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

Abstract

According to an aspect of the present invention, a wireless communication system comprises: a terminal-side communication device that has an antenna; and a wireless communication device that uses analog signals, which transport information by using the waveforms of an amplitude or a phase of light, to communicate with the terminal-side communication device, thereby performing the reception of signals received by the antenna and the transmission of signals that are to be radiated by the antenna. The wireless communication system uses Time Division Duplex (TDD) to perform wireless communication with a terminal, which is a communication target, via the antenna. The wireless communication device comprises: an uplink delay adjustment unit that adjusts the delay caused by the propagation of an uplink signal that is a signal flowing from the terminal through the antenna toward the wireless communication device; and a downlink delay adjustment unit that adjusts the delay caused by the propagation of a downlink signal that is a signal flowing from the wireless communication device through the antenna toward the terminal.

Description

Technical Field

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

Background Art

[0002] There is an increasing demand for communication systems having features such as high speed, large capacity, low latency, and connection of a large number of terminals, such as the fifth-generation mobile communication system (5G). In realizing such communication, discussions on Functional split for dividing the functional parts of a base station device have also been carried out. In 5G, the base station device is installed by being divided into logical nodes called CU (Centralized Unit), DU (Distributed Unit), and RU (Radio Unit) (see Non-Patent Document 1). Further, for the purpose of suppressing the transmission capacity of the FH (Front Haul) section between the DU and the RU and simplifying the wireless communication device corresponding to the RU (hereinafter referred to as "remote radio unit"), analog RoF (Radio-over-Fiber) in which communication between the wireless communication device corresponding to the CU and the DU (hereinafter referred to as "aggregation station") and the remote radio unit is performed using an analog optical modulation signal has been proposed (see Non-Patent Document 2). Furthermore, in order to realize high-speed and large-capacity communication, it is assumed that a high-frequency band such as millimeter wave is used, and the use of TDD (Time Division Duplex) technology is being studied to suppress an increase in the used frequency band in the uplink and downlink communication between the remote radio unit and a terminal such as a smartphone.

Prior Art Documents

Non-Patent Documents

[0003]

Non-Patent Document 1

Non-Patent Document 2

[0004] In general, in wireless communication using TDD technology, in order to avoid interference, the switching of the timing of wireless transmission and reception by one or more remote radio heads needs to be synchronized. That is, the timing at which the signal propagated from the central office to the remote radio head is radiated from the remote radio head needs to be substantially the same at one or more remote radio heads. Further, the timing at which one or more remote radio heads receive signals from the terminal also needs to be substantially the same. The accuracy of time synchronization is, for example, ±1.5 microseconds.

[0005] However, the time required for signal propagation between the central office and the remote radio head depends on the distance between the central office and the remote radio head. Therefore, in order to synchronize the transmission and reception timings of a plurality of remote radio heads, it is necessary to absorb the difference in signal propagation time caused by the difference in the distance between the central office and the remote radio head. Therefore, when the signal exchange between the central office and the remote radio head is performed by a digital signal, synchronization of the transmission and reception switching timing is performed using the buffering function for storing the signal (see Non-Patent Document 3).

[0006] On the other hand, in the case of analog RoF, since the signal exchange between the central office and the remote radio head is performed by an analog signal, it is difficult to buffer the signal. Therefore, in analog RoF, it is conceivable to achieve synchronization by advancing the signal from the central office to the remote radio head. Advancing the signal means that the transmission of the signal from the central office to the remote radio head is started at an earlier timing as the distance between the central office and the remote radio head is longer.

[0007] By performing such signal preemption, it is possible to synchronize the timing of transmitting a signal from the relay station to the terminal (i.e., the downstream signal). However, regarding the reception of the signal received by the relay station from the terminal by the aggregation station (i.e., the upstream signal), the longer the distance between the aggregation station and the relay station, the later the timing at which the aggregation station can receive the signal. Therefore, it is necessary for the aggregation station to be able to receive the signal until a late timing.

[0008] Thus, the longer the distance between the aggregation station and the relay station, the earlier the timing at which the aggregation station outputs the downstream signal, but the later the timing at which it receives the upstream signal. Here, in the case of analog RoF, since the electrical-to-optical and optical-to-electrical conversion devices are different for downstream and upstream, it is necessary to switch the path between downstream and upstream using a TDD switch or the like. Therefore, at the aggregation station, there may be a case where the timings of the downstream signal and the upstream signal collide. To avoid such a collision, there may also be a method of determining a timing called a guard time, during which communication is not performed. However, when determining the guard time, since communication is not performed during the guard time period, the communication efficiency decreases.

[0009] As described above, when performing TDD in communication between wireless communication devices using analog signals, there may be a deterioration in the quality of communication, such as a collision between the timings of the upstream signal and the downstream signal and a decrease in communication efficiency.

[0010] In view of the above circumstances, an object of the present invention is to provide a technique for suppressing a deterioration in the quality of communication in wireless communication using analog signals between wireless communication devices.

Means for Solving the Problem

[0011] One aspect of the present invention is a wireless communication device included in a wireless communication system that performs wireless communication with a communication target terminal via an antenna by TDD (Time Division Duplex). The wireless communication device includes a terminal-side communication device including an antenna and a wireless communication device that performs communication with the terminal-side communication device using an analog signal that transmits information by a waveform of an amplitude or a phase of light, and performs reception of a signal received by the antenna and transmission of a signal radiated by the antenna. The wireless communication device includes an uplink delay adjustment unit that adjusts a delay caused by propagation of an uplink signal, which is a signal flowing from the terminal to the wireless communication device via the antenna, and a downlink delay adjustment unit that adjusts a delay caused by propagation of a downlink signal, which is a signal flowing from the wireless communication device to the terminal via the antenna.

[0012] One aspect of the present invention is a wireless communication system that performs communication with a communication target terminal by TDD (Time Division Duplex). The wireless communication system includes a terminal-side communication device including an antenna and a wireless communication device that performs communication with the terminal-side communication device using an analog signal that transmits information by a waveform of an amplitude or a phase of light, and performs reception of a signal received by the antenna and transmission of a signal radiated by the antenna. The wireless communication device includes an uplink delay adjustment unit that adjusts a delay caused by propagation of an uplink signal, which is a signal flowing from the terminal to the wireless communication device via the antenna, and a downlink delay adjustment unit that adjusts a delay caused by propagation of a downlink signal, which is a signal flowing from the wireless communication device to the terminal via the antenna.

[0013] One aspect of the present invention is a wireless communication method provided in a wireless communication system including a terminal-side communication device including an antenna, and a wireless communication device that communicates with the terminal-side communication device using an analog signal that transmits information by the waveform of the amplitude or phase of light, and performs reception of a signal received by the antenna and transmission of a signal radiated by the antenna. The wireless communication method includes an upstream delay adjustment unit that adjusts a delay caused by propagation of an upstream signal, which is a signal flowing from the terminal to the wireless communication device via the antenna, and a downstream delay adjustment unit that adjusts a delay caused by propagation of a downstream signal, which is a signal flowing from the wireless communication device to the terminal via the antenna. The wireless communication method includes a first switching step of switching the operation of the antenna from a reception operation of receiving a signal transmitted by the terminal to a radiation operation of radiating a signal, and a second switching step of switching the operation of the antenna from the radiation operation to the reception operation.

Advantages of the Invention

[0014] According to the present invention, it is possible to suppress a decrease in communication quality in wireless communication using an analog signal for communication between wireless communication devices.

Brief Description of the Drawings

[0015]

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Mode for Carrying Out the Invention

[0016] (Embodiment) FIG. 1 is a diagram showing an example of the configuration of the wireless communication system 100 according to the embodiment. The wireless communication system 100 communicates with a terminal 9 capable of wireless communication such as a smartphone by TDD (Time Division Duplex). That is, the terminal 9 is a communication target of the wireless communication system 100. The wireless communication system 100 includes one or more sub-communication systems 10. The sub-communication system 10 includes an overhanging communication device 1, an aggregation communication device 2, a first communication support device 3, a second communication support device 4, and an analog transmission line 5. The overhanging communication device 1 includes an antenna 101. The aggregation communication device 2 is, for example, an aggregation station. The overhanging communication device 1 wirelessly transmits and receives signals to and from the terminal 9 through the antenna 101. One or more overhanging communication devices 1 are connected to the aggregation communication device 2. The overhanging communication device 1 is, for example, an overhanging station.

[0017] For the sake of simplicity in the following description, the wireless communication system 100 will be described by taking the case where different sub - communication systems 10 are independent of each other as an example. However, the different sub - communication systems 10 do not necessarily have to be independent of each other. Note that being independent of each other means that the signals flowing into one of any two sub - communication systems 10 do not flow into the other sub - communication system 10. Also, being independent of each other means that the devices included in one of any two sub - communication systems 10 do not control the operation of the devices included in the other sub - communication system 10. Note that the devices belonging to the sub - communication system 10 specifically mean the extending communication device 1, the aggregating communication device 2, the first communication support device 3, and the second communication support device 4.

[0018] The aggregating communication device 2 exchanges signals with the terminal 9 via the extending communication device 1. Specifically, the aggregating communication device 2 executes uplink signal processing and downlink signal processing. The uplink signal processing is a process of receiving a signal flowing from the terminal 9 to the aggregating communication device 2 (hereinafter referred to as the "uplink signal") and performing signal processing on the received uplink signal.

[0019] The downlink signal processing is a process related to the transmission of a signal flowing from the aggregating communication device 2 to the terminal 9 (hereinafter referred to as the "downlink signal"). The downlink signal processing includes, for example, downlink electrical signal generation processing. The downlink electrical signal generation processing is a process of generating an analog signal (hereinafter referred to as the "downlink electrical signal") that transmits information by the waveform of voltage or current and arrives at the first communication support device 3. The downlink electrical signal is transmitted from the extending communication device 1 to the terminal 9 after undergoing conversion to an optical signal and reconversion to an electrical signal. Therefore, the downlink electrical signal is a downlink signal in which information is represented by an electrical signal. The downlink electrical signal generation processing is specifically a process of generating a downlink electrical signal by controlling the operation of a power supply and a modulator.

[0020] The downlink signal processing includes, for example, scheduling processing. The scheduling processing is a process of controlling the allocation of communication resources to the terminal 9 and the timing of generating the downlink electrical signal.

[0021] The first communication support device 3 performs electro-optical conversion processing and opto-electrical conversion processing. The electro-optical conversion processing is a process of converting an input electrical signal into an optical signal by intensity modulation or the like. The electro-optical conversion processing is, for example, a process of converting an electrical signal into an optical signal by an electro-optical element. The opto-electrical conversion processing is a process of converting an input optical signal into an electrical signal and detecting the intensity-modulated or the like optical signal. The opto-electrical conversion processing is, for example, a process of converting an optical signal into an electrical signal by an opto-electrical element.

[0022] The first communication support device 3 converts the downstream electrical signal generated by the aggregation communication device 2 into a downstream optical signal by executing the electro-optical conversion processing. The downstream optical signal is an analog signal that transmits information by the waveform of the amplitude or phase of light and is an analog signal output from the first communication support device 3. The downstream optical signal is re-converted into an electrical signal in the second communication support device 4 and then transmitted from the overhanging communication device 1 to the terminal 9. Therefore, the downstream optical signal is a downstream signal in which information is represented by an optical signal.

[0023] The first communication support device 3 outputs the generated downstream optical signal to the analog transmission line 5. Further, the first communication support device 3 receives an optical signal (hereinafter referred to as "upstream optical signal") that has propagated through the analog transmission line 5.

[0024] The upstream optical signal is an analog signal that transmits information by the waveform of the amplitude or phase of light and is an analog signal arriving at the first communication support device 3. The upstream optical signal is a signal that has propagated from the terminal 9 to the overhanging communication device 1, has been converted into an optical signal in the second communication support device 4, and has arrived at the first communication support device 3. Therefore, the upstream optical signal is an upstream signal in which information is represented by an optical signal.

[0025] The first communication support device 3 converts an input upstream optical signal into an upstream electrical signal by executing optoelectronic conversion processing. The upstream electrical signal is an analog signal that transmits information by means of the waveform of voltage or current and is an analog signal output from the first communication support device 3. The upstream electrical signal is a signal obtained by converting the upstream optical signal. Therefore, the upstream electrical signal is an upstream signal in which information is represented by an electrical signal.

[0026] The first communication support device 3 includes an upstream path and a downstream path. The upstream path is a path through which the upstream signal propagates. The downstream path is a path through which the downstream signal propagates. The upstream path and the downstream path are spatially different paths. That is, the upstream path and the downstream path are, for example, different waveguides. Note that the upstream path and the downstream path included in the first communication support device 3 are paths through which an optical signal or an electrical signal flows.

[0027] The first communication support device 3 may include WDM (Wavelength Division Multiplexing) and perform signal transmission and reception with the second communication support device 4 via the analog transmission line 5 through the WDM. Specifically, the first communication support device 3 may receive an upstream optical signal by WDM and then convert each optical signal separated for each optical wavelength into an upstream electrical signal by optoelectronic conversion processing. Further, the first communication support device 3 may convert each of one or more downstream electrical signals into a downstream optical signal by electro-optical conversion processing and then multiplex them by WDM and output them to the analog transmission line 5 in the state of one downstream optical signal.

[0028] FIG. 2 is an explanatory diagram for explaining an example of the configuration included in the first communication support device 3 in the embodiment. In the example of FIG. 2, the first communication support device 3 includes a WDM 301, an optoelectronic element 302, an electro-optical element 303, an upstream delay adjustment unit 304, and a downstream delay adjustment unit 305. The WDM 301 is a WDM. The optoelectronic element 302 is an optoelectronic element. The electro-optical element 303 is an electro-optical element.

[0029] The upstream delay adjustment unit 304 adjusts the delay caused by the propagation of the upstream signal. More specifically, the upstream delay adjustment unit 304 generates a delay that reduces the difference between each sub-communication system 10 with respect to the time it takes for the upstream signal to propagate from the antenna 101 to the aggregation communication device 2, for the purpose of satisfying the predetermined upstream and downstream switching timing of TDD. The upstream delay adjustment unit 304 is, for example, a delay element.

[0030] Incidentally, the signal to be adjusted for delay by the upstream delay adjustment unit 304 may be a digital signal. In such a case, a digital signal is input to the upstream delay adjustment unit 304. When a digital signal is input to the upstream delay adjustment unit 304, an analog-to-digital converter is located in front of the upstream delay adjustment unit 304. A specific example of the configuration for inputting a digital signal to the upstream delay adjustment unit 304 will be described in detail in the modification example.

[0031] When the input signal is a digital signal, the upstream delay adjustment unit 304 adjusts the delay, for example, by performing buffering. The length of the delay to be generated is, for example, a length obtained based on the result of the operator of the wireless communication system 100 measuring the delay in advance. The time of the delay to be adjusted may be, for example, a result obtained based on the regularly measured delay time. The upstream delay adjustment unit 304 may be, for example, the signal propagation path itself, and have a length that generates only the delay obtained based on the pre-measured delay time. When the flowing signal is an electrical signal, the path may be, for example, a copper wire cable.

[0032] Specifically, the delay generated by the uplink delay adjustment unit 304 will be described. More specifically, taking as an example the case where a 5-second delay occurs in the sub-communication system 10 to be compared with respect to the reference sub-communication system 10, the delay generated by the uplink delay adjustment unit 304 will be described. In this case, the delay time generated by the uplink delay adjustment unit 304 in the reference sub-communication system 10 is, for example, 6 seconds, and the delay time generated by the uplink delay adjustment unit 304 in the sub-communication system 10 to be compared is, for example, 1 second. By doing so, the time difference (i.e., delay) between the reference sub-communication system 10 and the sub-communication system 10 to be compared is eliminated.

[0033] The 5-second time difference in the above example is, for example, the time measured by the operator. Based on the measured time, the operator controls the delay time generated by the uplink delay adjustment unit 304 of each sub-communication system 10, for example, via the input unit 22 or the communication unit 23 of the aggregation communication device 2. The input unit 22 and the communication unit 23 of the aggregation communication device 2 will be described later. The 5-second time difference in the above example is, for example, an example of the time of the delay measured periodically.

[0034] Note that the difference between each sub-communication system 10 in the time for the uplink signal to propagate from the antenna 101 to the aggregation communication device 2 mainly occurs due to the difference in the length of the analog transmission line 5. Therefore, the uplink delay adjustment unit 304 reduces the difference between each sub-communication system 10 in the time for the uplink signal to propagate through the analog transmission line 5.

[0035] The downlink delay adjustment unit 305 adjusts the delay caused by the propagation of the downlink signal. More specifically, the downlink delay adjustment unit 305 generates a delay that reduces the difference between each sub-communication system 10 in the time for the downlink signal to propagate from the aggregation communication device 2 to the antenna 101 for the purpose of satisfying the predetermined uplink and downlink switching timing of TDD. The downlink delay adjustment unit 305 is, for example, a delay element.

[0036] By the way, the signal to be adjusted for delay by the downstream delay adjustment unit 305 may be a digital signal. In such a case, a digital signal is input to the downstream delay adjustment unit 305. When a digital signal is input to the downstream delay adjustment unit 305, an analog-to-digital converter is located in front of the downstream delay adjustment unit 305. A specific example of the configuration for inputting a digital signal to the downstream delay adjustment unit 305 will be described in detail in the modification example.

[0037] When the input signal is a digital signal, the downstream delay adjustment unit 305 adjusts the delay, for example, by buffering. The length of the delay to be generated is, for example, a length obtained based on the result of the operator of the wireless communication system 100 measuring the delay in advance. The time of the delay to be adjusted may be, for example, a result obtained based on the time of the delay measured periodically. The downstream delay adjustment unit 305 may be, for example, the path itself through which the signal propagates, and has a length that generates only the delay obtained based on the measured delay time in advance. When the flowing signal is an optical signal, the path is, for example, an optical fiber. When the flowing signal is an electrical signal, the path may be, for example, a copper wire cable.

[0038] Specifically, the delay generated by the downstream delay adjustment unit 305 will be described. More specifically, taking as an example the case where a 5-second delay occurs in the sub-communication system 10 to be compared with respect to the reference sub-communication system 10, the delay generated by the downstream delay adjustment unit 305 will be described. In this case, the delay time generated by the downstream delay adjustment unit 305 in the reference sub-communication system 10 is, for example, 6 seconds, and the delay time generated by the downstream delay adjustment unit 305 in the sub-communication system 10 to be compared is, for example, 1 second. By doing so, the time difference (i.e., delay) between the reference sub-communication system 10 and the sub-communication system 10 to be compared is eliminated.

[0039] The 5-second time difference in the above example is, for example, the time measured by the operator. Based on the measured time, the operator controls the delay time generated by the downlink delay adjustment unit 305 of each sub-communication system 10 via, for example, the input unit 22 or the communication unit 23 of the aggregation communication device 2. The 5-second time difference in the above example is, for example, an example of the delay time measured periodically.

[0040] Note that the difference between each sub-communication system 10 in the time for the downlink signal to propagate from the aggregation communication device 2 to the antenna 101 mainly occurs due to the difference in the length of the analog transmission line 5. Therefore, the downlink delay adjustment unit 305 reduces the difference between each sub-communication system 10 in the time for the downlink signal to propagate through the analog transmission line 5.

[0041] In the example of FIG. 2, the uplink channel has the WDM 301 on the input side and the first path 31 of the uplink delay adjustment unit 304 on the output side. In the example of FIG. 2, the downlink channel has the downlink delay adjustment unit 305 on the input side and the second path 32 of the WDM 301 on the output side.

[0042] Returning to the description of FIG. 1. The second communication support device 4 also includes an uplink path and a downlink path. Note that the uplink path and the downlink path included in the second communication support device 4 are paths through which optical signals or electrical signals flow, similar to the uplink path and the downlink path included in the first communication support device 3. The second communication support device 4 executes electro-optical conversion processing and opto-electrical conversion processing. The second communication support device 4 further executes switching processing. The switching processing is processing for switching the operation of the antenna 101. Switching the operation of the antenna 101 means switching between the reception operation and the radiation operation of the antenna 101. The reception operation is the operation in which the antenna 101 receives the signal transmitted by the terminal 9. The radiation operation is the operation in which the antenna 101 radiates the signal. The terminal 9 receives the signal radiated by the antenna 101.

[0043] More specifically, the switching process is a process of switching, at a predetermined period according to the TDD timing, between a process of passing a signal path from the antenna 101 to the aggregation communication device 2 and a process of passing a signal path from the aggregation communication device 2 to the antenna 101. Specifically, the switching process is performed by a switch.

[0044] For example, by switching the switch on and off, the state in which the signal path from the antenna 101 to the aggregation communication device 2 is passed and the state in which the signal path from the aggregation communication device 2 to the antenna 101 is passed are switched. If the signal path from the antenna 101 to the aggregation communication device 2 is passed, the signal that has reached the antenna 101 from the terminal 9 reaches the aggregation communication device 2. That is, the antenna 101 is in a state of performing a reception operation.

[0045] On the other hand, if the signal path from the aggregation communication device 2 to the antenna 101 is passed, the signal output by the aggregation communication device 2 reaches the antenna 101 and is radiated. That is, the antenna 101 is in a state of performing a radiation operation. Therefore, the switching process is also a process of switching between a state in which a signal flows through the upstream channel and a state in which a signal flows through the downstream channel. By executing the switching process, TDD (Time Division Duplex) is realized.

[0046] FIG. 3 is an explanatory diagram for explaining an example of the configuration included in the second communication support device 4 in the embodiment. In the example of FIG. 3, the second communication support device 4 includes a WDM 401, an electro-optical element 402, a photoelectric element 403, a timing switch 404, and a switch control unit 405. The WDM 401 is a WDM. The electro-optical element 402 is an electro-optical element. The photoelectric element 403 is a photoelectric element.

[0047] The timing switch 404 is a switch that switches between a state where a signal flows through the upstream path and a state where a signal flows through the downstream path. Therefore, the switching between on and off of the timing switch 404 in FIG. 3 is an example of a switching process. The timing switch 404 switches between a state where a signal flows through the upstream path and a state where a signal flows through the downstream path under the control of the switch control unit 405.

[0048] The switch control unit 405 includes a processor 451 such as a CPU (Central Processing Unit) connected by a bus and a memory 452. The switch control unit 405 executes a program using the processor 451 and the memory 452. The switch control unit 405 is electrically connected to the timing switch 404 and controls the operation of the timing switch 404 by executing a program.

[0049] The timing of executing the switching process is, for example, a predetermined timing. More specifically, the execution of the switching process occurs at substantially the same timing in each sub-communication system 10 included in the wireless communication system 100. As a result, the TDD (Time Division Duplex) technology is realized.

[0050] Note that the timing of executing the switching process may be a timing determined based on communication with a predetermined device when the switch control unit 405 is configured to be communicable with the predetermined device. The predetermined device is, for example, the control unit 21 included in the aggregation communication device 2 described later. Note that the timing of generating the downstream electrical signal by the downstream electrical signal generation process is a timing that satisfies the condition that the period is synchronized with the period in which the switching process is executed. Therefore, the generation of the downstream electrical signal by the downstream electrical signal generation process and the execution of the switching process do not necessarily have to be executed at the same time as long as the execution periods are synchronized.

[0051] In the example of FIG. 3, the upstream path is a path where the input side is the timing switch 404 and reaches the WDM 401 via the electro-optical element 402. In the example of FIG. 3, the output side of the upstream path is the WDM 401.

[0052] In the example of FIG. 3, the downstream path is a path where the input side is the WDM 401 and reaches the timing switch 404 via the optoelectronic element 403. That is, in the example of FIG. 3, the output side of the downstream path is the timing switch 404.

[0053] Returning to the description of FIG. 1. The analog transmission line 5 is a transmission line that transmits an analog signal. More specifically, it is a transmission line that transmits an analog signal that transmits information by the waveform of the amplitude or phase of light. The analog transmission line 5 is connected to the first communication support device 3 and the second communication support device 4, and transmits an analog signal from one of the first communication support device 3 and the second communication support device 4 to the other. The analog transmission line 5 may be, for example, a single-mode fiber, a multi-core fiber, or a dispersion-shifted fiber. That is, the analog transmission line 5 may be, for example, a fiber.

[0054] Note that the distance of the path connecting the antenna 101 and the timing switch 404 is negligibly short compared to the distance from the timing switch 404 to the first communication support device 3. Therefore, the delay generated in the path from the antenna 101 to the timing switch 404 is negligibly long compared to the delay occurring between the timing switch 404 and the first communication support device 3.

[0055] FIG. 4 is a diagram showing an example of the hardware configuration of the overhanging communication device 1 in the embodiment. The overhanging communication device 1 includes a control unit 11 including a processor 91 such as a CPU and a memory 92 connected by a bus, and executes a program. The overhanging communication device 1 functions as a device including a control unit 11, an input unit 12, a communication unit 13, a storage unit 14, an output unit 15, an antenna 101, and a conductive circuit 102 by executing a program.

[0056] More specifically, the processor 91 reads out the program stored in the storage unit 14 and stores the read program in the memory 92. By executing the program stored in the memory 92, the protruding communication device 1 functions as a device including the control unit 11, the input unit 12, the communication unit 13, the storage unit 14, the output unit 15, the antenna 101, and the conductive circuit 102.

[0057] The control unit 11 controls the operations of various functional units included in the protruding communication device 1. The control unit 11 controls, for example, the operation of the output unit 15. The control unit 11 records various information in the storage unit 14, for example.

[0058] The input unit 12 is configured to include input devices such as a mouse, a keyboard, and a touch panel. The input unit 12 may be configured as an interface for connecting these input devices to the protruding communication device 1. The input unit 12 receives the input of various information to the protruding communication device 1.

[0059] The communication unit 13 is configured to include a communication interface for connecting the protruding communication device 1 to an external device. The communication unit 13 communicates with the external device via wire or wireless.

[0060] The storage unit 14 is configured using a computer-readable storage medium device such as a magnetic hard disk device or a semiconductor storage device. The storage unit 14 stores various information related to the protruding communication device 1. The storage unit 14 stores information input via the input unit 12 or the communication unit 13, for example.

[0061] The output unit 15 outputs various information. The output unit 15 is 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 output unit 15 may be configured as an interface for connecting these display devices to the protruding communication device 1. The output unit 15 outputs, for example, the information input to the input unit 12.

[0062] The conductive circuit 102 is a circuit connected to the antenna 101. The conductive circuit 102 propagates the upstream signal received by the antenna 101 to the second communication support device 4. The conductive circuit 102 propagates the downstream signal propagated from the second communication support device 4 to the antenna 101. The conductive circuit 102 and the antenna 101 may be provided outside the overhanging communication device 1.

[0063] FIG. 5 is a diagram showing an example of the hardware configuration of the aggregation communication device 2 in the embodiment. The aggregation communication device 2 includes a control unit 21 including a processor 93 such as a CPU and a memory 94 connected by a bus, and executes a program. The aggregation communication device 2 functions as a device including a control unit 21, an input unit 22, a communication unit 23, a storage unit 24, and an output unit 25 by executing a program.

[0064] More specifically, the processor 93 reads out the program stored in the storage unit 24 and stores the read program in the memory 94. By executing the program stored in the memory 94 by the processor 93, the aggregation communication device 2 functions as a device including a control unit 21, an input unit 22, a communication unit 23, a storage unit 24, an output unit 25, a signal generation unit 26, and a signal reception unit 27.

[0065] The control unit 21 controls the operations of various functional units included in the aggregation communication device 2. The control unit 21 executes, for example, downstream signal processing. That is, the control unit 21 controls the operation of the signal generation unit 26, for example, to generate a downstream signal. The control unit 21 executes, for example, upstream signal processing. The control unit 21 controls the operation of the output unit 25, for example. The control unit 21 records various information in the storage unit 24, for example.

[0066] The input unit 22 is configured to include input devices such as a mouse, a keyboard, and a touch panel. The input unit 22 may be configured as an interface for connecting these input devices to the aggregation communication device 2. The input unit 22 receives the input of various information to the aggregation communication device 2. The information input to the input unit 22 is, for example, the information carried by the signal generated by the aggregation communication device 2.

[0067] The communication unit 23 is configured to include a communication interface for connecting the aggregation communication device 2 to an external device. The communication unit 23 communicates with the external device via wired or wireless means. The external device may be, for example, a device that instructs the aggregation communication device 2 about the information carried by the signal generated by the aggregation communication device 2.

[0068] The storage unit 24 is configured using a computer-readable storage medium device such as a magnetic hard disk device or a semiconductor storage device. The storage unit 24 stores various information related to the aggregation communication device 2. The storage unit 24 stores, for example, the information input via the input unit 22 or the communication unit 23. The storage unit 24 stores, for example, various information generated by the execution of upstream signal processing. The storage unit 24 stores, for example, various information generated by the execution of downstream signal processing.

[0069] The output unit 25 outputs various information. The output unit 25 is configured to include a display device such as a CRT display, a liquid crystal display, or an organic EL display. The output unit 25 may be configured as an interface for connecting these display devices to the aggregation communication device 2. The output unit 25 outputs, for example, the information input to the input unit 22. The output unit 25 may display, for example, the result of the execution of upstream signal processing.

[0070] The signal generation unit 26 includes elements such as a power supply and a modulator, and generates a downstream electrical signal. The signal generation unit 26 is electrically connected to the second communication support device 4, and the downstream electrical signal generated by the signal generation unit 26 propagates to the second communication support device 4. The operation of the signal generation unit 26 is controlled by the control unit 21.

[0071] The signal reception unit 27 is electrically connected to the second communication support device 4, and receives the upstream electrical signal propagated from the second communication support device 4. The control unit 21 executes upstream signal processing on the signal received by the signal reception unit 27.

[0072] FIG. 6 is a diagram showing an example of the configuration of the control unit 21 included in the aggregation communication device 2 in the embodiment. The control unit 21 includes an uplink / downlink signal processing execution unit 210, a memory control unit 220, and an output control unit 230.

[0073] The uplink / downlink signal processing execution unit 210 executes uplink signal processing. More specifically, the uplink / downlink signal processing execution unit 210 executes uplink signal processing on the signal received by the signal reception unit 27. The uplink / downlink signal processing execution unit 210 executes downlink signal processing. Therefore, the uplink / downlink signal processing execution unit 210 controls the operation of the signal generation unit 26. The memory control unit 220 records various information in the memory unit 14. The output control unit 230 controls the operation of the output unit 25.

[0074] FIG. 7 is a flowchart showing an example of the processing flow executed in one sub-communication system 10 in the embodiment. The switch control unit 405 changes the operation of the antenna 101 from the reception operation to the radiation operation (step S101). Next, the uplink / downlink signal processing execution unit 210 executes downlink signal processing (step S102). By executing the downlink signal processing, a downlink signal is generated and radiated from the antenna 101. Next, the switch control unit 405 changes the operation of the antenna 101 from the radiation operation to the reception operation (step S103).

[0075] Since the operation of the antenna 101 is changed to the reception operation, the uplink signal transmitted by the terminal 9 starts to propagate from the antenna 101 toward the aggregation communication device 2. Next, the signal reception unit 27 receives the uplink signal (step S104). Next, the uplink / downlink signal processing execution unit 210 executes uplink signal processing (step S105). Hereinafter, the processing from step S101 to step S105 is repeated until a predetermined end condition is satisfied. The predetermined end condition is, for example, the condition that the power of the wireless communication system 100 is turned off.

[0076] Hereinafter, taking the wireless communication system 100 compatible with the 5G NR environment as an example with reference to FIGS. 8 and 9, the delay adjustment of the downlink signal and the delay adjustment of the uplink signal executed in one sub-communication system 10 will be described. The wireless communication system 100 compatible with the 5G NR environment is, for example, a wireless communication system 100 in which the aggregated communication device 2 has the functions of the CU (Centralized), DU (Distributed Unit), and RU (Radio Unit) in 5G NR.

[0077] The CU, DU, and RU in 5G NR are the CU, DU, and RU described in Non-Patent Document 1. FIGS. 8 and 9 illustrate the delay adjustment of the downlink signal and the delay adjustment of the uplink signal executed in one sub-communication system 10, taking the case where the aggregated communication device 2 has the functions of the CU, DU, and RU in 5G NR as an example.

[0078] That the aggregated communication device 2 has the functions of the CU, DU, and RU in 5G NR means that the aggregated communication device 2 operates as the CU, DU, and RU in 5G NR in communication. Operating as the RU in 5G NR means executing the processing performed by the RU in 5G NR (hereinafter referred to as "RU processing").

[0079] Operating as the CU in 5G NR means executing the processing performed by the CU in 5G NR (hereinafter referred to as "CU processing"). Operating as the DU in 5G NR means executing the processing performed by the DU in 5G NR (hereinafter referred to as "DU processing").

[0080] Therefore, that the aggregated communication device 2 has the functions of the CU, DU, and RU means that the control unit 21 executes the CU processing, DU processing, and RU processing. That the control unit 21 executes the CU processing, DU processing, and RU processing means, for example, that the uplink and downlink signal processing execution unit 210 executes the CU processing, DU processing, and RU processing. The execution of the CU processing, DU processing, and RU processing includes the execution of the uplink signal processing and the downlink signal processing.

[0081] FIG. 8 is an explanatory diagram for explaining the delay adjustment of a downlink signal executed by a combination of one aggregation communication device 2 and an overhanging communication device 1 in an embodiment. More specifically, FIG. 8 is an explanatory diagram for explaining the delay adjustment of a downlink signal executed by a combination of one aggregation communication device 2 and an overhanging communication device 1 in a wireless communication system 100 compatible with a 5G NR environment.

[0082] "O-DU" means a device that executes DU processing. "O-RU" means a device that executes RU processing. "RoF I / F" means an interface for transmission by analog RoF. "RoF section" means a section in which analog RoF transmission is performed. The RoF section means a section in which a signal propagates through the analog transmission line 5. "Ant port" means an antenna output. The horizontal axis in FIG. 8 indicates the time axis. t5 is the timing at which a signal is radiated from the antenna 101.

[0083] FIG. 8 shows that the device that executes DU processing may transmit a signal between times t1 and t3. Hereinafter, the period during which the device that executes DU processing transmits a signal is referred to as the DU transmission period. FIG. 8 shows that the device that executes RU processing may receive a signal between time t2 and time t4. Hereinafter, the period during which the device that executes RU processing receives a signal is referred to as the RU reception period. Note that times t1 to t5 are in the relationship of t1 ≦ t2 ≦ t3 ≦ t4 ≦ t5, and t1 is a time in the past compared to t5.

[0084] In this way, the DU transmission period and the RU reception period are determined by times t1, t2, t3, and t4. The specific times of times t1, t2, t3, and t4 are determined based on a first delay time, a second delay time, a third delay time, and a fourth delay time.

[0085] The first delay time is the minimum value of the delay that occurs in the FH section, which is determined in advance or obtained by measurement. The second delay time is the maximum value of the delay that occurs in the FH section, which is determined in advance or obtained by measurement. The FH section is a section that connects the device that executes the RU process and the device that executes the DU process and through which the signal propagates. The FH section is, for example, a section of the transmission line that connects the device that executes the RU process and the device that executes the DU process.

[0086] For example, when the device that executes the RU process and the device that executes the DU process are the same, such as when the control unit 21 executes the CU process, the DU process, and the RU process, the delay that occurs in the FH section may be the time difference between the timing at which the CU process and the DU process are executed and the timing at which the RU process is executed. Therefore, for example, when the device that executes the RU process and the device that executes the DU process are the same, such as when the control unit 21 executes the CU process, the DU process, and the RU process, the FH section is the signal path through which the signal is transmitted from the functional unit that executes the CU process and the DU process to the functional unit that executes the RU process.

[0087] The third delay time is the total time of the minimum value of the RU internal delay and the delay from the device that executes the RU process to the Ant port. The delay from the device that executes the RU process to the Ant port is the delay in the RoF section. The third delay time is determined in advance or obtained by measurement. The fourth delay time is the total time of the RU internal holding time, the maximum value of the RU internal delay, and the delay from the device that executes the RU process to the Ant port. The fourth measurement time is determined in advance or obtained by measurement. Note that the RU internal delay is the delay that occurs within the device that executes the RU process.

[0088] In the downlink signal delay adjustment performed by a combination of one aggregation communication device 2 and an extended communication device 1 in the wireless communication system 100 compatible with the 5G NR environment, when the CU, DU, and RU are the same device as described above, both the first delay time and the second delay time are set to 0. In the downlink signal delay adjustment performed by a combination of one aggregation communication device 2 and an extended communication device 1 in the wireless communication system 100 compatible with the 5G NR environment, the third delay time is set to the sum of the minimum value of the RU internal delay and the measured value of the delay from the RU to the Ant port.

[0089] Thus, in the downlink signal delay adjustment performed by a combination of one aggregation communication device 2 and an extended communication device 1 in the wireless communication system 100 compatible with the 5G NR environment, the adjustment is also performed based on the delay occurring in the RoF section.

[0090] Note that the downlink signal delay adjustment is performed by the downlink delay adjustment unit 305. Also, in the example of FIG. 8, since the device that executes the RU processing as described above is the aggregation communication device 2, the RoF section is the section where the signal is transmitted and is the section between the aggregation communication device 2 and the antenna 101. Therefore, the time of the delay adjusted by the downlink delay adjustment unit 305 in the downlink signal delay adjustment is the time based on the sum of the delay time that occurs in the section where the downlink signal propagates from the aggregation communication device 2 to the antenna 101 and the minimum value of the delay that occurs within the aggregation communication device 2. Note that the time of the delay adjusted by the downlink delay adjustment unit 305 in the downlink signal delay adjustment does not necessarily have to be based on the minimum value of the delay that occurs within the aggregation communication device 2.

[0091] FIG. 9 is an explanatory diagram for explaining the uplink signal delay adjustment performed by a combination of one aggregation communication device 2 and an extended communication device 1 in the embodiment. More specifically, FIG. 9 is an explanatory diagram for explaining the uplink signal delay adjustment performed by a combination of one aggregation communication device 2 and an extended communication device 1 in the wireless communication system 100 compatible with the 5G NR environment. The horizontal axis of FIG. 9 indicates the time axis. t6 is the timing at which the antenna 101 receives the signal.

[0092] FIG. 9 shows that the device for performing DU processing only needs to receive a signal between time t8 and t10. Hereinafter, the period during which the device for performing DU processing receives a signal is referred to as the DU reception period. FIG. 9 shows that the device for performing RU processing only needs to transmit a signal between time t7 and time t9. Hereinafter, the period during which the device for performing RU processing transmits a signal is referred to as the RU transmission period. Note that times t6 to t10 are in the relationship of t6 ≦ t7 ≦ t8 ≦ t9 ≦ t10, and t6 is a time earlier than t10.

[0093] Thus, the DU reception period and the RU transmission period are determined by times t7, t8, t9, and t10. The specific times of times t7, t8, t9, and t10 are determined based on the first delay time, the second delay time, the fifth delay time, and the sixth delay time.

[0094] The fifth delay time is the total time of the maximum value of the RU internal delay and the maximum value of the delay from the device performing RU processing to the Ant port. The fifth delay time is predetermined or obtained by measurement. The sixth delay time is the total time of the minimum value of the RU internal delay and the delay from the device performing RU processing to the Ant port. The sixth delay time is predetermined or obtained by measurement.

[0095] In the uplink signal delay adjustment performed by a combination of one aggregated communication device 2 and an outstretched communication device 1 in the wireless communication system 100 compatible with the 5G NR environment, when the CU, DU, and RU are the same device as described above, both the first delay time and the second delay time are set to 0. In the uplink signal delay adjustment performed by a combination of one aggregated communication device 2 and an outstretched communication device 1 in the wireless communication system 100 compatible with the 5G NR environment, the sixth delay time is set to the sum of the minimum value of the RU internal delay and the measured value of the delay from the device performing RU processing to the Ant port.

[0096] As described above, in the delay adjustment of the uplink signal executed by the combination of one aggregation communication device 2 and the extension communication device 1 in the wireless communication system 100 compatible with the 5G NR environment, the adjustment is also performed based on the delay occurring in the RoF section.

[0097] Note that the delay adjustment of the uplink signal is performed by the uplink delay adjustment unit 304. Also, in the example of FIG. 9, since the device that executes the RU processing as described above is the aggregation communication device 2, the RoF section is the section where the signal is transmitted and is the section between the aggregation communication device 2 and the antenna 101. Therefore, the time of the delay adjusted by the uplink delay adjustment unit 304 in the delay adjustment of the uplink signal is the time based on the sum of the time of the delay occurring in the section where the uplink signal propagates from the antenna 101 to the aggregation communication device 2 and the minimum value of the delay occurring in the aggregation communication device 2. Note that the time of the delay adjusted by the uplink delay adjustment unit 304 in the delay adjustment of the uplink signal does not necessarily have to be the time based on the minimum value of the delay occurring in the aggregation communication device 2.

[0098] The wireless communication system 100 configured as described above can appropriately transmit and receive the uplink signal and the downlink signal through their respective paths. Also, the transmission and reception timings of the uplink signal and the downlink signal can be appropriately adjusted in the aggregation communication device 2 so as to be synchronized with the timing of the transmission and reception switching of TDD in the antenna 101.

[0099] Therefore, in the wireless communication system 100, it is possible to suppress a deterioration in communication quality such as crosstalk between the uplink signal and the downlink signal and a decrease in communication efficiency.

[0100] (Modification example) The analog transmission path 5 is a transmission path that propagates an upstream signal and a downstream signal, and any path may be used as long as the degree of mutual interference between the upstream signal and the downstream signal is less than a predetermined standard due to a difference in frequency or a difference in space. The analog transmission path 5 is, for example, an optical fiber whose ends are connected to a WDM as shown in FIG. 1. The analog transmission path 5 may be, for example, a path that performs subcarrier multiplexing (SCM) transmission, or a path in which the transmission path for transmitting the upstream signal and the transmission path for transmitting the downstream signal are located at spatially different positions.

[0101] Note that the signals to be delay-adjusted by the upstream delay adjustment unit 304 and the downstream delay adjustment unit 305 do not necessarily have to be analog signals, and may be digital signals as described above. Here, an example of the configuration of the first communication support device 3 when the signals to be delay-adjusted by the upstream delay adjustment unit 304 and the downstream delay adjustment unit 305 are digital signals will be described with reference to FIGS. 11 and 12. Hereinafter, for simplicity of explanation, those having the same functions as the functional units described in FIGS. 1 to 3 will be denoted by the same reference numerals as in FIGS. 1 to 3, and the description thereof will be omitted.

[0102] FIG. 11 is a first diagram showing an example of the configuration of the first communication support device 3 in a modified example. FIG. 11 shows that a signal passing through the AD converter 306 is input to the upstream delay adjustment unit 304, and the output of the upstream delay adjustment unit 304 is input to the DA converter 307. The signal output from the optoelectronic device 302 is input to the AD converter 306. The AD converter 306 is an analog-to-digital converter that converts the input analog signal into a digital signal and outputs it. The DA converter 307 is a digital-to-analog converter that converts the input digital signal into an analog signal and outputs it.

[0103] FIG. 11 shows that a signal via the AD converter 308 is input to the downstream delay adjustment unit 305, and the output of the downstream delay adjustment unit 305 is input to the DA converter 309. The signal output by the DA converter 309 is input to the electro-optical element 303. The AD converter 308 is an analog-to-digital converter that converts the input analog signal into a digital signal and outputs it. The DA converter 309 is a digital-to-analog converter that converts the input digital signal into an analog signal and outputs it.

[0104] FIG. 12 is a second diagram showing an example of the configuration of the first communication support device 3 in a modified example. Hereinafter, for the sake of simplicity of explanation, the same components as those in FIG. 11 will be denoted by the same reference numerals as in FIG. 11, and the description thereof will be omitted. FIG. 12 shows that a signal via the AD converter 306 is input to the upstream delay adjustment unit 304. The signal output by the optoelectronic element 302 is input to the AD converter 306. The AD converter 306 is an analog-to-digital converter that converts the input analog signal into a digital signal and outputs it. In the example of FIG. 12, unlike the example of FIG. 11, the output of the upstream delay adjustment unit 304 propagates to the subsequent device (for example, the aggregation communication device 2) as a digital signal without being converted by a digital-to-analog converter.

[0105] Since the upstream delay adjustment unit 304 and the downstream delay adjustment unit 305 configured as shown in FIGS. 11 and 12 have a digital signal as the object of delay adjustment, the delay can be adjusted by the above-described buffering.

[0106] Note that in FIGS. 11 and 12, the case where both the upstream delay adjustment unit 304 and the downstream delay adjustment unit 305 handle a digital signal as the object of delay adjustment has been described as an example. However, only one of the object of delay adjustment of the upstream delay adjustment unit 304 and the object of delay adjustment of the downstream delay adjustment unit 305 may be a digital signal, and the other may be an analog signal.

[0107] Note that the upstream delay adjustment unit 304 and the downstream delay adjustment unit 305 do not necessarily have to be provided in the first communication support device 3, and may be provided in the aggregation communication device 2. Note that the upstream delay adjustment unit 304 and the downstream delay adjustment unit 305 do not necessarily have to be provided in the first communication support device 3, and may be provided in the second communication support device 4.

[0108] FIG. 10 is an explanatory diagram for explaining an example of the connection state of the upstream delay adjustment unit 304 and the downstream delay adjustment unit 305 in a modified example. When the second communication support device 4 includes the upstream delay adjustment unit 304 and the downstream delay adjustment unit 305, one side of the upstream delay adjustment unit 304 is connected to the timing switch 404 and the other side is connected to the electro-optical element 402. When the second communication support device 4 includes the upstream delay adjustment unit 304 and the downstream delay adjustment unit 305, one side of the downstream delay adjustment unit 305 is connected to the timing switch 404 and the other side is connected to the optoelectronic element 403.

[0109] Note that the upstream delay adjustment unit 304 and the downstream delay adjustment unit 305 are not limited to the example of FIG. 10, and may be located anywhere as long as they are on the path connecting the timing switch 404 and the overhanging communication device 1.

[0110] Note that the overhanging communication device 1 may have the function of an RU (Radio Unit) in 5G NR (New Radio), and the aggregation communication device 2 may have the functions of a CU and a DU. More specifically, the control unit 21 of the aggregation communication device 2 may execute CU processing and DU processing, and the control unit 11 of the overhanging communication device 1 may execute RU processing.

[0111] Note that the overhanging communication device 1, the aggregation communication device 2, the first communication support device 3, and the second communication support device 4 may each be implemented using a plurality of information processing devices communicably connected via a network. In this case, each functional unit included in each of the overhanging communication device 1, the aggregation communication device 2, the first communication support device 3, and the second communication support device 4 may be implemented in a distributed manner across a plurality of information processing devices.

[0112] Note that the extension communication device 1 and the second communication support device 4 do not necessarily need to be implemented as different devices. The extension communication device 1 and the second communication support device 4 may be implemented as a single device having both functions. Such a single device having both the functions of the extension communication device 1 and the second communication support device 4 may be implemented as, for example, an extension station.

[0113] Note that the aggregation communication device 2 and the first communication support device 3 do not necessarily need to be implemented as different devices. The aggregation communication device 2 and the first communication support device 3 may be implemented as, for example, a single device having both functions. Such a single device having both the functions of the aggregation communication device 2 and the first communication support device 3 may be implemented as, for example, an aggregation station.

[0114] Note that one aggregation communication device 2 may be connected to a plurality of extension communication devices 1. In such a case, delay adjustment is performed for each extension communication device 1.

[0115] The upstream delay adjustment unit 304 and the downstream delay adjustment unit 305 may be devices that include an analog-to-digital converter (ADC) and a digital-to-analog converter (DAC) and generate a delay by buffering a digital signal.

[0116] Although 5G has been used as an example of communication, the 5G communication standard is merely an example of the communication standard by the wireless communication system 100. The communication standard by the wireless communication system 100 may be another communication standard such as 6G as long as it is a communication standard that can use TDD.

[0117] Note that all or part of each function of the wireless communication system 100, the sub communication system 10, the extension communication device 1, the aggregation communication device 2, the first communication support device 3, and the second communication support device 4 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. A computer-readable recording medium is, for example, a portable medium such as a flexible disk, a magneto-optical disk, a ROM, or a CD-ROM, or a storage device such as a hard disk incorporated in a computer system. The program may be transmitted via a telecommunication line.

[0118] Note that the extension communication device 1 is an example of a terminal-side communication device. A device in which the extension communication device 1 and the second communication support device 4 are implemented as one device is also an example of a terminal-side communication device. The extension station is an example of a terminal-side communication device.

[0119] Note that the first communication support device 3 is an example of a wireless communication device that communicates with a terminal-side communication device using an analog signal that transmits information by the waveform of the amplitude or phase of light, and thereby receives the signal received by the antenna 101 and transmits the signal radiated by the antenna 101. Hereinafter, a wireless communication device that communicates with a terminal-side communication device using an analog signal that transmits information by the waveform of the amplitude or phase of light, and thereby receives the signal received by the antenna 101 and transmits the signal radiated by the antenna 101 is referred to as an aggregation-side communication device. A device in which the aggregation communication device 2 and the first communication support device 3 are implemented as one device is also an example of an aggregation-side communication device. Note that the own device is an example of an aggregation-side communication device.

[0120] Note that frequency conversion may be provided to the second communication support device or the extension communication device 1, and IFoF (IF over Fiber) may be used instead of analog RoF.

[0121] The process of step S101 is an example of the first switching step. The process of step S103 is an example of the second switching step.

[0122] As described above, the embodiments of the present invention have been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and designs and the like within the scope not departing from the gist of the present invention are also included.

Explanation of Reference Numerals

[0123] 100…Wireless communication system, 10…Sub communication system, 1…Overhanging communication device, 2…Aggregation communication device, 3…First communication support device, 4…Second communication support device, 5…Analog transmission line, 101…Antenna, 31…First path, 32…Second path, 301…WDM (Wavelength Division Multiplexing), 302…Optoelectronic element, 303…Electro-optic element, 304…Upward delay adjustment unit, 305…Downward delay adjustment unit, 306…AD converter, 307…DA converter, 308…AD converter, 309…DA converter, 401…WDM (Wavelength Division Multiplexing), 402…Electro-optic element, 403…Optoelectronic element, 404…Timing switch, 405…Switch control unit, 451…Processor, 452…Memory, 11…Control unit, 12…Input unit, 13…Communication unit, 14…Storage unit, 15…Output unit, 102…Conductive circuit, 21…Control unit, 22…Input unit, 23…Communication unit, 24…Storage unit, 25…Output unit, 26…Signal generation unit, 27…Signal reception unit, 210…Up and down signal processing execution unit, 220…Memory control unit, 230…Output control unit, 9…Terminal, 91…Processor, 92…Memory, 93…Processor, 94…Memory

Claims

1. A wireless communication device comprising a terminal-side communication device having an antenna and a wireless communication device that communicates with the terminal-side communication device using an analog signal that transmits information by the waveform of the amplitude or phase of light, and performs reception of the signal received by the antenna and transmission of the signal radiated by the antenna, and performing wireless communication with a terminal to be communicated with via the antenna by TDD (Time Division Duplex), the wireless communication device, an upstream delay adjustment unit that adjusts a delay caused by the propagation of an upstream signal, which is a signal flowing from the terminal to the wireless communication device via the antenna, a downstream delay adjustment unit that adjusts a delay caused by the propagation of a downstream signal, which is a signal flowing from the wireless communication device to the terminal via the antenna, comprising, wherein the upstream delay adjustment unit and the downstream delay adjustment unit exist as different from each other, the upstream delay adjustment unit is located on a first path that is one of the paths branched by WDM (Wavelength Division Multiplexing) and through which the upstream signal propagates, and the downstream delay adjustment unit is located on a second path that is another path branched by the WDM and through which the downstream signal propagates, the first path and the second path do not intersect, the upstream delay adjustment unit is not located on the second path, and the downstream delay adjustment unit is not located on the first path, Wireless communication device.

2. The time of the delay adjusted by the upstream delay adjustment unit is a time based on the time of the delay generated in the section where the upstream signal propagates from the antenna to the own device, The wireless communication device according to claim 1.

3. The time of the delay adjusted by the downstream delay adjustment unit is a time based on the time of the delay generated in the section where the downstream signal propagates from the own device to the antenna, The wireless communication device according to claim 1 or 2.

4. The upstream signal to be adjusted for delay by the upstream delay adjustment unit is a digital signal, The wireless communication device according to any one of claims 1 to 3.

5. The downstream signal to be adjusted for delay by the downstream delay adjustment unit is a digital signal, The wireless communication device according to any one of claims 1 to 4.

6. A wireless communication system that communicates with a terminal to be communicated with by TDD (Time Division Duplex), a terminal-side communication device having an antenna, A wireless communication device that performs reception of a signal received by the antenna and transmission of a signal radiated by the antenna by communicating with the terminal-side communication device using an analog signal that transmits information by a waveform of the amplitude or phase of light. Comprising: The wireless communication device includes: An upstream delay adjustment unit that adjusts a delay caused by propagation of an upstream signal, which is a signal flowing from the terminal to the wireless communication device via the antenna; A downstream delay adjustment unit that adjusts a delay caused by propagation of a downstream signal, which is a signal flowing from the wireless communication device to the terminal via the antenna; Comprising: The upstream delay adjustment unit and the downstream delay adjustment unit exist as different from each other; The upstream delay adjustment unit is located on a first path that is one of the paths branched by WDM (Wavelength Division Multiplexing) and through which the upstream signal propagates, and the downstream delay adjustment unit is located on a second path that is another path branched by the WDM and through which the downstream signal propagates; The first path and the second path do not intersect; The upstream delay adjustment unit is not located on the second path, and the downstream delay adjustment unit is not located on the first path. A wireless communication system. Claim 7 A wireless communication system that communicates with a communication target terminal by TDD (Time Division Duplex), comprising a terminal-side communication device having an antenna, and a wireless communication device that communicates with the terminal-side communication device using an analog signal that transmits information by the waveform of the amplitude or phase of light, and performs reception of the signal received by the antenna and transmission of the signal radiated by the antenna. The wireless communication device includes an uplink delay adjustment unit that adjusts a delay caused by the propagation of an uplink signal, which is a signal flowing from the terminal to the wireless communication device via the antenna, and a downlink delay adjustment unit that adjusts a delay caused by the propagation of a downlink signal, which is a signal flowing from the wireless communication device to the terminal via the antenna. The uplink delay adjustment unit and the downlink delay adjustment unit exist as different from each other. The uplink delay adjustment unit is located on a first path that is one of the paths branched by WDM (Wavelength Division Multiplexing) and through which the uplink signal propagates. The downlink delay adjustment unit is located on a second path that is another path branched by WDM and through which the downlink signal propagates. The first path and the second path do not intersect. The uplink delay adjustment unit is not located on the second path, and the downlink delay adjustment unit is not located on the first path. A wireless communication method executed by the wireless communication system, A first switching step of switching the operation of the antenna from a reception operation of receiving a signal transmitted by the terminal to a radiation operation of radiating a signal; A second switching step of switching the operation of the antenna from the radiation operation to the reception operation; A wireless communication method having the above.

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