JP5756005B2 - Communication system and communication method - Google Patents

Description

  The present invention relates to a communication system and a communication method.

  The radio communication system is configured, for example, such that the radio network control device is connected to the core network from the upstream side, the base station is connected to the radio network control device, and the base station is radio-connected to the radio terminals in the cell. The Here, the “cell” is an area in which one base station is in charge of wireless communication with a wireless terminal. “Upstream” refers to the core network side, and “downstream” refers to the wireless terminal side.

  In many cases, the wireless network control device and the base station are connected by a wired line such as an optical fiber. The base station includes a base station in which a baseband unit and a radio unit are integrated (hereinafter referred to as “integrated base station”) and a base station (hereinafter referred to as “integrated base station”) that is separately located. Referred to as "separated base station"). In the case of a separable base station, the baseband unit and the radio unit are connected by an optical fiber or the like.

  An optical fiber used for connection between devices installed at distant positions may cause a failure such as a physical disconnection due to a disaster or an accident. In this case, data transmission cannot be performed between devices connected via the optical fiber where the failure has occurred. Therefore, for example, when a failure occurs in an optical fiber that connects a certain wireless network control device and a base station, the communication of a wireless terminal located in the cell of the base station is unstable (communication impossible or difficult to connect) Become.

  As described above, when a failure occurs in the optical fiber, the wireless terminal located in the cell of the base station downstream of the failure occurrence location becomes unstable in communication, but other problems also occur. For example, if the base station downstream of the failure location continues to operate, it may adversely affect the surrounding wireless communication environment by transmitting unnecessary radio waves. In addition, if such a base station that does not contribute to wireless communication continues to operate, power is wasted.

JP 2000-102054 A

  In order to solve the above-mentioned problem of unnecessary radio wave transmission and wasteful power consumption, for example, when a failure occurs in a wired line, an invention of a base station that detects the failure and automatically stops transmission is known. (For example, refer to Patent Document 1).

  However, stopping the transmission of the base station can only prevent adverse effects such as unnecessary radio wave transmission and wasteful power consumption, and wireless terminals located in the cell of the base station downstream of the point of failure can communicate. The problem of becoming unstable cannot be solved.

  Accordingly, an object of the present invention made in view of such a point is to provide a communication system and a communication method that can reduce the number of wireless terminals that become unstable due to a failure when a failure occurs in a wired line as much as possible. It is in.

The invention of the communication system according to the first aspect to achieve the above object is as follows:
In a communication system comprising a base station having an operation mode that operates as a radio relay device, and a peripheral base station installed around the base station,
When the base station detects a network abnormality, it transmits the detection result to the neighboring base stations,
When the neighboring base station receives the detection result from the base station, the neighboring base station switches the base station to an operation mode as a radio relay device according to the influence of the network abnormality on the radio terminal in the cell of the base station. Or whether to stop the transmission of the base station,
The neighboring base station transmits, based on the determination result, an instruction to switch the base station to an operation mode as a radio relay device or an instruction to stop transmission of the base station to the base station. To do.

  The invention according to a second aspect is the communication system according to the first aspect, wherein the peripheral base station collects information on the base station from a core network, and the network abnormality is in a cell of the base station. The influence on the wireless terminal is calculated.

  The invention according to a third aspect is the communication system according to the first or second aspect, wherein when the base station detects network recovery, the base station switches to a normal mode and starts operation as a base station It is characterized by.

The invention of the communication system according to the fourth aspect to achieve the above object is as follows:
In a communication system comprising a radio relay device having an operation mode that operates as a base station, and a peripheral base station installed around the radio relay device,
When the wireless relay device detects a network abnormality, it transmits the detection result to a neighboring base station,
When the neighboring base station receives the detection result from the radio relay apparatus, an operation mode in which the radio relay apparatus is used as a base station according to the influence of the network abnormality on the radio terminal in the cell of the radio relay apparatus To determine whether or not to stop transmission of the wireless relay device,
The neighboring base station transmits, based on the determination result, an instruction to switch the radio relay apparatus to an operation mode as a base station or an instruction to stop transmission of the radio relay apparatus to the radio relay apparatus. Features.

  The invention according to a fifth aspect is the communication system according to the fourth aspect, wherein the peripheral base station collects information on the radio relay device from a core network, and the network abnormality is detected by the radio relay device. An effect on the wireless terminal in the cell is calculated.

  The invention according to a sixth aspect is the communication system according to the fourth or fifth aspect, wherein when the wireless relay device detects network recovery, the wireless relay device switches to a normal mode and starts operating as a wireless relay device It is characterized by doing.

  As described above, the solution of the present invention has been described as a system. However, the present invention can also be realized as a method, a program, and a storage medium storing the program, which are substantially equivalent to these. It should be understood that these are also included.

For example, the invention of the communication method according to the seventh aspect, in which the present invention is realized as a method,
A communication method in a communication system comprising a base station having an operation mode that operates as a radio relay device, and a peripheral base station installed around the base station,
When the base station detects a network abnormality, transmitting the detection result to a neighboring base station;
When the neighboring base station receives the detection result from the base station, the base station is switched to an operation mode as a radio relay apparatus according to the influence of the network abnormality on the radio terminal in the cell of the base station. Or determining whether to stop transmission of the base station;
The neighboring base station transmitting to the base station an instruction to switch the base station to an operation mode as a radio relay device or an instruction to stop transmission of the base station based on the determination result It is characterized by that.

The invention of the communication method according to the eighth aspect of realizing the present invention as a method is as follows:
A communication method in a communication system comprising a radio relay device having an operation mode operating as a base station, and a peripheral base station installed around the radio relay device,
When the wireless relay device detects a network abnormality, transmitting the detection result to a neighboring base station;
When the neighboring base station receives the detection result from the wireless relay device, the wireless relay device is operated as a base station according to the influence of the network abnormality on the wireless terminal in the cell of the wireless relay device. Determining whether to switch to or to stop transmission of the wireless relay device;
The neighboring base station, based on the determination result, transmitting an instruction to switch the radio relay apparatus to an operation mode as a base station or an instruction to stop transmission of the radio relay apparatus to the radio relay apparatus; It is characterized by including.

  ADVANTAGE OF THE INVENTION According to this invention, when a failure generate | occur | produces in a wired line, the communication system and communication method which can reduce the radio | wireless terminal which becomes communication unstable by the said failure as much as possible can be provided.

1 is a schematic diagram of a wireless communication system according to an embodiment of the present invention. It is a functional block diagram which shows schematic structure of the integrated base station which concerns on one Embodiment of this invention. It is a functional block diagram which shows schematic structure of the radio relay apparatus which concerns on one Embodiment of this invention. It is a figure which shows the case where there exists a failure in one place of the radio | wireless communications system of FIG. 5 is a flowchart of an operation according to the first embodiment of the present invention for minimizing the influence of the failure of FIG. It is a figure which shows the case where there exists a fault in the other location of the radio | wireless communications system of FIG. 7 is a flowchart of an operation according to a second embodiment of the present invention for minimizing the influence of the failure of FIG.

  Hereinafter, embodiments according to the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic diagram of a wireless communication system according to an embodiment of the present invention. The wireless communication system shown in FIG. 1 includes a core network 10, wireless network control devices 12-1 and 12-2, an integrated base station 14, a separation base station 16, a wireless relay device 22, and wireless terminals 24-1 to 24-1. 24-9.

  Note that FIG. 1 is merely an example of a wireless communication system, and the number of devices is not limited thereto. For example, the wireless communication system shown in FIG. 1 includes two wireless network control devices 12-1 and 12-2 as wireless network control devices, but this is not limited to two, and one or more wireless network control devices It may be an arbitrary number.

  Radio network control devices 12-1 and 12-2 are the same type of devices, and are collectively referred to as radio network control device 12 when collectively referred to. Hereinafter, the code is handled in the same manner. When distinguishing devices of the same type, the numbers after the hyphen are distinguished, and when referring generically, only the numbers before the hyphen are described.

  The core network 10 is connected to an external network such as the Internet and performs line switching.

  The radio network controller 12 is connected to the core network 10, the integrated base station 14, and the separated base station 16. The wireless network control device 12 performs wireless connection connection control, handover control, and the like.

  The integrated base station 14 is connected to the wireless network control device 12-1 by an optical fiber or the like. The integrated base station 14 integrally has a baseband function and a wireless function. The integrated base station 14 performs wireless communication with the wireless terminals 24-1 and 24-2 located in the cell. As shown in FIG. 2, the integrated base station 14 includes an IF (interface) unit 14A that transmits and receives data to and from the wireless network control device 12-1, and a wireless unit 14B in which a baseband function and a wireless function are integrated. And a control unit 14C that performs various controls of the integrated base station 14, and a storage unit 14D that stores information such as the base station ID of the integrated base station 14.

  The integrated base station 14 can also operate as a wireless relay device by switching the operation mode. When receiving an instruction from the neighboring base station to operate as a radio relay device, the integrated base station 14 operates as a radio relay device by switching the operation mode. Here, the peripheral base station is a base station installed around the integrated base station 14 and capable of wireless communication with the integrated base station 14. For example, if the separated base station 16 is located in the vicinity of the integrated base station 14 and the integrated base station 14 can wirelessly communicate with the separated base station 16, the separated base station 16 is a peripheral base station. possible.

  Furthermore, the integrated base station 14 can also stop transmission upon receiving an instruction from a neighboring base station. The integrated base station 14 gives instructions from the neighboring base stations to switch to an operation mode as a wireless relay device or stop transmission when a failure occurs in an optical fiber with the wireless network control device 12-1. Receive. These processes will be described later in the description of the flowchart of FIG.

  The separable base station 16 includes an IF (interface) unit 16A that transmits and receives data to and from the wireless network control device 12-1, a control unit 16B that performs various controls of the separable base station 16, and a base station of the separable base station 16. A storage unit 16C that stores information such as ID, coordinates, and the amount of available wireless resources, a baseband unit 18, and wireless units 20-1 to 20-3 are provided. The baseband unit 18 and the radio unit 20 are installed at a remote location and are connected by an optical fiber or the like.

  The separable base station 16 can also operate as a wireless relay device by switching the operation mode. When receiving an instruction to operate as a radio relay device from a neighboring base station, the separable base station 16 operates as a radio relay device by switching the operation mode. Here, the peripheral base station is a base station that is installed around the separable base station 16 and is capable of wireless communication with the separable base station 16. For example, if the integrated base station 14 is located in the vicinity of the separated base station 16 and the separated base station 16 can wirelessly communicate with the integrated base station 14, the integrated base station 14 can be a peripheral base station. .

  Furthermore, the separable base station 16 can also stop transmission upon receiving an instruction from a neighboring base station. The separable base station 16 gives instructions from the neighboring base stations to switch to an operation mode as a wireless relay device or stop transmission when a failure occurs in the optical fiber with the wireless network control device 12-1. Receive.

  For the downlink, the baseband unit 18 receives the downlink data from the radio network controller 12-1 via the IF unit 16A and the control unit 16B, converts the downlink data into a baseband signal, and then transmits the radio units 20-1 to 20-20. -3. Further, for the uplink, the baseband unit 18 receives the baseband signal from the radio units 20-1 to 20-3, converts it into uplink data, and then performs radio network control via the control unit 16B and the IF unit 16A. Output to the device 12-1.

  The radio unit 20 receives a baseband frequency signal from the baseband unit 18 for the downlink signal, up-converts the radio signal to a radio signal, and transmits the radio signal to the radio relay device 22 or the radio terminal 24. The radio unit 20 receives the radio signal from the radio relay device 22 or the radio terminal 24 for the uplink signal, down-converts it to the baseband frequency, and then outputs it to the baseband unit 18.

  The wireless relay device 22 is installed in an area where the radio waves of the integrated base station 14 and the separated base station 16 are difficult to reach due to the influence of an obstacle such as an urban area where high-rise buildings are lined up. In the example of the wireless communication system illustrated in FIG. 1, the wireless relay device 22 relays between the wireless unit 20-1 of the separation-type base station 16 and the wireless terminals 24-3 and 24-4. The radio relay device 22 receives a radio signal from the radio unit 20 and transmits it to the radio terminal 24 in the downlink. The radio relay device 22 receives a radio signal from the radio terminal 24 and transmits it to the radio unit 20 in the uplink. As shown in FIG. 3, the radio relay device 22 includes a base station side transmission / reception unit 22 </ b> A that transmits / receives data to / from the radio unit 20-1, a control unit 22 </ b> B that performs various controls of the radio relay device 22, and the radio relay device 22. A storage unit 22C that stores information such as a base station ID, coordinates, and a free radio resource amount, and a terminal-side transmission / reception unit 22D are provided. Further, the wireless relay device 22 includes an IF (interface) unit 22E that can transmit and receive data to and from the wireless network control device 12, and the control unit 22-B can transmit or receive the base station side transmission / reception unit 22A or The connection is switched to the IF unit 22E.

  Further, the wireless relay device 22 can also operate as a pico cell by switching the operation mode. Here, the pico cell refers to a base station having a small cell radius and having a cell radius of about several tens of meters. When receiving an operation instruction as a pico cell from a neighboring base station, the radio relay apparatus 22 operates as a pico cell by switching the operation mode.

  Furthermore, the radio relay apparatus 22 can also stop transmission upon receiving an instruction from a neighboring base station. The wireless relay device 22 gives instructions from the neighboring base stations to switch to the operation mode as a pico cell, stop transmission, etc. when a failure occurs in the optical fiber between the baseband unit 18 and the wireless unit 20-1. Receive. These processes will be described later in the description of the flowchart of FIG.

  In FIG. 1, the configuration in which the radio unit 20-1 of the separable base station 16 and the radio relay device 22 perform radio communication is shown as an example. The relay device 22 can perform wireless communication, and the other wireless unit 20-2 or 20-3 and the wireless relay device 22 can perform wireless communication. Further, the number of wireless relay devices 22 is not limited to one, and a plurality of wireless relay devices 22 may be installed in the wireless communication system shown in FIG.

  The wireless terminal 24 performs wireless communication with the integrated base station 14, the wireless units 20-1 to 20-3 or the wireless relay unit 22.

  Other functions of the integrated base station 14, the separated base station 16, the baseband unit 18, the wireless unit 20, and the wireless relay device 22 will be described later in the description of the flowcharts of FIGS.

(First embodiment)
FIG. 4 is a diagram showing a state in the case where a failure such as a physical disconnection occurs in the optical fiber connecting the wireless network control device 12-1 and the integrated base station 14 in the wireless communication system shown in FIG. It is.

  When a failure of the optical fiber as shown in FIG. 4 occurs, the wireless terminals 24-1 and 24-2 located in the cell of the integrated base station 14 downstream of the failure may be unstable in communication. There is.

  With reference to the flowchart of FIG. 5, when an optical fiber failure as shown in FIG. 4 occurs, a process for minimizing the influence of the optical fiber failure will be described. Note that FIG. 5 illustrates a case where a failure occurs in the optical fiber connecting the integrated base station 14 and the radio network controller 12-1, but the separate base station 16 and the radio network controller 12-1 are described. The same processing is performed when a failure occurs in the optical fiber connecting the two.

  The controller 14C of the integrated base station 14 periodically monitors whether the network status is normal (step S101). The controller 14C of the integrated base station 14 determines whether or not there is an abnormality in the network status (step S102). The control unit 14C of the integrated base station 14 continues to monitor the network status when an abnormality in the network status such as a failure in the optical fiber is not detected.

  When detecting an abnormality in the network status, the control unit 14C of the integrated base station 14 detects a synchronization signal transmitted by the neighboring base station and synchronizes with the synchronization signal (step S103).

  The control unit 14C of the integrated base station 14 transmits a signal indicating that the base station ID of the integrated base station 14 and a network abnormality have occurred to the synchronized peripheral base station (step S104).

  When the control unit of the peripheral base station receives the signal indicating that the base station ID and the network abnormality have occurred from the integrated base station 14, the control unit of the peripheral base station passes the radio network control device 12 based on the base station ID. The information of the integrated base station 14 is collected from the core network 10. The control unit of the peripheral base station, for example, the coordinates of the integrated base station 14, the transmission output when the integrated base station 14 transmits a control signal, the radio resource usage before the network abnormality detection of the integrated base station 14, The number of wireless terminals 24 around the integrated base station 14 and the cell status around the integrated base station 14 (coordinates of other peripheral base stations, transmission output when other peripheral base stations transmit control signals, etc. Information such as the amount of free radio resources of neighboring base stations) is collected (step S105).

  The control unit of the peripheral base station confirms the influence of the network abnormality on the wireless terminal 24 in the cell of the integrated base station 14 based on the information collected in step S105 (step S106). At this time, the control unit of the surrounding base station includes the coordinates of the integrated base station 14 included in the information collected from the core network 10, the radio resource usage before the network abnormality detection of the integrated base station 14, and the integrated type The coordinates of other neighboring base stations around the base station 14, the transmission output when the other neighboring base stations transmit control signals, the amount of free radio resources of other neighboring base stations, and other information The influence on the radio terminal 24 is confirmed using the coordinates of the station, the transmission output when the own station transmits a control signal, and the free radio resource amount of the own station. As a means for confirming the influence, the cell area of each neighboring base station is calculated from the coordinates of the own station, other neighboring base stations, and the transmission output when the control signal is transmitted, and the calculated plurality of neighboring base stations The degree of overlap between the cell area of the station and the cell area calculated from the coordinates of the integrated base station 14 and the transmission output when transmitting the control signal is calculated. Further, the cell area overlap between the integrated base station 14 and the plurality of peripheral base stations, the number of wireless terminals 24 around the integrated base station 14, and the free radio resource amounts of the own base station and other peripheral base stations From the comparison result of the total and the radio resource usage before the abnormality detection of the integrated base station 14, the local station and other peripheral base stations connect to the local station and other peripheral base stations by the wireless terminal 24 by handover. Check if communication is possible.

  The control unit of the peripheral base station determines whether to operate the integrated base station 14 as a wireless relay device or stop transmission from the collected information. For example, the overlap between the cell area of the integrated base station 14 confirmed in S106 and the cell areas of a plurality of neighboring base stations is less than a predetermined value, and many of the wireless terminals 24 in the cell of the integrated base station 14 communicate with each other. When it becomes unstable, the control unit of the neighboring base station determines to operate the integrated base station 14 as a wireless relay device. In addition, for example, the degree of overlap between the cell area of the integrated base station 14 confirmed in S106 and the cell areas of a plurality of neighboring base stations exceeds a predetermined value, and further, the radio resource before the abnormality detection of the integrated base station 14 is performed. The total amount of free radio resources of the own station and other neighboring base stations is larger than the amount used, and the radio terminal 24 in the cell of the integrated base station 14 can communicate with another base station by handover. In that case, the control unit of the neighboring base station determines to stop transmission of the integrated base station 14 (step S107).

  If it is determined in step S107 that the integrated base station 14 operates as a wireless relay device, the control unit of the neighboring base station transmits an instruction to that effect to the integrated base station 14 (step S108). If the control unit of the neighboring base station determines in step S107 that the integrated base station 14 does not operate as a wireless relay device, it transmits a transmission stop instruction to the integrated base station 14 (step S109).

  The control unit 14C of the integrated base station 14 periodically monitors the network status even after switching to the operation as the wireless relay device in accordance with the instruction in step S108 (step S110). The control unit 14C of the integrated base station 14 determines whether or not the network has been restored (step S111). The control unit 14C of the integrated base station 14 continues to monitor the network status when the network is not restored.

  When it is determined that the network has been restored, the control unit 14C of the integrated base station 14 switches to the normal mode and starts operation as a base station again (step S112).

  The control unit 14C of the integrated base station 14 periodically monitors the network status even after the transmission is stopped according to the instruction in step S109 (step S113). The control unit 14C of the integrated base station 14 determines whether or not the network has been restored (step S114). The control unit 14C of the integrated base station 14 continues to monitor the network status when the network is not restored.

  When it is determined that the network is restored, the control unit 14C of the integrated base station 14 cancels the transmission stop and starts the operation as the base station again (step S115).

  Thus, according to the present embodiment, even when an optical fiber failure as shown in FIG. 4 occurs, the influence can be minimized.

(Second Embodiment)
FIG. 6 is a diagram illustrating a state where a failure such as a physical disconnection occurs in the optical fiber connecting the baseband unit 18 and the wireless unit 20-1 in the wireless communication system illustrated in FIG.

  When a failure of the optical fiber as shown in FIG. 6 occurs, there is a possibility that the wireless terminals 24-3 to 24-5 located downstream of the failure occurrence may become unstable.

  With reference to the flowchart of FIG. 7, when an optical fiber failure as shown in FIG. 6 occurs, a process for minimizing the influence of the optical fiber failure will be described.

  The control unit 22B of the wireless relay device 22 periodically monitors whether the network status is normal (step S201). The control unit 22B of the wireless relay device 22 determines whether there is an abnormality in the network status (step S202). The control unit 22B of the wireless relay device 22 continues to monitor the network status when an abnormality in the network status such as a failure in the optical fiber is not detected.

  When detecting an abnormality in the network status, the control unit 22B of the wireless relay device 22 detects the synchronization signal transmitted by the neighboring base station and synchronizes with the synchronization signal (step S203).

  The control unit 22B of the wireless relay device 22 transmits a signal indicating that a base station ID of the wireless relay device 22 and a network abnormality have occurred to the synchronized neighboring base stations (step S204).

  When the control unit of the neighboring base station receives a signal indicating that the base station ID and the network abnormality have occurred from the wireless relay device 22, based on the base station ID, the control unit via the wireless network control device 12 Information on the wireless relay device 22 is collected from the core network 10. The control unit of the peripheral base station, for example, the coordinates of the radio relay device 22, the transmission output when the radio relay device 22 transmits a control signal, the radio resource usage before the network abnormality detection of the radio relay device 22, the radio relay device The number of wireless terminals 24 around 22 and the cell status around the wireless relay device 22 (coordinates of other peripheral base stations, transmission output when other peripheral base stations transmit control signals, Information such as the amount of available radio resources is collected (step S205).

  Based on the information collected in step S205, the control unit of the neighboring base station confirms the influence of the network abnormality on the wireless terminal 24 in the cell of the wireless relay device 22 (step S206). At this time, the control unit of the neighboring base station includes the coordinates of the wireless relay device 22 included in the information collected from the core network 10, the wireless resource usage before the network abnormality detection of the wireless relay device 22, and the wireless relay device 22 Coordinates of other neighboring base stations, transmission output when the other neighboring base stations transmit control signals, radio resource usage of other neighboring base stations, and other information Then, the influence on the wireless terminal 24 is confirmed using the transmission output when the local station transmits the control signal and the radio resource usage of the local station. As a means for confirming the influence, the cell area of each neighboring base station is calculated from the coordinates of the own station, other neighboring base stations, and the transmission output when the control signal is transmitted, and the calculated plurality of neighboring base stations The degree of overlap between the cell area of the station and the cell area calculated from the coordinates of the wireless relay device 22 and the transmission output when transmitting the control signal is confirmed. Also, the cell area overlap between the radio relay apparatus 22 and the plurality of neighboring base stations, the number of radio terminals 24 around the radio relay apparatus 22, and the total amount of free radio resources of the own station and other neighboring base stations From the comparison result with the radio resource usage before the abnormality detection of the radio relay device 22, the local station and other neighboring base stations can communicate by connecting the radio terminal 24 to the own station and other neighboring base stations by handover. Make sure.

  The control unit of the neighboring base station determines whether to operate the radio relay apparatus 22 as a pico cell or stop transmission from the collected information. For example, the overlap between the cell area of the wireless relay device 22 confirmed in S206 and the cell area of a plurality of neighboring base stations is less than a predetermined value, and many of the wireless terminals 24 in the cell of the wireless relay device 22 are unstable in communication. In such a case, the control unit of the neighboring base station determines to operate the radio relay apparatus 22 as a pico cell. In addition, for example, the degree of overlap between the cell area of the wireless relay device 22 confirmed in S206 and the cell areas of a plurality of neighboring base stations exceeds a predetermined value, and further, the radio resource usage before the abnormality detection of the wireless relay device 22 If the total amount of free radio resources of the local station and other neighboring base stations is larger than that, and the wireless terminal 24 in the cell of the wireless relay device 22 can communicate with another base station by handover, The control unit of the neighboring base station determines to stop transmission of the radio relay device 22 (step S207).

  If it is determined in step S207 that the wireless relay device 22 is to operate as a pico cell, the control unit of the neighboring base station transmits an instruction to that effect to the wireless relay device 22 (step S208). If the control unit of the neighboring base station determines in step S207 that the radio relay device 22 is not operated as a pico cell, the control unit transmits a transmission stop instruction to the radio relay device 22 (step S209).

  The control unit 22B of the wireless relay device 22 switches to the operation as a pico cell according to the instruction in step S208. The control unit 22B of the wireless relay device 22 switches the connection of the own control unit 22B from the base station side transmitting / receiving unit 22A to the IF unit 22E when switching to the operation as a pico cell. And the control part 22B of the radio relay apparatus 22 monitors the state of a network regularly, after switching to the operation | movement as a pico cell (step S210). The control unit 22B of the wireless relay device 22 determines whether or not the network has been restored (step S211). When the network is not restored, the control unit 22B of the wireless relay device 22 continues to monitor the network status.

  When it is determined that the network has been restored, the control unit 22B of the wireless relay device 22 switches to the normal mode, starts operation as the wireless relay device 22, and transmits a wireless signal between the wireless unit 20-1 and the wireless terminal 24. Is relayed (step S212).

  The control unit 22B of the wireless relay device 22 periodically monitors the network status even after stopping the transmission in response to the instruction in step S209 (step S213). The control unit 22B of the wireless relay device 22 determines whether or not the network has been restored (step S214). When the network is not restored, the control unit 22B of the wireless relay device 22 continues to monitor the network status.

  When it is determined that the network has been restored, the control unit of the wireless relay device 22 cancels the transmission stop and relays transmission / reception of the wireless signal between the wireless unit 20-1 and the wireless terminal 24 (step S215).

  Thus, according to the present embodiment, even when an optical fiber failure as shown in FIG. 6 occurs, the influence can be minimized.

  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.

DESCRIPTION OF SYMBOLS 10 Core network 12 Wireless network control apparatus 14 Integrated base station 14A IF part 14B Radio | wireless part 14C Control part 14D Memory | storage part 16 Separation-type base station 16A IF part 16B Control part 16C Memory | storage part 18 Baseband unit 20 Wireless unit 22 Wireless relay apparatus 22A Base station side transmission / reception unit 22B Control unit 22C Storage unit 22D Terminal side transmission / reception unit 22E IF unit 24 Wireless terminal

Claims (8)

In a communication system comprising a base station having an operation mode that operates as a radio relay device, and a peripheral base station installed around the base station,
When the base station detects a network abnormality, it transmits the detection result to the neighboring base stations,
When the neighboring base station receives the detection result from the base station, the neighboring base station switches the base station to an operation mode as a radio relay device according to the influence of the network abnormality on the radio terminal in the cell of the base station. Or whether to stop the transmission of the base station,
The neighboring base station transmits, based on the determination result, an instruction to switch the base station to an operation mode as a radio relay device or an instruction to stop transmission of the base station to the base station. Communication system.   The communication system according to claim 1, wherein the neighboring base station collects information on the base station from a core network, and calculates an influence of the network abnormality on the wireless terminal in the cell of the base station. A communication system.   3. The communication system according to claim 1, wherein the base station switches to a normal mode and starts an operation as a base station when detecting the restoration of the network. In a communication system comprising a radio relay device having an operation mode operating as a base station, and a peripheral base station installed around the radio relay device,
When the wireless relay device detects a network abnormality, it transmits the detection result to a neighboring base station,
When the neighboring base station receives the detection result from the radio relay apparatus, an operation mode in which the radio relay apparatus is used as a base station according to the influence of the network abnormality on the radio terminal in the cell of the radio relay apparatus To determine whether or not to stop transmission of the wireless relay device,
The neighboring base station transmits, based on the determination result, an instruction to switch the radio relay apparatus to an operation mode as a base station or an instruction to stop transmission of the radio relay apparatus to the radio relay apparatus. A featured communication system.   5. The communication system according to claim 4, wherein the neighboring base station collects information about the radio relay device from a core network, and an influence of the network abnormality on the radio terminal in a cell of the radio relay device. Calculating a communication system.   6. The communication system according to claim 4, wherein the wireless relay device switches to a normal mode and starts an operation as a wireless relay device when detecting the restoration of the network. A communication method in a communication system comprising a base station having an operation mode that operates as a radio relay device, and a peripheral base station installed around the base station,
When the base station detects a network abnormality, transmitting the detection result to a neighboring base station;
When the neighboring base station receives the detection result from the base station, the base station is switched to an operation mode as a radio relay apparatus according to the influence of the network abnormality on the radio terminal in the cell of the base station. Or determining whether to stop transmission of the base station;
The neighboring base station transmitting to the base station an instruction to switch the base station to an operation mode as a radio relay device or an instruction to stop transmission of the base station based on the determination result A communication method characterized by the above. A communication method in a communication system comprising a radio relay device having an operation mode operating as a base station, and a peripheral base station installed around the radio relay device,
When the wireless relay device detects a network abnormality, transmitting the detection result to a neighboring base station;
When the neighboring base station receives the detection result from the wireless relay device, the wireless relay device is operated as a base station according to the influence of the network abnormality on the wireless terminal in the cell of the wireless relay device. Determining whether to switch to or to stop transmission of the wireless relay device;
The neighboring base station, based on the determination result, transmitting an instruction to switch the radio relay apparatus to an operation mode as a base station or an instruction to stop transmission of the radio relay apparatus to the radio relay apparatus; A communication method comprising:

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