Wireless communication device, wireless communication method, and program

Abstract

A wireless communication device according to one aspect of the present invention comprises a control unit that controls communication between a terminal device and a plurality of extension stations capable of communicating with the terminal device. The control unit executes determination processing for determining, as the extension station that communicates with the terminal device, the extension station having the highest reception strength at the time when the terminal device receives a wireless signal transmitted by said extension station from among extension stations each having an amount which has a predetermined degree or higher correlation with the reception strength and is less than a predetermined value.

Description

[Technical Field]

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

[0002] For next-generation wireless communication systems, it has been proposed to simplify the base station of the radio access network (RAN), which consists of an aggregation station (or base station) and a base station. Specifically, it has been proposed to simplify the base station by performing analog-radio-over-fiber (A-RoF) transmission between the aggregation station and the base station.

[0003] The base station in such a proposal includes an antenna and an optical modulator / demodulator. The base station receives wireless signals sent from terminal devices such as PCs and smartphones using the antenna. The base station performs electrical-to-optical conversion (E / O conversion) to convert the wireless signals received by the antenna into optical signals using an optical modulator. Such base stations may include an amplifier to amplify the received wireless signals. The base station also uses an antenna to transmit wireless signals to terminal devices such as PCs and smartphones. The base station uses an optical demodulator to perform optical-to-electrical conversion (O / E conversion) to convert the optical signals sent from the central station into electrical signals. Such base stations may include an amplifier to amplify the wireless signals to be transmitted. [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] Umesh et al., O-RAN Fronthaul Specifications Overview, NTT DOCOMO Technical Journal Vol. 27 No. 1 (Apr. 2019) [Non-patent document 2] Ito et al., Efficient Accommodation of Diverse High-Frequency Band Wireless Systems Using Analog RoF, NTT Technical Journal Vol. 32 No. 3 (2020) [Non-patent document 3] Uchida et al., "Study on High-Frequency Band Distributed Antenna Systems for the 6G Era," IEICE Technical Report RCS2020-148, pp. 73-78, December 2020. Summary of the Invention [Problem to be solved by the invention]

[0005] However, in such wireless communication systems, if the power of the wireless signal sent from the terminal device is high, harmonics are generated due to nonlinear distortion caused by the nonlinearity of the optical modulator.The harmonics generated by nonlinear distortion in this way can reduce the signal-to-noise power ratio and degrade communication quality.

[0006] In view of the above circumstances, an object of the present invention is to provide a technique for suppressing degradation in the quality of wireless communication. [Means for solving the problem]

[0007] One aspect of the present invention is a wireless communication device that includes a control unit that controls communication between a terminal device and multiple base stations that can communicate with the terminal device, and the control unit executes a determination process to determine the base station with the strongest reception strength among the base stations that have a correlation of a predetermined degree or more with the reception strength when the terminal device receives a radio signal transmitted from the base station, which is less than a predetermined value.

[0008] One aspect of the present invention is a wireless communication method implemented by a wireless communication system, comprising: a control unit that controls communication between a plurality of base stations that can communicate with a terminal device and the terminal device, the control unit performing a determination process to determine, among the base stations where a quantity that has a correlation of a predetermined degree or more with the reception strength when the terminal device receives a radio signal transmitted from the base station is less than a predetermined value, the base station with the strongest reception strength as the base station that will communicate with the terminal device; and a central station that controls communication between the base stations and the terminal device, the central station performing a determination process to determine, based on location information indicating the position of the terminal device, the base station that is closest to the terminal device among the base stations excluding base stations whose distance to the position indicated by the location information is shorter than a predetermined distance as the base station that will communicate with the terminal device, the wireless communication method having a determination step in which the control unit central station performs the determination process.

[0009] One aspect of the present invention is a program for causing a computer to function as the wireless communication device described above. [Effects of the Invention]

[0010] According to the present invention, it is possible to suppress degradation of the quality of wireless communication. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a diagram showing an example of the configuration of a wireless communication system according to a first embodiment. [Figure 2] FIG. 2 is a diagram showing an example of the hardware configuration of a central station in the first embodiment. [Figure 3] FIG. 2 is a diagram showing an example of the hardware configuration of a base station in the first embodiment. [Figure 4] 5 is a flowchart showing an example of the flow of processing executed in the wireless communication system of the first embodiment. [Figure 5] FIG. 10 is a diagram showing an example of the configuration of a wireless communication system according to a second embodiment. [Figure 6] FIG. 10 is a diagram showing an example of the hardware configuration of a central station in the second embodiment. [Figure 7] FIG. 10 is a diagram showing an example of the hardware configuration of a base station in the second embodiment. [Figure 8] FIG. 10 is a diagram showing an example of the hardware configuration of a terminal device according to a second embodiment. [Figure 9] 10 is a flowchart showing an example of the flow of processing executed in a wireless communication system according to the second embodiment. [Figure 10] FIG. 10 is a diagram showing an example of the configuration of a wireless communication system 100b according to a third embodiment. [Figure 11] FIG. 11 is a diagram showing an example of the hardware configuration of a central station in the third embodiment. [Figure 12] FIG. 11 is a diagram showing an example of the hardware configuration of a base station according to the third embodiment. [Figure 13] FIG. 11 is a diagram showing an example of the hardware configuration of a terminal device according to a third embodiment. [Figure 14] 10 is a flowchart showing an example of the flow of processing executed in a wireless communication system according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] (First embodiment) FIG. 1 is a diagram showing an example of the configuration of a wireless communication system 100 according to the first embodiment. The wireless communication system 100 is a radio access network (RAN). The wireless communication system 100 includes a central station (Central Unit) 1 and a plurality of base stations (Distributed Units, Remote Units, Distributed Stations) 2. The central station 1 is a central station in the RAN. The central station 1 controls communication between the base station 2 and a terminal device 3. The base station 2 is a base station in the RAN. The base station 2 is capable of communicating with the terminal device 3.

[0013] The terminal device 3 is a terminal device equipped with a wireless communication function, such as a smartphone or a personal computer. The terminal device 3 is capable of transmitting information indicating an identifier for identifying the terminal device itself (hereinafter referred to as "terminal identification information"). The terminal device 3 is capable of receiving wireless signals. The terminal device 3 communicates with the base station 2, and transmits a signal indicating content such as text, video, or still image (hereinafter referred to as "content signal") to the base station 2. The signal indicating text is, for example, an email.

[0014] The central station 1 includes a control unit 11 having a processor 91 such as a CPU (Central Processing Unit) and a memory 92 connected by a bus, and executes a program.

[0015] The control unit 11 executes a terminal location information acquisition process and a first communication partner determination process. The terminal location information acquisition process is a process for acquiring location information of the terminal device 3. Location information is information indicating a location.

[0016] The terminal location information acquisition process is a process of using, for example, a GPS (Global Positioning System) to acquire location information of the terminal device 3. Note that the data amount of the location information is smaller than the data amount of the content signal transmitted from the terminal device 3 to the base station 2.

[0017] The terminal position information acquisition process may be, for example, a process of controlling the operation of one or more base stations 2 and using a predetermined positioning technique to acquire the position information of the terminal device 3. The predetermined positioning technique is, for example, a process of performing one-point positioning in which, when the base station performs beamforming, the direction and distance to the terminal device are estimated from the beam direction and RTT (Round Trip Time) to the terminal device, or a process of performing three-point positioning using the received power at the terminal device from multiple base stations.

[0018] The first communication partner determination process is a process for determining a base station 2 (hereinafter referred to as a "communication station") that will communicate with a terminal device 3, based on the location information of the terminal device 3 acquired by the terminal location information acquisition process. Specifically, of the base stations 2, excluding the base stations 2 whose distance to the location indicated by the acquired location information is shorter than a predetermined distance, the base station 2 that is closest to the terminal device 3 is determined as the communication station. Therefore, the first communication partner determination process also uses information indicating the location of each base station 2 (hereinafter referred to as "base station location information").

[0019] The control unit 11 controls the base station 2 (i.e., the communication station) determined as the communication station by the first communication partner determination process. Under the control of the control unit 11, the communication station receives a content signal transmitted from the terminal device 3. The communication station converts the received content signal into an optical signal and transmits it to the central station 1.

[0020] In this way, a base station 2 that is closer to the terminal device 3 than a predetermined distance is not selected as a communication station. Since the signal strength is stronger the closer the distance, the first communication partner determination process suppresses the generation of harmonics due to nonlinear distortion. On the other hand, the signal strength weakens as the distance increases, making communication unstable. Therefore, of the base stations 2 located at a distance greater than a predetermined distance from the terminal device 3, the base station 2 closest to the terminal device 3 is selected as the communication station, thereby suppressing communication instability.

[0021] The location information acquisition process and the first communication partner determination process are each executed at a predetermined timing, for example, the location information acquisition process and the first communication partner determination process are each executed repeatedly at the same cycle.

[0022] 2 is a diagram showing an example of the hardware configuration of the central station 1 in the first embodiment. As described above, the central station 1 includes the control unit 11 and executes a program. By executing the program, the central station 1 functions as a device including the control unit 11, an interface unit 12, and a storage unit 13.

[0023] More specifically, the processor 91 reads out a program stored in the storage unit 13 and stores the read out program in the memory 92. The processor 91 executes the program stored in the memory 92, whereby the aggregate station 1 functions as a device including the control unit 11, the interface unit 12, and the storage unit 13.

[0024] The control unit 11 performs, for example, a terminal location information acquisition process. The control unit 11 performs, for example, a first communication partner determination process. The control unit 11 controls, for example, the operation of each functional unit provided in the central station 1. The control unit 11 controls, for example, the operation of one or more base stations 2 via, for example, the interface unit 12. The control unit 11 acquires, for example, information stored in the memory unit 13. The process of acquiring the information stored in the memory unit 13 is specifically reading.

[0025] The interface unit 12 includes a communication interface for connecting the central station 1 to an external device. The interface unit 12 communicates with the external device via wired or wireless communication. The external device is, for example, a base station 2 that is to be controlled by the control unit 11. The control unit 11 controls the operation of the base station 2 that is to be controlled and acquires the location information of the terminal device 3, for example, in a terminal location information acquisition process.

[0026] The external device is, for example, a device that is a source of transmitting the location information of the terminal device 3. In such a case, the interface unit 12 acquires the location information of the terminal device 3 transmitted by the device that is a source of transmitting the location information of the terminal device 3. The device that is a source of transmitting the location information of the terminal device 3 acquires the location information of the terminal device 3 using, for example, GPS.

[0027] The external device is, for example, a communication station. In this case, the interface unit 12 communicates with the communication station. The communication station receives a content signal transmitted from the terminal device 3. The communication station that has received the content signal converts the received content signal into an optical signal and transmits it to the aggregate station 1. The aggregate station 1 receives the content signal transmitted by the communication station.

[0028] The interface unit 12 may be configured to include an input device such as a mouse, a keyboard, or a touch panel. The interface unit 12 may be configured as an interface that connects these input devices to the central station 1. In this way, the interface unit 12 may accept input of various information to the central station 1 via the input device, either wired or wireless.

[0029] The interface unit 12 may output various types of information. The interface unit 12 may be configured to include a display device such as a CRT (Cathode Ray Tube) display, a liquid crystal display, or an organic EL (Electro-Luminescence) display. The interface unit 12 may be configured as an interface that connects these display devices to the central station 1. The interface unit 12 may output information input to the interface unit 12, for example. The interface unit 12 may also be configured to include a touch panel, for example.

[0030] The storage unit 13 is configured using a computer-readable storage medium device (non-transitory computer-readable recording medium) such as a magnetic hard disk device or a semiconductor storage device. The storage unit 13 stores various information related to the central station 1. The storage unit 13 stores information required for, for example, the terminal location information acquisition process and the first communication partner determination process. The storage unit 13 stores various information generated by, for example, the operation of the control unit 11. The storage unit 13 stores, for example, information acquired by the interface unit 12. The storage unit 13 stores base station location information in advance.

[0031] 3 is a diagram showing an example of the hardware configuration of the base station 2 in the first embodiment. The base station 2 is equipped with a control unit 21 including a processor 93 such as a CPU and a memory 94 connected by a bus, and executes a program. By executing the program, the base station 2 functions as a device including the control unit 21, an interface unit 22, and a storage unit 23.

[0032] More specifically, the processor 93 reads out a program stored in the storage unit 23 and stores the read program in the memory 94. The processor 93 executes the program stored in the memory 94, causing the base station 2 to function as a device including the control unit 21, the interface unit 22, and the storage unit 23.

[0033] The control unit 21 controls the operation of each functional unit included in the base station 2, for example. The control unit 21 controls the operation of a signal source 221 included in the interface unit 22, for example. The control unit 21 controls the operation of an optical modulator 223 included in the interface unit 22, for example. The control unit 21 is controlled by a control unit 11 included in the central station 1, for example.

[0034] The interface unit 22 includes a communication interface for connecting the base station 2 to an external device. The interface unit 22 communicates with the external device via wired or wireless communication. The external device is, for example, the central station 1. The external device is, for example, the terminal device 3.

[0035] The interface unit 22 includes, for example, a signal source 221, an antenna 222, and an optical modulator 223. The signal source 221 generates, in the form of an electric signal, a signal to be radiated wirelessly from the antenna 222. The signal source 221 operates under the control of, for example, a control unit 21 which operates under the control of a control unit 11 included in the central station 1.

[0036] The antenna 222 is an antenna. The antenna 222 emits the signal generated by the signal source 221 in the form of a radio signal. The antenna 222 receives, for example, a content signal transmitted by the terminal device 3. The optical modulator 223 converts the content signal received by the antenna 222 into an optical signal. The content signal converted into an optical signal by the optical modulator 223 propagates toward the central station 1. The optical modulator 223 operates, for example, under the control of a control unit 21 which operates under the control of a control unit 11 provided in the central station 1.

[0037] The interface unit 22 may be configured to include input devices such as a mouse, a keyboard, a touch panel, etc. The interface unit 22 may be configured as an interface that connects these input devices to the base station 2. In this way, the interface unit 22 may receive input of various information to the base station 2 via the input device, either wired or wireless.

[0038] The interface unit 22 may output various types of information. The interface unit 22 may be configured to include a display device such as a CRT display, a liquid crystal display, or an organic EL display. The interface unit 22 may be configured as an interface that connects these display devices to the base station 2. The interface unit 22 may output, for example, information input to the interface unit 22. Furthermore, the interface unit 22 may be configured to include, for example, a touch panel.

[0039] The storage unit 23 is configured using a computer-readable storage medium device (non-transitory computer-readable recording medium) such as a magnetic hard disk device or a semiconductor storage device. The storage unit 23 stores various information related to the base station 2. The storage unit 23 stores various information generated by the operation of the control unit 21, for example. The storage unit 23 stores information acquired by the interface unit 22, for example.

[0040] 4 is a flowchart showing an example of the flow of processing executed in the wireless communication system 100 of the first embodiment. The control unit 11 executes location information acquisition processing (step S101). Next, the control unit 11 executes first communication partner determination processing (step S102). Next, the control unit 11 controls the operation of the interface unit 12 to start communication between the base station 2 determined as a communication station by the first communication partner determination processing and the terminal device 3 (step S103). Next, the content signal transmitted by the terminal device 3 is acquired by the communication station (step S104).

[0041] The wireless communication system 100 of the first embodiment configured as described above includes a control unit 11 that executes a location information acquisition process and a first communication partner determination process. In the first communication partner determination process, the base station 2 that is closest to the terminal device 3 is determined as the base station 2 that will communicate with the terminal device 3, among the base stations 2, excluding the base stations 2 whose distance to the position indicated by the location information acquired in the location information acquisition process is shorter than a predetermined distance.

[0042] Incidentally, a wireless signal is an electromagnetic wave, and the strength of the electromagnetic wave weakens as the distance increases. Furthermore, the stronger the electromagnetic wave, the more likely it is that nonlinear distortion due to the nonlinearity of the optical modulator will occur. Therefore, by the first communication partner determination process, a base station other than a base station 2 that is too close to the terminal device 3 is determined as the base station 2 that will communicate with the terminal device 3, thereby suppressing the occurrence of nonlinear distortion due to the nonlinearity of the optical modulator. As a result, the wireless communication system 100 can suppress degradation in the quality of wireless communication.

[0043] (Second embodiment) 5 is a diagram showing an example of the configuration of a wireless communication system 100a according to the second embodiment. Hereinafter, the same components as those shown in FIGS. 1 to 3 will be given the same reference numerals and descriptions thereof will be omitted.

[0044] The wireless communication system 100a is a radio access network (RAN). The wireless communication system 100 includes a central station 1a and a plurality of base stations 2a. The central station 1a is a central station in the RAN. The central station 1a is capable of communicating with a terminal device 3a. The central station 1a controls communication between the base station 2a and the terminal device 3a. The base station 2a is a base station in the RAN. The base station 2a is capable of communicating with the terminal device 3a.

[0045] The central station 1a includes a control unit 11a having a processor 91a such as a CPU and a memory 92a connected by a bus, and executes a program. The central station 1a controls communication between the base station 2a and the terminal device 3a by executing the program.

[0046] The base station 2a, under the control of the central station 1a, emits a radio signal (hereinafter referred to as a "test signal") of a predetermined strength at a predetermined timing. The test signal will be described in detail later.

[0047] The terminal device 3a is a terminal device equipped with a wireless communication function, such as a smartphone or a personal computer. The terminal device 3a is capable of transmitting terminal identification information, which is information indicating an identifier for identifying the terminal device itself. The terminal device 3a is also capable of receiving wireless signals. The terminal device 3a communicates with the base station 2a and transmits, for example, a content signal to the base station 2a.

[0048] Unlike the terminal device 3, the terminal device 3a receives one or more test signals within a predetermined period. Hereinafter, the period during which one or more test signals are received is referred to as a test signal reception period. The test signal reception period is, for example, a period of a predetermined length that occurs periodically at a predetermined cycle.

[0049] The terminal device 3a performs an intensity measurement process to measure the intensity of each test signal received during the test signal reception period. In this case, the timing at which the multiple base stations 2 radiate the test signals may or may not be simultaneous, but if they are simultaneous, the waveform of the test signal will be different for each base station 2a. If they are not simultaneous, the radiation timing will be in a predetermined order.

[0050] In this way, the test signal is a radio signal whose strength is a predetermined strength independent of the base station 2a and whose waveform or timing is associated one-to-one with each base station 2a. Therefore, the terminal device 3a that receives the test signal can determine which base station 2a transmitted the test signal.

[0051] The terminal device 3a includes a control unit 31a having a processor 95a such as a CPU and a memory 96a connected by a bus, and executes a program. When the control unit 31a receives a test signal, it executes a sender determination process for each received test signal. The sender determination process is a process for determining the base station 2a that is the sender of the received test signal based on the received test signal.

[0052] Furthermore, when the control unit 31a receives a test signal, the control unit 31a executes the above-described strength measurement process for each received test signal. By executing the strength measurement process, the control unit 31a measures the strength of the received test signal when it is received by the control unit 31a.

[0053] The terminal device 3a performs a source determination process and a strength measurement process for each test signal received within the test signal reception period, and then transmits information indicating the results of the strength measurement process for each base station 2a determined by the source determination process to the aggregation station 1a.

[0054] Hereinafter, information indicating the results of the intensity measurement process for each base station 2a determined by the transmission source determination process will be referred to as “determination result information.” More specifically, the determination result information is information indicating, for each base station 2a that is the source of the test signal, the intensity of the test signal transmitted from each base station 2a at the location of the terminal device 3a.

[0055] Since a wireless signal is an electromagnetic wave, and the strength of the electromagnetic wave weakens as the distance increases, the content indicated by the determination result information can also be information indicating the distance between the terminal device 3a and the base station 2a.

[0056] The terminal device 3a transmits the terminal identification information together with the determination result information to the central station 1a.

[0057] As described above, the central station 1a can communicate with the terminal device 3a. The central station 1a acquires the determination result information and terminal identification information transmitted by the terminal device 3a, and executes a second communication partner determination process based on the acquired determination result information and terminal identification information.

[0058] The second communication partner determination process is a process of determining a base station 2a as a communication partner of the terminal device 3a indicated by the terminal identification information based on the determination result information. More specifically, it is a process of determining the base station 2a with the strongest intensity indicated by the determination result information as the communication partner (i.e., communication station) of the terminal device 3a indicated by the terminal identification information, among the base stations 2a whose intensity indicated by the determination result information is equal to or less than a predetermined intensity.

[0059] More specifically, the second communication partner determination process is performed by the control unit 11a.

[0060] The control unit 11a controls the operation of the base station 2a determined as the communication station by the second communication partner determination process, and starts communication with the terminal device 3a. Under the control of the control unit 11a, the communication station receives a content signal transmitted by the terminal device 3a. The communication station converts the received content signal into an optical signal and transmits it to the central station 1a.

[0061] 6 is a diagram showing an example of the hardware configuration of the central station 1a in the second embodiment. The central station 1a includes the control unit 11a and executes a program as described above. By executing the program, the central station 1a functions as a device including the control unit 11a, the interface unit 12a, and the storage unit 13a.

[0062] More specifically, the processor 91a reads out a program stored in the storage unit 13a and stores the read program in the memory 92a. The processor 91a executes the program stored in the memory 92a, causing the aggregate station 1a to function as a device including the control unit 11a, the interface unit 12a, and the storage unit 13a.

[0063] The control unit 11a performs, for example, a second communication partner determination process. The control unit 11a controls, for example, the operation of each functional unit provided in the central station 1a. The control unit 11a controls the operation of one or more base stations 2a, for example, via the interface unit 12a. The control unit 11a acquires, for example, information stored in the memory unit 13. The process of acquiring the information stored in the memory unit 13 is specifically reading.

[0064] The control unit 11a communicates with the terminal device 3a via, for example, the interface unit 12a. The control unit 11a acquires determination result information and terminal identification information through communication with the terminal device 3a.

[0065] The interface unit 12a includes a communication interface for connecting the central station 1a to an external device, and communicates with the external device via wire or wirelessly.

[0066] The external device is, for example, the terminal device 3a. In this case, the interface unit 12a acquires the determination result information and terminal identification information transmitted by the terminal device 3a.

[0067] The external device is, for example, the base station 2a that has been determined as the communication partner (i.e., communication station) of the terminal device 3a indicated by the terminal identification information through the second communication partner determination process. In this case, the interface unit 12a communicates with the communication station.

[0068] The communication station receives the content signal transmitted from the terminal device 3a indicated by the terminal identification information. The communication station that has received the content signal converts the received content signal into an optical signal and transmits it to the central station 1a. The central station 1a receives the content signal transmitted from the communication station.

[0069] The interface unit 12a may be configured to include an input device such as a mouse, a keyboard, or a touch panel. The interface unit 12a may be configured as an interface that connects these input devices to the central station 1a. In this way, the interface unit 12a may accept input of various information to the central station 1a via the input device, either wired or wireless.

[0070] The interface unit 12a may output various types of information. The interface unit 12a may be configured to include a display device such as a CRT display, a liquid crystal display, or an organic EL display. The interface unit 12a may be configured as an interface that connects these display devices to the central station 1a. The interface unit 12a may output information input to the interface unit 12a, for example. The interface unit 12a may also be configured to include a touch panel, for example.

[0071] The storage unit 13a is configured using a computer-readable storage medium device (non-transitory computer-readable recording medium) such as a magnetic hard disk device or a semiconductor storage device. The storage unit 13a stores various information related to the central station 1a. The storage unit 13a stores information necessary for, for example, a communication partner determination process. The storage unit 13a stores various information generated by, for example, the operation of the control unit 11a. The storage unit 13a stores information acquired by, for example, the interface unit 12a.

[0072] 7 is a diagram showing an example of the hardware configuration of the base station 2a in the second embodiment. The base station 2a is equipped with a control unit 21a including a processor 93a such as a CPU and a memory 94a connected by a bus, and executes a program. By executing the program, the base station 2a functions as a device including the control unit 21a, an interface unit 22a, and a storage unit 23a.

[0073] More specifically, the processor 93a reads out a program stored in the storage unit 23a and stores the read program in the memory 94a. The processor 93a executes the program stored in the memory 94a, causing the base station 2a to function as a device including the control unit 21a, the interface unit 22a, and the storage unit 23a.

[0074] The control unit 21a controls the operation of each functional unit included in the base station 2a, for example. The control unit 21a controls the operation of the signal source 221a included in the interface unit 22a, for example. The control unit 21a controls the operation of the optical modulator 223a included in the interface unit 22a, for example. The control unit 21a is controlled by the control unit 11a included in the central station 1a, for example.

[0075] The interface unit 22a includes a communication interface for connecting the base station 2a to an external device. The interface unit 22a communicates with the external device via wired or wireless communication. The external device is, for example, the central station 1a or the terminal device 3a.

[0076] The interface unit 22a includes, for example, a signal source 221a, an antenna 222a, and an optical modulator 223a. The signal source 221a generates a signal in the form of an electrical signal to be radiated wirelessly from the antenna 222a. The signal source 221a operates under the control of, for example, a control unit 21a which operates under the control of a control unit 11a included in the central station 1a.

[0077] The antenna 222a is an antenna. The antenna 222a emits a signal generated by the signal source 221a in the form of a radio signal. The antenna 222a receives, for example, a content signal transmitted by the terminal device 3a. The optical modulator 223a converts the content signal received by the antenna 222a into an optical signal. The content signal converted into an optical signal by the optical modulator 223a propagates toward the central station 1a. The optical modulator 223a operates, for example, under the control of a control unit 21a which operates under the control of a control unit 11a provided in the central station 1a.

[0078] The above-mentioned test signal is generated by a signal source 221a under the control of the control unit 21a and is radiated from an antenna 222a.

[0079] The interface unit 22a may be configured to include input devices such as a mouse, a keyboard, a touch panel, etc. The interface unit 22a may be configured as an interface that connects these input devices to the base station 2a. In this way, the interface unit 22a may accept input of various information to the base station 2a via the input device, either wired or wireless.

[0080] The interface unit 22a may output various types of information. The interface unit 22a may be configured to include a display device such as a CRT display, a liquid crystal display, or an organic EL display. The interface unit 22a may be configured as an interface that connects these display devices to the base station 2a. The interface unit 22a may output, for example, information input to the interface unit 22a. Furthermore, the interface unit 22a may be configured to include, for example, a touch panel.

[0081] The storage unit 23a is configured using a computer-readable storage medium device (non-transitory computer-readable recording medium) such as a magnetic hard disk device or a semiconductor storage device. The storage unit 23a stores various types of information related to the base station 2a. The storage unit 23a stores various types of information generated by the operation of the control unit 21a, for example. The storage unit 23a stores information acquired by the interface unit 22a, for example.

[0082] 8 is a diagram showing an example of the hardware configuration of the terminal device 3a in the second embodiment. The terminal device 3a is equipped with a control unit 31a including a processor 95a such as a CPU and a memory 96a connected by a bus, and executes a program. By executing the program, the terminal device 3a functions as a device including the control unit 31a, an interface unit 32a, and a storage unit 33a.

[0083] More specifically, the processor 95a reads the program stored in the storage unit 33a and stores the read program in the memory 96a. The processor 95a executes the program stored in the memory 96a, causing the terminal device 3a to function as a device including the control unit 31a, the interface unit 32a, and the storage unit 33a.

[0084] The control unit 31a controls, for example, the operation of each functional unit included in the terminal device 3a. The control unit 31a executes, for example, a transmission source determination process. The control unit 31a executes, for example, a strength measurement process. The control unit 31a controls, for example, the operation of the interface unit 22a to transmit determination result information and terminal identification information to the central station 1a.

[0085] The interface unit 32a includes a communication interface for connecting the terminal device 3a to an external device. The interface unit 32a communicates with the external device via wired or wireless communication. The external device is, for example, the central station 1a. In this case, the interface unit 32a transmits, for example, determination result information and terminal identification information to the central station 1a.

[0086] The external device is, for example, the base station 2a. In this case, the interface unit 32a receives, for example, a test signal. The test signal received by the interface unit 32a is acquired by the control unit 31a. The control unit 31a executes a transmission source determination process and an intensity measurement process based on the acquired test signal. The interface unit 32a also transmits a content signal.

[0087] The interface unit 32a may be configured to include input devices such as a mouse, a keyboard, a touch panel, etc. The interface unit 32a may be configured as an interface that connects these input devices to the terminal device 3a. In this way, the interface unit 32a may accept input of various information to the terminal device 3a via the input device, either wired or wireless.

[0088] The interface unit 32a may output various types of information. The interface unit 32a may be configured to include a display device such as a CRT display, a liquid crystal display, or an organic EL display. The interface unit 32a may be configured as an interface that connects these display devices to the terminal device 3a. The interface unit 32a may output information input to the interface unit 32a, for example. The interface unit 32a may also be configured to include a touch panel, for example.

[0089] The storage unit 33a is configured using a computer-readable storage medium device (non-transitory computer-readable recording medium) such as a magnetic hard disk device or a semiconductor storage device. The storage unit 33a stores various information related to the terminal device 3a. The storage unit 33a stores various information generated by the operation of the control unit 31a, for example. The storage unit 33a stores information acquired by the interface unit 32a, for example. The storage unit 33a stores terminal identification information in advance, for example.

[0090] 9 is a flowchart showing an example of the flow of processing executed in the wireless communication system 100a of the second embodiment. During a test signal reception period, the terminal device 3a acquires one or more test signals (step S201). More specifically, during the test signal reception period, the interface unit 32a acquires one or more test signals. Next, the control unit 31a executes a transmission source determination process and an intensity measurement process for each test signal acquired in step S201 (step S202). Next, the control unit 31a transmits determination result information and terminal identification information to the central station 1a via the interface unit 32a (step S203).

[0091] Next, the central station 1a receives the determination result information and the terminal identification information (step S204). More specifically, the interface unit 12a included in the central station 1a acquires the determination result information and the terminal identification information. Next, the control unit 11a executes a second communication partner determination process based on the determination result information and the terminal identification information acquired in step S204 (step S205).

[0092] The control unit 11a controls the operation of the interface unit 12a to control the operation of the base station 2a determined as the communication station by the second communication partner determination process, and starts communication with the terminal device 3a indicated by the terminal identification information (step S103). Next, the communication station acquires the content signal transmitted from the terminal device 3a indicated by the terminal identification information (step S207).

[0093] The wireless communication system 100a of the second embodiment configured as described above includes a terminal device 3a that executes a strength measurement process and a control unit 11a that executes a second communication partner determination process. The second communication partner determination process is a process for determining the base station 2a with the strongest strength among the base stations 2a whose strength is equal to or less than a predetermined strength as the communication partner of the terminal device 3a.

[0094] Incidentally, nonlinear distortion due to the nonlinearity of optical modulators is more likely to occur as the intensity of the electromagnetic wave increases. Furthermore, since the intensity of the electromagnetic wave weakens as the distance increases, if the intensity of the signal received from the sender is strong, it means that when a signal is sent to that sender, the strength of the signal received from the sender is of the same intensity.

[0095] Therefore, the second communication partner determination process is a process of determining a base station 2a other than the base station 2a whose signal reception strength by the terminal device 3a is too strong as the base station 2a that will communicate with the terminal device 3a. Therefore, in the communication between the base station 2a determined in this way and the terminal device 3a, the occurrence of nonlinear distortion due to the nonlinearity of the optical modulator is suppressed. As a result, the wireless communication system 100a can suppress deterioration in the quality of wireless communication.

[0096] (Third embodiment) Fig. 10 is a diagram showing an example of the configuration of a wireless communication system 100b according to the third embodiment. Hereinafter, the same components as those shown in Figs. 1 to 9 are denoted by the same reference numerals and description thereof will be omitted.

[0097] The wireless communication system 100b is a radio access network (RAN). The wireless communication system 100b includes a central station 1b and a plurality of base stations 2b. The central station 1b is a central station in the RAN. The central station 1b is capable of communicating with a terminal device 3b. The central station 1b controls communication between the base station 2b and the terminal device 3b. The base station 2b is a base station in the RAN. The base station 2b is capable of communicating with the terminal device 3b.

[0098] The central station 1b includes a control unit 11b having a processor 91b such as a CPU and a memory 92b connected by a bus, and executes a program, which controls communication between the base station 2b and the terminal device 3b.

[0099] Under the control of the central station 1b, each base station 2b emits a reference signal at a predetermined timing. The reference signal is a radio signal emitted by the base station 2b with a predetermined intensity. The reference signal may include predetermined information necessary for the terminal device 3b to initially connect to the wireless communication system 100b.

[0100] The terminal device 3b is a terminal device with a wireless communication function, such as a smartphone or a personal computer. The terminal device 3b can transmit terminal identification information, which is information indicating an identifier that identifies the terminal device itself. The terminal device 3b can also receive wireless signals. The terminal device 3b communicates with the base station 2b, and transmits, for example, a content signal to the base station 2b. The terminal device 3b can also communicate with the central station 1b. The terminal device 3b transmits information regarding the quality of communication with each base station 2b included in the wireless communication system 100b (hereinafter referred to as "communication quality information") to the central station 1b.

[0101] Specifically, the communication quality is the strength of the reference signal received by the terminal device 3b. Therefore, the communication quality information is specifically information indicating the reception strength of each reference signal transmitted from each base station 2b when received by the terminal device 3b.

[0102] The terminal device 3b acquires communication quality information by, for example, measuring the strength of each received reference signal.

[0103] The terminal device 3b includes a control unit 31b having a processor 95b such as a CPU and a memory 96b connected by a bus, and executes a program. When the control unit 31b receives a test signal, the control unit 31b measures the strength of each test signal received by the terminal device 3b. In this way, the control unit 31b obtains communication quality information.

[0104] The control unit 31b transmits the acquired communication quality information to the central station 1b via the communication unit. The terminal device 3b transmits the terminal identification information together with the communication quality information to the central station 1b.

[0105] As described above, the central station 1b can communicate with the terminal device 3b. The central station 1b acquires the terminal identification information and communication quality information transmitted by the terminal device 3b, and executes a third communication partner determination process based on the acquired terminal identification information and communication quality information.

[0106] The third communication partner determination process is a process of determining a base station 2b as a communication partner of the terminal device 3b indicated by the terminal identification information based on the communication quality information. More specifically, it is a process of determining the base station 2b with the strongest strength indicated by the communication quality information as the communication partner (i.e., communication station) of the terminal device 3b indicated by the terminal identification information, among the base stations 2b whose strength indicated by the communication quality information is equal to or less than a predetermined strength.

[0107] More specifically, the third communication partner determination process is performed by the control unit 11b.

[0108] The control unit 11b controls the operation of the base station 2b that has been determined as the communication station by the third communication partner determination process, and starts communication with the terminal device 3b. The communication station converts the received content signal into an optical signal and transmits it to the central station 1b.

[0109] 11 is a diagram showing an example of the hardware configuration of the central station 1b in the third embodiment. The central station 1b includes the control unit 11b and executes a program as described above. By executing the program, the central station 1b functions as a device including the control unit 11b, the interface unit 12b, and the storage unit 13b.

[0110] More specifically, the processor 91b reads a program stored in the storage unit 13b and stores the read program in the memory 92b. The processor 91b executes the program stored in the memory 92b, whereby the central station 1b functions as a device including the control unit 11b, the interface unit 12b, and the storage unit 13b.

[0111] The control unit 11b performs, for example, a third communication partner determination process. The control unit 11b controls, for example, the operation of each functional unit provided in the central station 1b. The control unit 11b controls the operation of one or more base stations 2b via, for example, the interface unit 12b. The control unit 11b acquires, for example, information stored in the memory unit 13b. The process of acquiring the information stored in the memory unit 13b is specifically reading.

[0112] The control unit 11b communicates with the terminal device 3b via, for example, the interface unit 12b. The control unit 11b acquires terminal identification information and communication quality information through communication with the terminal device 3b.

[0113] The interface unit 12b includes a communication interface for connecting the central station 1b to an external device, and communicates with the external device via wire or wirelessly.

[0114] The external device is, for example, the terminal device 3b. In this case, the interface unit 12b acquires the terminal identification information and communication quality information transmitted by the terminal device 3b.

[0115] The external device is, for example, the base station 2b determined as the communication partner (i.e., communication station) of the terminal device 3b indicated by the terminal identification information through the third communication partner determination process. In this case, the interface unit 12b communicates with the communication station.

[0116] The communication station receives the content signal transmitted from terminal device 3b indicated by the terminal identification information. The communication station that has received the content signal converts the received content signal into an optical signal and transmits it to central station 1b. Central station 1b receives the content signal transmitted by the communication station.

[0117] The interface unit 12b may be configured to include an input device such as a mouse, a keyboard, or a touch panel. The interface unit 12b may be configured as an interface that connects these input devices to the central station 1b. In this way, the interface unit 12b may accept input of various information to the central station 1b via the input device, either wired or wireless.

[0118] The interface unit 12b may output various types of information. The interface unit 12b may be configured to include a display device such as a CRT display, a liquid crystal display, or an organic EL display. The interface unit 12b may be configured as an interface that connects these display devices to the central station 1b. The interface unit 12b may output information input to the interface unit 12b, for example. The interface unit 12b may also be configured to include a touch panel, for example.

[0119] The storage unit 13b is configured using a computer-readable storage medium device (non-transitory computer-readable recording medium) such as a magnetic hard disk device or a semiconductor storage device. The storage unit 13b stores various information related to the central station 1b. The storage unit 13b stores information necessary for, for example, the third communication partner determination process. The storage unit 13b stores, for example, various information generated by the operation of the control unit 11b. The storage unit 13b stores, for example, information acquired by the interface unit 12b.

[0120] 12 is a diagram showing an example of the hardware configuration of a base station 2b in the third embodiment. The base station 2b includes a control unit 21b having a processor 93b such as a CPU and a memory 94b connected by a bus, and executes a program. By executing the program, the base station 2b functions as a device including the control unit 21b, an interface unit 22b, and a storage unit 23b.

[0121] More specifically, the processor 93b reads out a program stored in the storage unit 23b and stores the read program in the memory 94b. The processor 93b executes the program stored in the memory 94b, causing the base station 2b to function as a device including the control unit 21b, the interface unit 22b, and the storage unit 23b.

[0122] The control unit 21b controls the operation of each functional unit included in the base station 2b, for example. The control unit 21b controls the operation of the signal source 221b included in the interface unit 22b, for example. The control unit 21b controls the operation of the optical modulator 223b included in the interface unit 22b, for example. The control unit 21b is under the control of the control unit 11b included in the central station 1b, for example.

[0123] The interface unit 22b includes a communication interface for connecting the base station 2b to an external device. The interface unit 22b communicates with the external device via wired or wireless communication. The external device is, for example, the central station 1b or the terminal device 3b.

[0124] The interface unit 22b includes, for example, a signal source 221b, an antenna 222b, and an optical modulator 223b. The signal source 221b generates, in the form of an electrical signal, a signal to be radiated wirelessly from the antenna 222b. The signal source 221b operates under the control of, for example, a control unit 21b which operates under the control of a control unit 11b included in the central station 1b.

[0125] The antenna 222b is an antenna. The antenna 222b emits a signal generated by the signal source 221b in the form of a radio signal. The antenna 222b receives, for example, a content signal transmitted by the terminal device 3b. The optical modulator 223b converts the content signal received by the antenna 222b into an optical signal. The content signal converted into an optical signal by the optical modulator 223b propagates toward the central station 1b. The optical modulator 223b operates, for example, under the control of a control unit 21b which operates under the control of a control unit 11b provided in the central station 1b.

[0126] The above-mentioned reference signal is generated by a signal source 221b under the control of the control unit 21b and is radiated from an antenna 222b.

[0127] The interface unit 22b may be configured to include input devices such as a mouse, a keyboard, a touch panel, etc. The interface unit 22b may be configured as an interface that connects these input devices to the base station 2b. In this way, the interface unit 22b may accept input of various information to the base station 2b via the input device, either wired or wireless.

[0128] The interface unit 22b may output various types of information. The interface unit 22b may be configured to include a display device such as a CRT display, a liquid crystal display, or an organic EL display. The interface unit 22b may be configured as an interface that connects these display devices to the base station 2b. The interface unit 22b may output, for example, information input to the interface unit 22b. Furthermore, the interface unit 22b may be configured to include, for example, a touch panel.

[0129] The storage unit 23b is configured using a computer-readable storage medium device (non-transitory computer-readable recording medium) such as a magnetic hard disk device or a semiconductor storage device. The storage unit 23b stores various types of information related to the base station 2b. The storage unit 23b stores various types of information generated by the operation of the control unit 21b, for example. The storage unit 23b stores information acquired by the interface unit 22b, for example.

[0130] 13 is a diagram showing an example of the hardware configuration of a terminal device 3b in the third embodiment. The terminal device 3b includes a control unit 31b including a processor 95b such as a CPU and a memory 96b connected by a bus, and executes a program. By executing the program, the terminal device 3b functions as a device including the control unit 31b, an interface unit 32b, and a storage unit 33b.

[0131] More specifically, the processor 95b reads the program stored in the storage unit 33b and stores the read program in the memory 96b. The processor 95b executes the program stored in the memory 96b, causing the terminal device 3b to function as a device including the control unit 31b, the interface unit 32b, and the storage unit 33b.

[0132] The control unit 31b controls, for example, the operation of each functional unit included in the terminal device 3b. The control unit 31b acquires communication quality information based on each reference signal acquired via, for example, the interface unit 32b. The control unit 31b controls, for example, the operation of the interface unit 22b to transmit the terminal identification information and the communication quality information to the central station 1b.

[0133] The interface unit 32b includes a communication interface for connecting the terminal device 3b to an external device. The interface unit 32b communicates with the external device via wired or wireless communication. The external device is, for example, the central station 1b. In this case, the interface unit 32b transmits, for example, terminal identification information and communication quality information to the central station 1b.

[0134] The external device is, for example, the base station 2b. In this case, the interface unit 32b receives, for example, a reference signal. The test signal received by the interface unit 32b is acquired by the control unit 31b. The interface unit 32b also transmits a content signal.

[0135] The interface unit 32b may be configured to include input devices such as a mouse, a keyboard, a touch panel, etc. The interface unit 32b may be configured as an interface that connects these input devices to the terminal device 3b. In this way, the interface unit 32b may accept input of various information to the terminal device 3b via the input device, either wired or wireless.

[0136] The interface unit 32b may output various types of information. The interface unit 32b may be configured to include a display device such as a CRT display, a liquid crystal display, or an organic EL display. The interface unit 32b may be configured as an interface that connects these display devices to the terminal device 3b. The interface unit 32b may output information input to the interface unit 32b, for example. The interface unit 32b may also be configured to include a touch panel, for example.

[0137] The storage unit 33b is configured using a computer-readable storage medium device (non-transitory computer-readable recording medium) such as a magnetic hard disk device or a semiconductor storage device. The storage unit 33b stores various information related to the terminal device 3b. The storage unit 33b stores, for example, various information generated by the operation of the control unit 31b. The storage unit 33b stores, for example, information acquired by the interface unit 32b. The storage unit 33b stores, for example, terminal identification information in advance.

[0138] 14 is a flowchart showing an example of the flow of processing executed in the wireless communication system 100b of the third embodiment. The terminal device 3b acquires one or more reference signals and acquires communication quality information based on the acquired reference signals (step S301). For example, the terminal device 3b acquires communication quality information based on each reference signal and the timing at which each reference signal is received. At this time, the terminal device 3b determines, for example, which base station 2b is the sender of each reference signal, based on the timing at which each reference signal is received.

[0139] Next, the terminal device 3b transmits the terminal identification information and the communication quality information to the central station 1b (step S302). Next, the control unit 11b acquires the terminal identification information and the communication quality information via the interface unit 12b (step S303). Next, the control unit 11b executes a third communication partner determination process based on the terminal identification information and the communication quality information (step S304).

[0140] Next, the control unit 11b controls the operation of the interface unit 12b to start communication between the base station 2b, which has been determined as the communication station by the third communication partner determination process, and the terminal device 3b (step S305). Next, the content signal transmitted by the terminal device 3b is acquired by the communication station (step S306).

[0141] The wireless communication system 100b of the third embodiment configured as described above determines a communication station according to the reception strength of a reference signal at the terminal device 3b. At this time, the communication station is determined to be the base station 2b with the strongest communication quality information among the base stations 2b whose communication quality information indicates an intensity equal to or less than a predetermined intensity. Therefore, in the transmission and reception of content signals between the communication station and the terminal device 3b, the occurrence of nonlinear distortion due to the nonlinearity of the optical modulator is suppressed. Therefore, the wireless communication system 100b can suppress degradation of wireless communication quality.

[0142] (Regarding the first and third embodiments) As described above, in the first communication partner determination process of the first embodiment, the base station 2 of the communication partner is determined according to the position of the terminal device 3. More specifically, in the determination according to the position, the base station 2 that is located at a position where the strength of the radio signal received by the terminal device 3 is neither too strong nor too weak is determined to be the communication station.

[0143] On the other hand, in the third communication partner determination process of the third embodiment, as described above, the base station 2b in which the strength of the reference signal received by the terminal device 3b is neither too strong nor too weak is determined to be the communication station. In this way, the first communication partner determination process is actually a third communication partner determination process that uses location information indicating distance information, which is a physical quantity correlated with the strength of a wireless signal, instead of communication quality information indicating strength.

[0144] It can be said that both the control unit 11 and the control unit 11b execute a determination process. The determination process is a process of determining, as a communication station, the base station with the strongest terminal reception strength among the base stations whose amount of correlation with the terminal reception strength is less than a predetermined value and is equal to or greater than a predetermined value. The terminal reception strength is the reception strength when the terminal device receives a wireless signal (e.g., a reference signal) transmitted from the base station.

[0145] The quantity having a correlation of a predetermined degree or more with the terminal reception strength is, for example, the distance between the terminal device and the base station. In such a case, the location information of the terminal device is obtained, for example, by GPS as described above. The location information of the terminal device may be obtained using a positioning technique. Therefore, the distance between the terminal device and the base station is obtained, for example, by GPS. The distance between the terminal device and the base station is obtained, for example, by using a positioning technique.

[0146] The amount having a correlation of a predetermined degree or more with the terminal reception strength may be, for example, the reception strength itself when the terminal device receives a radio signal transmitted from a base station.

[0147] (Variation) The location information acquired in the terminal location information acquisition process is the location of the terminal device 3 estimated based on the history of past locations of the terminal device 3 obtained by GPS, positioning, etc., and may indicate the location of the terminal device 3 at the time when the base station 2 and the terminal device 3 communicate after the determination process is executed.

[0148] Therefore, the distance between the terminal device and the base station may be the position of the terminal device 3 estimated based on the history of past positions of the terminal device 3 obtained by GPS, positioning, etc., and may be obtained based on the position of the terminal device 3 at the time when the base station 2 and the terminal device 3 communicate after the determination process is executed.

[0149] The estimation is performed, for example, by a technique such as a one-point positioning process in which the direction and distance are estimated from the beam direction and RTT (Round Trip Time) to the terminal device when the base station performs beamforming, or a three-point positioning process using the received power at the terminal device from multiple base stations.

[0150] Each of the central station 1, central station 1a, central station 1b, base station 2, base station 2a, and base station 2b may be implemented using a plurality of information processing devices communicably connected via a network. In this case, the processes executed by the control unit 11, control unit 11a, control unit 21, and control unit 21a may be distributed and executed by the plurality of information processing devices.

[0151] All or part of the functions of the central station 1, central station 1a, central station 1b, base station 2, base station 2a, and base station 2b may be realized using hardware such as an ASIC (Application Specific Integrated Circuit), a PLD (Programmable Logic Device), or an FPGA (Field Programmable Gate Array). The program may be recorded on a computer-readable recording medium. Examples of computer-readable recording media include portable media such as flexible disks, magneto-optical disks, ROMs, and CD-ROMs, and storage devices such as hard disks built into computer systems. The program may be transmitted via a telecommunications line.

[0152] Each of the central stations 1 and 1b is an example of a wireless communication device.

[0153] 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. [Explanation of symbols]

[0154] REFERENCE SIGNS LIST 100, 100a, 100b... wireless communication system, 1, 1a, 1b... central station, 2, 2a, 2b... base station, 3, 3a, 3b... terminal device, 11, 11a, 11b... control unit, 12, 12a, 12b... interface unit, 13, 13a, 13b... storage unit, 21, 21a, 21b... control unit, 22, 22a, 22b... interface unit, 221, 221a, 221b... signal source, 222, 222a, 222b... antenna, 223, 223a, 223b... optical modulator, 23, 23a, 23b... storage unit, 31a, 31b... control unit, 32a, 32b... interface unit, 33a, 33b... storage unit, 91, 91a, 91b... processor, 92, 92a, 92b...memory, 93, 93a, 93b...processor, 94, 94a, 94b...memory, 95a, 95b...processor, 96a, 96b...memory

Claims

1. a control unit that controls communication between a plurality of base stations that can communicate with the terminal device and the terminal device; Equipped with the control unit executes a determination process to determine, among the base stations having a correlation of a predetermined degree or more with respect to the reception strength when the terminal device receives the wireless signal transmitted from the base station, the base station having the strongest reception strength as the base station to communicate with the terminal device, the amount of the correlation being less than a predetermined value. Wireless communication device.

2. the quantity is the received intensity; The wireless communication device of claim 1 .

3. the quantity is the distance between the terminal device and the base station; The wireless communication device of claim 1 .

4. The distance is obtained using a GPS (Global Positioning System). The wireless communication device according to claim 3 .

5. The distance is obtained using positioning technology. The wireless communication device according to claim 3 .

6. the distance is a position of the terminal device estimated based on the position of the terminal device, and is obtained based on the position of the terminal device at a timing when the base station and the terminal device communicate after the determination process is executed.

6. The wireless communication device according to claim 4 or 5.

7. A wireless communication method is executed by a wireless communication device, the wireless communication device including a control unit that controls communication between a plurality of base stations that can communicate with a terminal device and the terminal device, wherein the control unit executes a determination process to determine a base station with the strongest reception strength among base stations that have a correlation of a predetermined degree or more with a reception strength when the terminal device receives a wireless signal transmitted from the base station that is less than a predetermined value, as the base station that will communicate with the terminal device, a determination step in which the control unit executes the determination process; A wireless communication method comprising:

8. A program for causing a computer to function as the wireless communication device according to claim 1.

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