JP2016146594A - Base station and radio communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the occurrence of a handover in burst at a base station fault.SOLUTION: The base station radio communicating with a mobile station includes: a plurality of RF units each receiving a first frame to transmit to the mobile station according to the first frame, and according to reception from the mobile station, transmitting the payload of a second frame; a plurality of baseband units each transmitting the payload of the first frame to each RF unit, and receiving the second frame from the RF unit; and a control unit which selects an RF unit which receives the first frame and transmits the second frame according to the states of the RF unit and the baseband unit, and also selects a baseband unit which transmits the first frame and receives the second frame.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a base station and a wireless communication system.

  When a failure occurs in a wireless base station that is a communication infrastructure, radio waves from the base station cannot reach the area covered by the failed base station. There are base stations arranged in the surroundings, but when there is not enough power, an area where radio waves do not reach and communication called a dead spot is impossible occurs.

  There are also wireless communication infrastructures used for public transportation such as railways and airports represented by social infrastructure. In such highly public communications, the effects of dead spots are enormous. On the other hand, Patent Document 1 states that “the downlink transmission power is increased for all or some of the radio base stations that manage neighboring cells that are adjacent to the cell of the radio base station where the failure has occurred. Techniques for “instructing” are disclosed.

JP 2003-078938 A

  If the technique disclosed in Patent Document 1 is used, the occurrence of dead spots can be prevented. However, since handover is simultaneously performed from a base station in which a failure has occurred to a base station having increased transmission power, there is a risk that bursty handover signaling messages will be generated and will not be in time for the handover process.

  In particular, in a radio communication system used for social infrastructure instead of a mobile phone, a sufficient frequency band is not always allocated. AeroMACS (Aeronautical Mobile Airport Communication System), which is being considered as an airport aerial mobile communication system, has a narrow radio band and few signaling messages that can be processed per hour. This is a big risk.

  Accordingly, an object of the present invention is to suppress the occurrence of bursty handover due to a base station failure.

  A representative base station according to the present invention receives a first frame in a base station that performs radio communication with a mobile station, transmits the first frame to the mobile station based on the first frame, and receives from the mobile station. And a baseband unit for transmitting the payload of the first frame to the RF unit and receiving the second frame from the RF unit. A plurality of RF units that receive the first frame and transmit the second frame according to the state of the RF unit and the baseband unit, select the RF unit that transmits the second frame, and transmit the first frame; It has a control part which selects the baseband part which receives 2 frames.

  According to the present invention, it is possible to suppress the occurrence of bursty handover due to a base station failure.

1 is a diagram illustrating an example of a configuration of a wireless communication system according to a first embodiment. It is a figure which shows the example of the block configuration of the base station of Example 1. FIG. It is a figure which shows the example of the downlink signal frame format in the base station of Example 1. FIG. It is a figure which shows the example of the upstream signal frame format in the base station of Example 1. FIG. FIG. 6 is a diagram illustrating an example of a relief sequence from an RF failure according to the first embodiment. FIG. 5 is a diagram illustrating an example of a relief sequence from a baseband failure according to the first embodiment. FIG. 6 is a diagram illustrating an example of a processing flow in a control unit according to the first embodiment. 6 is a diagram illustrating an example of a configuration of a wireless communication system according to a second embodiment. FIG. It is a figure which shows the example of the block configuration of the base station of Example 2. FIG. FIG. 10 is a diagram illustrating an example of a repair sequence according to the second embodiment. FIG. 10 is a diagram illustrating an example of a processing flow in a control unit according to the second embodiment. 10 is a diagram illustrating an example of a wireless frame configuration in Embodiment 2. FIG. It is a figure which shows the example of the block configuration of the base station of Example 3. FIG.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In the embodiment, an airport plane aerial mobile communication system such as AeroMACS will be described as an example. However, in an equivalent system, the same effect can be obtained, and it is obvious that such a system is also within the scope of the description. It is. In the following description, the communication method between the base station and the mobile station conforms to WiMAX (Worldwide Interoperability for Microwave Access), but the communication method in the embodiment is not limited to WiMAX, and other communication methods are used. There may be.

  An example of the configuration of the wireless communication system according to the first embodiment will be described with reference to FIG. In an airport plane air mobile communication system, a plurality of base stations are generally installed redundantly so that a dead spot does not occur when a base station fails. For this reason, the wireless communication system includes a plurality of base stations (101 having an antenna (115-1, 115-2, 125-1, 125-2) for performing wireless communication with the mobile station (102-1). −1, 101-2) and a router switch (103) for connecting the base stations (101-1, 101-2) to each other and the core network device (104). The mobile station (102-1) can be connected to an intranet or the Internet (not shown) via the base stations (101-1, 101-2) and the core network device (104).

[Hardware movement]
FIG. 2 is a diagram illustrating an example of a block configuration of the base station (101-1). The base station (101-1) includes a control unit (111) that controls the base station (101-1), and a baseband (BB) unit that modulates and demodulates radio signals in the base station (101-1) (112-1), a baseband failure detection unit (116-1) that detects a failure in the baseband unit (112-1), a standby baseband unit (112-2) that operates when a failure occurs, and a baseband failure Detection unit (116-2), RF (Radio Frequency) unit (113-1) that transmits and receives radio signals, and fault detection unit (114-1) that can detect a decrease in radio transmission output of the RF unit (113-1) And an antenna unit (115-1) for transmitting a radio signal from the RF unit (113-1) and receiving a radio signal from the mobile station (102-1).

  As shown in FIG. 2, the failure detection unit (114-1) detects the radio transmission output of the RF unit (113-1) by branching the connection with the antenna unit (115-1). Therefore, it is possible to detect a radio signal received by the antenna unit (115-1) by detecting other than the transmission frequency of the RF unit (113-1). Further, the base station (101-1) includes a standby RF unit (113-2), a failure detection unit (114-2), an antenna unit (115-2), and a reference clock for the entire base station (101-1). And a clock master unit (117) for supplying a reference clock to each unit in the base station (101-1).

  Each baseband unit (112-1, 112-2) and RF unit (113-1, 113-2) transfer, for example, CPRI (Common Public) in order to transfer communication contents with the mobile station (102-1). Radio Interface) (registered trademark) or the like is connected by a cable (150) for transferring a frame format. Fault information output from each fault detection unit (114-1, 114-2, 116-1, 116-2) is also sent to the control unit (111) via this cable (150). Based on the failure information, the control unit (111) determines which RF unit (113-1, 113-2) transmits information generated by which baseband unit (112-1, 112-2). . The determination result is output again to the cable (150) as control information. The baseband units (112-1, 112-2) and the RF units (113-1, 113-2) operate according to the control information.

  The control unit (111) may include a processor, a memory, and a communication circuit of the cable (150). A program of a processing flow described later may be stored in the memory, and the processor may read the program from the memory and read / write information necessary for executing the program to / from the memory to realize the operation of the control unit (111). Further, the cable (150) may be a printed wiring on a substrate or the like, as long as it can transmit a frame, and may be a wiring of a backplane or a motherboard.

  The operation when transmitting a downlink signal will be specifically described. The baseband units (112-1, 112-2) convert the signal received from the core network device (104) into a signal format for sending out as a radio signal. Basically, the baseband unit (112-1) and the baseband unit (112-2) can perform the same operation. Information from the core network device (104) can enter both baseband units (112-1, 112-2), perform the same processing, and generate the same transmission signal.

  When one of the baseband unit (112-1) and baseband unit (112-2) is operating as a normal system, the other is in a standby state as a backup system and is waiting for call information transfer from the normal system Waiting. The transmission signal generated by the normal system is developed on the cable (150) according to the frame format described with reference to FIG. 3A.

  FIG. 3A is a diagram showing an example of a downlink signal frame format communicated via the cable (150). The header part (301) is generated by the control unit (111). The failure communication header 1 (302) is generated by the baseband failure detection unit (116-1) so that the control unit (111) can determine whether the baseband unit (112-1) is operating normally. . The failure communication header 2 (303) is generated by the baseband failure detection unit (116-2) so that the control unit (111) can determine whether the baseband unit (112-2) is operating normally. . The payload part (304) and the payload part (305) are information generated by the baseband part (112-1) or the baseband part (112-2).

  Since the two baseband units (112-1, 112-2) and the baseband failure detection unit (116-1, 116-2) are distributed with a common clock from the clock master unit (117), they are completely It can be synchronized and information can be generated in the appropriate time domain within the frame format. In the example shown in FIG. 3A, the payload part (304) is generated by the baseband part (112-1) and the payload part (305) is generated by the baseband part (112-2). It is not limited. In the header part (301) generated by the control part (111), each baseband part (112-1, 112-2) uses the time domain of the payload part (304) or the payload part (305). Instruction information for generating information is incorporated, and for example, both the payload part (304) and the payload part (305) may be generated by the baseband part (112-1).

  In addition, in the header part (301) generated by the control part (111), instruction information indicating whether a radio signal is transmitted via the RF part (113-1) or the RF part (113-2) is also incorporated. It is. Since the control unit (111) can also obtain accurate timing by common clock distribution from the clock master unit (117), information can be generated in an appropriate time domain. The RF unit (113-1) and the RF unit (113-2) that have received the completed frame are instructed to transmit based on the information in the header unit (301) or the RF unit (113-1) or The RF unit (113-2) extracts information from the designated payload unit (304, 305), converts the information into an RF signal, and connects to the antenna unit (115-1) or the antenna unit (115-2). ) To transmit a radio signal.

  A case where an uplink signal is received will be specifically described. The antenna unit (115-1) or the antenna unit (115-2) receives a radio signal from the mobile station (102-1). The received signal is converted into a baseband signal by the RF unit (113-1) or the RF unit (113-2) to be a digital signal. The RF unit (113-1) or RF unit (113-2) converted into the baseband signal is completely synchronized because the common clock is distributed from the clock master unit (117).

  FIG. 3B is a diagram showing an example of an upstream signal frame format communicated via the cable (150). The header part (311) is generated by the control unit (111). The failure communication header 1 (312) is generated by the RF failure detection unit (114-1) so that the control unit (111) can determine whether the RF unit (113-1) is operating normally. The failure communication header 2 (313) is generated by the RF failure detection unit (114-2) so that the control unit (111) can determine whether the RF unit (113-2) is operating normally.

  The RF unit (113-1) and the RF unit (113-2) generate respective designated payload units (314, 315) using the converted baseband signal in accordance with the header unit (311). In the example shown in FIG. 3B, the payload portion (314) is generated by the RF portion (113-1), and the payload portion (315) is generated by the RF portion (113-2). is not. In the header part (301) generated by the control part (111), each RF part (113-1, 113-2) uses either the payload part (314) or the payload part (315) for information. For example, both the payload part (314) and the payload part (315) may be generated by the RF part (113-1).

  The control unit (111) monitors the failure communication header portion 1 (312) and the failure communication header portion 2 (313) of the upstream signal frame, and determines which RF portion (113-1, 113-2) according to the information. Determine whether to use. Then, the control unit (111) monitors the faulty communication header part 1 (302) and the faulty communication header part 2 (303) of the downlink signal frame, and baseband part (112-1) or baseband part (112- 2) Determine whether to perform the process. The baseband unit (112-1) or the baseband unit (112-2) selected by the determination of the control unit (111) is the designated payload portion (314, 315) of the upstream signal frame flowing through the cable (150). ), The information is extracted and processed, and the processing result is transmitted to the core network device (104).

[Software movement]
FIG. 4A is a diagram illustrating an example of a relief sequence when a decrease in wireless output occurs in the RF unit (113-1). Mobile station (102-1), RF unit (113-1), failure detection unit (114-1), baseband (BB) unit (112-1), RF unit (113-2), baseband (BB) The unit (112-2) and the control unit (111) are as described above. First, the baseband unit (112-1) establishes a call connection state (401) with the mobile station (102-1) via the RF unit (113-1). For this purpose, the payload part (304, 305) may be generated by the baseband part (112-1), and the payload part (314, 315) may be generated by the RF part (113-1).

  The RF unit (113-1) and the baseband unit (112-1) transmit and receive a downlink signal frame and an uplink signal frame (not shown), and the RF unit (113-1) transmits information on the downlink signal frame. This is an example in which a decrease in wireless output occurs in the RF unit (113-1) as a failure (402) when transmitting with a wireless signal. The failure detection unit (114-1) detects a decrease in the wireless output of the RF unit (113-1), and uses the failure communication header unit 1 (312) to send a wireless output decrease notification (403) to the control unit (111). Send to.

  The control unit (111) that has received the wireless power reduction notification (403) determines that the RF unit (113-1) cannot be used continuously, selects the RF unit (113-2), and selects the baseband unit (112- 1, 112-2) and the header section (301, 311) of the frame connecting the RF section (113-1, 113-2) is changed (404). The connection change between the baseband unit (112-1, 112-2) and the RF unit (113-1, 113-2) is changed to the baseband unit (112-1, 112-2) as a change notification (405). It is transmitted to the RF unit (113-1, 113-2).

  Here, the transmission of the change notification (405) may be broadcast, or may be unicast four times while changing the destination. By changing the instructions of the header sections (301, 311), the downlink signal output from the baseband section (112-1) is transferred to the mobile station (102-1) via the standby RF section (113-2). ). Conversely, the uplink signal from the mobile station (102-1) received via the standby RF unit (113-2) is also processed by the baseband unit (112-1). Then, a call connection state (406) is established.

  The RF unit (113-2) may be released from the standby state by the change notification (405). The RF unit (113-2) monitors the signal on the cable (150) even in the standby state, and the baseband units (112-1, 112-2) and the RF unit (113-1) are also connected to the cable (150). The above signal is monitored, the change notification (405) is omitted, and the baseband part (112-1) and the RF part (113-2) are connected according to the instruction of the header part (301, 311). Also good.

  FIG. 4B is a diagram illustrating an example of a repair sequence when a failure occurs in the baseband unit (112-1). Mobile station (102-1), RF unit (113-1), baseband (BB) unit (112-1), fault detection unit (116-1), RF unit (113-2), baseband (BB) The unit (112-2) and the control unit (111) are as described above. First, the baseband unit (112-1) establishes a call connection state (411) with the mobile station (102-1) via the RF unit (113-1). For this purpose, the payload part (304, 305) may be generated by the baseband part (112-1), and the payload part (314, 315) may be generated by the RF part (113-1).

  The RF unit (113-1) and the baseband unit (112-1) transmit and receive a downlink signal frame and an uplink signal frame (not shown), and the RF unit (113-1) transmits information on the downlink signal frame. This is an example in which a failure (412) occurs in the baseband unit (112-1) when transmitting with a radio signal. The failure detection unit (116-1) detects a failure in the baseband unit (112-1), and transmits a baseband failure notification (413) to the control unit (111) using the failure communication header unit 1 (302). To do.

  The control unit (111) that has received the baseband failure notification (413) determines that the baseband unit (112-1) cannot be used continuously, selects the baseband unit (112-2), and selects the baseband unit (112-2). 112-1) is notified of a call information transfer instruction (414). Upon receiving the call information transfer instruction (414), the baseband unit (112-1) transfers (415) the call information to the standby baseband unit (112-2). Based on the transferred call information, the baseband unit (112-2) may be set with the terminal ID of the mobile station (102-1) in communication set in the baseband unit (112-1). . Since the baseband part (112-2) is in the same base station (101-1) as the baseband part (112-1), the same base station ID and modulation frequency as the baseband part (112-1) Etc. may be set in advance.

  In addition, the control unit (111) changes the header part (301, 311) of the frame connecting the baseband unit (112-1, 112-2) and the RF unit (113-1, 113-2) (416). To do. The connection change between the baseband unit (112-1, 112-2) and the RF unit (113-1, 113-2) is changed to the baseband unit (112-1, 112-2) as a change notification (417). It is transmitted to the RF unit (113-1, 113-2). Here, the transmission of the change notification (417) may be broadcast, or may be unicast four times while changing the destination.

  After the call information is transferred, the downlink signal output from the standby baseband unit (112-2) passes through the RF unit (113-1) by changing the instructions of the header units (301, 311). To be transmitted to the mobile station (102-1). Conversely, an uplink signal from the mobile station (102-1) received via the RF unit (113-1) is also processed by the baseband unit (112-2) of the standby system. Then, the call connection state (418) is established.

  The baseband unit (112-2) may be released from the standby state by a change notification (417). The baseband unit (112-2) monitors the signal on the cable (150) even in the standby state, and the baseband unit (112-1) and the RF unit (113-1, 113-2) are also connected to the cable (150). ) The above signal is monitored, the change notification (417) is omitted, and the baseband part (112-2) and the RF part (113-1) are connected only by the instruction of the header part (301, 311). It may be.

  FIG. 5 is a diagram illustrating an example of a processing flow of the control unit (111) for realizing the sequence described with reference to FIGS. 4A and 4B. The control unit (111) starts the service (451), and then monitors the failure. For the failure monitoring, the failure monitoring (452) for determining the wireless output decrease notification (403) from the failure detection unit (114-1) described with reference to FIG. 4A and the failure detection unit described with reference to FIG. 4B There is a failure monitoring (453) for determining a baseband failure notification (413) from (116-1). Here, the fault monitoring (452) may determine a notification of a decrease in radio output from the standby fault detection unit (114-2), and the fault monitoring (453) is the standby fault detection unit (116-2). The baseband failure notification from may be determined.

  If no failure occurs, the control unit (111) determines NO in both the failure monitoring (452) and the failure monitoring (453), and repeats the failure monitoring. When the determination of the fault monitoring (452) is YES, that is, when the wireless output decrease notification (403) is received, the control unit (111) selects the RF unit without the wireless output decrease, changes the header part (455), Notify (456) the change. If the determination of the failure monitoring (453) is YES, that is, if the baseband failure notification (413) is received, the control unit (111) selects the baseband unit (112-2) having no failure and transfers the call information. The instruction (414) is instructed by transmitting it to the baseband part (112-1) (454), the header part is changed (455), and the change is notified (456).

  As described above, the rescue operation in the base station (101-1) is performed without detecting the stop of the radio output of the base station (101-1) to which the mobile station (102-1) was connected. be able to. Thereby, it is possible to prevent a bursty handover from occurring when a failure occurs in the base station (101-1).

  FIG. 6 is a diagram illustrating an example of a wireless communication system according to the second embodiment. The core network device (104), router switch (103), and mobile station (102-1) are as described above. A storage unit (501) for aggregating information related to the connection of the mobile station (102-1) connected by each base station (501-1, 501-2) is newly connected by the router switch (103). Further, as will be described below, the base stations (501-1, 501-2) do not have a backup system inside each.

  FIG. 7 shows an example of the block configuration of the base stations (501-1, 501-2). By using FIGS. 7 and 8, a base station (501-1, 501-2) is previously configured as a pair. An example will be described in which a failure of the RF unit (113) mounted on the station (501-1) is detected by the RF unit (123) mounted on the base station (501-2). Note that the pair here is a pair that can wirelessly communicate with the mobile station (102-1) in any of the base stations (501-1, 501-2), and has, for example, the same wireless communicable area. Also good.

  The base station (501-1) includes a control unit (111) for managing fault conditions in the base station (501-1), a baseband unit (112) capable of modulating and demodulating multiple frequencies, and multiple frequency bands. RF unit (113) capable of performing wireless transmission / reception processing, a failure detection unit (114) that can detect a decrease in transmission power of the RF unit (113), and an antenna unit (115 that performs radio communication with the mobile station (102-1)) ). Further, each of the baseband units (112, 122) includes a frame generation unit (115, 125) that is not shown in FIG. 2 in order to generate a wireless frame.

  The base station (501-1) is connected to the storage unit (502) and the base station (501-2) via the router switch (103). Similarly, the base station (501-2) has a baseband unit (122) capable of modulating and demodulating multiple frequencies, an RF unit (123) capable of transmitting and receiving multiple frequency bands, and transmission of the RF unit. A failure detection unit (124) that can detect a decrease in power and an antenna unit (125) that performs wireless communication with the mobile station (102-2) are configured. Here, the base station (501-1) and the base station (501-2) provide services using radio waves (512, 513) of different frequencies so as not to cause radio wave interference.

  FIG. 8 is a diagram showing an example of a repair sequence from a failure in the base station (501-1). First, when the call connection state (601) is established between the base station (501-1) and the mobile station (102-1), the base station (501-1) transfers (602) the call information when the call connection is completed. The call information is stored in the storage unit (502). At this time, the RF section (113) of the base station (501-1) transmits and receives the radio wave (512) at the service frequency of the base station (501-1), and the fault detection section (114) 512), while monitoring the transmission of the service frequency of the base station (501-2) (513). By doing so, the failure detection unit (114) can monitor a decrease in transmission power of the RF unit (123) of the base station (501-2).

  On the other hand, the RF unit (113) of the base station (501-2) also transmits and receives radio waves (513) at the service frequency of the base station (501-2), and the failure detection unit (124) transmits radio waves (513 at the service frequency). ) While receiving the radio wave (512) of the service frequency of the base station (501-1). By doing so, the failure detection unit (124) can monitor the decrease in transmission power of the RF unit (113) of the base station (501-1).

  As shown in FIG. 7, when a failure occurs in the RF unit (113) of the base station (501-1), the failure detection unit (124) of the base station (501-2) The transmission power of the base station (501-1) is detected to be lower when the transmission power of 1 is not received. As shown in FIG. 8, as the failure detection (604) for the failure (603), the failure detection unit (124) of the base station (501-2) that has detected the decrease in transmission power detects the decrease in transmission power by the base station ( 501-2) is notified to the control unit (121). The control unit (121) of the base station (501-2) that is notified of the decrease in transmission power obtains the base station information of the base station (501-1) and the call information that was connected to the base station (501-1). In order to obtain it, a call information request (605) is transmitted to the storage unit (502).

  The storage unit (502) that has received the call information request (605) uses the base station information and call information of the requested base station (501-1) as the call information transfer (603), and the base station (501-2). To the control unit (121). The control unit (121) of the base station (501-2) that has received the call information transfer (606) receives the base station (501-1) in addition to the frequency of the radio wave (513) currently in service to the baseband unit (122). ) Instruct to also modulate and demodulate the frequency of the radio wave (512) served by

  Further, the baseband unit (122) is set with the terminal ID of the mobile station (102-1) and the base station ID of the base station (501-1). By using the base station information and call information of the base station (501-1) acquired from the storage unit (502), modulation and demodulation equivalent to those of the baseband unit (112) of the base station (501-1) are continued. be able to. In addition, the control unit (121) of the base station (501-2) transmits to the RF unit (123) the radio wave ( Instruct to perform transmission processing of frequency 512).

  Since the base station information of the base station (501-1) is included only in the radio wave (512) served by the base station (501-1), the service of the base station (501-2) is applied even if this rescue process is applied. The connection with the mobile station (102-2) that has been connected using the radio wave (513) is not affected. The mobile station (102-1) can receive the radio wave received from the base station (501-1) via the baseband part (122) and the RF part (123) of the base station (501-2). Therefore, the call connection state can be returned (607), and the call connection can be continued without operating the general sequence of handover.

  An example of the processing flow of the control unit (121) will be described with reference to FIG. The control unit (121) starts a service (701), and then monitors fault information (702). When a failure notification is received from the failure detection unit (125), the control unit (121) acquires the base station information and call information of the base station (501-1) set in advance to the storage unit (502). A request is made (703). The control unit (121) that acquired (704) the base station information and call information of the base station (501-1) sends the base station (501-1) to the baseband unit (122) of the base station (501-2). ) Instructs the frequency modulation and base station ID of the radio wave (512) served by) (705), and sends the frequency of the radio wave (512) served by the base station (501-1) to the RF unit (123) However, it instructs to perform wireless communication (706).

  The failure detection unit (114, 124) may use normality monitoring information included in the configuration of the wireless frame. When monitoring the decrease in transmission power between base stations (501-1, 501-2), the downlink signal from the base station (501-1, 501-2) and the mobile station ( 102-1, 102-2) In the communication system that separates the uplink signals on the time axis, as shown in FIG. 10, the frame generation unit (115) of the base station (501-1) to be monitored A radio wave is transmitted by fixedly assigning a normal confirmation signal (802) to the final time region of the time resource (801) assigned for transmission (downlink signal). For the time resource (803) allocated to reception (uplink signal), an uplink signal from the mobile station (102-1) is allocated so that radio waves from the mobile station (102-1) can be received.

  The base station (501-2) for monitoring shortens the time resource (804) allocated for transmission (downlink signal) by the normal confirmation signal (802) from the base station (501-1), and shortens that amount. The normal confirmation signal (802) from the base station (501-1) is interfered with the uplink signal from the mobile station (102-1) by expanding the time resource (805) allocated to reception (uplink signal) only It can receive without. The mobile station (102-1) recognizes the time domain of the normal confirmation signal (802) as a downlink signal for other mobile stations, so that the base station (501-1) and the mobile station (102-1) There is no impact on communication.

  At this time, in the base station (501-1) to be monitored and the base station (101-2) to be monitored, the Frame generation unit (115) and the Frame generation unit (125) replace the wireless frame configuration for each frame. Each other's normality confirmation signal can be received for each frame. Further, the normality confirmation signal (802) may be a signal pattern decided between the base stations (501-1, 501-2). For example, it may be determined that reception is possible when a specific pattern is obtained by CRC (Cyclic Redundancy Check).

  As described above, even if the base station (501-1, 501-2) does not have a backup system inside, the base station (501-2) can perform the repair operation with the mobile station (102-1). The call connection status can be established. Thereby, it is possible to prevent a bursty handover from occurring when a failure occurs in the base station (501-1). Further, by including the normal confirmation signal (802) in the configuration of the wireless frame, it becomes easy to detect a failure of the base station (501-1) to be monitored.

  In the third embodiment, as shown in FIG. 11, the baseband unit (112-1, 112-2) and the RF unit (113-1, 113-2) are physically installed separately from each other. The operation of the failure detection unit (114-1, 114-2, 116-1, 116-2) is as described in the first and second embodiments. The clock master unit (117) supplies a reference clock to the control unit (111), the baseband units (112-1, 112-2), and the failure detection unit (116-1, 116-2). Even if the baseband part (112-1, 112-2) and the RF part (113-1, 113-2) are physically installed separately, the baseband part (112-1, By receiving clock distribution from 112-2), timing synchronization is also possible in the RF units (113-1, 113-2).

  It is also possible to install the baseband units (112-1, 112-2) indoors (901) and the RF units (113-1, 113-2) outdoors. By making it possible to install them separately in this way, it becomes easy to install base station equipment. In addition, the baseband unit (112-1, 112-2), RF unit (113-1), and standby RF unit (113-2) are separate power units (904, 903-1, 903-2). By supplying power, for example, even if an overcurrent due to lightning strikes the RF unit (113-1), the entire base station will not be disturbed. For this purpose, the cable (902) may be an insulating optical cable. Corresponding to the cable (902) being cut, the cable (902) connecting the baseband part (112-1, 112-2) and the RF part (113-1, 113-2) is ring-shaped. It may be.

  As described above, the base station facility can be easily laid, and the communication with the mobile station can be continued by locally stopping the base station.

101-1 base station 101-2 base station 111 control unit 112-1 baseband unit 112-2 baseband unit 113-1 RF unit 113-2 RF unit 114-1 fault detection unit 114-2 fault detection unit 116-1 Failure detection unit 116-2 Failure detection unit

Claims (14)

In a base station that communicates wirelessly with a mobile station,
A plurality of RF units for receiving a first frame, transmitting to the mobile station based on the first frame, and transmitting a payload of a second frame based on reception from the mobile station;
A plurality of baseband units for transmitting the payload of the first frame to the RF unit and receiving the second frame from the RF unit;
According to the state of the RF unit and the baseband unit, the RF unit that receives the first frame and transmits the second frame is selected, the first frame is transmitted, and the second frame is transmitted. A base station comprising a control unit that selects a baseband unit to receive. The base station further includes a clock unit that supplies a reference clock to the RF unit, the baseband unit, and the control unit,
The control unit generates the header of the first frame and the header of the second frame based on the reference clock,
The RF unit transmits the payload of the second frame based on the reference clock,
The baseband unit transmits the payload of the first frame based on the reference clock,
The base station according to claim 1, wherein the base station and the payload of the first frame and the header and payload of the second frame are respectively configured. The control unit according to claim 2, wherein the control unit changes the header of the first frame and the header of the second frame according to a failure of the RF unit or a failure state of the baseband unit. Base station. The base station according to claim 3, wherein the control unit notifies the RF unit and the baseband unit of a change in the header of the first frame and the header of the second frame. Each of the header of the first frame and the header of the second frame includes instruction information of the RF part and instruction information of the baseband part,
The control unit changes the instruction information of the header of the first frame and the instruction information of the header of the second frame in accordance with a failure of the RF unit or a failure state of the baseband unit. The base station according to claim 3. Each of the first frame and the second frame includes a failure notification header;
A failure detection unit of the RF unit that detects a failure of the RF unit and generates failure state information of a failure notification header of the second frame;
A failure detection unit of the baseband unit that detects a failure of the baseband unit and generates failure state information of the failure notification header of the first frame;
Further comprising
The controller is
According to the failure status information in the failure notification header of the second frame, change the instruction information of the RF unit,
The base station according to claim 5, wherein the baseband unit instruction information is changed in accordance with information on a failure state in a failure notification header of the first frame. The controller is
Based on the failure status information in the failure notification header of the first frame, the failure of the first baseband portion in the plurality of baseband portions is determined, and the second in the plurality of baseband portions is determined. Select the baseband part of
Instructing transfer of call information to the first baseband unit,
The first baseband portion is
When transfer of the call information is instructed from the control unit, the call information is transferred to the second baseband unit,
The second baseband portion is
The base station according to claim 6, wherein when the call information is transferred from the first baseband unit, identification information of the mobile station is set based on the transferred call information. In a wireless communication system having a plurality of base stations and a storage unit that communicate with a mobile station,
A first base station of the plurality of base stations is
A first baseband section;
A first RF section;
A first antenna unit for transmitting a signal from the RF unit;
A first control unit for transferring call information to the storage unit,
A second base station of the plurality of base stations is
A second baseband section;
A second RF section;
A second antenna section;
A second failure detection unit connected to the second antenna unit for detecting transmission of the first base station;
In response to the detection of the second failure detection unit, the storage unit is requested to transfer the call information, and the call information acquired by the request is sent to the second baseband unit and the second RF unit. And a second control unit to be set. The first base station is
The first baseband unit includes a first frame generation unit that allocates a normal confirmation signal to a predetermined time region in a first transmission time resource to the mobile station;
The first RF unit transmits radio waves of a first frequency from the first antenna unit,
The second base station is
The second baseband unit includes a second frame generation unit that allocates a second transmission time resource that does not overlap with the first transmission time resource;
The wireless communication system according to claim 8, wherein the failure detection unit detects transmission of a radio wave having the first frequency by the second antenna unit. The first base station is
A first failure detection unit connected to the first antenna unit for detecting transmission of the second base station;
The first control unit requests transfer of the call information to the storage unit in response to detection of the first failure detection unit, and the call information acquired by the request is transmitted to the first baseband unit. The wireless communication system according to claim 9, wherein the wireless communication system is set in the first RF unit. The wireless communication system according to claim 10, wherein the call information includes an identifier of the mobile station. In a base station that communicates wirelessly with a mobile station,
A plurality of RF units for receiving a first frame, transmitting to the mobile station based on the first frame, and transmitting a payload of a second frame based on reception from the mobile station;
A plurality of baseband units for transmitting the payload of the first frame to the RF unit and receiving the second frame from the RF unit;
A communication cable for connecting the plurality of RF units and the plurality of baseband units;
The RF unit is supplied with a reference clock from the baseband unit via the communication cable,
According to the state of the RF unit and the baseband unit, the RF unit that receives the first frame and transmits the second frame is selected, the first frame is transmitted, and the second frame is transmitted. A base station comprising a control unit that selects a baseband unit to receive. The plurality of baseband units are supplied with power from a first power source,
The base station according to claim 12, wherein each of the plurality of RF units is independent of each other and receives power supply from a power source independent of the first power source. The base station according to claim 13, wherein the communication cable is an insulating optical cable.

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