JP5594169B2 - Mobile communication system, transmission path control server, and communication method - Google Patents

Description

  The present invention relates to a communication technology of a mobile communication system.

  Currently, there are information transmission systems such as a safety information providing system for victims during natural disasters (see Patent Document 1 below) and a system for collecting a plurality of weather information (see Patent Document 2 below). In such an information transmission system, information is transmitted via a public communication network such as a fixed telephone line network and a mobile phone communication network.

  However, in an information transmission system that performs information transmission using a public communication network, if an abnormality occurs in the public communication network such as a failure of a radio base station or a disconnection of a communication line, information transmission cannot be performed normally. There was a problem. An abnormality in the public network occurs, for example, when a disaster occurs.

  In response to such a problem, Patent Document 3 below proposes a system that secures a communication transmission path in the event of a disaster by performing wireless communication directly between wireless communication devices installed in public facilities. ing. According to this system, since information can be transmitted without going through the public communication network, information can be transmitted even when the public network is damaged. Moreover, in the following Patent Document 4, a simple mobile network is configured by a plurality of portable wireless access points, and the existing mobile communication infrastructure is connected by connecting the simple mobile network to another network via a satellite mobile phone. There has been proposed a system that enables calls between IP mobile phones even in a disaster area that is not functioning. Patent Document 5 below proposes a satellite communication system in which a center station and a plurality of portable earth stations communicate with each other via a communication satellite in order to cope with a case where a public telephone line network is damaged in a disaster. Has been.

JP 2002-342859 A JP 2005-100130 A JP 2010-81005 A JP 2008-263282 A Japanese Patent Application Laid-Open No. 08-316897 JP-A-11-285047

  The conventional method as described above uses a new communication network (for example, a simple mobile network) different from the existing public network to transmit information at the time of abnormality through a transmission path not via the existing public network. Make it possible. In order to realize this method, it is necessary to newly provide a communication network for backup in the event of an abnormality, which is expensive. Even if a disaster occurs, the public network is not completely unusable because it is unlikely that all functions of the public network will stop.

  In view of the above-described problems, an object of the present invention is to provide a mobile communication system that can continue to provide a communication service even when an abnormality occurs with a simple configuration.

  Each aspect of the present invention employs the following configurations in order to solve the above-described problems.

  A first aspect includes a plurality of base stations that can be wirelessly connected to at least one other base station, and a base station that is individually connected to each of the plurality of base stations and connects the plurality of base stations to a communication switching center The present invention relates to a mobile communication system including a control device and a transmission path control server capable of communicating with the plurality of base stations via satellite communication. In the first aspect, the transmission path control server includes, from each base station, operation information collection means for collecting base station information including operation status information of each base station using satellite communication, and radio for each base station. Based on the base station information collected by the operation information collecting means and the setting information obtaining means for obtaining the setting information related to other base stations that can be connected, the base station control device is individually selected from the plurality of base stations. Realized by wireless connection between base stations based on setting information acquired by the setting information acquisition means by identifying isolated base stations that cannot communicate and a base station controller that can individually communicate with the base station controller A transmission path determining means for determining an emergency transmission path from the isolated base station to the live base station, and transmitting emergency transmission path information for forming the emergency transmission path to a plurality of base stations using satellite communication; Equipped with a. In addition, each of the plurality of base stations transmits an operation status detection unit that detects an operation status of the base station, and base station information including information on the operation status detected by the operation status detection unit using satellite communication. Operation status transmission means for transmitting to the control server, and inter-base station transmission means for establishing a wireless connection with at least one other base station indicated by the emergency transmission path information received from the transmission path control server via satellite communication And comprising. In addition, at least one isolated base station of the plurality of base stations wirelessly transmits traffic related to the mobile terminal in the wireless area of the own base station to the live base station using the wireless connection established by the inter-base station transmission means. Base station processing means.

  A 2nd aspect is related with the transmission-line control server which can communicate via each of several base stations which can be wirelessly connected with at least 1 other base station via satellite communication. The transmission path control server according to the second aspect includes an operation information collection unit that collects base station information including operation status information of each base station from each base station using satellite communication, and wireless connection related to each base station Based on the base station information collected by the setting information acquisition means for acquiring other possible base station setting information and the operation information collection means, each base station is selected as a communication switching center from a plurality of base stations. Based on the setting information acquired by the setting information acquisition unit, the isolated base station that cannot be individually communicated with the base station control device to be connected and the live base station that can be individually communicated with the base station control device are identified. Determine the emergency transmission path from the isolated base station to the live base station, which is realized by wireless connection between the base stations, and use satellite communication for emergency transmission path information to form the emergency transmission path And a transmission path determining means for transmitting to said plurality of base stations.

  A third aspect relates to a communication method executed by a computer capable of communicating via satellite communication with each of a plurality of base stations that can be wirelessly connected to at least one other base station. In the communication method according to the third aspect, the computer collects base station information including operation status information of each base station from each base station using satellite communication, and wireless connection is possible for each base station. A step of acquiring setting information relating to other base stations, and a base station controller for connecting each base station to a communication switching center from among a plurality of base stations based on the collected base station information The step of identifying an isolated base station that cannot communicate with the base station and a live base station that can individually communicate with the base station controller, and based on the acquired setting information, realized by wireless connection between the base stations, Determining an emergency transmission path from an isolated base station to a live base station, and transmitting emergency transmission path information for forming the emergency transmission path to a plurality of base stations using satellite communication. And, to run.

  As another aspect of the present invention, a program that causes a computer to realize the configuration of the second aspect described above may be used, or a computer-readable storage medium that records such a program may be used.

  According to each aspect described above, it is possible to provide a mobile communication system that can continue to provide communication services even when an abnormality occurs with a simple configuration.

The figure which shows notionally the structural example of a mobile communication system. The block diagram which shows notionally the structural example of a transmission-line control server. The block diagram which shows notionally the structural example of the base station in 1st Embodiment. The sequence diagram which shows the operation example of the transmission path control server in 1st Embodiment, and a base station. The flowchart which shows the example of the determination process of an emergency transmission path. The block diagram which shows notionally the structural example of the transmission path control server in 2nd Embodiment. The block diagram which shows notionally the structural example of the base station in 2nd Embodiment. The sequence diagram which shows the operation example of the transmission path control server in 2nd Embodiment, and a base station.

  Hereinafter, each embodiment of the present invention will be described. In addition, each embodiment given below is an illustration, respectively, and this invention is not limited to the structure of each following embodiment.

[First Embodiment]
〔System configuration〕
FIG. 1 is a diagram conceptually illustrating a configuration example of a mobile communication system. The mobile communication system 1 in the present embodiment includes a plurality of base stations 10, a transmission path control server 20, a base station control device 30, and the like.

  The plurality of base stations 10 are shown as 10 (# 1), 10 (# 2), 10 (# 3), and 10 (# 4) in FIG. Hereinafter, these will be referred to as the base station 10 unless it is particularly necessary to distinguish them. The base station 10 is also called a BS (Base Station), a CS (Cell Station), a BTS (Base Transceiver Station), a Node B, or the like. The base station 10 performs wireless communication with the user mobile terminal 5 existing in the wireless communication area, and connects the user mobile terminal 5 to the mobile communication system 1. The base station 10 is configured to be wirelessly connectable with at least one other base station.

  The user mobile terminal 5 is a general user terminal such as a mobile phone or a mobile PC (Personal Computer). Hereinafter, the user mobile terminal 5 is referred to as a user terminal 5. The user terminal 5 receives a predetermined communication (call) service provided by the mobile communication system 1 by establishing a radio link with any one of the base stations 10. The present embodiment does not limit the configuration of the user mobile terminal 5 and the service provided from the mobile communication system 1.

  The base station controller 30 is individually connected to each of the plurality of base stations 10, and each of the plurality of base stations 10 is connected to a communication switching station (MPE (Multimedia Processing Equipment) 3 or MSC (Mobile Switching Center) shown in FIG. 4 etc.). The base station controller 30 is called a BSC (Base Station Controller), an RNC (Radio Network Controller), or the like. Hereinafter, the base station control device 30 may be referred to as a BSC 30 as shown in FIG.

  The BSC 30 receives traffic related to the user terminal 5 from the base station 10 and relays the traffic to the communication switching center that is the target of the traffic. For example, if the traffic is a conventional telephone call signal, the BSC 30 sends the call signal to the MSC 4 which is a switching center of a PSTN (Public Switched Telephone Networks) 8. On the other hand, if the traffic is a communication call signal such as an IP (Internet Protocol) telephone or IP communication, the BSC 30 sends the call signal to the MPE 3 which is an exchange station of the IP core network 7. Note that the processing content for the traffic sent from the base station 10 in the BSC 30 may be any known technique, and the present embodiment does not limit it.

  When the BSC 30 receives the traffic sent from the communication switching center, the BSC 30 sends the traffic to the base station 10 to which the user terminal 5 that is the destination of the traffic is wirelessly connected. The processing content for the traffic sent from the communication switching center in the BSC 30 at the normal time (normal time) may be any known technique, and the present embodiment does not limit it.

  When there is a base station 10 in a communication disabled state, the BSC 30 transmits the traffic to be sent to the base station 10 in the communication disabled state to the base station 10 (live with relay) corresponding to the instruction from the transmission path control server 20. To the base station). In addition, since this embodiment does not limit the processing of the communication switching center such as MPE3, MSC4, etc., the description thereof is omitted here.

  The transmission path control server 20 is communicably connected to the BSC 30 and the like via a network for managing the BSC 30 and the base station 10 (for example, the public network 9 shown in FIG. 1). Hereinafter, the transmission path control server 20 is also simply referred to as the control server 20. The control server 20 can wirelessly communicate with a plurality of base stations 10 by satellite communication via the communication satellite 2.

〔Device configuration〕
Hereinafter, each configuration example of the transmission path control server 20 and the base station 10 in the first embodiment will be described. FIG. 2 is a block diagram conceptually showing a configuration example of the transmission path control server 20.

  As shown in FIG. 2, the control server 20 includes a satellite communication unit 201, an operation information collection unit 202, a setting information acquisition unit 203, a disaster detection unit 204, a transmission path determination unit 207, and the like. As a hardware configuration, the control server 20 includes, for example, a CPU (Central Processing Unit), a memory (RAM (Random Access Memory), ROM (Read Only Memory), hard disk, etc.), an input / output interface, and the like.

  For example, the control server 20 realizes each processing unit by executing a program stored in the memory by the CPU. The satellite communication unit 201 is a satellite communication device including a satellite antenna that transmits and receives radio waves exchanged with the communication satellite 2, a transceiver that modulates and demodulates the radio waves, and between the satellite communication device and other processing units. It may be configured from a processing unit or the like that functions as an interface. In addition, this embodiment does not restrict | limit the implementation method of said each process part.

  The satellite communication unit 201 performs satellite communication via the communication satellite 2 with a plurality of base stations 10 according to instructions from other processing units. In addition, since this embodiment does not limit the method of satellite communication via the communication satellite 2, the detailed description thereof is omitted here.

  The operation information collection unit 202 collects base station information including operation status information of each base station from each base station 10 using the satellite communication. The base station information may be transmitted from each base station 10 in a predetermined cycle or at an arbitrary timing, or may be transmitted from each base station 10 in response to a request from the transmission path control server 20. For example, the operation information collection unit 202 transmits a transmission request for base station information when the disaster detection unit 204 detects the occurrence of a disaster. Details of the operation status information will be described later.

  The disaster detection unit 204 acquires disaster occurrence information (disaster occurrence signal) and notifies the operation information collection unit 202 of it. The disaster occurrence information is acquired from, for example, a server device of a public institution such as the Ministry of Land, Infrastructure, Transport and Tourism or the Japan Meteorological Agency connected via a network such as the public network 9. The disaster occurrence information may be input from an operator via a user interface (not shown), or may be uniquely detected by a detector included in the transmission path control server 20.

  The setting information acquisition unit 203 acquires setting information regarding other base stations that can be wirelessly connected with respect to each base station 10. For example, when the base station 10 (# 2) can be wirelessly connected to the base stations 10 (# 1) and 10 (# 3), the setting information of the base station 10 (# 2) includes the base station 10 (# 2). Each base station identification information that can specify # 1) and 10 (# 3) is set together with its priority. The setting information may be stored in advance in the memory of the control server 20, or may be included in the base station information collected by the operation information collection unit 202. The acquired setting information is sent to the transmission path determination unit 207.

  Based on the operation status information of the base station information collected by the operation information collection unit 202, the transmission path determination unit 207 includes an isolated base station that cannot communicate with the BSC 30 and the BSC 30 from the plurality of base stations 10. Identify live base stations that can communicate. Further, the transmission path determination unit 207 is an emergency transmission path from the isolated base station to the live base station realized by wireless connection between the base stations 10 based on the setting information acquired by the setting information acquisition unit 203. To decide. The transmission path determination unit 207 generates emergency transmission path information for forming the emergency transmission path, and instructs the satellite communication unit 201 to transmit the emergency transmission path information.

  The transmission path determination unit 207 determines an emergency transmission path as follows. First, the transmission path determination unit 207 includes, in the setting information, the first isolated base station that is not included in the setting information of the other live base stations among the plurality of live base stations that include the isolated base station in the setting information. A station is selected, and a connection between the selected live base station and the first isolated base station is determined. Next, the transmission path determination unit 207 uses other live base stations and the first isolated base station as candidates, except for the live base station determined to be connected to the first isolated base station, and has not yet been determined. A base station to be connected to an isolated base station is determined. A specific method for determining an emergency transmission path will be described in the section of an operation example.

  The emergency transmission path information includes information for forming at least one emergency transmission path. The emergency transmission path is a path formed by wireless connection between base stations, and is a path for transmitting traffic related to the user terminal 5 in the radio area of the isolated base station. Therefore, the information for forming the emergency transmission path includes at least one pair of base station identification information indicating a pair of base stations to be wirelessly connected.

  Therefore, the live base station included in the emergency transmission path is required to relay traffic sent from other isolated base stations to the BSC 30. The required live base station is also referred to as a live base station with relay. On the other hand, the isolated base station included in the emergency transmission path requests that the traffic related to the user terminal 5 in its own radio area be transmitted not to the BSC 30 but to the live base station included in the emergency transmission path. Is done.

  Further, when a plurality of isolated base stations are included in the emergency transmission path, at least one isolated base station among the plurality of isolated base stations relays traffic sent from other isolated base stations to the live base station. And traffic related to the user terminal 5 in its own wireless area is required to be transmitted not to the BSC 30 but to the live base station included in the emergency transmission path. Such an isolated base station is also referred to as an isolated base station with relay.

  FIG. 3 is a block diagram conceptually showing a configuration example of the base station 10 in the first embodiment. As shown in FIG. 3, the base station 10 includes a satellite communication unit 101, an operation status detection unit 102, an operation status transmission unit 103, an inter-base station transmission unit 106, a base station processing unit 107, and the like. Each of these processing units constituting the base station 10 is realized by hardware elements, software elements, or a combination thereof.

  A hardware component is a hardware circuit such as a field programmable gate array (FPGA), an application specific integrated circuit (ASIC), a gate array, a combination of logic gates, a signal processing circuit, an analog circuit, etc. is there. Software components are tasks, processes, and the like realized by executing data (programs) on one or more memories by one or more processors (for example, CPU, DSP (Digital Signal Processor), etc.) A software component (fragment) like a function. The present embodiment does not limit the method of realizing each processing unit.

  The satellite communication unit 101 is a satellite communication device including a satellite antenna that transmits and receives radio waves exchanged with the communication satellite 2, a transceiver that modulates and demodulates the radio waves, and between this satellite communication device and other processing units. It may be configured from a processing unit or the like that functions as an interface. The satellite communication unit 101 performs satellite communication with the control server 20 via the communication satellite 2 according to an instruction from another processing unit.

  The operating status detection unit 102 detects the operating status of itself (base station 10), and sends a signal indicating the detected operating status to the operating status transmission unit 103. In addition, since a well-known technique should just be utilized for the specific detection method of an operating condition, description is abbreviate | omitted here.

  The operating status transmission unit 103 generates operating status information indicating its own operating status based on the signal from the operating status detection unit 102, and transmits base station information including the operating status information to the satellite communication unit 101. To instruct. The operation status information includes base station identification information regarding the base station 10 of itself and data indicating the operation status. The data indicating the operating status includes information that can specify a live base station, an isolated base station, an abnormal base station, and the like as information specifying the current operating status of the base station.

  The operating status transmission unit 103 specifies its own operating status based on the signal from the operating status detection unit 102. For example, when an abnormality in a link between the base station 10 and the BSC 30 (hereinafter also referred to as a connection line) is detected, the operation status transmission unit 103 determines its own base station as an isolated base station. When an abnormality in the inter-base station transmission unit 106 that is a processing unit for wireless connection with another base station 10 or an abnormality in the connection line is detected, the operation status transmission unit 103 Determine the station as an abnormal base station. An abnormal base station means a base station that cannot be remedied by forming an emergency transmission path. Note that the data indicating the operating status may include detailed abnormality data including an abnormality location and abnormality content.

  The operation status detection unit 102 and the operation status transmission unit 103 may operate at arbitrary timing or periodically, and a transmission request for base station information transmitted from the control server 20 via satellite communication is received by the satellite communication unit 101. You may make it operate | move in response to having received.

  The inter-base station transmission unit 106 receives at least one other base station as necessary to realize an emergency transmission path included in the emergency transmission path information received from the satellite communication unit 101 from the control server 20. And establish a wireless connection. Other base stations that are targets for establishing a wireless connection use other base stations included in the setting information for the base station 10 as candidates.

  The inter-base station transmission unit 106 includes, for example, an inter-base station transmission device including a transmission antenna, a reception antenna, a radio processing unit, and the like, a processing unit that functions as an interface between the inter-base station transmission device and another processing unit, etc. Consists of In this case, the transmitting antenna transmits a signal having directivity toward the other base station set in the setting information, and the receiving antenna receives a signal from the other base station set in the setting information. To do.

  The plurality of base stations 10 are respectively arranged at predetermined positions according to a communication area or the like for wireless communication with the user terminal 5. That is, since the base stations 10 are not arranged for the purpose of wireless connection with each other, even if the transmission / reception antenna of the inter-base station transmission unit 106 is used, geographical conditions (distance, etc.), etc. Therefore, there is a limit to the range where wireless communication is possible. Therefore, in the present embodiment, information related to other base stations that can be wirelessly connected to each base station 10 is set in the setting information in advance. In this setting information, priority is added to each of the other base stations. The priority order is set based on radio conditions of each base station, load distribution of transmission capacity, and the like. For example, among the other base stations that can be wirelessly connected, a higher priority is given in order from a base station with good radio conditions.

  Based on the emergency transmission path information from the control server 20 and the operation status data of the own base station generated by the operation status transmission unit 103 as described above, the base station processing unit 107 determines the request type of the own base station. It is specified as any one of a base station, an isolated base station, a live base station with relay, an isolated base station with relay, an abnormal base station, and the like.

  For example, when the operation status of the base station is a live base station, and the base station identification information of the base station is included in the emergency transmission path, the base station processing unit 107 displays the base station live with relay. Decide on a base station. When the operation status of the base station is a live base station and the base station identification information of the base station is not included in the emergency transmission path, the base station processing unit 107 sets the base station to a normal live station. Decide on a base station.

  When the operation status of the own base station is an isolated base station and there are a plurality of other base station identification information paired with the base station identification information of the own base station in the emergency transmission path, the base station processing unit 107 Determines its own base station as an isolated base station with relay. In addition, when the operation status of the base station is an isolated base station and there is one other base station identification information set in a pair with the base station identification information of the base station in the emergency transmission path, the base station The processing unit 107 determines its own base station as a normal isolated base station. If the operation status of the own base station is an abnormal base station, the base station processing unit 107 determines the own base station as an abnormal base station.

  The base station processing unit 107 switches processing as follows according to the identified request type of the own base station.

  When the base station is a normal live base station, the base station processing unit 107 executes known processing related to the base station (hereinafter referred to as known base station processing). The known base station processing is to receive a radio signal transmitted from the user terminal 5 existing in its own radio area, generate traffic corresponding to the radio signal, and place this traffic on the connection line. This includes processing for transmitting to the BSC 30, receiving traffic from the BSC 30, generating a radio signal corresponding to this traffic, and transmitting this radio signal to the user terminal 5 existing in its own radio area. Here, the traffic includes user plane signals such as voice and data, and control plane signals.

  When the base station is a live base station with relay, the base station processing unit 107, in addition to the known base station processing, transmits another base station via a wireless connection established by the inter-base station transmission unit 106. Processing for transmitting traffic sent from a station to the BSC 30 on the connection line and transferring traffic for another base station sent from the BSC 30 to another base station via the wireless connection Execute. Accordingly, the base station processing unit 107 of the live base station with relay places the traffic related to the user terminal 5 existing in its own radio area and the traffic from other base stations on the connection line.

  When the base station is a normal isolated base station, the base station processing unit 107 executes processing in which the known base station processing is changed as follows. Specifically, the base station processing unit 107 establishes a wireless connection without transmitting traffic corresponding to the wireless signal transmitted from the user terminal 5 existing in its own wireless area to the BSC 30 on the connection line. To other base stations. In addition, the base station processing unit 107 receives traffic transferred from other base stations via a wireless connection, and transmits a radio signal corresponding to the traffic to the user terminal 5 existing in its own radio area. .

  When the base station is an isolated base station with relay, the base station processing unit 107 performs the following processing in addition to the above processing when the base station is an isolated base station. That is, the base station processing unit 107 transmits traffic transmitted from the first base station via the first wireless connection to the second base station via the second wireless connection, and the second The traffic for the first base station sent from the base station via the second wireless connection is transmitted to the first base station via the first wireless connection.

[Operation example]
FIG. 4 is a sequence diagram illustrating an operation example of the transmission path control server 20 and the base station 10 in the first embodiment.

  In the control server 20, when the disaster detection unit 204 acquires disaster occurrence information (S41), the operation information collection unit 202 sends a base station information transmission request via the communication satellite 2 in order to collect the base station information. It transmits to each base station 10 using satellite communication (S42). The request may include disaster occurrence information.

  In each base station 10, when a transmission request for base station information is received by the satellite communication, the operation status detection unit 102 detects the operation status of the base station 10 (S43). The operating status transmitting unit 103 generates operating status information based on the detection signal from the operating status detecting unit 102 (S44). The operating status information includes base station identification information and operating status data regarding the own base station 10. According to the operation status data, it can be specified that each base station 10 is a live base station, an isolated base station, or an abnormal base station. Such operating status information is held by the base station 10 itself, and is transmitted as base station information to the control server 20 by satellite communication via the satellite communication unit 101 (S45).

  In the control server 20, the operation information collection unit 202 acquires base station information from each base station 10 via the satellite communication unit 201 (S46). The collected base station information is held by the control server 20 so that it can be referred to the transmission path determination unit 207. At this time, the setting information acquisition unit 203 acquires setting information regarding each base station 10. This setting information stores base station identification information of other base stations that can be wirelessly connected to each base station 10.

  The transmission path determination unit 207 determines an emergency transmission path based on the operation status information of the base station information collected by the operation information collection unit 202 and the setting information acquired by the setting information acquisition unit 203 (S47). . The transmission path determination unit 207 generates emergency transmission path information for forming the determined emergency transmission path (S48), and transmits this emergency transmission path information to each base station 10 by satellite communication via the satellite communication unit 201. Transmit (S49). The emergency transmission path information stores at least one pair of base station identification information as information for forming at least one emergency transmission path.

  In each base station 10, the inter-base station transmission unit 106 establishes a wireless connection with at least one other base station as necessary based on the emergency transmission path information received via the satellite communication unit 101. (S50). Specifically, when the emergency transmission path information includes an emergency transmission path including the base station identification information of the own base station, the inter-base station transmission unit 106 transmits the other The base station 10 is specified, and a wireless connection is established with the other specified base station 10.

  Subsequently, the base station processing unit 107 determines the request type of the base station 10 based on the emergency transmission path information from the control server 20 and the operation status data (S44) of the base station 10 based on the operation status data (S44). It is specified as any one of a live base station, an isolated base station, a live base station with relay, an isolated base station with relay, an abnormal base station, and the like (S51). Thereafter, the base station processing unit 107 performs traffic transmission / reception processing according to the specified request type of the own base station 10.

  At this time, when the base station processing unit 107 confirms that communication between base stations is normally performed by the wireless connection (S52), the base station processing unit 107 transmits the fact to the control server 20 using satellite communication (S53).

FIG. 5 is a flowchart illustrating an example of emergency transmission path determination processing.
The transmission path determination unit 207 classifies each base station 10 as an isolated base station or a live base station based on the operation status information of the base station information collected by the operation information collection unit 202 (S61).

  Based on such classification information and the setting information of each base station 10 acquired by the setting information acquisition unit 203, the transmission path determination unit 207 extracts a base station having an isolated base station in the setting information as a comparison target. (S62). Thereby, all base stations in which at least one of the other base stations that can be wirelessly connected is an isolated base station are extracted.

  The transmission path determination unit 207 determines whether or not there is a base station extracted as a comparison target, in other words, whether or not there is a base station having an isolated base station in the setting information among the comparison target base stations. Is determined (S63). If there is no base station having an isolated base station in the setting information among the base stations to be compared (S63; NO), the process ends.

  If there is a base station having an isolated base station in the setting information among the base stations to be compared (S63; YES), the transmission path determination unit 207 further includes other base stations to be compared. It is determined whether or not there is a base station having an isolated base station not included in the setting information of the comparison target base station in the setting information (S64). In other words, it is determined whether or not there are a plurality of base stations whose setting information includes the same isolated base station among the base stations to be compared.

  When there is a base station having the isolated base station not included in the setting information of the other comparison target base station in the setting information (S64; YES), the transmission path determining unit 207 determines the relationship between the base station and the isolated base station. The connection between them is determined (S65). On the other hand, the transmission path determination unit 207 is the same as the other comparison target base station when there is no base station having the isolated base station not included in the setting information of the other comparison target base station in the setting information (S64; NO). Among the plurality of comparison target base stations having the isolated base station as setting information, the connection between the comparison target base station having the highest priority and the isolated base station is determined (S66).

  When the connection is determined as described above, the transmission path determination unit 207 excludes the determined comparison target base station from the comparison target, and adds the determined isolated base station to the comparison target as a live base station ( (S67) The processing after step (S63) is executed again.

[Operation and Effect in First Embodiment]
As described above, in the first embodiment, when the disaster occurrence information is acquired by the control server 20, the operation status information is collected from each base station 10 by the control server 20. Then, depending on the operation status of each base station 10 and information on other base stations that can be wirelessly connected to each base station 10, from the isolated base station to the live base station realized by the wireless connection between the base stations. An emergency transmission path is determined.

  The emergency transmission path information for forming this emergency transmission path is transmitted from the control server 20 to each base station 10 by satellite communication, and is determined by the control server 20 by establishing a wireless connection between the base stations 10. An emergency transmission path is realized. Thereby, the isolated base station that can no longer communicate with the BSC 30 due to a disaster or the like causes the traffic related to the user terminal 5 in the own radio area to be transmitted instead of the connection line between the own base station 10 and the BSC 30. It becomes possible to send / receive data to / from the BSC 30 using the emergency transmission path.

  Therefore, according to the first embodiment, by implementing an emergency transmission path using wireless connection between base stations, an isolated base station 10 (isolated base station) that cannot communicate with the BSC 30 due to a disaster or the like can be obtained. Even if it occurs, it is possible to continue providing the communication service to the user terminal 5 existing in the wireless area of the isolated base station. Since the emergency transmission path is realized by the inter-base station transmission unit 106 of each base station 10, according to the first embodiment, a simple communication network formed by using a new node is not provided. With such a configuration, the effects as described above can be obtained.

  In addition, since communication between the control server 20 and each base station 10 uses satellite communication, the communication can be continued even when an abnormality occurs in the public network 9 or the like. Furthermore, since the emergency transmission path is determined based on the operation status information collected from each base station 10, even if there is an abnormal base station that cannot communicate with other nodes, It is possible to determine an optimum emergency transmission path except for such an abnormal base station.

  In the emergency transmission path determination method described above, the emergency transmission path is configured such that the live base station is wirelessly connected to any one isolated base station and the isolated base station is wirelessly connected to a maximum of two other base stations. To be determined. Therefore, according to the first embodiment, even when an emergency transmission path is used, it is possible to prevent a situation in which traffic is concentrated on one live base station, so that service provision can be continued stably. Can do.

[Second Embodiment]
Hereinafter, a mode in which the control server 20 controls the directions of the directivity main axes of the transmission antenna and the reception antenna included in the inter-base station transmission unit 106 of each base station 10 will be described as a second embodiment. Hereinafter, the mobile communication system 1 according to the second embodiment will be described focusing on the content different from the first embodiment. Note that the same contents as in the first embodiment are omitted as appropriate.

  FIG. 6 is a block diagram conceptually showing a configuration example of the transmission path control server 20 in the second embodiment. The control server 20 in the second embodiment further includes an antenna information generation unit 208 and a base station information database (DB) 209 in addition to the configuration of the first embodiment. These processing units are also realized by executing a program stored in the memory by the CPU.

  The base station information DB 209 stores antenna information of each base station 10. The antenna information includes position information (latitude, longitude, height, etc.) of the transmission antenna and the reception antenna that the inter-base station transmission unit 106 of each base station 10 has. Hereinafter, the transmission antenna and the reception antenna possessed by the inter-base station transmission unit 106 of each base station 10 may be referred to as the transmission antenna and the reception antenna of each base station 10.

  When the emergency transmission path is determined by the transmission path determination unit 207, the antenna information generation unit 208 relates to the pair of base stations 10 forming the emergency transmission path, and directs the transmission antenna and the reception antenna of the inter-base station transmission unit 106. The direction of the sex main axis is determined respectively. Thus, the direction of the directivity of the transmitting antenna of one base station 10 and the direction of the directivity of the receiving antenna of the other base station 10 are such that the pair of base stations 10 are wirelessly connected to each other with high sensitivity. Direction is determined. Specifically, the direction of the directivity main axis of the transmission antenna of one base station 10 is matched with the direction of the main directivity of the reception antenna of the other base station 10.

  In this determination, the antenna information generation unit 208 acquires the position information of the transmission antenna and the reception antenna related to the base station pair from the base station information DB 209 and uses this position information. The antenna information generation unit 208 generates antenna control information indicating the directions of the directional principal axes of the determined transmission antenna and reception antenna, holds the antenna control information by itself, and sends it to the satellite communication unit 201.

  The antenna information generation unit 208 corrects the direction of the antenna directivity axis indicated by the antenna control information determined and held as described above based on the reception sensitivity information collected by the operation information collection unit 202. . The antenna information generation unit 208 generates antenna control information indicating the direction of the corrected antenna directivity main axis, holds the antenna control information by itself, and sends it to the satellite communication unit 201.

  Thereby, the antenna control information is transmitted to each base station 10 by the satellite communication unit 201 via the communication satellite 2 together with the emergency transmission path information sent from the transmission path determination unit 207.

  The operation information collection unit 202 performs a process of collecting reception sensitivity information from each base station 10 using satellite communication in addition to the contents of the first embodiment. This reception impression information indicates the reception sensitivity at the reception antenna of each base station 10. As the reception sensitivity, a reception level, a signal-to-noise ratio (SNR), or the like is used. The reception sensitivity information is collected at a predetermined cycle or at an arbitrary timing after receiving notification of operation of emergency transmission path communication.

  FIG. 7 is a block diagram conceptually showing a configuration example of the base station 10 in the second embodiment. As shown in FIG. 7, in the base station 10 in the second embodiment, in addition to the configuration of the first embodiment, the inter-base station transmission unit 106 includes a movable unit 111, an antenna control unit 112, a reception sensitivity detection unit 113, and the like. Have These processing units are also realized by hardware elements, software elements, or a combination thereof.

  The movable unit 111 changes the directions of the directivity main axes of the transmission antenna and the reception antenna of the inter-base station transmission unit 106 according to the signal from the antenna control unit 112. For example, the movable unit 111 includes a movable shaft that supports each antenna and an electric actuator that supplies power to the movable shaft. In addition, this embodiment does not limit the specific implementation form of the movable part 111.

  The antenna control unit 112 changes the direction of the directivity main axes of the transmission antenna and the reception antenna to the movable unit 111 based on the antenna control information received together with the emergency transmission path information from the control server 20 via the satellite communication unit 101. Let Under the control of the antenna control unit 112, the direction of the directivity axis of the transmission antenna and the reception antenna of the inter-base station transmission unit 106 is directed to the direction indicated by the antenna control information.

  The reception sensitivity detection unit 113 detects the reception sensitivity of signals from other base stations at the reception antenna of the inter-base station transmission unit 106 at a predetermined cycle or at an arbitrary timing. Since a well-known technique should just be utilized about this detection method of receiving sensitivity, description is abbreviate | omitted here. The reception sensitivity detection unit 113 generates reception sensitivity information indicating the detected reception sensitivity, and transmits the reception sensitivity information to the control server 20 via the satellite communication unit 101 by satellite communication.

[Operation example]
FIG. 8 is a sequence diagram illustrating an operation example of the transmission path control server 20 and the base station 10 in the second embodiment. In FIG. 8, the same reference numerals as those in FIG. 4 are assigned to the same contents as those in the first embodiment. Hereinafter, the operation example of the second embodiment will be described focusing on the content different from the first embodiment.

  Also in the second embodiment, the processing from the processing (S41) to the processing (S48) is executed as in the first embodiment.

  In the control server 20, when the transmission path determination unit 207 generates emergency transmission path information (S48), the antenna information generation unit 208 relates to each pair of base stations 10 that form the emergency transmission path, and the inter-base station transmission unit 106 The directions of the main directivity axes of the transmitting antenna and the receiving antenna are determined. The antenna information generation unit 208 generates antenna control information indicating the directions of the directional principal axes of the determined transmission antenna and reception antenna for each base station 10 (S81). The generated antenna control information is transmitted to each base station 10 through the satellite communication unit 201 together with the emergency transmission path information (S82).

  In each base station 10, when the inter-base station transmission unit 106 receives the emergency transmission path and the antenna control information, the antenna control unit 112 transmits the transmission antenna and the reception antenna to the movable unit 111 based on the antenna control information. The direction of the directivity main axis is changed (S83). Thereby, the direction of the directivity main axis of the transmission antenna and the reception antenna of each base station 10 is directed to the direction in which the reception sensitivity of signals from other base stations 10 connected wirelessly increases. As a result, a wireless connection is established between the base stations indicated by the emergency transmission path information (S50), and the emergency transmission path is realized.

  Thereafter, similarly to the first embodiment, the process (S51) to the process (S53) are executed.

  After notifying the control server 20 of the operation of the emergency transmission line communication, in each base station 10, the reception sensitivity detection unit 113 receives signals from other base stations at the reception antenna of the inter-base station transmission unit 106 at an arbitrary timing. And receiving sensitivity information indicating the detected receiving sensitivity is generated (S84). The reception sensitivity detection unit 113 transmits the generated reception sensitivity information to the control server 20 via the satellite communication unit 101 (S85).

  In the control server 20, when the operation information collection unit 202 receives the reception sensitivity information transmitted from each base station 10 by satellite communication, the antenna information generation unit 208 increases the reception sensitivity based on the received reception sensitivity information. The direction of the antenna directivity main axis indicated by the already held antenna control information is corrected in the estimated direction. The antenna information generation unit 208 generates the antenna control information indicating the direction of the corrected antenna directivity principal axis for each base station 10 (S86). The antenna information generation unit 208 transmits the generated antenna control information to each base station 10 via the satellite communication unit 201 (S87).

  In each base station 10, the inter-base station transmission unit 106 receives this antenna control information, and the antenna control unit 112 transmits to the movable unit 111 the directivity main axes of the transmission antenna and the reception antenna based on this antenna control information. The direction is changed (S88).

[Operations and effects in the second embodiment]
As described above, in the second embodiment, an emergency transmission path is determined by the control server 20, and the directivity axis directions of the transmission antenna and the reception antenna for wireless connection between base stations that realize the emergency transmission path are determined. The directivity axis direction is adjusted to the determined direction by the movable unit 111 and the antenna control unit 112 of the base station 10. Further, while the emergency transmission path is realized and operated, each base station 10 monitors the reception sensitivity in the wireless connection, and the reception sensitivity is sent to the control server 20 so that the control server 20 sets the reception sensitivity. The corresponding directivity axis direction is adjusted accordingly.

Therefore, according to the second embodiment, the directivity axis directions of the transmission antenna and the reception antenna for the radio connection between the base stations are adjusted so as to have high reception sensitivity, so that the reception quality in the emergency transmission path is improved. Can do. As a result, according to the second embodiment, it is possible to continue providing the communication service in a high quality state even in the communication mode using the emergency transmission path when an abnormality occurs.
[Modification]
In each of the above-described embodiments, as illustrated in FIGS. 4 and 8, the example in which the emergency transmission path is determined and realized when the disaster occurrence information is acquired by the transmission path control server 20 has been described. These processes may be executed when an abnormality is detected as an operation status in the base station 10. In this case, instead of the process (S41) in the sequence of FIG. 4 and FIG. 8, the transmission path control server 20 may perform a process of receiving base station information from the base station 10 in which an abnormality has occurred. Thereafter, the process (S42) to the process (S45) may be executed for the other base station 10.

  In the plurality of flowcharts used in the above description, a plurality of steps (processes) are described in order, but the execution order of the process steps executed in the present embodiment is not limited to the description order. In the present embodiment, the order of the processing steps shown in the figure can be changed within a range that does not hinder the contents. Moreover, each above-mentioned embodiment and each modification can be combined in the range with which the content does not conflict.

DESCRIPTION OF SYMBOLS 1 Mobile communication system 2 Communication satellite 5 User mobile terminal (user terminal)
10 base station 20 transmission path control server (control server)
30 Base Station Controller (BSC)
101, 201 Satellite communication unit 102 Operation status detection unit 103 Operation status transmission unit 106 Inter-base station transmission unit 107 Base station processing unit 111 Movable unit 112 Antenna control unit 113 Reception sensitivity detection unit 202 Operation information collection unit 203 Setting information acquisition unit 204 Disaster detection unit 207 Transmission path determination unit 208 Antenna information generation unit 209 Base station information database (DB)

Claims (7)

A plurality of base stations that can be wirelessly connected to at least one other base station; a base station controller that is individually connected to each of the plurality of base stations and connects the plurality of base stations to a communication switching center; In a mobile communication system including a transmission path control server capable of communicating with a base station of a satellite via satellite communication,
The transmission path control server is
From each of the base stations, operation information collecting means for collecting base station information including operation status information of each base station using satellite communication,
Setting information acquisition means for acquiring setting information related to other base stations that can be wirelessly connected to each base station;
Based on the base station information collected by the operation information collecting means, the isolated base station that cannot communicate with the base station control device individually from the plurality of base stations and the individual communication with the base station control device. An emergency transmission path from the isolated base station to the live base station, which is realized by wireless connection between the base stations based on the setting information acquired by the setting information acquisition unit, by identifying a possible live base station A transmission path determining means for determining and transmitting emergency transmission path information for forming the emergency transmission path to the plurality of base stations using satellite communication;
With
Each of the plurality of base stations is
An operation status detection means for detecting the operation status of the base station;
Operating status transmitting means for transmitting base station information including information on operating status detected by the operating status detecting means to the transmission path control server using satellite communication;
Inter-base station transmission means for establishing a wireless connection with at least one other base station indicated by the emergency transmission path information received from the transmission path control server via satellite communication;
With
At least one isolated base station of the plurality of base stations is
Base station processing means for wirelessly transmitting traffic related to mobile terminals in the wireless area of the own base station to a live base station using a wireless connection established by the inter-base station transmission means;
A mobile communication system comprising: The transmission path determination means first uses, as the setting information, a first isolated base station that is not included in the setting information of another live base station among a plurality of live base stations including the isolated base station in the setting information. Other live base stations except for the live base station that determines the connection between the live base station including the first base station and the first base station, Using the first isolated base station as a candidate, determine a base station to be connected to an undecided isolated base station,
The mobile communication system according to claim 1. The base station processing means is configured when the own base station is an isolated base station and traffic from another base station is received via the first wireless connection established by the inter-base station transmission means. Transmits the traffic related to the mobile terminal in the radio area of its own base station and the traffic from the other base station to another different base station via the second radio connection established by the inter-base station transmission means. When the own base station is a live base station and traffic from another base station is received via the radio connection established by the inter-base station transmission means, the radio area of the own base station Transmitting the traffic related to the mobile terminal and the traffic from the other base station to the base station controller.
The mobile communication system according to claim 1 or 2. The inter-base station transmission means includes
Movable means for changing the direction of the directional main axes of the transmitting antenna and the receiving antenna for establishing a wireless connection with the at least one other base station;
Antenna control for causing the movable means to change the directions of the directional main axes of the transmitting antenna and the receiving antenna based on antenna control information received together with the emergency transmission path information from the transmission path control server via satellite communication. Means,
Including
The transmission path control server is
The position information of the transmission antenna and the reception antenna related to the base station pair forming the emergency transmission path determined by the transmission path determination means is acquired, and based on the acquired position information, the transmission antenna and the reception antenna related to the base station pair Antenna information generating means for determining the direction of the main axis of the directivity and generating the antenna control information indicating the determined direction;
The mobile communication system according to any one of claims 1 to 3, further comprising: The inter-base station transmission means includes
Reception sensitivity detection means for detecting reception sensitivity of signals from the at least one other base station at the reception antenna;
Further including
The operation information collection means of the transmission path control server collects the reception sensitivity information from each base station using satellite communication,
The antenna information generation unit of the transmission path control server corrects the direction of the directivity main axis of the transmission antenna and the reception antenna in each base station based on the reception sensitivity information collected by the operation information collection unit, Generating the antenna control information indicating the corrected direction;
The antenna control means transmits the reception sensitivity information detected by the reception sensitivity detection means to the transmission path control server using satellite communication, and the satellite communication from the transmission path control server according to the transmission of the reception sensitivity information. Based on the antenna control information received via, the movable means changes the direction of the directivity main axis of the transmitting antenna and the receiving antenna.
The mobile communication system according to claim 4. In a transmission path control server capable of communicating via satellite communication with each of a plurality of base stations that can be wirelessly connected to at least one other base station,
From each of the base stations, operation information collecting means for collecting base station information including operation status information of each base station using satellite communication,
Setting information acquisition means for acquiring setting information related to other base stations that can be wirelessly connected to each base station;
Based on the base station information collected by the operation information collecting means, an isolated base station that cannot individually communicate with a base station controller that connects each base station to a communication switching center from among the plurality of base stations And a live base station that can communicate with the base station controller individually, and based on the setting information acquired by the setting information acquisition means, realized by wireless connection between the base stations, from the isolated base station A transmission path determining means for determining an emergency transmission path to the live base station, and transmitting emergency transmission path information for forming the emergency transmission path to the plurality of base stations using satellite communication;
A transmission path control server comprising: In a communication method executed by a computer capable of communicating via satellite communication with each of a plurality of base stations wirelessly connectable with at least one other base station,
The computer is
Collecting each base station information including operation status information of each base station from each base station using satellite communication;
Obtaining setting information about other base stations that can be wirelessly connected to each of the base stations;
Based on the collected base station information, an isolated base station that cannot individually communicate with a base station controller that connects each base station to a communication switching center from among the plurality of base stations, and the base station control Identifying live base stations that can communicate with the device individually;
Determining an emergency transmission path from the isolated base station to the live base station realized by wireless connection between base stations based on the acquired setting information;
Transmitting emergency transmission path information for forming the emergency transmission path to the plurality of base stations using satellite communication;
The communication method characterized by performing.

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