicle other than a vehicle (e.g., a ship, an airplane, etc.) or a device provided therein. The sensing transmitter 10 may be a sensor or a device provided therein. Note that the sensing transmitter 10 may be called a terminal, a mobile station, a mobile terminal, a mobile device, a mobile unit, a subscriber station, a subscriber terminal, a subscriber device, a subscriber unit, a wireless station, a wireless terminal, a wireless device, a wireless unit, a remote station, a remote terminal, a remote device, a remote unit, etc. The sensing transmitter 10 may be a device adapted for one or more of enhanced Mobile Broadband (eMBB), Ultra-Reliable and Low Latency Communications (URLLC), and massive Machine Type Communications (mMTC).

[0025] The sensing receiver 20 receives a sensing signal and a communication signal from the sensing transmitter 10. The sensing receiver 20 may be a device that wirelessly communicates with the sensing transmitter 10, and may be, for example, a base station device that operates in accordance with the 3GPP 5G NR specification. The sensing receiver 20 may also be a base station device that complies with other older or newer 3GPP specifications.

[0026] In the embodiment, the sensing transmitter 10 corresponds to a terminal device and the sensing receiver 20 corresponds to a base station device, but such a configuration is merely an example. For example, the sensing transmitter 10 may correspond to a base station device and the sensing receiver 20 may correspond to a terminal device. Furthermore, both the sensing transmitter 10 and the sensing receiver 20 may correspond to a terminal device. In other words, the sensing transmitter 10 may be any wireless communication device that transmits a sensing signal. The sensing receiver 20 may be any wireless communication device that receives a sensing signal.

[0027] 2, the sensing transmitter 10 includes, as hardware elements, a processor 101, a memory 102, an input / output interface 103, a transceiver 104, and an antenna 105. The above elements provided in the sensing transmitter 10 are connected to each other by an internal bus. Note that the sensing transmitter 10 may include hardware elements other than the elements shown in FIG. 2.

[0028] The processor 101 is a computing element that realizes various functions of the sensing transmitter 10. The processor 101 may be a system-on-a-chip (SoC) that includes elements such as a central processing unit (CPU), a graphics processing unit (GPU), and a memory controller.

[0029] The memory 102 is configured by at least one storage medium such as a RAM (Random Access Memory) or an eMMC (embedded Multi Media Card). The memory 102 is an element that temporarily or permanently stores programs and data used to execute various processes in the sensing transmitter 10. The programs include one or more instructions for operating the sensing transmitter 10. The processor 101 implements the functions of the sensing transmitter 10 by expanding and executing the programs stored in the memory 102 in the memory 102 and / or a system memory (not shown).

[0030] The input / output interface 103 is an interface that receives operations on the sensing transmitter 10 and supplies the operations to the processor 101, and also presents various information to the user. The input / output interface 103 is, for example, a touch panel.

[0031] The transceiver 104 is a circuit that performs various signal processing to realize wireless communication, and includes a baseband processor and an RF circuit. The transceiver 104 transmits and receives wireless signals to and from the sensing receiver 20 via the antenna 105.

[0032] 3, the sensing transmitter 10 has, as functional blocks, a control unit 110 and a communication unit 120. The communication unit 120 has at least one transmission unit 121 and at least one reception unit 122.

[0033] The control unit 110 may include at least one processor 101 and at least one memory 102. In other words, the control unit 110 may be realized by the processor 101 and the memory 102. The control unit 110 executes various control processes in the sensing transmitter 10. For example, the control unit 110 controls wireless communication with the sensing receiver 20 via the communication unit 120. That is, the control unit 110 transmits and receives data / information / messages via the communication unit 120.

[0034] The communication unit 120 includes a transceiver 104 and an antenna 105. In other words, the communication unit 120 is realized by the transceiver 104 and the antenna 105. The communication unit 120 wirelessly communicates with the sensing receiver 20 by transmitting and receiving radio signals to and from the sensing receiver 20. Two or more transceivers 104 and two or more antennas 105 may be included in the communication unit 120.

[0035] The control unit 110 operates to execute various processes in the sensing transmitter 10 of this embodiment.

[0036] 4, the sensing receiver 20 has, as hardware elements, a processor 201, a memory 202, a network interface 203, a transceiver 204, and an antenna 205. The above elements provided in the sensing receiver 20 are connected to each other by an internal bus. Note that the sensing receiver 20 may have hardware elements other than the elements shown in FIG. 4.

[0037] The processor 201 is a computing element that realizes various functions of the sensing receiver 20. The processor 201 may be a CPU, and may further include other processors such as a GPU.

[0038] The memory 202 is composed of at least one storage medium such as a read-only memory (ROM), a RAM, a hard disk drive (HDD), or a solid state drive (SSD). The memory 202 is an element that temporarily or permanently stores programs and data used to execute various processes in the sensing receiver 20. The programs include one or more instructions for operating the sensing receiver 20. The processor 201 implements the functions of the sensing receiver 20 by expanding and executing the programs stored in the memory 202 in the memory 202 and / or a system memory (not shown).

[0039] The network interface 203 is an interface used to send and receive signals to and from other sensing receivers 20 and the core network 30 .

[0040] The transceiver 204 is a circuit that performs various signal processing to realize wireless communication, and includes a baseband processor and an RF circuit. The transceiver 204 transmits and receives wireless signals to and from the sensing transmitter 10 via an antenna 205.

[0041] 5, the sensing receiver 20 has, as functional blocks, a control unit 210, a communication unit 220, and a network communication unit 230. The communication unit 220 has at least one transmission unit 221 and at least one reception unit 222.

[0042] The control unit 210 may include at least one processor 201 and at least one memory 202. In other words, the control unit 210 may be realized by the processor 201 and the memory 202. The control unit 210 executes various control processes in the sensing receiver 20. For example, the control unit 210 controls wireless communication with the sensing transmitter 10 via the communication unit 220. That is, the control unit 210 transmits and receives data / information / messages via the communication unit 220. Furthermore, for example, the control unit 210 controls communication with other nodes (e.g., other sensing receivers 20, nodes of the core network 30) via the network communication unit 230.

[0043] The communication unit 220 includes a transceiver 204 and an antenna 205. In other words, the communication unit 220 is realized by the transceiver 204 and the antenna 205. The communication unit 220 wirelessly communicates with the sensing transmitter 10 by transmitting and receiving radio signals to and from the sensing transmitter 10. Two or more transceivers 204 and two or more antennas 205 may be included in the communication unit 220.

[0044] The network communication unit 230 includes the network interface 203. In other words, the network communication unit 230 is realized by the network interface 203. The network interface 203 transmits and receives signals to and from the network (and thus to the other nodes described above).

[0045] The control unit 210 operates to execute various processes in the sensing receiver 20 of this embodiment.

[0046] 1.2 Logical Functional Configuration of Sensing Transmitter The following describes the logical functional configuration of the sensing transmitter 10. As shown in Fig. 6, the sensing transmitter 10 has a sensing signal generating unit 10a, a modulating unit 10b, and a radio wave transmitting unit 10c, which are logical functional blocks for performing sensing according to the first embodiment.

[0047] The sensing signal generator 10a generates a sensing signal to be transmitted to the sensing receiver 20. The sensing signal includes data and a reference signal (RS). The sensing signal generator 10a is realized by the control unit 110 / processor 101.

[0048] The modulation unit 10b weights the sensing signal generated by the sensing signal generation unit 10a. The modulation is performed by executing FTT in the ODFM system, as will be described later. The modulation unit 10b is realized by the control unit 210 / processor 201.

[0049] The radio wave transmitting unit 10c transmits a sensing signal to the sensing receiver 20. The radio wave transmitting unit 10c also receives a communication signal at the sensing receiver 20. The radio wave transmitting unit 10c is realized by the communication unit 120 / transmitter / receiver 104 and the antenna 105.

[0050] 1.3 Logical Functional Configuration of the Sensing Device The logical functional configuration of the sensing receiver 20 will be described below. The sensing receiver 20 is the entity that performs sensing according to the first embodiment, and therefore will be referred to as the "sensing device 20." As shown in FIG. 7 , the sensing device 20 has a radio wave receiving unit 20a, a channel estimating unit 20b, a demodulating unit 20c, a propagation matrix generating unit 20d, and a detection target identifying unit 20e, which are logical functional blocks for performing sensing according to the first embodiment.

[0051] The radio wave receiving unit 20a receives a sensing signal from the sensing transmitter 10. The radio wave receiving unit 20a also receives a communication signal from the sensing transmitter 10. The radio wave receiving unit 20a is realized by the communication unit 220 / transmitter / receiver 204 and the antenna 205.

[0052] The channel estimation unit 20b calculates the phase difference of the reference signal included in the sensing signal based on the sensing signal from the sensing transmitter 10. The channel estimation unit 20b is realized by the control unit 210 / processor 201.

[0053] The demodulator 20c demodulates the data included in the sensing signal based on the phase difference of the reference signal calculated by the channel estimator 20b. The demodulator 20c is realized by the controller 210 / processor 201.

[0054] The propagation matrix generation unit 20d generates a propagation matrix, which is a matrix of phase differences corresponding to each symbol of the reference signal, based on the phase difference of the reference signal calculated by the channel estimation unit 20b. The propagation matrix generation unit 20d also generates a propagation matrix, which is a matrix of phase differences corresponding to each symbol of data, based on the phase difference of the data estimated by the channel estimation unit 20b. Hereinafter, in order to distinguish between the propagation matrix of the phase difference of the reference signal and the propagation matrix of the phase difference of the data, the propagation matrix of the phase difference of the reference signal will be referred to as a "first propagation matrix" and the propagation matrix of the phase difference of the data will be referred to as a "second propagation matrix." The propagation matrix generation unit 20d is realized by the control unit 210 / processor 201.

[0055] The detection target identification unit 20e detects the detection target based on the second propagation matrix (and the first propagation matrix). For example, the detection target identification unit 20e identifies the position of the detection target based on the first propagation matrix and the second propagation matrix as well as the position of the sensing transmitter 10. The detection target identification unit 20e is realized by the control unit 210 / processor 201.

[0056] 1.4 Resource Structure of Sensing Signal In this embodiment, the sensing signal is transmitted by inserting a reference signal using, for example, the OFDM scheme in accordance with the 5G NR specification. According to the 5G NR specification, the OFDM scheme forms a grid consisting of resource elements (REs) on the frequency axis (subcarrier) axis and the time axis (slot). N x M REs form a resource block (RB). Data and a reference signal are allocated at regular intervals as OFDM symbols in each RE. For example, a demodulation reference signal (DMRS) is used as the reference signal. The DMRS is a reference signal used when demodulating data.

[0057] In Figure 8, three RBs, RB1, RB2, and RB3, are shown as an example. As shown in Figure 8, in each of RB1, RB2, and RB3, data represented by white squares are arranged at regular intervals, and DMRSs represented by black squares are also arranged at regular intervals. In the example shown in Figure 8, DMRSs are arranged every third DMRS in the time axis direction and every other DMRS in the frequency axis direction. Note that the symbol arrangement within the resource block shown in Figure 8 is merely an example.

[0058] Hereinafter, symbols corresponding to reference signals such as DMRS will be referred to as reference signal symbols, and symbols corresponding to data will be referred to as data symbols.

[0059] Reference signal symbols may not be arranged at equal intervals in the OFDM resource structure. For example, in accordance with the 3GPP 5G NR specification, a random sequence is generated for the DMRS, so that reference signal symbols corresponding to the DMRS may not be arranged at equal intervals in the OFDM resource structure. As shown in FIG. 8, a gap GP exists between RB2 and RB3. Due to this gap, the reference signal symbols are not arranged at equal intervals across RB2 and RB3 on the time axis. The fact that the reference signal symbols are not arranged at equal intervals may cause false detection, as described below.

[0060] 1.5 Detection of a target using phase difference In sensing, the sensing transmitter 10 transmits a sensing signal, and the sensing device 20 receives the sensing signal. At this time, a phase difference may occur in the signal waveform of the sensing signal as the sensing signal propagates. The phase means a deviation (delay) from a sine wave in the time domain and / or frequency domain of the waveform of the sensing signal. A sine wave is expressed by equation (1), Equation (1) In equation (1), A represents amplitude, ω represents angular frequency, and α represents phase. The phase at t=0 is referred to as the initial phase. The phase difference means the difference between the phase when the sensing transmitter 10 transmits a sensing signal (initial phase) and the phase when the sensing device 20 receives the sensing signal (received phase). The phase difference indicates the variation of sensing fluctuation in the frequency domain, the variation of sensing fluctuation in the time domain, and / or the variation between antennas 205 of the sensing device 20. Hereinafter, the terms phase difference and phase fluctuation will be used interchangeably.

[0061] The sensing process detects the target by analyzing changes in the frequency spectrum of the sensing signal. This spectral change is represented by a phase difference. Conventional techniques calculate the phase difference from the sensing signal, generate a propagation matrix from the phase difference, and perform a DFT on the propagation matrix. By performing the DFT, the phase difference is represented as signal strength. Therefore, the target is detected by determining peaks or changes in the signal waveform at the DFT frequency after performing the DFT.

[0062] The DMRS is a signal known to the sensing device 20. Therefore, the sensing device 20 can calculate the phase difference of the reference signal symbols shown in FIG.

[0063] When the sensing device 20 receives a sensing signal, it calculates a phase difference between the sensing signal and a reference signal symbol to generate a propagation matrix. The upper part of Fig. 9 shows the signal waveform when the sensing signal is received. The sensing transmitter 10 performs FFT when transmitting the sensing signal, thereby OFDM-modulating the sensing signal. As shown in Fig. 9, the sensing signal has three peaks p １ , p ２ , and p ３ is occurring.

[0064] Then, the sensing device 20 performs a DFT on the propagation matrix. By performing the DFT, the signal waveform of the sensing signal is represented by the DFT frequency. The lower part of Figure 9 shows the signal waveform of the sensing signal after performing the DFT. The signal waveform is represented by the DFT frequency and the signal strength.

[0065] As shown in Figure 9, after the sensing signal is subjected to DFT, the frequency of the waveform obtained from the sensing signal can be obtained. In this way, by calculating the phase difference from the DMRS and performing DFT on the propagation matrix, the peak p １ , p ２ , and p ３ Peak p corresponding to １ ', p ２ ', and p ３ ' can be determined.

[0066] 1.6 False Detection of Detection Target As described above, reference signal symbols may not be arranged at equal intervals in the OFDM resource structure. In the example shown in Figure 8, within the same RB, reference signal symbols are arranged every third symbol along the time axis, but since there is a gap GP between RB2 and RB3, the reference signal symbols may not be arranged at equal intervals across RB2 and RB3 on the time axis.

[0067] The upper part of Figure 10 shows the OFDM resource structure of RB2 and RB3 shown in Figure 8. As shown in Figure 10, in RB2, reference signal symbols are allocated to RE2, RE5, RE8, and RE11 on the time axis (slot). Also, in RB3, reference signal symbols are allocated to RE19, RE22, RE26, and RE28 on the time axis via gaps GP. For convenience, in Figure 10, reference signal symbols in RB3 are represented by consecutive numbers from the reference signal symbols in RB2.

[0068] In the OFDM resource structure shown in Figure 10, assuming that there is no gap GP, the reference signal symbols are allocated to REs 14, 17, 20, and 23 on the time axis within RB 3. In contrast, corresponding to the gap GP between RB 2 and RB 3, the reference signal symbols within RB 2 and the reference signal symbols within RB 3 are not allocated at equal intervals.

[0069] As described above, a reference signal such as a DMRS is a signal known to the sensing device 20, so the sensing device 20 can calculate a phase difference from the initial phase of each reference signal symbol of the sensing signal. On the other hand, the data included in the sensing signal is not known to the sensing device 20, so the sensing device 20 cannot calculate a phase difference of the data symbols.

[0070] In the prior art, in order to estimate the phase difference of the data symbols, the symbols of the sensing signal are interpolated using the reference signal symbols. For example, linear interpolation or spline interpolation is used for the interpolation. As shown in Fig. 11, the symbols are interpolated using the reference signal symbols shown by the white circles for the reference signal symbols of the sensing signal shown by the black circles. In the section corresponding to the above-mentioned gap GP, the section without symbols is long, so that more reference signal symbols are interpolated.

[0071] After the sensing signal is interpolated, a DFT is performed on the interpolated sensing signal. As shown in FIG. 12, after the DFT is performed, the sensing signal has a peak p １ and p ２ Peak p corresponding to １ ' and p ２ In the signal shown in FIG. 10, in the section where no peak exists, the peak p ｅ is represented.

[0072] Peak p ｅAs described above, as a result of interpolating more reference signal symbols into sections where there are no symbols, the phase differences of more inserted reference signal symbols are represented as peaks on the DFT frequency axis. Since the sensing device 20 detects the detection target by determining peaks, such interpolation can lead to false detection.

[0073] As described above, since the reference signals are not arranged at equal intervals on the time axis, long intervals without symbols may occur on the time axis, and since more reference signals are used to fill these intervals, the above-mentioned false detection may occur more easily. In addition to the fact that the reference signals are not arranged at equal intervals on the time axis, the propagation characteristics of the sensing signal may cause symbols to shift on the time axis. This may also cause the above-mentioned false detection.

[0074] 1.7 Data Symbol Phase Difference Estimation As described above, in the conventional technology, a sensing signal is interpolated using a reference signal to estimate the phase difference of a data symbol, but the interpolation can cause false detection. In the first embodiment, the phase difference of a data symbol is estimated based on the phase difference of a reference signal symbol. Since the phase difference of a data symbol is estimated without interpolation using a reference signal, the possibility of false detection as described above can be reduced.

[0075] An example of sensing processing according to the first embodiment will be described with reference to Fig. 13. In the processing shown in Fig. 13, the sensing device 20 detects the distance to the detection target based on a sensing signal from the sensing transmitter 10. Note that in this embodiment, as an example of detecting the detection target, the distance to the detection target is detected, but detecting the distance is merely an example.

[0076] In step S1301, the radio wave receiving unit 20a of the sensing device 20 receives a sensing signal transmitted from the sensing transmitter 10. The sensing transmitter 10 performs OFDM modulation on the sensing signal to be transmitted to the sensing device 20. For the modulated sensing signal, data symbols and reference signal symbols as shown in FIG. 8 are arranged in the OFDM resource structure.

[0077] Next, the channel estimation unit 20b of the sensing device 20 calculates the phase difference of each of the reference signal symbols arranged in the OFDM resource structure for the sensing signal (step S1302). As described above, the reference signal such as the DMRS is known to the sensing device 20. Therefore, the channel estimation unit 20b can calculate the phase difference for each of the reference signal symbols based on the initial phase when the sensing transmitter 10 transmits the sensing signal and the received phase when the sensing device 20 receives the sensing signal.

[0078] Next, the demodulator 20c of the sensing device 20 demodulates the data included in the sensing signal based on the phase difference of the reference signal symbols calculated by the channel estimator 20b (step S1303).

[0079] Next, the propagation matrix generation unit 20d of the sensing device 20 generates a first propagation matrix based on the phase difference calculated by the channel estimation unit 20b for each of the reference signal symbols (step S1304). The first propagation matrix is ​​a matrix of phase differences for each of the reference signal symbols included in the sensing signal, and is defined as the first propagation matrix pv １ is expressed as in equation (2). Equation (2) Equation (2) represents a matrix of phase differences of reference signal symbols arranged in the ODFM resource structure shown in Fig. 14. The ODFM resource structure shown in Fig. 14 corresponds to RB2 shown in the upper part of Fig. 10. pd in Equation (2) ０２ represents the phase difference of the reference signal symbol allocated to RE (0, 2) in RB2. ０２ represents the initial phase of the reference signal symbol located in RE (0, 2). ０２ represents the received phase of the reference signal symbol located in RE (0, 2).

[0080] Next, the channel estimation unit 20b estimates a phase difference for each data symbol of the data demodulated in step S1303 based on the phase difference calculated in step S1302 (step S1305). In estimating the phase difference for each data symbol, each data symbol is associated with any reference signal symbol based on its position on the frequency and / or time axis.

[0081] For example, as shown in Figure 15, data symbols allocated to REs (0,0), (0,1), (1,0), (1,1), and (1,2) in RB2 are associated with the reference signal symbol allocated to RE (0,2) in RB2. In Figure 15, data symbols allocated to REs (0,0), (0,1), (1,0), (1,1), and (1,2) are represented by squares with vertical lines. Reference signal symbols allocated to RE (0,2) are represented by squares with diagonal lines drawn in the upper left direction.

[0082] Also, as shown in Figure 15, data symbols allocated to REs (0,3), (0,4), (1,3), (1,4), and (1,5) in RB2 are associated with the reference signal symbol allocated to RE (0,5) in RB2. In Figure 15, data symbols allocated to REs (0,3), (0,4), (1,3), (1,4), and (1,5) are represented by boxes with horizontal lines. Reference signal symbols allocated to RE (0,5) are represented by boxes with diagonal lines drawn from the top right.

[0083] As described above, each data symbol is associated with one of the reference signal symbols based on its position on the frequency and / or time axis, and the phase difference of each data symbol is estimated based on the phase difference of the corresponding reference signal symbol. In the process of step S1305, the channel estimator 20b may associate the data symbols with the reference signal symbols based on the positions of the reference signal symbols and the data symbols arranged in the OFDM resource structure.

[0084] Instead, for example, when the sensing transmitter 100 functions as a base station conforming to the 5G NR specification, downlink control information (DCI), which is information indicating an OFDM resource structure, is notified in advance. Therefore, the channel estimation unit 20b may identify in advance the OFDM resource structure of the sensing signal based on the DCI, and associate data symbols with reference signal symbols based on the structure.

[0085] The phase difference of the data symbol may be estimated to have the same value as the phase difference calculated for the corresponding reference signal symbol. In this case, the second propagation matrix pv ２ is expressed as in equation (3). Formula (3) pd in formula (3) ００ represents the phase difference of the data symbol located in RE (0,0) in RB2. As mentioned above, the phase difference of the data symbol is estimated to have the same value as the phase difference calculated for the corresponding reference signal symbol. Therefore, pd ００ is (id ０２ -rd ０２ ) is estimated from pd ０１ , pd １０ , and pd １１ The same is true for the phase differences of data symbols placed in REs (0,1), (1,0), and (1,1), which are expressed as:

[0086] Alternatively, the phase difference of a data symbol may be estimated as a value obtained by adding or subtracting a constant value to or from the phase difference calculated for the corresponding reference signal symbol, the constant value being a value corresponding to the shift of the data symbol relative to the corresponding reference signal symbol on the frequency and / or time axis.

[0087] For example, in the example shown in Figure 15, the data symbol allocated to RE (0,0) in RB2 is shifted by two symbols in the negative direction on the time axis with respect to the reference signal symbol allocated to RE (0,2) in RB2. In this case, the phase difference of the data symbol allocated to RE (0,0) is estimated according to equation (4). Equation (4) In equation (4), 2s is the phase difference corresponding to two symbols on the time axis.

[0088] 15, the data symbol allocated to RE (0, 1) in RB2 is shifted by one symbol in the negative direction on the time axis relative to the reference signal symbol allocated to RE (0, 2) in RB2. In this case, the phase difference of the data symbol allocated to RE (0, 1) is estimated according to equation (5). Equation (5) In equation (5), 1s is the phase difference corresponding to one symbol on the time axis.

[0089] 15, the data symbol allocated to RE (1,0) in RB2 is shifted by two symbols in the negative direction on the time axis and by one symbol in the positive direction on the frequency axis with respect to the reference signal symbol allocated to RE (0,2) in RB2. In this case, the phase difference of the data symbol allocated to RE (1,0) is estimated according to Equation (6). Equation (6) In equation (6), 1f is the phase difference corresponding to one symbol on the frequency axis, and 2s is the phase difference corresponding to two symbols on the time axis.

[0090] In the above example, a certain value is added or subtracted for each data symbol based on its position relative to the corresponding reference signal symbol on the frequency and / or time axis. In this example, the value to be added or subtracted is calculated for each data symbol based on its position relative to the corresponding reference signal symbol on the frequency and / or time axis, which can improve the accuracy of the detection target. However, estimating the above value for each data symbol increases the calculation load.

[0091] Instead of calculating the value to be added or subtracted for each data symbol, a common value may be used for a plurality of data symbols associated with a reference signal symbol. For example, in the example shown in Fig. 15, it has been described above that the reference signal symbol arranged in RE (0,2) in RB2 is associated with data symbols arranged in REs (0,0), (0,1), (1,0), (1,1), and (1,2).

[0092] In this example, for example, a phase difference may be estimated as described above for a data symbol placed in RE (1, 2) or RE (0, 1) that is placed closest to a reference signal symbol on the frequency and / or time axis, and the estimated phase difference may also be used for other data symbols. When the phase difference of a data symbol placed in RE (1, 2) is also used for other data symbols, a second propagation matrix pv ２ is expressed as in equation (7). In equation (7), 1f is a phase difference corresponding to one symbol on the frequency axis. The data symbol allocated to RE (1, 2) is shifted by one symbol in the positive direction on the frequency axis with respect to the reference signal symbol allocated to RE (0, 2) in RB2, and therefore the value with 1f added is also used for other data symbols.

[0093] In the above example, the common value may be estimated for a data symbol that is located closest to the reference signal symbol on the frequency and / or time axis among the data symbols corresponding to the reference signal symbol. Alternatively, the common value may be estimated for a data symbol that is located farthest from the reference signal symbol on the frequency and / or time axis among the data symbols corresponding to the reference signal symbol. Furthermore, the common value may be estimated for a randomly selected data symbol among the data symbols corresponding to the reference signal symbol.

[0094] Furthermore, instead of calculating the value to be added or subtracted based on the position of the data symbol on the frequency and / or time axis, a predetermined value, i.e., a fixed value, may be added or subtracted from the phase difference calculated for the reference signal symbol. The fixed value is, for example, a value calculated in advance based on experimental results.

[0095] 15, the propagation matrix generation unit 20d generates a second propagation matrix based on the phase difference of the data symbols estimated in step S1305 (step S1306). The second propagation matrix is ​​generated as described above.

[0096] Next, the detection target identification unit 20e of the sensing device 20 detects the distance to the detection target based on the second propagation matrix generated in step S1306 and the position of the sensing transmitter 10 (step S1307). The distance to the detection target can be calculated by performing a DFT on the second propagation matrix to determine a peak in the waveform of the sensing signal and based on the peak and the position of the sensing transmitter 10. Note that the position of the sensing transmitter 10 may be notified as position information from the sensing transmitter 10, for example.

[0097] As described above, the first embodiment has been described. According to the first embodiment, the phase difference of a data symbol is estimated based on the phase difference calculated for a reference signal symbol. In this way, it is not necessary to interpolate a reference signal for a section where there is no symbol, and it is possible to improve the accuracy of detecting a detection target and reduce the possibility of false detection.

[0098] 2. Second Embodiment Next, a second embodiment will be described. In the first embodiment, data is demodulated based on a second propagation matrix, which is a matrix of phase differences between data symbols. In the second embodiment, a propagation matrix is ​​used in which a first propagation matrix, which is a matrix of phase differences between reference signal symbols, is combined with a second propagation matrix.

[0099] An example of sensing processing according to the second embodiment will be described with reference to Fig. 16. In the processing shown in Fig. 16, the sensing device 20 also detects the distance to the detection target based on the sensing signal from the sensing transmitter 10.

[0100] In step S1601, the radio wave receiving unit 20a of the sensing device 20 receives the sensing signal transmitted from the sensing transmitter 10. This process is similar to the process of step S1301 shown in Fig. 13, and therefore a detailed description thereof will be omitted.

[0101] Next, the channel estimation unit 20b of the sensing device 20 calculates the phase difference of each of the reference signal symbols arranged in the OFDM resource structure for the sensing signal (step S1602). This process is similar to the process of step S1302 shown in Fig. 13, and therefore a detailed description thereof will be omitted.

[0102] Next, the demodulator 20c of the sensing device 20 demodulates the data included in the sensing signal based on the phase difference of the reference signal symbols calculated by the channel estimator 20b (step S1603). This process is similar to the process of step S1303 shown in Fig. 13, so a detailed description thereof will be omitted.

[0103] Next, the channel estimation unit 20b estimates the phase difference for each data symbol of the data demodulated in step S1303 based on the phase difference calculated in step S1602 (step S1604). This process is similar to the process of step S1305 shown in Fig. 13, so a detailed description thereof will be omitted.

[0104] Next, the propagation matrix generation unit 20d of the sensing device 20 generates a propagation matrix based on the phase difference of the reference signal symbol calculated in step S1602 and the phase difference of the data symbol estimated in step S1604 (step S1605). The propagation matrix generated in step S1605 is referred to as a "third propagation matrix" to distinguish it from the first propagation matrix and the second propagation matrix. The third propagation matrix pv ３ is expressed as in equation (8). Formula (8) In formula (8), pd ００ , pd ０１ , pd １０ , pd １１ , and pd １２pd represents the phase difference of the data symbols allocated to REs (0,0), (0,1), (1,0), (1,1), and (1,2), respectively. ００ , pd ０１ , pd １０ , pd １１ , and pd １２ is the phase difference pd of the corresponding reference signal ０２ It is estimated based on

[0105] The third propagation matrix is ​​a propagation matrix that includes a phase difference of the reference signal symbols compared to the second propagation matrix, and therefore has fewer sections without symbols. Thus, the third propagation matrix forms a more precise matrix.

[0106] Next, the detection target identification unit 20e of the sensing device 20 detects the distance to the detection target based on the third propagation matrix generated in step S1605 and the position of the sensing transmitter 10 (step S1606). This process is similar to the process of step S1307 shown in Fig. 13, and therefore a detailed description thereof will be omitted.

[0107] The second embodiment has been described above. According to the second embodiment, there is also no need to interpolate a reference signal for a section where there are no symbols, and the possibility of false detection as described above can be reduced. Furthermore, according to the second embodiment, a propagation matrix is ​​generated by combining a phase difference calculated for a reference signal symbol and a phase difference estimated for a data symbol, thereby improving the accuracy of detecting a detection target and further reducing the possibility of false detection.

[0108] 3. Third Embodiment Next, a third embodiment will be described. As described above, in the conventional technology, reference signal symbols are interpolated in sections where there are no symbols in the sensing signal. Hereinafter, this conventional technology method will be referred to as the "interpolation method." In contrast to this method, in the first and second embodiments, the phase difference of the data symbols is estimated based on the phase difference of the reference signal symbols. Hereinafter, the methods according to the first and second embodiments will be referred to as the "data symbol phase difference estimation method."

[0109] In the data symbol phase difference estimation method, the phase difference of a data symbol is estimated based on the phase difference of a reference signal symbol. The phase difference of a data symbol is not calculated from a known initial phase like the reference signal symbol, but is estimated based on the phase difference of the corresponding reference signal symbol. Therefore, the estimated phase difference of a data symbol may deviate from the actual value.

[0110] As mentioned above, the data symbol phase difference estimation method improves the accuracy of detecting the detection target compared to the interpolation method. However, depending on the communication conditions around the sensing device 20, for example, the phase difference of the sensing signal may increase due to the communication environment, resulting in a large deviation. In such a situation, the data symbol phase difference estimation method may result in lower accuracy than the interpolation method.

[0111] In the third embodiment, when performing sensing processing, it is determined whether to adopt the interpolation method or the data symbol phase difference estimation method depending on the conditions. In other words, depending on the conditions, the interpolation method, which is a conventional technique, is adopted to detect the detection target.

[0112] In the third embodiment, the sensing device 20 determines whether to use the interpolation method or the data symbol phase difference estimation method based on whether an error is detected in the data included in the sensing signal received. If there is an error in the data, the phase difference of the sensing signal may increase due to the communication environment, resulting in a higher deviation. Due to this deviation, in some cases, using the data symbol phase difference estimation method may increase the possibility of false detection compared to using the interpolation method. Therefore, in such cases, the interpolation method is used when performing the sensing process.

[0113] The functional configuration of the sensing device 20 according to the third embodiment will be described. As shown in Fig. 17, the sensing device 20 includes a radio wave receiving unit 20a, a channel estimating unit 20b, a demodulating unit 20c, a propagation matrix generating unit 20d, and a detection target identifying unit 20e, as well as a decoding unit 20f and an error detecting unit 20g. The radio wave receiving unit 20a, the channel estimating unit 20b, the demodulating unit 20c, the propagation matrix generating unit 20d, and the detection target identifying unit 20e are the same as those described in the first embodiment, and therefore detailed description thereof will be omitted.

[0114] The decoding unit 20f decodes the data demodulated by the demodulation unit 20c. The decoding unit 20f is realized by the control unit 210 / processor 201.

[0115] The error detection unit 20g detects errors in the data decoded by the decoding unit 20f. Errors may be detected using, for example, a cyclic redundancy check (CRC) code added to the sensing signal data. The error detection unit 20g is realized by the control unit 210 / processor 201.

[0116] An example of sensing processing according to the third embodiment will be described with reference to Fig. 18. In the processing shown in Fig. 18, the sensing device 20 also detects the distance to the detection target based on the sensing signal from the sensing transmitter 10.

[0117] In step S1801, the radio wave receiving unit 20a of the sensing device 20 receives the sensing signal transmitted from the sensing transmitter 10. This process is similar to the process of step S1301 shown in Fig. 13, and therefore a detailed description thereof will be omitted.

[0118] Next, the channel estimation unit 20b of the sensing device 20 calculates the phase difference of each of the reference signal symbols arranged in the OFDM resource structure for the sensing signal (step S1802). This process is similar to the process of step S1302 shown in Fig. 13, and therefore a detailed description thereof will be omitted.

[0119] Next, the demodulator 20c of the sensing device 20 demodulates the data included in the sensing signal based on the phase difference of the reference signal symbols calculated by the channel estimator 20b (step S1803). This process is similar to the process of step S1303 shown in Fig. 13, so a detailed description thereof will be omitted.

[0120] Next, the propagation matrix generation unit 20d of the sensing device 20 generates a first propagation matrix for each reference signal symbol based on the phase difference calculated by the channel estimation unit 20b (step S1804). This process is similar to the process of step S1304 shown in Fig. 13, and therefore a detailed description thereof will be omitted.

[0121] Next, the decoding unit 20f of the sensing device 20 decodes the data demodulated by the demodulation unit 20c in step S1803 (step S1805).

[0122] Next, the error detection unit 20g of the sensing device 20 determines whether or not an error has occurred based on the data decoded by the decoding unit 20f in step S1805 (step S1806). As described above, errors are detected using the CRC code added to the data.

[0123] If it is determined in step S1806 that no error has occurred, the process proceeds to step S1807. On the other hand, if it is determined that an error has occurred, the process proceeds to step S1809.

[0124] In step S1807, the channel estimation unit 20b estimates a phase difference for each data symbol of the data demodulated in step S1803 based on the phase difference calculated in step S1802. This process is similar to the process of step S1305 shown in Fig. 13, and therefore a detailed description thereof will be omitted.

[0125] Next, the propagation matrix generation unit 20d generates a second propagation matrix based on the phase difference of the data symbols estimated in step S1807 (step S1808). This process is similar to the process of step S1306 shown in Fig. 13, and therefore a detailed description thereof will be omitted.

[0126] In step S1808, the first propagation matrix and the second propagation matrix may be combined to generate a third propagation matrix, as described in the second embodiment. In this case, in the subsequent step S1810, the third propagation matrix may be used instead of the second propagation matrix.

[0127] In step S1809, the propagation matrix generation unit 20d interpolates a section where there is no symbol in the first propagation matrix generated in step S1804 using a reference signal. This process corresponds to the interpolation process according to the prior art.

[0128] Next, the detection target identification unit 20e of the sensing device 20 detects the distance to the detection target (step S1810) based on the second propagation matrix generated in step S1808 or the first propagation matrix interpolated in step S1809, and the position of the sensing transmitter 10. This process is similar to the process of step S1307 shown in Fig. 13, and therefore a detailed description thereof will be omitted.

[0129] As described above, the third embodiment has been described. According to the third embodiment, by employing a data symbol phase difference estimation method, it is possible to prevent an increase in the possibility of erroneous detection due to the communication environment.

[0130] 4. Fourth Embodiment Next, a fourth embodiment will be described. In the fourth embodiment, when a sensing process is executed, it is determined whether to employ the interpolation method or the data symbol phase difference estimation method depending on the conditions.

[0131] The functional configuration of the sensing device 20 according to the fourth embodiment will be described. As shown in Fig. 19, the sensing device 20 includes a radio wave receiving unit 20a, a channel estimating unit 20b, a demodulating unit 20c, a propagation matrix generating unit 20d, and a detection target identifying unit 20e, as well as a signal-to-noise and interference ratio estimating unit 20h. The radio wave receiving unit 20a, the channel estimating unit 20b, the demodulating unit 20c, the propagation matrix generating unit 20d, and the detection target identifying unit 20e are the same as those described in the first embodiment, and therefore detailed description thereof will be omitted.

[0132] The signal-to-noise and interference ratio estimator 20h estimates the signal-to-noise and interference ratio of the received signal based on the signal power and noise power of the signal received from the sensing transmitter 10 and other devices. The signal-to-noise and interference ratio estimator 20h is realized by the control unit 210 / processor 201.

[0133] An example of sensing processing according to the fourth embodiment will be described with reference to Fig. 20. In the processing shown in Fig. 20, the sensing device 20 also detects the distance to the detection target based on the sensing signal from the sensing transmitter 10.

[0134] In step S2001, the radio wave receiving unit 20a of the sensing device 20 receives the sensing signal transmitted from the sensing transmitter 10. This process is similar to the process of step S1301 shown in Fig. 13, and therefore a detailed description thereof will be omitted.

[0135] Next, the channel estimation unit 20b of the sensing device 20 calculates the phase difference of each of the reference signal symbols arranged in the OFDM resource structure for the sensing signal (step S2002). This process is similar to the process of step S1302 shown in Fig. 13, and therefore a detailed description thereof will be omitted.

[0136] Next, the demodulator 20c of the sensing device 20 demodulates the data included in the sensing signal based on the phase difference of the reference signal symbols calculated by the channel estimator 20b (step S2003). This process is similar to the process of step S1303 shown in Fig. 13, so a detailed description thereof will be omitted.

[0137] Next, the propagation matrix generation unit 20d of the sensing device 20 generates a first propagation matrix for each reference signal symbol based on the phase difference calculated by the channel estimation unit 20b (step S2004). This process is similar to the process of step S1304 shown in Fig. 13, and therefore a detailed description thereof will be omitted.

[0138] Next, the signal-to-noise and interference ratio estimation unit 20h of the sensing device 20 estimates the signal-to-noise and interference ratio of the sensing signal based on the signal power of the sensing signal received by the radio wave receiving unit 20a in step S2001. Then, the signal-to-noise and interference ratio estimation unit 20h determines whether the estimated signal-to-noise and interference ratio is equal to or less than a predetermined value, for example, 1 (step S2005).

[0139] If it is determined in step S2005 that the signal-to-noise-and-interference ratio is equal to or less than the predetermined value, the process proceeds to step S2006. On the other hand, if it is determined that the signal-to-noise-and-interference ratio is greater than the predetermined value, the process proceeds to step S2008.

[0140] In step S2006, the channel estimation unit 20b estimates a phase difference for each data symbol of the data demodulated in step S2003 based on the phase difference calculated in step S2002. This process is similar to the process of step S1305 shown in Fig. 13, and therefore a detailed description thereof will be omitted.

[0141] Next, the propagation matrix generation unit 20d generates a second propagation matrix based on the phase difference of the data symbols estimated in step S2006 (step S2007). This process is similar to the process of step S1306 shown in Fig. 13, so a detailed description thereof will be omitted.

[0142] In step S2007, the first propagation matrix and the second propagation matrix may be combined to generate a third propagation matrix, as described in the second embodiment. In this case, in the subsequent step S2009, the third propagation matrix may be used instead of the second propagation matrix.

[0143] In step S2008, the propagation matrix generation unit 20d interpolates a section where there is no symbol in the first propagation matrix generated in step S2004 using a reference signal. This process corresponds to the interpolation process according to the prior art.

[0144] Next, the detection target identification unit 20e of the sensing device 20 detects the distance to the detection target (step S2009) based on the second propagation matrix generated in step S2007 or the first propagation matrix interpolated in step S2008, and the position of the sensing transmitter 10. This process is similar to the process of step S1307 shown in Fig. 13, and therefore a detailed description thereof will be omitted.

[0145] As described above, the fourth embodiment has been described. The fourth embodiment also employs a data symbol phase difference estimation method, thereby making it possible to prevent an increase in the possibility of erroneous detection due to the communication environment.

[0146] 5. Fifth Embodiment Next, a fifth embodiment will be described. As described above, reference signal symbols included in a sensing signal may not be arranged at equal intervals in an OFDM resource structure. The fact that the reference signal symbols are not arranged at equal intervals may cause false detection.

[0147] In accordance with the 5G NR specification, in the OFDM resource structure, a guard interval called a cyclic prefix (CP) is inserted at the beginning of each OFDM symbol to prevent interference between symbols. In the 5G NR specification, the CP length varies for each inserted CP. The difference in CP length for each inserted CP causes reference signal symbols to be arranged at uneven intervals, and therefore data symbols to be arranged at uneven intervals. In this embodiment, the phase difference of the data symbols is corrected based on the CP length of the inserted CP.

[0148] The functional configuration of the sensing device 20 according to the fifth embodiment will be described. As shown in Fig. 21 , the sensing device 20 includes a radio wave receiving unit 20a, a channel estimating unit 20b, a demodulating unit 20c, a propagation matrix generating unit 20d, and a detection target identifying unit 20e, as well as a phase difference correcting unit 20i. The radio wave receiving unit 20a, the channel estimating unit 20b, the demodulating unit 20c, the propagation matrix generating unit 20d, and the detection target identifying unit 20e are the same as those described in the first embodiment, and therefore detailed description thereof will be omitted.

[0149] The phase difference correction unit 20i corrects the phase difference of the reference signal symbol based on the CP length of the CP arranged in the OFDM resource structure. The phase difference correction unit 20i is realized by the control unit 210 / processor 201.

[0150] An example of sensing processing according to the fifth embodiment will be described with reference to Fig. 22. In the processing shown in Fig. 22 as well, the sensing device 20 detects the distance to the detection target based on the sensing signal from the sensing transmitter 10.

[0151] In step S2201, the radio wave receiving unit 20a of the sensing device 20 receives the sensing signal transmitted from the sensing transmitter 10. This process is similar to the process of step S1301 shown in Fig. 13, and therefore a detailed description thereof will be omitted.

[0152] Next, the channel estimation unit 20b of the sensing device 20 calculates the phase difference of each of the reference signal symbols arranged in the OFDM resource structure for the sensing signal (step S2202). This process is similar to the process of step S1302 shown in Fig. 13, and therefore a detailed description thereof will be omitted.

[0153] Next, the demodulator 20c of the sensing device 20 demodulates the data included in the sensing signal based on the phase difference of the reference signal symbols calculated by the channel estimator 20b (step S2203). This process is similar to the process of step S1203 shown in Fig. 13, so a detailed description thereof will be omitted.

[0154] Next, the propagation matrix generation unit 20d of the sensing device 20 generates a first propagation matrix for each reference signal symbol based on the phase difference calculated by the channel estimation unit 20b (step S2204). This process is similar to the process of step S1304 shown in Fig. 13, and therefore a detailed description thereof will be omitted.

[0155] Next, the channel estimation unit 20b estimates the phase difference for each data symbol of the data demodulated in step S2203 based on the phase difference calculated in step S2202 (step S2205). This process is similar to the process of step S1305 shown in Fig. 13, so a detailed description will be omitted.

[0156] Next, the phase difference corrector 20i corrects the phase difference of the data symbol estimated in step 2205 based on the CP length of the corresponding CP (step S2206). An example of correcting the phase difference will be described with reference to FIG.

[0157] FIG. 23 shows slot 1 and slot 2 in the OFDM resource structure. CP1 is placed at the beginning of slot 1, and CP2 is placed at the beginning of slot 2. That is, a CP is placed at the beginning of each predetermined time unit. Furthermore, reference signal symbol RS1 is placed in slot 1, and RS2 is placed in slot 2. All data symbols in slot 1 are associated with RS1, and all data symbols in slot 2 are associated with RS2. That is, the phase difference of each data symbol in slot 1 is estimated based on the phase difference of RS1, and the phase difference of each data symbol in slot 2 is estimated based on the phase difference of RS2.

[0158] As shown in Fig. 23, for example, the data symbols in slot 1 are shifted on the time axis by the CP length of CP1. Therefore, the phase difference correction unit 20i calculates, for example, the phase difference pd １ may be estimated as follows: In equation (9), id １ represents the initial phase of RS1. １ represents the reception phase of RS1. 1s is the phase difference corresponding to one symbol on the time axis. １ is the phase difference corresponding to the CP length of CP1.

[0159] Phase difference pd of DS1１ is corrected based on the CP length of the corresponding CP1. The correction of the data symbol may also be based on the difference in CP length between the CPs. For example, when the CP length of CP2 is longer than the CP length of CP1, the phase difference correction unit 20i corrects the phase difference pd ２ may be estimated as follows: In equation (10), id ２ represents the initial phase of RS2. ２ represents the reception phase of RS2. 1s is the phase difference corresponding to one symbol on the time axis. １ is the phase difference corresponding to the CP length of CP1, and cp ２ is the phase difference corresponding to the CP length of CP2.

[0160] As explained above, the phase difference pd of DS2 ２ In the example shown in equation (10), the CP length of CP1 is used as a reference, and the phase difference pd ２ is corrected.

[0161] 22 , the propagation matrix generation unit 20d generates a second propagation matrix based on the phase difference of the data symbols corrected in step S2206 (step S2207). Note that in step S2207, as described in the second embodiment, the first propagation matrix and the second propagation matrix may be combined to generate a third propagation matrix.

[0162] Next, the detection target identification unit 20e of the sensing device 20 detects the distance to the detection target based on the second propagation matrix generated in step S2207 and the position of the sensing transmitter 10 (step S2208). This process is similar to the process of step S1307 shown in Fig. 13, and therefore a detailed description thereof will be omitted.

[0163] As described above, the fifth embodiment has been described. According to the fifth embodiment, the phase difference of the data symbols is corrected based on the CP length, and therefore the data symbols are arranged at equal intervals, thereby improving the accuracy of detecting the detection target and further reducing the possibility of false detection.

[0164] 6. Other Embodiments In the above-described embodiment, the phase difference of a data symbol is estimated based on the phase difference of the corresponding reference signal symbol. An example has been described in which a value to be added to or subtracted from the estimated phase difference is calculated for each data symbol based on its position relative to the corresponding reference signal symbol on the frequency and / or time axis. This example improves detection accuracy, but imposes a heavy computational load.

[0165] Alternatively, an example has been described in which a common value to be added to or subtracted from the estimated phase difference is calculated based on the position of one of the data symbols, such as the data symbol that is positioned closest to the reference signal symbol on the frequency and / or time axis, among the data symbols corresponding to the reference signal symbol. This example has lower detection accuracy than the above-mentioned method, but also has a lower calculation load.

[0166] Furthermore, an example has been described in which the above-mentioned common value is a fixed value. This example has even lower detection accuracy than the above-mentioned method, but also has an even lower calculation load. Furthermore, an example has been described in which the phase difference of the data symbol is set to the same value as the phase difference of the corresponding reference signal symbol. This example has even lower detection accuracy than the above-mentioned method, but also has an even lower calculation load.

[0167] Which of the above-mentioned methods is to be adopted is determined in consideration of the balance between detection accuracy and calculation load. For example, as described in the third and fourth embodiments, which method to adopt may be determined depending on the communication conditions around the sensing device 20.

[0168] In the above-described embodiment, the communication status around the sensing device 20 is determined based on whether an error has occurred in the data included in the sensing device or whether the signal-to-noise and interference ratio of the sensing signal is equal to or less than a predetermined value. In addition to the above-described example, the communication status may be determined based on, for example, a result of measuring channel state information (CSI).

[0169] While the embodiments for carrying out the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments. It is to be understood that the above-described embodiments are merely examples and that various modifications are possible.

[0170] The words, phrases, and other expressions used in the above embodiments are merely examples and may be replaced with substantially identical or similar expressions. In particular, since the technology according to the above embodiments relates to technical specifications, the expressions in the above embodiments may be replaced with substantially identical or similar expressions in technical specifications (e.g., technical specifications cited in this specification).

[0171] The information transmitted and received in the above embodiment may be contained in the same or a different message or element already described in the technical specifications, or may be contained in a newly defined message or element. The information transmitted and received in the above embodiment may be transmitted and received using a different layer and / or a different channel than those in the above embodiment.

[0172] The means and / or functions provided by the devices described in the above embodiments can be provided by software recorded in a tangible memory device and a computer that executes the software, software alone, hardware alone, or a combination thereof. For example, if any of the above devices is provided by an electronic circuit that is hardware, it can be provided by a digital circuit including a large number of logic circuits, or an analog circuit.

[0173] The device described in the above embodiment executes a program stored in a non-transitory tangible storage medium, and the execution of the program executes a method corresponding to the program.

[0174] 8. Supplementary Notes Some or all of the above embodiments and modified examples may also be described as in the following supplementary notes, but are not limited to the contents of the supplementary notes. Below, a relationship is expressed in which a supplementary note that is dependent on multiple supplementary notes is dependent on another supplementary note that is dependent on multiple supplementary notes. All of the dependency relationships of the supplementary notes expressed below are included in the above embodiments.

[0175] (Supplementary Note 1) A sensing device (20) comprising a control unit (210) and a communication unit (220), wherein the communication unit is configured to receive a sensing signal from a sensing transmitter (10), and the control unit is configured to: calculate a phase difference of a reference signal included in the sensing signal; demodulate data included in the sensing signal; estimate a phase difference of the demodulated data based on the phase difference of the reference signal; generate a propagation matrix based on the phase difference of the data; and detect a detection target based on the propagation matrix.

[0176] (Supplementary Note 2) The sensing device according to Supplementary Note 1, wherein the control unit is further configured to associate the data with the reference signal, and estimate a phase difference of the data based on a phase difference of the reference signal associated with the data.

[0177] (Supplementary Note 3) The sensing device according to Supplementary Note 1 or 2, wherein the data is arranged in an OFDM resource structure as a data symbol, and the reference signal is arranged in the OFDM resource structure as a reference signal symbol.

[0178] (Supplementary Note 4) The sensing device according to Supplementary Note 3, wherein the control unit is further configured to associate the data with the reference signal based on positions of the data symbols and the reference signal symbols on a frequency and / or time axis.

[0179] (Supplementary Note 5) The sensing device according to Supplementary Note 4, wherein the control unit is further configured to add or subtract a value calculated based on the position of the data symbol relative to the reference signal symbol on the frequency and / or time axis to or from the phase difference of the data.

[0180] (Supplementary Note 6) The sensing device described in Supplementary Note 5, wherein the control unit is further configured to associate a plurality of data symbols with the reference signal symbol, and for each of the plurality of data symbols, add or subtract a value calculated based on the position of the data symbol on the frequency and / or time axis relative to the reference signal symbol to the phase difference of the data.

[0181] (Supplementary Note 7) The sensing device described in Supplementary Note 5, wherein the control unit is further configured to: associate a plurality of data symbols with the reference signal symbol; calculate a common value based on the position of any of the plurality of data symbols on the frequency and / or time axis relative to the reference signal symbol; and add or subtract the common value to or from the phase difference of each of the plurality of data symbols.

[0182] (Supplementary Note 8) The sensing device described in Supplementary Note 5, wherein the control unit is further configured to: associate multiple data symbols with the reference signal symbols; and add or subtract a predetermined fixed value to the phase difference of each of the multiple data symbols.

[0183] (Supplementary Note 9) The sensing device according to any one of Supplementary Notes 1 to 8, wherein the control unit is further configured to generate the propagation matrix further based on a phase difference of the reference signal.

[0184] (Supplementary Note 10) The sensing device described in any one of Supplementary Notes 1 to 9, wherein the control unit is further configured to determine a communication state around the sensing device, and, depending on the communication state, determine whether to perform the following: estimating a phase difference of the demodulated data based on a phase difference of the reference signal; and generating a propagation matrix based on the phase difference of the data.

[0185] (Supplementary Note 11) The sensing device according to Supplementary Note 10, wherein the control unit is further configured to determine the communication status by: decoding the demodulated data; and determining whether or not an error has occurred in the decoded data.

[0186] (Supplementary Note 12) The sensing device according to Supplementary Note 10, wherein the control unit is further configured to determine the communication status by estimating a signal-to-noise and interference ratio of the sensing signal and determining whether the signal-to-noise and interference ratio is equal to or less than a predetermined value.

[0187] (Supplementary Note 13) The sensing device according to Supplementary Note 3, wherein a CP is arranged in the OFDM resource structure, and the control unit is further configured to correct a phase difference of the data based on a CP length of the CP.

[0188] (Supplementary Note 14) The sensing device according to Supplementary Note 13, wherein the control unit is further configured to correct a phase difference of the data based on a phase difference corresponding to the CP length.

[0189] (Supplementary Note 15) The sensing device described in Supplementary Note 13, wherein a CP is arranged for each predetermined time unit, and the control unit is further configured to correct a phase difference of the data based on a phase difference corresponding to a difference between a CP length of a first CP and a CP length of a second CP among the CPs.

[0190] (Supplementary Note 16) A method executed by a sensing device (20), comprising: receiving a sensing signal from a sensing transmitter (10); calculating a phase difference of a reference signal included in the sensing signal; demodulating data included in the sensing signal; estimating a phase difference of the demodulated data based on the phase difference of the reference signal; generating a propagation matrix based on the phase difference of the data; and detecting a detection target based on the propagation matrix.

[0191] (Supplementary Note 17) A program that, when executed, causes a processor (101) in a sensing device (20) to perform the following: receiving a sensing signal from a sensing transmitter (10); calculating a phase difference of a reference signal included in the sensing signal; demodulating data included in the sensing signal; estimating a phase difference of the demodulated data based on the phase difference of the reference signal; generating a propagation matrix based on the phase difference of the data; and detecting a detection target based on the propagation matrix.

[0192] (Supplementary Note 18) A computer-readable non-transient tangible recording medium storing a program that, when executed, causes a processor (101) in a sensing device (20) to perform the following: receive a sensing signal from a sensing transmitter (10); calculate a phase difference of a reference signal included in the sensing signal; demodulate data included in the sensing signal; estimate a phase difference of the demodulated data based on the phase difference of the reference signal; generate a propagation matrix based on the phase difference of the data; and detect a detection target based on the propagation matrix.

[0193] The disclosures of the above prior art documents and references are incorporated herein by reference.

Claims

1. A sensing device (20) comprising a control unit (210) and a communication unit (220), wherein the communication unit is configured to receive a sensing signal from a sensing transmitter (10), and the control unit is configured to: calculate a phase difference of a reference signal included in the sensing signal; demodulate data included in the sensing signal; estimate a phase difference of the demodulated data based on the phase difference of the reference signal; generate a propagation matrix based on the phase difference of the data; and detect a detection target based on the propagation matrix.

2. The sensing device according to claim 1, wherein the control unit is further configured to: associate the data with the reference signal; and estimate a phase difference of the data based on a phase difference of the reference signal associated with the data.

3. The sensing device according to claim 1, wherein the data is arranged in an OFDM resource structure as a data symbol, and the reference signal is arranged in the OFDM resource structure as a reference signal symbol.

4. The sensing device according to claim 3, wherein the control unit is further configured to associate the data with the reference signal based on the positions of the data symbols and the reference signal symbols on the frequency and / or time axis.

5. The sensing device of claim 4, wherein the control unit is further configured to add or subtract a value calculated based on the position of the data symbol relative to the reference signal symbol on the frequency and / or time axis to the phase difference of the data.

6. The sensing device of claim 5, wherein the control unit is further configured to associate a plurality of data symbols with the reference signal symbol, and, for each of the plurality of data symbols, to add or subtract a value calculated based on the position of the data symbol on the frequency and / or time axis relative to the reference signal symbol to the phase difference of the data.

7. The sensing device of claim 5, wherein the control unit is further configured to: associate a plurality of data symbols with the reference signal symbol; calculate a common value based on the position of any one of the plurality of data symbols relative to the reference signal symbol on the frequency and / or time axis; and add or subtract the common value from the phase difference of each of the plurality of data symbols.

8. The sensing device of claim 5, wherein the control unit is further configured to: associate a plurality of data symbols with the reference signal symbols; and add or subtract a predetermined fixed value to the phase difference between each of the plurality of data symbols.

9. The sensing device according to claim 1, wherein the control unit is further configured to generate the propagation matrix further based on a phase difference of the reference signal.

10. The sensing device of claim 1, wherein the control unit is further configured to: determine a communication state around the sensing device; and, depending on the communication state, determine whether to perform the following: estimating a phase difference of the demodulated data based on the phase difference of the reference signal; and generating a propagation matrix based on the phase difference of the data.

11. The sensing device according to claim 10, wherein the control unit is further configured to determine the communication status by: decoding the demodulated data; and determining whether or not an error has occurred in the decoded data.

12. The sensing device according to claim 10, wherein the control unit is further configured to determine the communication status by: estimating a signal-to-noise and interference ratio of the sensing signal; and determining whether the signal-to-noise and interference ratio is equal to or less than a predetermined value.

13. The sensing device according to claim 3, wherein a CP is arranged in the OFDM resource structure, and the control unit is further configured to correct a phase difference of the data based on a CP length of the CP.

14. The sensing device according to claim 13, wherein the control unit is further configured to correct a phase difference of the data based on a phase difference corresponding to the CP length.

15. The sensing device of claim 13, wherein a CP is arranged for each predetermined time unit, and the control unit is further configured to correct the phase difference of the data based on a phase difference corresponding to a difference between the CP length of a first CP and the CP length of a second CP among the CPs.

16. A method performed by a sensing device (20), comprising: receiving a sensing signal from a sensing transmitter (10); calculating a phase difference of a reference signal included in the sensing signal; demodulating data included in the sensing signal; estimating a phase difference of the demodulated data based on the phase difference of the reference signal; generating a propagation matrix based on the phase difference of the data; and detecting a detection target based on the propagation matrix.

17. A program that, when executed, causes a processor (101) in a sensing device (20) to perform the following: receive a sensing signal from a sensing transmitter (10); calculate a phase difference of a reference signal included in the sensing signal; demodulate data included in the sensing signal; estimate a phase difference of the demodulated data based on the phase difference of the reference signal; generate a propagation matrix based on the phase difference of the data; and detect a detection target based on the propagation matrix.

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