Wireless communication system and method for estimating Doppler shift amount

Abstract

Provided is a wireless communication system wherein: a plurality of transmission devices are each provided with a transmission unit that transmits a wireless signal; a wireless communication device is provided with one or more antennae that receive wireless signals transmitted from the plurality of transmission devices and a waveform transmission unit that transmits, to a reception device, waveform data which indicates the waveform of reception signals received by the one or more antennae; and the reception device is provided with a reception unit that receives the waveform data transmitted by the wireless communication device, a signal storage unit that stores a reception signal which indicates the waveform data received by the reception unit, an information conversion unit that converts the reception signal of a prescribed period stored by the signal storage unit into an information matrix of two or more dimensions, a frame detection unit that detects the beginning and frame length of a plurality of frames included in the reception signal for the prescribed period by performing feature amount detection in the information matrix of two or more dimensions, and an estimation unit that estimates at least the Doppler shift amount of each frame on the basis of the information matrix of two or more dimensions and of the beginning and frame length of the plurality of frames.　

Description

[Technical Field]

[0001] The present invention relates to a wireless communication system and a method for estimating a Doppler shift amount. [Background technology]

[0002] With the development of IoT (Internet of Things) technology, the installation of IoT terminals equipped with various sensors in various locations is being considered. IoT terminals may be installed in places where it is difficult to install base stations, such as on marine buoys, ships, and mountainous areas. Therefore, a system has been proposed in which data collected by IoT terminals installed in various locations is relayed to base stations installed on the ground by relay devices installed on low-earth orbit satellites.

[0003] In a satellite sensing platform, signals transmitted from each IoT device experience different Doppler shifts depending on the device's location. As a result, signals with different Doppler shifts within a frame arrive at the receiving antenna of a low-earth orbit satellite at random times. Preambles also experience different Doppler shifts for each IoT device, making time synchronization processing based on correlation with known signals difficult. Non-Patent Document 1 proposes DFS (Doppler frequency shift) estimation using preambles and postambles. [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] “Data-Aided Doppler frequency shift estimation and compensation for UAVs”, IEEE Internet of things journal., vol.1. no.1. jan. 2020. Summary of the Invention [Problem to be solved by the invention]

[0005] However, in communication systems with low data rates, the overhead becomes a problem, and conventionally, it has been impossible to estimate the amount of Doppler shift for multiple signals that have undergone different Doppler shifts without performing correlation detection or the like.

[0006] In view of the above circumstances, an object of the present invention is to provide a technology that can detect signal frames and estimate the amount of Doppler shift for multiple signals that have undergone different Doppler shifts, without incurring overhead due to the insertion of a dedicated preamble for time synchronization. [Means for solving the problem]

[0007] One aspect of the present invention is a wireless communication system having a plurality of transmitting devices, a mobile wireless communication device, and a receiving device, wherein the plurality of transmitting devices are equipped with a transmitting unit that transmits wireless signals, the wireless communication device is equipped with one or more antennas that receive the wireless signals transmitted from the plurality of transmitting devices, and a waveform transmitting unit that transmits waveform data indicating a waveform of the received signals received by the one or more antennas to the receiving device, and the receiving device is equipped with a receiving unit that receives the waveform data transmitted from the wireless communication device, a signal storage unit that stores the received signals indicated by the waveform data received by the receiving unit, an information converting unit that converts the received signals for a predetermined period stored in the signal storage unit into a two- or higher dimensional information matrix, a frame detecting unit that detects the beginnings and frame lengths of a plurality of frames included in the received signals for the predetermined period by detecting features in the two- or higher dimensional information matrix, and an estimating unit that estimates at least an amount of Doppler shift of each frame based on the two- or higher dimensional information matrix and the beginnings and frame lengths of the plurality of frames detected by the frame detecting unit. The two-dimensional or higher information matrix is ​​a time- and frequency-based spectrogram and a power-based spectrogram. It is a wireless communication system.

[0008] One aspect of the present invention is a wireless communication system having a plurality of transmitting devices, a mobile wireless communication device, and a receiving device. Doppler shift estimation method the plurality of transmitting devices transmit radio signals, the wireless communication device transmits waveform data to the receiving device indicating waveforms of received signals received by one or more antennas that receive the radio signals transmitted from the plurality of transmitting devices, the receiving device receives the waveform data transmitted by the wireless communication device, the receiving device converts the received signals for a predetermined period stored in a signal storage unit that stores the received signals indicated by the received waveform data into a two- or more dimensional information matrix, the receiving device detects the beginnings and frame lengths of a plurality of frames included in the received signals for the predetermined period by detecting features in the two- or more dimensional information matrix, and estimates the Doppler shift amount of at least each frame based on the two- or more dimensional information matrix and the detected beginnings and frame lengths of the plurality of frames. The two-dimensional or higher dimensional information matrix is ​​a spectrogram based on time and frequency, and a spectrogram based on power. , a method for estimating the amount of Doppler shift. [Effects of the Invention]

[0009] According to the present invention, it is possible to detect signal frames and estimate the amount of Doppler shift for a plurality of signals that have undergone different Doppler shifts without incurring overhead due to the insertion of a dedicated preamble for time synchronization. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a configuration diagram of a wireless communication system according to an embodiment. [Figure 2] FIG. 10 is a diagram showing an example of received waveform information obtained by a base station. [Figure 3] FIG. 1 is a diagram illustrating an example of a spectrogram based on time and frequency. [Figure 4] FIG. 2 is a sequence diagram showing a flow of a reception process of the wireless communication system according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. 1 is a configuration diagram of a wireless communication system 1 according to an embodiment. The wireless communication system 1 has a plurality of terminal stations 20, mobile relay stations 30, and base stations 40. The wireless communication system 1 may have any number of terminal stations 20, mobile relay stations 30, and base stations 40. It is assumed that the number of terminal stations 20 is large.

[0012] The terminal station 20 collects data such as environmental data detected by a sensor and transmits it wirelessly to the mobile relay station 30. For example, when the mobile relay station 30 instructs the terminal station 20 on a transmission timing, the terminal station 20 wirelessly transmits the collected data to the mobile relay station 30 at the instructed transmission timing. The terminal station 20 is, for example, an IoT (Internet of Things) terminal. The terminal station 20 is one aspect of a transmission device.

[0013] The mobile relay station 30 is an example of a wireless communication device that is mounted on a mobile body and whose communication area changes over time. The mobile relay station 30 of this embodiment is provided on a LEO (Low Earth Orbit) satellite. The altitude of the LEO satellite is 2000 km or less, and it orbits the Earth once every 1.5 hours. The terminal station 20 and the base station 40 are installed on the Earth, such as on land or sea. Hereinafter, a wireless signal transmitted from the terminal station 20 to the mobile relay station 30 will be referred to as a terminal uplink signal, and a signal transmitted from the mobile relay station 30 to the base station 40 will be referred to as a base station downlink signal.

[0014] Because the mobile relay station 30 mounted on the LEO satellite communicates while moving at high speed, the time during which each terminal station 20 and base station 40 can communicate with the mobile relay station 30 is limited. Specifically, from the ground, the mobile relay station 30 passes overhead every few minutes. The terminal station 20 collects and stores data such as environmental data detected by sensors. The terminal station 20 transmits a terminal uplink signal containing the collected data at a timing when communication with the mobile relay station 30 is possible. The mobile relay station 30 receives terminal uplink signals transmitted from each of the multiple terminal stations 20 while moving above the Earth. The mobile relay station 30 accumulates the data received from each terminal station 20 via the terminal uplink signal and wirelessly transmits the accumulated data to the base station 40 via a base station downlink signal at a timing when communication with the base station 40 is possible. The base station 40 acquires the data collected by the terminal station 20 from the received base station downlink signal.

[0015] The mobile relay station 30 has an antenna used for wireless communication with the terminal station 20 and an antenna used for wireless communication with the base station 40. Therefore, the mobile relay station 30 can perform wireless communication with the terminal station 20 and wireless communication with the base station 40 in parallel.

[0016] Mobile relay stations can be mounted on geostationary satellites, drones, or unmanned aerial vehicles such as HAPS (High Altitude Platform Station). However, although relay stations mounted on geostationary satellites have a wide ground coverage area (footprint), their high altitude means that the link budget for IoT devices installed on the ground is very small. On the other hand, relay stations mounted on drones or HAPS have a high link budget but a narrow coverage area.

[0017] Furthermore, drones require batteries, and HAPS require solar panels. In this embodiment, a mobile relay station 30 is mounted on a LEO satellite. Therefore, the link budget is kept within limits, and since LEO satellites orbit outside the atmosphere, there is no air resistance and fuel consumption is low. The footprint is also larger than when a relay station is mounted on a drone or HAPS.

[0018] The base station 40 acquires from the mobile relay station 30 a plurality of received signals that have been subjected to different Doppler shifts due to transmission from each terminal station 20 to the mobile relay station 30, and detects the start timing of the plurality of received signals and estimates the amount of Doppler shift without performing correlation detection or the like on the acquired plurality of received signals. Furthermore, the base station 40 collectively detects signals of a plurality of communication methods based on the base station downlink signal transmitted from the mobile relay station 30. The base station 40 is one aspect of a receiving device.

[0019] The terminal station 20 and the base station 40 are installed at specific locations on the earth, such as on land or sea.

[0020] The configuration of each device will be explained. The terminal station 20 includes a data storage unit 21, a transmission unit 22, and one or more antennas 23. FIG. 1 shows a case where the terminal station 20 includes one antenna 23. The data storage unit 21 stores environmental data detected by a sensor. The transmission unit 22 communicates with the mobile relay station 30. The transmission unit 22 reads out the environmental data from the data storage unit 21 as terminal transmission data, and wirelessly transmits a terminal uplink signal in which the read terminal transmission data is set from the antenna 23.

[0021] The transmitter 22 transmits signals, for example, by LPWA (Low Power Wide Area). LPWA includes LoRaWAN (registered trademark), Sigfox (registered trademark), LTE-M (Long Term Evolution for Machines), NB (Narrow Band)-IoT, etc., but any wireless communication method can be used. The transmitter 22 may transmit signals to other terminal stations 20 by time division multiplexing, OFDM (Orthogonal Frequency Division Multiplexing), etc. The transmitter 22 may perform beamforming of signals to be transmitted from the multiple antennas 23 by a method predetermined for the wireless communication method used.

[0022] The mobile relay station 30 includes one or more antennas 31, a terminal communication unit 32, a data storage unit 33, a base station communication unit 34, and one or more antennas 35. In FIG. 1, the mobile relay station 30 includes one antenna 31 and one antenna 35.

[0023] The terminal communication unit 32 communicates wirelessly with the terminal station 20. The terminal communication unit 32 has a receiving unit 321 and a received waveform recording unit 322. The receiving unit 321 receives a terminal uplink signal via the antenna 31. The received waveform recording unit 322 samples the received waveform of the terminal uplink signal received by the receiving unit 321 and generates waveform data indicating the values ​​obtained by the sampling. The received waveform recording unit 322 writes received waveform information, which sets the reception time of the terminal uplink signal at the antenna 31 and the generated waveform data, into the data storage unit 33. The received waveform information written by the received waveform recording unit 322 is stored in the data storage unit 33.

[0024] The base station communication unit 34 transmits the received waveform information to the base station 40 by a base station downlink signal of any wireless communication method.

[0025] The base station 40 includes an antenna 41, a receiver 42, a base station signal reception processor 43, and a terminal signal reception processor 44. The receiver 42 converts the base station downlink signal received by the antenna 41 into an electrical signal. The base station signal reception processor 43 demodulates and decodes the received signal converted into an electrical signal by the receiver 42, and obtains received waveform information. The base station signal reception processor 43 outputs the received waveform information to the terminal signal reception processor 44.

[0026] The terminal signal reception processing unit 44 includes a signal storage unit 441, an information conversion unit 442, a frame detection unit 443, an estimation unit 444, a classifier 445, and a plurality of reception processing units 446-1 to 446-P (P is an integer of 2 or more).

[0027] The signal storage unit 441 stores received waveform information obtained by the base station signal reception processing unit 43.

[0028] The information converter 442 converts a plurality of pieces of received waveform information stored in the signal storage unit 441, which have been acquired over a time period sufficiently longer than the frame length of the received signal (for example, five or ten times the frame length), into an information matrix of two or more dimensions. For example, the information matrix of two or more dimensions is a spectrogram based on time and frequency.

[0029] The frame detection unit 443 detects one or more frames that have undergone a Doppler shift using a feature detection technique for the spectrogram acquired by the information conversion unit 442. Here, the frame is a frame included in the received waveform information, and is terminal transmission data from the terminal station 20. The frame detection unit 443 detects frames that have undergone a Doppler shift using, for example, line segment detection as a feature detection technique. Existing technology is used for line segment detection.

[0030] Furthermore, the frame detection unit 443 detects the frame start timing and frame length based on one or more frames detected in the spectrogram. The frame start timing indicates the time of the start of the detected frame. The frame length indicates the length of the detected frame.

[0031] The estimation unit 444 estimates the amount of Doppler shift based on one or more frames detected in the spectrogram by the frame detection unit 443. The amount of Doppler shift represents the amount of Doppler shift that has occurred in the detected frame. The estimation unit 444 outputs to the classifier 445 information on the start timing and frame length of the frame detected by the frame detection unit 443, in addition to each piece of received waveform information and the amount of Doppler shift.

[0032] The classifier 445 classifies each piece of received waveform information for each wireless communication method based on each piece of received waveform information and the estimation result output from the estimation unit 444. For example, the classifier 445 estimates the wireless communication method of each piece of received waveform information by using the frame length detected by the frame detection unit 443, the occupied bandwidth obtained from the received waveform information, and the channel used, and classifies the received waveform information for each wireless communication method.

[0033] Reception processing units 446-1 to 446-P acquire terminal transmission data by performing reception processing using the wireless communication method used for transmission by terminal station 20. Each reception processing unit 446 performs reception processing for a different wireless communication method. Each reception processing unit 446 acquires terminal transmission data by performing reception processing based on the corresponding wireless communication method on the frames classified and input by classifier 445.

[0034] The reception processing performed by the reception processing units 446-1 to 446-P includes demodulation and decoding of waveform data. Here, the reception processing units 446-1 to 446-P may perform processing to compensate for the Doppler shift of the terminal uplink signal received by the antenna 31 of the mobile relay station 30 before performing demodulation. The Doppler shift suffered by the terminal uplink signal received by the antenna 31 of the mobile relay station 30 may be estimated from the occupied bandwidth obtained from the received waveform information, or may be estimated from the slope of the result of line segment detection, or may be calculated in advance based on the position of the terminal station 20 and orbital information of the LEO on which the mobile relay station 30 is mounted. When calculating the Doppler shift based on LEO orbital information, the LEO orbital information is information about the orbit of the LEO satellite on which the mobile relay station 30 is mounted, and is information that makes it possible to obtain, for example, the position, speed, and movement direction of the LEO satellite at any time.

[0035] Next, the processing performed by base station 40 will be described with reference to Figures 2 and 3. Figure 2 is a diagram showing an example of received waveform information obtained by base station 40, and Figure 3 is a diagram showing an example of a spectrogram based on time and frequency. Figure 2 shows received waveform information of terminal uplink signals transmitted from five terminal stations 20. Information conversion unit 442 of base station 40 acquires a spectrogram based on time and frequency shown in Figure 3 using a plurality of pieces of received waveform information stored in signal storage unit 441, which have been acquired over a time period sufficiently longer than the frame length of one received signal.

[0036] Thereafter, frame detection unit 443 of base station 40 detects frames by line segment detection in the spectrogram shown in Fig. 3. In this way, frame detection unit 443 of base station 40 detects frames surrounded by circles 6-1 to 6-5 in Fig. 3. In the following description, the frame surrounded by circle 6-1 will be referred to as the first frame, the frame surrounded by circle 6-2 as the second frame, the frame surrounded by circle 6-3 as the third frame, the frame surrounded by circle 6-4 as the fourth frame, and the frame surrounded by circle 6-5 as the fifth frame.

[0037] The frame detection unit 443 of the base station 40 detects the frame start timing and frame length based on each of the detected first to fifth frames. The estimation unit 444 of the base station 40 estimates the amount of Doppler shift based on each of the detected first to fifth frames. In the example shown in FIG. 3, the frame detection unit 443 detects the start timing of the first frame as time t11, the start timing of the second frame as time t21, the start timing of the third frame as time t31, the start timing of the fourth frame as time t41, and the start timing of the fifth frame as time t51.

[0038] Furthermore, the frame detection unit 443 detects the start point and end point of the line segment in the first frame, and estimates the difference between the detected start point and end point as the frame length. In the example shown in Fig. 3, the frame detection unit 443 detects the start point "t11" and end point "t12" of the line segment in the first frame, and estimates the difference (t11 - t12) as the frame length. The frame detection unit 443 estimates the frame lengths of the second to fifth frames in a similar manner.

[0039] For example, in the example shown in FIG. 3, the frame detection unit 443 detects the start point "t21" and the end point "t22" of the line segment in the second frame and estimates the difference (t21-t22) as the frame length. For example, in the example shown in FIG. 3, the frame detection unit 443 detects the start point "t31" and the end point "t32" of the line segment in the third frame and estimates the difference (t31-t32) as the frame length. For example, in the example shown in FIG. 3, the frame detection unit 443 detects the start point "t41" and the end point "t42" of the line segment in the fourth frame and estimates the difference (t41-t42) as the frame length. For example, in the example shown in FIG. 3, the frame detection unit 443 detects the start point "t51" and the end point "t52" of the line segment in the fifth frame and estimates the difference (t51-t52) as the frame length.

[0040] The estimation unit 444 obtains the gradient of the line segment in the first frame and estimates the obtained gradient as the amount of Doppler shift in the first frame. The estimation unit 444 also estimates the amount of Doppler shift in each of the second to fifth frames in a similar manner.

[0041] In this manner, in this embodiment, the frame start timing, frame length, modulation method, and Doppler shift amount can be estimated using a simple method.

[0042] The operation of the wireless communication system 1 will now be described. FIG. 4 is a sequence diagram showing the flow of reception processing in the wireless communication system 1 according to the embodiment. The mobile relay station 30 receives a terminal uplink signal transmitted from the terminal station 20 (step S101). The mobile relay station 30 acquires received waveform information based on the received terminal uplink signal and writes the acquired received waveform information to the data storage unit 33. The base station communication unit 34 transmits the received waveform information to the base station 40 by a base station downlink signal of any wireless communication method (step S102).

[0043] The receiving unit 42 of the base station 40 receives a base station downlink signal via the antenna 41 (step S103). The receiving unit 42 converts the received base station downlink signal into an electrical signal. The base station signal receiving processing unit 43 demodulates and decodes the received signal converted into an electrical signal by the receiving unit 42 to obtain received waveform information (step S104). The base station signal receiving processing unit 43 stores the received waveform information in the signal storage unit 441 (step S105). The processing from step S101 to step S105 is executed every time a terminal uplink signal is transmitted from the terminal station 20 to the mobile relay station 30 and communication between the mobile relay station 30 and the base station 40 becomes possible.

[0044] The information conversion unit 442 acquires a spectrogram based on time and frequency using the received waveform information for a predetermined period stored in the signal storage unit 441 (step S106). The information conversion unit 442 outputs each piece of received waveform information and the acquired spectrogram to the frame detection unit 443.

[0045] The frame detection unit 443 detects one or more frames that have undergone a Doppler shift using a feature detection technique for the spectrogram acquired by the information conversion unit 442 (step S107).

[0046] The frame detection unit 443 detects the frame start timing and frame length for each of the detected one or more frames based on the detected one or more frames and the spectrogram (step S108). The frame detection unit 443 outputs each received waveform information, the spectrogram, and information related to the detected one or more frames (e.g., the frame start timing and frame length) to the estimation unit 444. The estimation unit 444 estimates the amount of Doppler shift based on the one or more frames and the spectrogram (step S109). The estimation unit 444 associates each received waveform information with the information related to the one or more frames and the estimation result (e.g., the amount of Doppler shift), and outputs them to the classifier 445.

[0047] Classifier 445 receives as input each piece of received waveform information output from estimation unit 444 and information related to one or more frames. Classifier 445 classifies each piece of received waveform information based on the input pieces of received waveform information and information related to one or more frames, and outputs each piece of received waveform information to reception processing units 446-1 to 446-P according to the classification result (step S109). For example, received waveform information corresponding to a terminal uplink signal transmitted from terminal station 20 to mobile relay station 30 using the first wireless communication scheme is output to reception processing unit 446 (e.g., reception processing unit 446-1) that performs reception processing according to the first wireless communication scheme, and received waveform information corresponding to a terminal uplink signal transmitted from terminal station 20 to mobile relay station 30 using the second wireless communication scheme is output to reception processing unit 446 (e.g., reception processing unit 446-2) that performs reception processing according to the second wireless communication scheme.

[0048] Each reception processing unit 446 acquires terminal transmission data by demodulating and decoding the input reception waveform information (step S110). This allows the base station 40 to collectively detect signal frames of multiple wireless communication methods, regardless of the preamble sequence or modulation method.

[0049] The wireless communication system 1 configured as described above enables a simple method for detecting multiple signals that have undergone different Doppler shifts. Specifically, the wireless communication system 1 stores received waveform information based on base station downlink signals transmitted from the mobile relay station 30, converts the received waveform information for a predetermined period into a two- or higher-dimensional information matrix, detects feature values ​​in the two- or higher-dimensional information matrix to detect the start timings and frame lengths of multiple frames included in the received waveform information for the predetermined period, and estimates the amount of Doppler shift for at least each frame based on the two- or higher-dimensional information matrix and the start timings and frame lengths of the multiple frames. This makes it possible to estimate the amount of Doppler shift for multiple signals that have undergone different Doppler shifts without generating overhead.

[0050] Furthermore, in the wireless communication system 1, multiple frames included in the received signal for a predetermined period are detected by detecting line segments in a two-dimensional or higher dimensional information matrix, which makes it possible to simultaneously detect signals of multiple wireless communication methods regardless of the preamble sequence or modulation method.

[0051] A modification of the wireless communication system 1 will now be described. The mobile relay station 30 may be configured to include multiple antennas 31 and receive terminal uplink signals transmitted from the terminal station 20, and the base station 40 may be configured to include multiple antennas 41 and receive base station downlink signals transmitted from the mobile relay station 30. In this configuration, the base station 40 performs detection on the antennas, corrects the deviation in the start timing due to the arrival time difference based on the detection result, and then performs MIMO equalization processing.

[0052] In the above embodiment, the mobile body on which the mobile relay station is mounted is described as a LEO satellite, but it may also be a geostationary satellite or another flying body that flies in the sky, such as a drone or HAPS.

[0053] Some or all of the processing performed by base station 40 in the above-described embodiment may be implemented by a computer. In this case, a program for implementing this function may be recorded on a computer-readable recording medium, and the program recorded on the recording medium may be loaded into a computer system and executed to implement the function. Note that the term "computer system" here includes hardware such as an OS and peripheral devices. Furthermore, the term "computer-readable recording medium" refers to portable media such as flexible disks, optical magnetic disks, ROMs, and CD-ROMs, as well as storage devices such as hard disks built into a computer system.

[0054] Furthermore, the term "computer-readable recording medium" may include a medium that dynamically stores a program for a short period of time, such as a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line, or a medium that stores a program for a fixed period of time, such as a volatile memory within a computer system that serves as a server or client in such a case. The program may also be one that realizes part of the above-mentioned functions, or one that can realize the above-mentioned functions in combination with a program already stored in the computer system, or one that can be realized using a programmable logic device such as an FPGA (Field Programmable Gate Array).

[0055] Although an embodiment of the present invention has been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and includes designs within the scope of the gist of the present invention. [Industrial Applicability]

[0056] The present invention can be applied to a technology for communicating with a mobile object equipped with a mobile relay station. [Explanation of symbols]

[0057] 1...wireless communication system, 20...terminal station, 21...data storage unit, 22...Transmitter, 30...Mobile relay station, 40...Base station, 31...antenna, 32...Terminal communication unit, 33...Data storage unit 34...Base station communication unit, 35...antenna, 41...antenna, 42...receiving unit, 43...base station signal receiving processing unit, 44...terminal signal receiving processing unit, 441...signal storage unit, 442...Information conversion unit, 443...Frame detection section 444... Estimation Department, 445...classifier, 446-1 to 446-P... Receiving processing section

Claims

1. A wireless communication system having a plurality of transmitting devices, a mobile wireless communication device, and a receiving device, the plurality of transmitting devices each include a transmitting unit that transmits a radio signal; The wireless communication device one or more antennas for receiving the radio signals transmitted from the plurality of transmitting devices; a waveform transmitting unit that transmits waveform data indicating a waveform of a received signal received by the one or more antennas to the receiving device; Equipped with The receiving device a receiving unit that receives the waveform data transmitted by the wireless communication device; a signal storage unit that stores the received signal indicated by the waveform data received by the receiving unit; an information conversion unit that converts the received signals for a predetermined period stored in the signal storage unit into an information matrix of two or more dimensions; a frame detection unit that detects the beginning and length of a plurality of frames included in the received signal for a predetermined period by detecting a feature amount in the two-dimensional or higher dimensional information matrix; an estimation unit that estimates at least the amount of Doppler shift of each frame based on the two- or more-dimensional information matrix and the beginning and frame length of the plurality of frames detected by the frame detection unit; Equipped with A wireless communication system in which the two or more dimensional information matrix is ​​a time- and frequency-based spectrogram and a power-based spectrogram.

2. the frame detection unit detects a plurality of frames included in the received signal for a predetermined period by performing line segment detection in the two- or more dimensional information matrix.

10. The wireless communication system of claim 1.

3. a classifier that classifies the plurality of frames detected by the frame detection unit into wireless communication systems based on the detected frame length, an occupied bandwidth obtained by the received signal, and a channel used; and a plurality of reception processing units that perform reception processing according to each wireless communication system.

3. The wireless communication system according to claim 1 or 2.

4. A method for estimating a Doppler shift amount in a wireless communication system having a plurality of transmitting devices, a moving wireless communication device, and a receiving device, comprising: the plurality of transmitting devices transmit radio signals; the wireless communication device transmits to the receiving device waveform data indicating waveforms of received signals received by one or more antennas that receive the wireless signals transmitted from the plurality of transmitting devices; the receiving device receives the waveform data transmitted by the wireless communication device; the receiving device converts the received signals for a predetermined period stored in a signal storage unit that stores the received signals indicated by the received waveform data into an information matrix of two or more dimensions; the receiving device detects the beginnings and frame lengths of a plurality of frames included in the received signal for a predetermined period by detecting features in the two- or more-dimensional information matrix; estimating a Doppler shift amount for at least each frame based on the two-dimensional or higher information matrix and the beginning and frame length of the detected plurality of frames; The two-dimensional or higher dimensional information matrix is ​​a time- and frequency-based spectrogram and a power-based spectrogram. Doppler shift estimation method.

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