JP2014017600A - Communication device, radio communication system, and communication control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To determine a synchronization destination that allows proper timing of frames to be set.SOLUTION: A communication device puts information indicating that the communication device is transmitting and receiving radio signals at timing based on reception timing of radio signals transmitted by another communication device into transmission data and transmits the transmission data by radio signals in order that another communication device does not select the communication device as a synchronization destination communication device.

Description

  The present invention relates to a communication device that performs wireless communication, a wireless communication system, and a communication control method.

  In a wireless communication system (for example, a PHS employing a TDD / TDMA system), if there is a difference in timing of wireless signals transmitted from a plurality of base stations, processing such as handoff may be hindered or interference may occur between base stations. It occurs.

  For this reason, processing (frame synchronization processing) for matching the timings of frames for transmitting and receiving radio signals between base stations is performed. In this frame synchronization processing, a control signal transmitted by a specific base station is received by another base station, and the timing of the frame generated in advance by the other base station based on the reception timing of the control signal is corrected. It is carried out.

  Here, the specific base station is a base station that is set to serve as a reference when performing frame synchronization processing. Then, the specific base station generates a frame at the transmission timing and the reception timing of the radio signal determined using, for example, a line clock supplied from a wired line. Then, the other base station corrects the timing of the frame generated in advance by the same method as that of the specific base station with reference to the frame generated by the specific base station.

  Also, a technique has been proposed in which a specific base station determines a transmission timing and a reception timing by using a signal (1PPS signal) from a GPS satellite provided with a GPS receiver instead of using a line clock. (For example, patent document 1). Then, another base station, for example, a base station that does not include a GPS receiver, synchronizes hierarchically with the base station having the GPS receiver and determines transmission timing and reception timing.

JP 2000-164837 A

  When a base station equipped with a GPS receiver cannot receive a signal from a GPS satellite, it cannot determine the frame timing by itself. In this case, it is conceivable to synchronize the frame timing with another base station equipped with a GPS receiver.

  In this case, there is a high possibility that other base stations cannot receive signals from GPS satellites. And even if it synchronizes with such other base stations, there is a high possibility that a deviation occurs in the transmission / reception timing of the radio signal. However, it is not possible to determine which of the plurality of base stations existing in the wireless communication system has become unable to determine the frame timing by itself.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a communication device, a wireless communication system, and a communication control method that can determine a communication device that transmits and receives a radio signal at an appropriate frame timing as a synchronization destination. It is said.

  In order to solve the above-described problems, a typical configuration according to the present invention is a communication device, and the own device transmits wirelessly from another communication device so that the own device is not determined by the synchronization destination communication device. It is characterized by comprising a control unit for transmitting information indicating that a wireless signal is being transmitted / received at a timing based on the signal reception timing in data transmitted by the own device using a wireless signal.

  The control unit may transmit the information when a signal to be referred to when generating a frame for transmitting and receiving a radio signal cannot be acquired.

  In addition, when the reference signal cannot be acquired, the control unit switches to other identification information different from the identification information of the own device that is set when the reference signal can be acquired, and the switched other identification Information may be used as the information.

  In addition, when the control unit cannot acquire the signal to be referred to, the control unit stores and transmits the information in an area for storing identification information indicating a transmission destination of the downlink control information included in the downlink control information. May be.

  In order to solve the above-described problem, another configuration according to the present invention is a communication device, and the other communication device transmitted from another communication device is different from the other communication device. When information indicating that a radio signal is being transmitted / received at a timing based on the reception timing of the radio signal to be transmitted is received from the other communication device, the other communication device transmits a frame in which the device transmits / receives a radio signal. It is characterized in that it is not used as a synchronization destination.

  In order to solve the above-described problem, another configuration according to the present invention is a wireless communication system including a plurality of communication devices, in order to prevent one communication device from determining its own device as a synchronization destination communication device. A control unit for transmitting information included in the data transmitted by the wireless device using data indicating that the wireless device transmits / receives a wireless signal at a timing based on the reception timing of the wireless signal transmitted from another communication device. It is characterized by providing.

  In order to solve the above-mentioned problem, another configuration according to the present invention is based on the timing based on the reception timing of the radio signal transmitted from the other communication device so that the own device is not determined by the synchronization destination communication device. The information indicating that the wireless signal is being transmitted and received is transmitted by being included in the data transmitted by the own device using the wireless signal.

  According to the present invention, it is possible to determine a synchronization destination that can set an appropriate timing of a frame.

It is the figure which showed schematic structure of the radio | wireless communications system which concerns on this embodiment. It is the block diagram which showed the schematic structure of the base station which concerns on this embodiment. It is the block diagram which showed the schematic structure of the base station which concerns on this embodiment. It is the flowchart which showed the radio | wireless communication process in the base station which concerns on this embodiment. It is the flowchart which showed the radio | wireless communication process in the base station which concerns on this embodiment. It is a figure which shows the outline | summary of identification information. It is a figure which shows the outline | summary of SCCH. It is the block diagram which showed the schematic structure of the mobile station which concerns on this embodiment.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a diagram showing a configuration of a wireless communication system according to an embodiment of the present invention. The wireless communication system 10 includes a plurality of base stations (base stations 20 and 30), a network 40, and a mobile station 50 as communication devices. The plurality of base stations include a base station 20 (20a, 20b) having a GPS receiver and a base station 30 (30m, 30n) not having a GPS receiver (details will be described later).

  The base station 20 and the base station 30 perform radio communication with the mobile station 50. Base station 20 and base station 30 receive data from network 40 and transmit the data to mobile station 50. The base station 20 and the base station 30 receive data from the mobile station 50 and transmit it to the network 40. Furthermore, each base station can transmit data to other base stations by wireless communication.

  In addition, the base station 20 and the base station 30 perform frame synchronization processing in order to match the frame timing with any of the other base stations. Here, the base station 20a has a reference base station (1) that is set so that the transmission timing and reception timing of the radio signal in the frame generated by itself are used as a reference when other base stations perform frame synchronization processing. Next base station). The base station 20b and the base station 30m are secondary base stations that correct the timing of the frames generated by each using the reception timing of the downlink control signal transmitted by the base station 20a. The base station 30n is a tertiary base station that corrects the timing of a previously generated frame using the reception timing of the downlink control signal transmitted by the base station 30m. Hereinafter, the “n-th order” in the n-th order base station (n is an integer of 1 or more) that hierarchically corrects the frame timing based on the reference base station as described above is referred to as a subordinate order.

  FIG. 2 is a diagram illustrating a configuration of the base station according to the present embodiment. The base station 20 includes a communication unit 210, a GPS receiver 220, an interface (I / F) unit 230, a storage unit 240, a control unit 250, and an antenna ANT.

  The communication unit 210 receives an uplink radio signal transmitted from the mobile station 50 via the antenna ANT or a downlink radio signal transmitted from another base station, converts it into a baseband signal (down-conversion), and then performs demodulation and decoding. Data is obtained by processing. The communication unit 210 outputs the obtained data to the control unit 250.

  In addition, the communication unit 210 performs coding and modulation of data from the control unit 250 to obtain a baseband signal, and then converts (upconverts) the baseband signal into a downlink radio signal. The communication unit 210 transmits a downlink radio signal to the mobile station 50 or an uplink radio signal to another base station via the antenna ANT.

  The GPS receiver 220 receives a signal (1PPS signal) transmitted from the GPS. Then, GPS receiver 220 outputs the received signal to control unit 250.

  The I / F unit 230 receives data addressed to the mobile station 50 from the network 40. In addition, the I / F unit 230 transmits data received from the mobile station 50 toward the network 40. Further, the I / F unit 230 transmits / receives data to / from other base stations via the network 40 or directly.

  The storage unit 240 is configured by a memory, for example, and stores various information used for control in the base station 20 and the like. Further, the storage unit 240 stores the subordinate order from the reference base station (for example, the base station 20b in FIG. 1 is secondary) used when performing the frame synchronization processing. Further, the storage unit 240 stores information related to the cell ID (identification information) of the own station, and the identification information includes information related to the dependent order of the own station.

  The control part 250 is comprised by CPU, for example, and controls the various functions which the base station 20 comprises. Further, the control unit 250 uses the 1PPS signal output from the GPS receiver 220 at a predetermined timing such as when the base station 20 is started up or during a predetermined period during which wireless communication with the mobile station 50 is not performed. A frame for transmitting / receiving a radio signal (transmission / reception timing of the radio signal) is newly generated. Then, the control unit 250 of the base station 20 that is not the reference base station further uses the reception timing of the downlink control signal transmitted from another base station received by the communication unit 210 to generate the timing of the generated frame (wireless Signal transmission / reception timing).

  On the other hand, when the 1PPS signal used to generate a frame for transmitting and receiving a radio signal cannot be acquired from the GPS receiver 220, the control unit 250 uses a stable clock required for generating a frame as an external clock. It is no longer supplied from the source (here GPS satellites). In this case, the control unit 250 receives, via the communication unit 210, a downlink control signal transmitted by another base station existing in the vicinity. The control unit 250 sets the reference base station included in the reception quality (for example, RSSI) of the downlink control signal received from other neighboring base stations and the identification information of the other base station included in the received downlink control signal. Using the information indicating the dependent order as a reference, another base station to be synchronized is specified. Then, the control unit 250 uses the reception timing of the downlink control signal transmitted by the other base station that is the identified synchronization destination, and the timing of the frame at which the other base station transmits / receives the radio signal (transmission / reception of the radio signal). Timing) is determined, and the timing of the frame is set to the timing of the frame at which the local station transmits and receives a radio signal (air synchronization). The specific details of the other base stations to be synchronized in the control unit 250 will be described later.

  Then, after air synchronization, the control unit 250 includes information for preventing the base station from determining the base station as a synchronization destination in data transmitted by the base station using a radio signal, and transmits the data via the communication unit 210. Information transmitted by the control unit 250 so as not to determine the own base station as a synchronization destination base station will be described later.

  In addition, when receiving information from another base station so that the own station is not determined as the synchronization destination base station, the control unit 250 performs control so that the other base station that has transmitted the information is not determined as the synchronization destination.

  FIG. 3 is a diagram illustrating the configuration of the base station according to the present embodiment. The base station 30 includes a communication unit 310, a line clock acquisition unit 320, an interface (I / F) unit 330, a storage unit 340, a control unit 350, and an antenna ANT.

  The communication unit 310 receives an uplink radio signal transmitted from the mobile station 50 via the antenna ANT or a downlink radio signal transmitted from another base station, converts it into a baseband signal (down-conversion), and then performs demodulation and decoding. Data is obtained by processing. Communication unit 310 outputs the obtained data to control unit 350.

  Further, the communication unit 310 performs coding and modulation of data from the control unit 350 to obtain a baseband signal, and then converts (upconverts) the baseband signal into a downlink radio signal. The communication unit 310 transmits a downlink radio signal to the mobile station 50 or an uplink radio signal to another base station via the antenna ANT.

  The line clock acquisition unit 320 periodically acquires a clock signal supplied via a wired line. Then, the line clock acquisition unit 320 outputs the acquired clock signal to the control unit 350.

  The I / F unit 330 receives data addressed to the mobile station 50 from the network 40. Further, the I / F unit 330 transmits the data received from the mobile station 50 toward the network 40. Further, the I / F unit 330 transmits / receives data to / from other base stations via the network 40 or directly.

  The storage unit 340 is configured by a memory, for example, and stores various information used for control in the base station 30 and the like. Further, the storage unit 340 stores a subordinate order from the reference base station (for example, the base station 30n in FIG. 1 is tertiary) used when performing the frame synchronization processing. Further, the storage unit 340 stores information related to the cell ID (identification information) of the own station, and the identification information includes information related to the dependent order of the own station.

  The control unit 350 is configured by a CPU, for example, and controls various functions provided in the base station 30. Further, the control unit 350 uses the clock signal output from the line clock acquisition unit 320 at a predetermined timing such as when the base station 30 is started up or during a predetermined period during which wireless communication with the mobile station 50 is not performed. Generate a frame for transmitting and receiving radio signals. Then, the control unit 350 of the base station 30 that is not the reference base station uses the reception timing of the downlink control signal transmitted from another base station that is received by the communication unit 310 to generate the generated frame timing (radio signal). Transmission / reception timing).

  In addition, when the control unit 350 receives information from another base station so that the own base station (the other base station) is not determined as a synchronization destination base station, the control unit 350 transmits the other base station that transmitted the information to the synchronization destination. (The details will be described later).

  Next, radio communication processing of the base station 20 in the radio communication system 10 will be described with reference to FIG.

  FIG. 4 is a flowchart showing communication processing in the base station 20 shown in FIG.

  First, in step S401 in FIG. 4, the control unit 250 of the base station 20 starts up the base station 20, performs a predetermined period during which wireless communication with the mobile station 50 is not performed, or performs wireless communication with the mobile station 50. At a predetermined timing such as a preset period within a possible period (in-service), an attempt is made to acquire the 1PPS signal output from the GPS receiver 220.

  When the 1PPS signal can be acquired from the GPS receiver 220 (corresponding to step S402 Yes), the control unit 250 generates a frame using the acquired 1PPS signal in step S407.

  If the own station is the reference base station (primary base station) in step S408 (corresponding to Yes in step S408), the control unit 250 ends the process.

  On the other hand, when the own station is not the reference base station (primary base station) in step S408 (corresponding to No in step S408), control unit 250 transmits from other base stations to be synchronized in step S409. The transmission / reception timing of the generated frame is corrected using the received timing of the downlink control signal, and the process is terminated.

  On the other hand, when the 1PPS signal cannot be acquired from the GPS receiver 220 (corresponding to Step S402 No), the control unit 250 transmits a downlink control signal transmitted by another base station existing in the vicinity via the communication unit 210 in Step S403. Using the information indicating the subordinate order with respect to the reference base station included in the reception quality of the downlink control signal and the identification information of other base stations included in the downlink control signal. To identify other base stations. Here, when specifying other base stations to be synchronized, the control unit 250 identifies, for example, another base station having a small dependent order as a synchronization destination, or a plurality of other base stations having the same dependent order. When a downlink control signal from the base station is received, a radio signal transmitted from each of these base stations having a high reception quality may be specified as a synchronization destination. However, among the other base stations that have received the downlink control signal, the control unit 250 transmits another information for preventing the own base station (the other base station) from determining the base station to be synchronized with. Stations are not specified as synchronization destinations.

  In step S404, the control unit 250 uses the reception timing of the downlink control signal transmitted by the other base station that is the identified synchronization destination, and the frame timing (radio signal) that the other base station transmits and receives the radio signal. Transmission / reception timing) is determined, and the timing of the frame is set to the timing of the frame in which the local station transmits and receives a radio signal (air synchronization).

  In step S405, the control unit 250 includes information for preventing the base station from determining the base station as a synchronization destination in the data transmitted by the base station using a radio signal.

  In step S <b> 406, the control unit 250 transmits data including information for preventing the base station from being determined as a synchronization destination base station via the communication unit 210.

  FIG. 5 is a flowchart showing communication processing in the base station 20 shown in FIG. 2 or the base station 30 shown in FIG.

  In step S501, the control unit 250 of the base station 20 or the control unit 350 of the base station 30 receives data including information for preventing the base station from being determined as a synchronization destination base station from another base station. To do.

  In step S502, the control unit 250 or the control unit 350 determines that the other base station that has transmitted the information received in step S501 is not a synchronization destination base station, and ends the process.

  Next, information for preventing the base station 20 in the synchronization destination base station from determining that the base station 20 in FIG. In addition, as a method of including information for preventing a local station from being determined as a synchronization destination base station in data to be transmitted with a radio signal, there are the following processes.

(First process)
The control unit 250 of the base station 20 cannot acquire the 1PPS signal from the GPS receiver 220, and after the air synchronization with the other specified base station, the dependent order of the own station (for example, the base station 20b in FIG. Is switched to information indicating that the local station is in air synchronization. Then, the control unit 250 changes the cell ID (identification information) of the own station before the air synchronization (normal state) in accordance with the switching to the information indicating that the own station is in the air synchronization. Switching from the identification information to another identification information (identification information during air synchronization) stored in the storage unit 240 and indicating that air synchronization is in progress.

  Here, FIG. 6 shows an outline of identification information of a base station in PHS as an example of a cell ID (identification information) in the base station 20. Here, the operator identification code included in the identification information is a code for identifying the operator who manages the wireless communication system 10, and is an area where a unique code is assigned to each operator. The general call area number is an area to which a code indicating an area in which a plurality of base stations including the base station 20 notify incoming calls to mobile stations all at once is assigned. Further, the additional ID includes information on “advancement” indicating what modulation system the base station 20 supports, and information (frame synchronization version) indicating the subordinate order in the base station 20. Space is allocated. In this way, areas to which various types of information are allocated are defined, and identification information is set by storing information in each area. Then, the controller 250 cannot acquire the 1PPS signal from the GPS receiver 220, and after the air synchronization with the other specified base station, the information included in the area related to the dependent order is that the local station is in the air synchronization. It is switched to the identification information during air synchronization, which is information indicating.

  Then, the control unit 250 includes the identification information of the switched own station (identification information during air synchronization) in the downlink control signal transmitted by the own station as a radio signal, control information when transmitting user data, or the like. To send. Then, the other base station received by the downlink control signal including the transmitted identification information refers to the area of the subordinate order included in the identification information, so that the base station that transmitted the downlink control information It can be determined that synchronization is in progress, and can be determined not to be a synchronization destination.

(Second process)
In addition, when the control unit 250 of the base station 20 cannot acquire the 1PPS signal from the GPS receiver 220 and synchronizes with another identified base station, for example, the base station 20 is a base station of a wireless communication system such as PHS. Information indicating that the local station is in air synchronization with another base station is transmitted at each predetermined timing (for example, 20 communication frame intervals) allocated to transmit the channel allocation control channel (SCCH).

  Specifically, when there is no information to be notified to the mobile station etc. at the timing of transmitting the SCCH, other information (for example, retransmission of broadcast channel, incoming information channel, etc.) based on a predetermined priority order Is sent. At the timing of transmitting the SCCH, in other information, in the lower order of priority, for example, a radio resource information notification message for notifying information on radio resources or a PCH without information (hereinafter referred to as idle PCH). ) Is prescribed. Therefore, if the 1PPS signal cannot be acquired from the GPS receiver and there is no information to notify the mobile station etc. at the timing of transmitting the SCCH after air synchronization with the other specified base station, the own station is in air synchronization. By transmitting information indicating that the information is included in the SCCH (hereinafter referred to as a pseudo SCCH), the base station is notified that the own station is in air synchronization.

  Here, FIG. 7 shows an outline of SCCH transmitted by the base station in PHS. Here, R included in SCCH is a ramp time for transient response, S is a start symbol, PR is a preamble, UW is a synchronization word, CI is a channel type, and CS-ID is a base station set ID. (Identification information), PS-ID indicates the identification information of the transmission destination, I indicates the allocation information of the communication channel to be notified to the transmission destination, and CRC indicates the area where the cyclic redundancy code is stored. And the control part 250 stores the information which shows that the own station is in air synchronization in the area | region (PS-ID) containing the identification information of the transmission destination in SCCH.

  Thereafter, the control unit 250 transmits SCCH (pseudo SCCH) in which information indicating that the own station is in air synchronization is transmitted via the communication unit 210 at the timing of transmitting the SCCH. Then, the other base station that has received the transmitted pseudo SCCH refers to the area (PS-ID) including the identification information of the transmission destination, so that the base station that has transmitted the pseudo SCCH is in air synchronization. Can be determined that synchronization to the base station is “impossible”, and it can be determined not to be a synchronization destination.

  Next, operations related to wireless communication between the base station 20 and the mobile station 50 before and after transmitting information for preventing the base station 20 in FIG. 2 from determining the base station as a synchronization destination base station will be described.

  FIG. 8 is a diagram illustrating the configuration of the mobile station according to the present embodiment. The mobile station 50 includes a communication unit 510, a storage unit 540, a control unit 550, and an antenna ANT.

  The communication unit 510 receives a downlink radio signal transmitted from the base station 20 or 30 via the antenna ANT, converts it into a baseband signal (down-conversion), and then performs demodulation and decoding processing to obtain data. Communication unit 510 outputs the obtained data to control unit 550.

  The communication unit 510 performs coding and modulation of data from the control unit 550 to obtain a baseband signal, and then converts (upconverts) the baseband signal into a downlink radio signal. The communication unit 510 transmits an uplink radio signal to the base station 20 or 30 via the antenna ANT.

  The storage unit 540 is configured by a memory, for example, and stores various information used for control in the mobile station 50 and the like.

  The control unit 550 is configured by a CPU, for example, and controls various functions provided in the mobile station 50. Further, when performing wireless communication with the base station 20 or 30, the control unit 550 makes a channel assignment request via the communication unit 510, or the communication quality of a communication channel used for wireless communication with the base station 20 or 30. When the communication quality deteriorates, a communication channel switching request is made to the connected base station.

  Next, in the base station 20 and the mobile station 50 when the base station 20 in FIG. 2 transmits information for preventing the base station as the synchronization destination base station from determining the own station according to the above (first processing). Operations related to wireless communication will be described.

  The control unit 250 of the base station 20 cannot acquire the 1PPS signal from the GPS receiver 220, and after the air synchronization with the specified other base station, the control information is switched from the identification information in the normal state to the identification information in the air synchronization. The identification information during air synchronization is included in the downlink control signal and transmitted.

  At this time, before the base station 20 switches the identification information, the mobile station 50 that exists in the cell area of the base station 20 and is not in radio communication with the base station 20 moves along with the switching of the identification information. 50 control units 550 transmit a location registration request to the base station 20 via the communication unit 510.

  In addition, before the base station 20 switches the identification information, the mobile station 50 that exists in the cell area of the base station 20 and is in wireless communication with the base station 20 before and after the switching of the identification information is in wireless communication. Cannot receive the downlink control information or the like to grasp the switching of the identification information of the base station 20. Therefore, the control unit 550 of the mobile station 50 deteriorates the communication quality of the communication channel used for wireless communication due to movement or the like, and when making a communication channel switching request to the base station 20, The identification information before switching (identification information in the normal state) is transmitted to the base station 20.

  In such a case, the control unit 250 of the base station 20 may recognize that the identification information of the own station included in the switching request is identification information in a normal state different from the current identification information (identification information during area synchronization). The switching request is accepted, and the mobile station 50 is controlled to switch the communication channel. Thereby, even in the mobile station 50 in a situation where it cannot be understood that the switching of the identification information has been performed, the wireless communication with the base station 20 can be continuously performed.

  Next, in the base station 20 and the mobile station 50 when the base station 20 in FIG. 2 transmits information for preventing the base station as the synchronization destination base station from determining the own station according to the above (second processing). Operations related to wireless communication will be described.

  The control unit 250 of the base station 20 cannot acquire the 1PPS signal from the GPS receiver 220, and sends a pseudo SCCH to notify the other specified base stations that the local station is in air synchronization after air synchronization. To do.

  In this case, the information indicating that the own station is in air synchronization, which is transmitted by the control unit 250 of the base station 20, is included in the area (PS-ID) including the identification information of the transmission destination in the pseudo SCCH. Therefore, even if the control unit 550 of the mobile station 50 receives the pseudo SCCH, the control unit 550 recognizes that it is not the SCCH addressed to itself and does not perform processing corresponding to the SCCH. As a result, only the other base station can be notified that the own station is in the air synchronization, and the mobile station 50 does not perform any special processing, so the processing load on the mobile station 50 is reduced. it can.

  Although the present invention has been described based on the drawings and examples, it should be noted that those skilled in the art can easily make various modifications and corrections based on the present disclosure. Therefore, it should be noted that these variations and modifications are included in the scope of the present invention.

  For example, functions included in each member, each means, each step, etc. can be rearranged so as not to be logically contradictory, and a plurality of means, steps, etc. can be combined or divided into one. Is possible.

  In the above embodiment, when the control unit 250 of the base station 20 cannot acquire the 1PPS signal from the GPS receiver 220, the control unit 250 transmits information for preventing the own base station from being determined as a synchronization destination base station. However, when a 1 PPS signal can be acquired from the GPS receiver 220 thereafter, transmission of information for preventing the synchronization-destination base station from determining it may be stopped. In this case, in the above (first process), the identification information of the base station 20 is switched from the identification information during air synchronization to the identification information in the normal state, and in the above (second process), the pseudo SCCH May be stopped.

  Further, in the above embodiment, when the base station 30 receives information from the base station 20 so that the synchronization destination base station is not determined, the base station 30 is not determined as the synchronization destination. However, since the base station 30 is supplied with a stable clock required for generating a frame from an external clock source (here, a line clock), the base station 30 can generate a frame with an appropriate transmission / reception timing, and transmit / receive Therefore, the control unit 350 of the base station 30 may determine the base station 20 that has transmitted the information not to be determined by the base station as the synchronization destination base station. In addition, the control unit 250 of the base station 20 does not determine the other base station 20 as the synchronization destination regardless of whether or not the information is received from the other base station 20 to the synchronization destination base station. Also good.

  Furthermore, in the above embodiment, the base station is used as the communication apparatus. However, in addition to this, the present invention may be applied to a radio relay apparatus that relays data transmitted and received between the base station and the mobile station. Good.

  10 communication system 20, 30 base station, 40 network, 50 mobile station, 210, 310, 510 communication unit, 220 GPS receiver, 230, 330 I / F unit, 240, 340, 540 storage unit, 250, 350, 550 control unit, 320 line clock acquisition unit, ANT antenna.

Claims (7)

  In order to prevent the own device from being determined as a synchronization destination communication device, the own device transmits information indicating that the own device is transmitting / receiving a radio signal at a timing based on a reception timing of a radio signal transmitted from another communication device. A communication device comprising: a control unit that transmits data included in a wireless signal. The communication device according to claim 1,
The control unit transmits the information when a signal to be referred to when generating a frame for transmitting and receiving a radio signal cannot be acquired. The communication device according to claim 2,
When the reference signal cannot be acquired, the control unit switches to other identification information that is different from the identification information of the own device that is set when the reference signal can be acquired. A communication apparatus used as the information. The communication device according to claim 2,
When the control unit cannot acquire the signal to be referenced, the control unit stores the information in an area for storing identification information indicating a transmission destination of the downlink control information included in downlink control information, and transmits the information. A communication device.   Information transmitted by another communication device and indicating that the other communication device is transmitting / receiving a radio signal at a timing based on a reception timing of a radio signal transmitted from another communication device different from the other communication device. Is received from the other communication device, the other communication device is not set as a synchronization destination of a frame in which the device transmits and receives a radio signal. A wireless communication system including a plurality of communication devices,
One communication device
In order to prevent the own device from being determined as a synchronization destination communication device, the own device transmits information indicating that the own device is transmitting / receiving a radio signal at a timing based on a reception timing of a radio signal transmitted from another communication device. A wireless communication system comprising: a control unit that transmits data included in a wireless signal. In order to prevent the own device from being determined as a synchronization destination communication device, the own device transmits information indicating that the own device is transmitting / receiving a radio signal at a timing based on a reception timing of a radio signal transmitted from another communication device. A communication control method comprising transmitting data included in data transmitted by a radio signal.

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