Wireless communication system, position estimation method, and wireless communication device

Abstract

This wireless communication system comprises a first communication device and one or more second communication devices that communicate with the first communication device. The first communication device comprises: a wireless unit that forms a plurality of candidate beams in different directions and transmits a signal for each of the candidate beams, the wireless unit receiving a response to the signal received by the one or more second communication devices; a wireless control unit that acquires quality information related to the candidate beams for each of the candidate beams on the basis of the response received by the wireless unit; and a position estimating unit that refers to correspondence information in which the quality information for each of the candidate beams is associated with position information, and estimates the position of the one or more second communication devices on the basis of the quality information acquired by the wireless control unit for each of the candidate beams. The one or more second communication devices transmit a response to the signal transmitted from the first communication device.　

Description

[Technical Field]

[0001] The present invention relates to a wireless communication system, a position estimation method, and a wireless communication device. [Background technology]

[0002] Examples of wireless communication using millimeter waves and quasi-millimeter waves, which are classified as high frequency bands, include 3GPP (3rd Generation Partnership Project) (registered trademark) 5G (5th Generation) NR (New Radio) and IEEE802.11ad. These wireless communication technologies have advantages such as the ability to secure a wider bandwidth than conventional microwave bands, and the ability to travel in a more directional direction, resulting in less interference with other communications. For this reason, they are being put into practical use as a means of realizing high-capacity wireless communication (see, for example, Non-Patent Document 1).

[0003] The amount of distance attenuation in a wireless propagation path increases as the frequency increases. Therefore, in millimeter-wave communications, wireless communication devices typically transmit signals by forming directional beams (beamforming) toward the other wireless communication device. It is also common for wireless communication devices to form directional beams to receive signals.

[0004] Fig. 7 is a diagram showing an example of a wireless communication system that uses beamforming in a general millimeter wave band. The wireless communication system shown in Fig. 7 includes a wireless communication device 50 and a wireless communication device 60. The wireless communication device 50 selects a beam that maximizes the received power at the opposing wireless communication device 60 from among directional beams B1 to B9 (hereinafter referred to as "candidate beams") that the wireless communication device 50 can form. In IEEE802.11ad, for example, beam selection is performed by a procedure called SLS (Sector Level Sweep) (see, for example, Non-Patent Document 2).

[0005] The SLS described in Non-Patent Document 2 will now be explained. First, the wireless communication device (initiator) that starts communication sequentially transmits signals using available beams in a time-division manner. At this time, the wireless communication device (responder) on the opposing side receives the signal transmitted from the initiator using a beam with the maximum beam width and measures the received power. The responder may also transmit signals sequentially using beams in a similar manner. Regarding the initiator's beam selection, the responder completes the beam selection by sharing with the initiator the ID of the beam that has the maximum received power.

[0006] Similarly, in 5G NR, multiple signal blocks called SS / PBCH (Synchronization Signal / Physical Broadcast CHannel) are transmitted sequentially in a time-division manner for each beam of the wireless communication device. The opposing wireless communication device reads these and feeds back information about the beam with the highest received power to the wireless communication device, completing the initial beam selection.

[0007] In addition to the large attenuation over distance in high-frequency bands, if an obstruction appears in the propagation path between the antennas of the transmitting and receiving wireless communication devices, propagation loss increases rapidly, making signal transmission difficult. For this reason, high-frequency band communications are generally assumed to be transmitted in a line-of-sight environment, where there are no obstructions between the antennas of the communicating wireless communication devices. In such cases, the direction of the beam used by a wireless communication device directly indicates the direction of the opposing wireless communication device. In addition, a wireless communication device equipped with a distance estimation function using the round-trip time (RTT) of a signal, as described in Non-Patent Document 3, can estimate the position of another wireless communication device using the signal itself transmitted from the wireless communication device.

[0008] Among wireless communication devices, if the location of a terminal station device can be determined, it is expected that advanced communication control based on the location can be realized. For example, as shown in Non-Patent Document 4, base station switching based on the location of the wireless communication device enables stable base station switching without being affected by instantaneous power fluctuations. The location of a wireless communication device is generally determined outdoors using a global navigation satellite system (GNSS) such as the global positioning system (GPS) or the global navigation satellite system (GLONASS), while indoors it is generally determined using methods such as Bluetooth (registered trademark) low energy (BLE) or ultra wide band (UWB). However, these location measurement methods require the wireless communication device to be equipped with a position measurement unit such as a dedicated antenna or a positioning wireless receiver. To estimate the location of a wireless communication device that does not have a position measurement unit, terminal positioning based on the communication signal itself is required. [Prior art documents] [Non-patent literature]

[0009] [Non-Patent Document 1] Takinami et al., "Standardization Trends and Elemental Technologies of Millimeter-Wave Wireless LAN Systems," IEICE Communications Society Magazine, Fall 2016, No. 38, pp. 100-106 [Non-patent document 2] IEEE, “Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications Amendment 3: Enhancements for Very High Throughput in the 60 GHz Band” (IEEE Std 802.11ad-2012), 2012 / 12 / 28 [Non-patent document 3] Iwakuni et al., “Experimental Evaluation of Handover Control Using Ranging Function in High-Frequency Band Wireless Communication Systems,” B-5-56, 2020 IEICE Society Conference [Non-patent document 4] T. Iwakuni, D. Uchida, S. Wai and N. Kita, “Millimeter-Wave Handover Experiment in 293 km / h Mobility Environment using Position Estimated from Wireless Communication Signal”, 2021 IEEE 94th Vehicular Technology Conference (VTC2021-Fall), 2021, pp. 1-5, doi: 10.1109 / VTC2021-Fall52928.2021.9625347. Summary of the Invention [Problem to be solved by the invention]

[0010] Terminal positioning using the communication signals themselves has an inherent problem. That is, when wireless communication devices communicating with each other are in close proximity but the direct line-of-sight path is blocked, the signal may be transmitted by being reflected by surrounding objects. FIG. 8 is a diagram for explaining the problem of terminal positioning using the communication signals themselves. FIG. 8 shows a situation in which an object 71 exists in the direct line-of-sight path between wireless communication device 50 and wireless communication device 60, and an object 72 exists in the direction of beam B9 used by wireless communication device 50.

[0011] Under such circumstances, it is not necessarily the case that the wireless communication device 60 is located in the direction of the beam used by the wireless communication device 50. For example, if the beam B9 used by the wireless communication device 50 is reflected by an object 72 located in the direction of the beam B9 and reaches the wireless communication device 60, the wireless communication device 50 may determine that the wireless communication device 60 is located in the direction of the beam B9. Therefore, there are cases where the positioning of the wireless communication device cannot be accurately determined using the communication signal itself.

[0012] In view of the above circumstances, an object of the present invention is to provide a technique that can more accurately estimate the position of a wireless communication device using signals used for communication. [Means for solving the problem]

[0013] One aspect of the present invention is a wireless communication system comprising a first communication device and one or more second communication devices that communicate with the first communication device, wherein the first communication device forms multiple candidate beams in different directions and transmits a signal for each candidate beam, and comprises a radio unit that receives responses to the signals received by the one or more second communication devices, a radio control unit that acquires quality information regarding the candidate beam for each candidate beam based on the responses received by the radio unit, and a position estimation unit that estimates the position of the one or more second communication devices based on the quality information for each candidate beam acquired by the radio control unit, by referring to correspondence information that corresponds the quality information for each candidate beam with position information, and wherein the one or more second communication devices transmit responses to the signals transmitted from the first communication device.

[0014] One aspect of the present invention is a position estimation method performed by a wireless communication system including a first communication device and one or more second communication devices that communicate with the first communication device, in which the first communication device forms multiple candidate beams in different directions and transmits a signal for each candidate beam, receives responses to the signals received by the one or more second communication devices, acquires quality information regarding the candidate beams for each candidate beam based on the received responses, refers to correspondence information in which the quality information for each candidate beam is associated with position information, and estimates the positions of the one or more second communication devices based on the acquired quality information for each candidate beam, and the one or more second communication devices transmit responses to the signals transmitted from the first communication device.

[0015] One aspect of the present invention is a wireless communication device that includes a radio unit that forms multiple candidate beams in different directions and transmits a signal for each candidate beam, and receives quality information regarding the candidate beam obtained for each signal received by an opposing device from the opposing device for each candidate beam, and a position estimation unit that estimates position information of the opposing device based on the quality information for each candidate beam received by the radio unit, by referring to correspondence information that associates the quality information for each candidate beam with position information. [Effects of the Invention]

[0016] According to the present invention, it is possible to more accurately estimate the position of a wireless communication device using signals used for communication. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a diagram illustrating an example of the configuration of a wireless communication system according to an embodiment. [Figure 2] FIG. 2 is a diagram illustrating an example of a functional configuration of a base station according to an embodiment. [Figure 3] FIG. 10 is a diagram illustrating an example of a quality information table according to the embodiment. [Figure 4] 1 is a diagram illustrating an example of the configuration of a wireless communication terminal (without a positioning function) according to an embodiment. [Figure 5] 1 is a diagram illustrating an example of the configuration of a wireless communication terminal (with a positioning function) according to an embodiment. [Figure 6] 10 is a flowchart showing the flow of a position estimation process performed by a base station in the embodiment. [Figure 7] FIG. 1 is a diagram illustrating an example of a wireless communication system that uses beamforming in a general millimeter wave band. [Figure 8] FIG. 1 is a diagram for explaining a problem with terminal positioning using a communication signal itself. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a diagram showing an example of the configuration of a wireless communication system 100 according to an embodiment. The wireless communication system 100 includes a base station 10 and a plurality of wireless communication terminals 20. Although Fig. 1 shows two wireless communication terminals 20-1 and 20-2, the wireless communication system 100 may include three or more wireless communication terminals 20.

[0019] The base station 10 communicates with the wireless communication terminals 20-1 and 20-2. For example, the base station 10 sequentially forms a plurality of candidate beams in different directions and transmits a signal for each candidate beam. A candidate beam is a beam having directivity in a specific direction. FIG. 1 shows nine candidate beams B1 to B9 as the candidate beams formed by the base station 10. The base station 10 sequentially forms, for example, candidate beams B1 to B9 and transmits a signal for each candidate beam. The candidate beams B1 to B9 have different directivities. Note that the number of candidate beams formed by the base station 10 is not particularly limited. As shown in FIG. 1, when the base station 10 forms candidate beam B9 and transmits a signal, the transmitted signal is reflected by an object 31 and reaches the wireless communication terminal 20-1.

[0020] The base station 10 receives a response from the wireless communication terminal 20 to a signal transmitted using the formed candidate beam. The base station 10 acquires quality information for each candidate beam based on the received response. The base station 10 estimates the position of the wireless communication terminal 20 based on the acquired quality information for each candidate beam. The quality information is information related to the candidate beam, and may be, for example, a received signal strength indication (RSSI) of a signal (e.g., a response) transmitted from the wireless communication terminal 20 obtained when the base station 10 uses a candidate beam, a signal-to-noise ratio (SNR) obtained by estimating noise, information for identifying which candidate beam was used, such as the ID of the candidate beam actually used for communication, or information on the transmission distance acquired by a distance estimation function (e.g., RTT), or a combination thereof.

[0021] The wireless communication terminal 20-1 communicates with the base station 10. The wireless communication terminal 20-1 is a communication device that does not have a positioning function. The positioning function is a function for determining the position of the wireless communication terminal 20. The positioning function is a function that determines the position using GNSS such as GPS or GLONASS outdoors, and a function that determines the position using a method such as BLE or UWB indoors, but either method may be used. The wireless communication terminal 20-1 receives a signal transmitted from the base station 10 and transmits a response to the received signal to the base station 10. The response may be, for example, a signal indicating that the signal transmitted from the base station 10 has been received.

[0022] The wireless communication terminal 20-2 communicates with the base station 10. The wireless communication terminal 20-2 is a communication device equipped with a positioning function. The wireless communication terminal 20-2 receives a signal transmitted from the base station 10 and transmits a response to the received signal to the base station 10. Furthermore, in response to a request from the base station 10, the wireless communication terminal 20-2 transmits to the base station 10 location information measured by the positioning function.

[0023] Depending on the positional relationship between the base station 10 and the wireless communication terminals 20-1 and 20-2, the wireless communication terminals 20-1 and 20-2 may not be able to receive all of the signals transmitted by the base station 10 using each candidate beam. Therefore, the wireless communication terminals 20-1 and 20-2 only need to transmit to the base station 10 responses to the received signals.

[0024] 2 is a diagram illustrating an example of the functional configuration of the base station 10 according to the embodiment. The base station 10 includes a data processing unit 11, a wireless control unit 12, a wireless unit 13, an antenna 14, an information management unit 15, a quality information storage unit 16, and a position estimation unit 17.

[0025] The data processing unit 11 inputs and outputs data to and from a host device located above the base station 10 or another base station. For example, the data processing unit 11 outputs the location information of the wireless communication terminal 20 estimated by the location estimation unit 17 to a host device located above the base station 10 or another base station.

[0026] The wireless control unit 12 controls the wireless unit 13. For example, the wireless control unit 12 sequentially switches between multiple candidate beams and instructs the wireless unit 13 to transmit a signal for each candidate beam. The wireless control unit 12 acquires quality information for each candidate beam based on the response for each candidate beam received by the wireless unit 13. Furthermore, when location information is received by the wireless unit 13, the wireless control unit 12 acquires the received location information.

[0027] The radio unit 13 controls the amplitude or phase of the antenna 14 to form multiple candidate beams in different directions in accordance with instructions from the radio control unit 12, and transmits signals by sequentially switching among the multiple candidate beams. The radio unit 13 receives a signal (e.g., a response) transmitted from the radio communication terminal 20 via the antenna 14.

[0028] Antenna 14 forms multiple candidate beams in different directions under the control of radio unit 13. Antenna 14 transmits signals by emitting radio waves using the formed candidate beams. Antenna 14 receives radio waves transmitted from wireless communication terminal 20 using the formed candidate beams.

[0029] The information management unit 15 associates the quality information for each candidate beam acquired by the wireless control unit 12 with the location information and registers them in the quality information storage unit 16. For example, when the information management unit 15 obtains both the quality information for each candidate beam and the location information from the wireless control unit 12, it registers the obtained quality information for each candidate beam with the location information in the quality information storage unit 16.

[0030] The quality information storage unit 16 stores a quality information table. The quality information table is a table in which information related to quality information is registered. In the quality information table, quality information for each candidate beam is associated with position information.

[0031] The position estimation unit 17 refers to the quality information table and estimates the position of the wireless communication terminal 20 based on the quality information for each candidate beam acquired by the wireless control unit 12. For example, the position estimation unit 17 estimates the position of the wireless communication terminal 20-1 that does not have a positioning function.

[0032] Fig. 3 is a diagram showing an example of a quality information table in an embodiment. As shown in Fig. 3, the quality information table has a plurality of records in which information related to quality information for each candidate beam is registered. Each record has values ​​of quality information and location information for each candidate beam. The quality information for each candidate beam registered in each record represents quality information acquired by the wireless control unit 12 based on a response received by the wireless unit 13. In Fig. 3, a value of received signal strength is registered as an example of quality information. The location information registered in each record represents location information acquired in advance by a wireless communication terminal 20 equipped with a location positioning function.

[0033] The location information may be acquired, for example, by moving the self-propelled robot to a specified location using wireless communication terminal 20 previously installed on the self-propelled robot, or by using the location positioning function of wireless communication terminal 20-2, such as a smartphone, if the wireless communication terminal 20-2 has a location positioning function. While FIG. 3 illustrates the location information as a two-dimensional value, the location information may also be three-dimensional. Furthermore, the quality information table may include information on the orientation of the antenna provided in wireless communication terminal 20.

[0034] 4 is a diagram showing an example of the configuration of a wireless communication terminal 20-1 (without a positioning function) in the embodiment. The wireless communication terminal 20-1 includes a wireless unit 21-1, an antenna 22-1, and a control unit 23-1.

[0035] The radio unit 21-1 transmits a signal via the antenna 22-1 in accordance with an instruction from the control unit 23-1. For example, the radio unit 21-1 transmits a response to the signal transmitted from the base station 10 to the base station 10.

[0036] The antenna 22-1 transmits and receives radio waves. The antenna 22-1 converts the received radio waves into electrical signals and outputs them to the radio unit 21-1. The antenna 22-1 radiates the signals output from the radio unit 21-1 as radio waves.

[0037] The control unit 23-1 controls the operation of the wireless communication terminal 20-1. For example, the control unit 23-1 controls the wireless unit 21-1 to transmit a response to a received signal.

[0038] 5 is a diagram showing an example of the configuration of a wireless communication terminal 20-2 (with a positioning function) in the embodiment. The wireless communication terminal 20-2 includes a wireless unit 21-2, an antenna 22-2, a control unit 23-2, and a position measurement unit 24-2.

[0039] Radio unit 21-2 transmits a signal via antenna 22-2 in accordance with instructions from control unit 23-2. For example, radio unit 21-2 transmits a response to a signal transmitted from base station 10 to base station 10. Furthermore, radio unit 21-2 transmits to base station 10 location information measured by location measurement unit 24-2 in addition to the response to the signal transmitted from base station 10.

[0040] The antenna 22-2 transmits and receives radio waves. The antenna 22-2 converts the received radio waves into electrical signals and outputs them to the radio unit 21-2. The antenna 22-2 radiates the signals output from the radio unit 21-2 as radio waves.

[0041] The control unit 23-2 controls the operation of the wireless communication terminal 20-2. For example, the control unit 23-2 controls the wireless unit 21-2 to transmit a response to a received signal. The control unit 23-2 controls the location measurement unit 24 to measure location information in accordance with an instruction from the base station 10.

[0042] The position measurement unit 24-2 measures the position of the wireless communication terminal 20-2 in accordance with instructions from the control unit 23-2.

[0043] FIG. 6 is a flowchart showing the flow of the position estimation process performed by the base station 10 in the embodiment. The wireless control unit 12 determines whether the opposing wireless communication terminal 20 includes the position measurement unit 24 (step S101). As an example, the determination of whether the opposing wireless communication terminal 20 includes the position measurement unit 24 may be made based on a connection request signal transmitted by the wireless communication terminal 20 when connecting to the base station 10. Specifically, the wireless communication terminal 20 transmits to the base station 10 a connection request signal including information indicating whether the wireless communication terminal 20 includes the position measurement unit 24. The wireless control unit 12 of the base station 10 determines that the opposing wireless communication terminal 20 includes the position measurement unit 24 when the connection request signal transmitted from the opposing wireless communication terminal 20 includes information indicating that the wireless communication terminal 20 includes the position measurement unit 24, and determines that the opposing wireless communication terminal 20 does not include the position measurement unit 24 when the connection request signal includes information indicating that the wireless communication terminal 20 does not include the position measurement unit 24. Note that this determination method is just an example, and whether the opposing wireless communication terminal 20 includes the position measurement unit 24 may be determined using other methods.

[0044] When wireless control unit 12 determines that the opposing wireless communication terminal 20 is equipped with a position measurement unit 24 (step S101-YES), it causes wireless communication terminal 20 equipped with the position measurement unit 24 (e.g., wireless communication terminal 20-2) to measure its position and report the result (step S102). Specifically, wireless control unit 12 controls wireless unit 13 to transmit a signal including an instruction to measure the position. Under the control of wireless control unit 12, wireless unit 13 transmits the signal including the instruction to measure the position via antenna 14 to wireless communication terminal 20 equipped with the position measurement unit 24 (e.g., wireless communication terminal 20-2).

[0045] The position measurement unit 24-2 of the wireless communication terminal 20-2 measures its position in accordance with instructions included in the signal transmitted from the base station 10. The wireless communication terminal 20-2 transmits a signal including the measured position information to the base station 10 via the antenna 22-2. As a result, the base station 10 acquires the position information of the wireless communication terminal 20-2. Next, the wireless control unit 12 of the base station 10 controls the wireless unit 13 to transmit signals using each candidate beam. The wireless unit 13 controls at least one of the amplitude and phase of the antenna 14 under the control of the wireless control unit 12, and transmits signals using each candidate beam while sequentially changing the candidate beam (step S103). As a result, the wireless communication terminal 20-2 receives signals for each candidate beam. The wireless communication terminal 20-2 transmits a response to the received signal for each candidate beam to the base station 10. Note that the wireless communication terminal 20-2 transmits a response to the received signal to the base station 10 every time it receives a signal for a candidate beam.

[0046] The radio unit 13 of the base station 10 receives a response to the signal from each candidate beam. The radio unit 13 outputs the received response to the radio control unit 12. Every time the radio unit 13 receives a response, it outputs the received response to the radio control unit 12. The radio control unit 12 acquires quality information for each response output from the radio unit 13 (step S104). The radio control unit 12 outputs the location information acquired in the processing of step S102 and the quality information for each candidate beam acquired in the processing of step S104 to the information management unit 15. The information management unit 15 associates the location information output from the radio control unit 12 with the quality information for each candidate beam and registers them in a quality information table (step S105).

[0047] In the processing of step S101, if the wireless control unit 12 determines that the opposing wireless communication terminal 20 does not include a position measurement unit 24 (step S101-NO), it controls the wireless unit 13 to transmit signals for each candidate beam. The wireless unit 13 controls at least one of the amplitude and phase of the antenna 14 in accordance with the control of the wireless control unit 12, and transmits signals for each candidate beam while sequentially changing the candidate beam (step S106). As a result, the wireless communication terminal 20-1 receives signals for each candidate beam. The wireless communication terminal 20-1 transmits a response to the received signal for each candidate beam to the base station 10. Note that every time the wireless communication terminal 20-1 receives a signal for a candidate beam, it transmits a response to the received signal to the base station 10.

[0048] The radio unit 13 of the base station 10 receives a response to the signal from each candidate beam. The radio unit 13 outputs the received response to the radio control unit 12. Every time the radio unit 13 receives a response, it outputs the received response to the radio control unit 12. The radio control unit 12 acquires quality information for each response output from the radio unit 13 (step S107). The radio control unit 12 outputs the acquired quality information for each candidate beam to the position estimation unit 17. The position estimation unit 17 refers to the quality information table stored in the quality information storage unit 16, and estimates the position of the radio communication terminal 20 (e.g., radio communication terminal 20-1) that does not include a position measurement unit 24, based on the quality information for each candidate beam acquired by the radio control unit 12 (step S108).

[0049] Specifically, the position estimation unit 17 first reads out the quality information table stored in the quality information storage unit 16. Next, the position estimation unit 17 refers to the quality information items of the candidate beams in the read quality information table and selects a record having a value closest to the quality information for each candidate beam acquired by the wireless control unit 12. A combination of quality information for beams B1 to B9 is registered in one record of the quality information table. Therefore, the position estimation unit 17 selects the combination of quality information closest to the combination of quality information for each candidate beam acquired by the wireless control unit 12 from the combinations of quality information for each candidate beam registered in each record of the quality information table.

[0050] The quality information and location information for each candidate beam registered in the quality information table are registered as discrete values. Therefore, the location estimation unit 17 performs regression analysis to select a record having a value closest to the quality information for each candidate beam acquired by the wireless control unit 12. The regression analysis may be performed using, for example, linear regression, or any method such as a k-nearest neighbor method or a random forest method. The location estimation unit 17 estimates the location information associated with the combination of quality information in the selected record as the location of the wireless communication terminal 20-1 not equipped with a location measurement unit 24.

[0051] According to the wireless communication system 100 configured as described above, it is possible to estimate the position of a wireless communication device with higher accuracy using signals used for communication. Specifically, in the wireless communication system 100, the base station 10 includes a wireless unit 13 that forms multiple candidate beams in different directions, transmits signals for each candidate beam, and receives responses to the signals received by the wireless communication terminal 20; a wireless control unit 12 that acquires quality information about each candidate beam based on the responses received by the wireless unit 13; and a position estimation unit 17 that refers to a quality information table and estimates the position of the wireless communication terminal 20 based on the quality information for each candidate beam acquired by the wireless control unit 12. As a result, even if the opposing wireless communication terminal 20 does not include a position measurement unit 24, it is possible to estimate the position of the opposing wireless communication terminal 20 by referring to the quality information of each candidate beam used by the base station 10. Therefore, even when communication is performed using a reflected path, it is possible to estimate the position of the opposing wireless communication terminal 20 using the communication signals themselves, without providing the wireless communication terminal 20 with a positioning function. As a result, it is possible to estimate the position of the wireless communication device with higher accuracy using signals used for communication.

[0052] In the wireless communication system 100, when the location information of the opposing wireless communication terminal 20 can be acquired, the acquired location information of the wireless communication terminal 20 is associated with quality information of the candidate beams used by the base station 10 and registered in a quality information table. This makes it possible to estimate the location of the opposing wireless communication terminal 20 by referring to the quality information of each candidate beam used by the base station 10.

[0053] A modification of the wireless communication system 100 will now be described. (Variation 1) In the above-described embodiment, the wireless communication system 100 is configured to include the wireless communication terminal 20-1 without a positioning function and the wireless communication terminal 20-2 with a positioning function, but the wireless communication system 100 may be configured to include only the wireless communication terminal 20 without a positioning function. For example, if correspondence information between target position information and quality information is registered in the quality information table, it is not necessary to register new position information in the wireless communication system 100. Therefore, if correspondence information between target position information and quality information is registered in the quality information table, the wireless communication system 100 may be configured to include only the wireless communication terminal 20 without a positioning function.

[0054] (Variation 2) In the above-described embodiment, the position estimation unit 17 is configured to estimate the position of the wireless communication terminal 20 based on one piece of quality information. However, the position estimation unit 17 may be configured to estimate the position of the wireless communication terminal 20 based on a combination of multiple pieces of quality information. For example, the position estimation unit 17 may estimate the position of the wireless communication terminal 20 based on a combination of the received signal strength and the signal-to-noise power ratio, or another combination may be used. When estimating the position of the wireless communication terminal 20 based on a combination of the received signal strength and the signal-to-noise power ratio, at least the values ​​of the received signal strength and the signal-to-noise power ratio are registered for each candidate beam in the quality information table as quality information for each candidate beam. Furthermore, the wireless control unit 12 acquires the received signal strength and the signal-to-noise power ratio for each candidate beam based on a response obtained from the wireless communication terminal 20. The position estimation unit 17 then refers to the quality information table and estimates the position of the wireless communication terminal 20 based on the quality information (received signal strength and the signal-to-noise power ratio) for each candidate beam acquired by the wireless control unit 12.

[0055] (Variation 3) In the above-described embodiment, the base station 10 is configured to estimate the position of the wireless communication terminal 20. On the other hand, if the wireless communication terminal 20 is configured to sequentially form multiple candidate beams in different directions and transmit a signal for each candidate beam, the wireless communication terminal 20 may be configured to estimate the position of the base station 10 using a method similar to that of the base station 10. In this configuration, the wireless communication terminal 20 is configured to sequentially form multiple candidate beams in different directions and transmit a signal for each candidate beam in the radio unit 21, antenna 22, and control unit 23, and further includes an information management unit 15, a quality information storage unit 16, and a position estimation unit 17. The base station 10 receives a signal transmitted from the wireless communication terminal 20 and transmits a response to the received signal to the wireless communication terminal 20.

[0056] (Regarding correspondence with claims) The base station 10 is one aspect of a first communication device, a second communication device, and a wireless communication device. The wireless communication terminal 20 is one aspect of a first communication device, a second communication device, and a wireless communication device. When the base station 10 is the first communication device, the wireless communication terminal 20 is the second communication device, and when the base station 10 is the second communication device, the wireless communication terminal 20 is the first communication device.

[0057] Some or all of the functional units of the base station 10 and the wireless communication terminal 20 in the above-described embodiments are realized as software by one or more processors, such as a CPU (Central Processing Unit), executing a program stored in a storage device having a non-volatile storage medium (non-transitory storage medium) and a memory. The program may be recorded on a computer-readable non-transitory storage medium. Examples of computer-readable non-transitory storage media include portable media such as flexible disks, magneto-optical disks, ROMs (Read Only Memory), CD-ROMs (Compact Discs), and storage devices such as hard disks built into computer systems.

[0058] Some or all of the functional units of the base station 10 and the wireless communication terminal 20 may be realized using hardware including electronic circuits (electronic circuits or circuitry) using, for example, an LSI (Large Scale Integrated circuit), an ASIC (Application Specific Integrated Circuit), a PLD (Programmable Logic Device), or an FPGA (Field Programmable Gate Array).

[0059] Although an embodiment of the present invention has been described above in detail 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]

[0060] The present invention can be applied to a technique for estimating the position of a wireless communication device that does not have a position measurement function. [Explanation of symbols]

[0061] 10... base station, 20, 20-1, 20-2... wireless communication terminal, 11... data processing unit, 12... wireless control unit, 13... wireless unit, 14, 22-1, 22-2... antenna, 15... information management unit, 16... quality information storage unit, 17... position estimation unit, 21-1, 21-2... wireless unit, 23-1, 23-2... control unit, 24... position measurement unit

Claims

1. A wireless communication system including a first communication device and one or more second communication devices that communicate with the first communication device, The first communication device a radio unit that forms a plurality of candidate beams in different directions, transmits a signal for each candidate beam, and receives a response to the signal received by the one or more second communication devices; a radio control unit that acquires quality information about the candidate beams for each candidate beam based on the response received by the radio unit; a position estimation unit that estimates the positions of the one or more second communication devices based on the quality information for each candidate beam acquired by the wireless control unit, by referring to correspondence information that is information in which position information measured by a communication device having a position positioning unit that measures a position and quality information for each candidate beam acquired by communication with the communication device are previously associated with each other; Equipped with the one or more second communication devices; A wireless communication system that transmits a response to the signal transmitted from the first communication device.

2. The one or more second communication devices include at least a second communication device that does not have a position measurement unit that measures a position, the position estimation unit refers to the correspondence information and estimates, as the position of the second communication device not comprising the position measurement unit, position information associated with quality information that is closest to the quality information for each candidate beam obtained based on the response for each candidate beam from the second communication device not comprising the position measurement unit received by the wireless unit.

10. The wireless communication system of claim 1.

3. The position estimation unit determines quality information that is closest to the quality information for each candidate beam acquired by the radio control unit by performing a regression analysis.

3. The wireless communication system according to claim 2.

4. further comprising an information management unit that manages the correspondence information; When there is a second communication device including a position measurement unit that measures a position among the one or more second communication devices, the radio unit of the first communication device receives position information in addition to the response for each candidate beam from the second communication device including the position measurement unit, The information management unit associates the quality information for each candidate beam obtained based on the response received from the second communication device including the position measurement unit with the location information and registers the associated information. A wireless communication system according to any one of claims 1 to 3.

5. A position estimation method performed by a wireless communication system including a first communication device and one or more second communication devices that communicate with the first communication device, The first communication device, forming a plurality of candidate beams in different directions and transmitting a signal for each candidate beam; receiving a response to the signal received at the one or more second communication devices; Obtaining quality information for each candidate beam based on the received response; By referring to correspondence information in which location information measured by a communication device having a location positioning unit that measures a location is associated in advance with quality information for each candidate beam obtained by communication with the communication device, the location of the one or more second communication devices is estimated based on the quality information for each acquired candidate beam; the one or more second communication devices; A location estimation method, further comprising transmitting a response to a signal transmitted from the first communication device.

6. a radio unit that forms a plurality of candidate beams in different directions, transmits a signal for each candidate beam, and receives a response to the signal received by an opposite device; a radio control unit that acquires quality information about the candidate beams for each candidate beam based on the response received by the radio unit; a position estimation unit that estimates the position of the opposing device based on the quality information for each candidate beam acquired by the wireless control unit, by referring to correspondence information that is information in which position information measured by a communication device having a position positioning unit that measures a position and quality information for each candidate beam acquired by communication with the communication device are previously associated with each other; A wireless communication device comprising:

Images