JP2011135439A - Mobile relay system, mobile relay station and mobile relay method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mobile relay system, along with a mobile relay station and a mobile relay method, capable of efficiently performing communications of a terminal in a moving vehicle. <P>SOLUTION: Terminals 2a, 2b or the like in a moving vehicle 5 communicate with a base station 4a existing on the outside of the vehicle through a mobile relay station 1. The mobile relay station 1 detects a plurality of communicable base stations around the mobile relay station 1, confirms communication quality with each base station at each predetermined time and transmits communication quality information of communication with the base station 4a communicating at present and other base stations to the base station 4a at each predetermined time. When the other base station has communication quality of a predetermined value or higher as compared with the base station 4a, the base station 4a outputs a handover request to the mobile relay station 1 so as to switch connection to the base station 4b with the best communication quality. Receiving a connection switching request from the base station 4a, the mobile relay station 1 outputs a connection allocation request and a connection request to the base station 4b so as to switch connection to the base station 4b. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a mobile relay system, a mobile relay station, and a mobile relay method for relaying communication between a base station and a terminal.

  When mobile terminals such as mobile phones and laptop computers communicate in mobile vehicles such as trains and buses, the mobile terminal itself moves at high speed, so the mobile terminal connects from the connected base station to other base stations. It is necessary to perform switching (handover) one after another at high speed. For this reason, the communication of the base station or the mobile terminal may be interrupted and the communication may become unstable. In addition, processing for switching the connection occurs in the mobile terminal, and wasteful power consumption is consumed.

  In view of this, a technique has been studied in which a mobile relay station is installed in a vehicle, and the mobile relay station relays communication between a mobile terminal in the vehicle and an external base station, thereby performing stable communication in the mobile vehicle.

In recent years, a relay device of a specific communication carrier is provided in a moving vehicle such as a train, and a plurality of base stations corresponding to the communication carrier are installed along the line. The terminal in the train performs wireless LAN communication with the relay device, and the relay device performs WiMAX (Worldwide Interoperability for Microwave Access) communication with a base station dedicated to the communication carrier. Since a plurality of base stations are installed along the railway line, the relay apparatus can ensure stable communication even when handover is performed between the base stations. However, since the communication method differs between communication with a terminal (wireless LAN communication) and communication with a base station (WiMAX communication), the relay apparatus needs to convert the communication method. In addition, the above-described relay device and communication method are dedicated to a specific communication carrier, and the terminal itself must be contracted with this communication carrier to be able to connect, so a dedicated ID and connection device are required. Therefore, there is a need for a repeater that can provide stable communication quality with the same communication method. In Patent Document 1, a mobile terminal in a train communicates with a mobile base station in the train while the train is moving. Discloses a technique for handing over from a mobile base station to a fixed base station when approaching the next stop station.

JP 2004-032155 A

  However, the technology of Patent Document 1 performs a handover from a mobile base station to a fixed base station every time a mobile terminal approaches the stop station, so that the fixed base station can be used even at a stop station on the way, which is not the original destination. Handover was in progress. When it departs from a stop station on the way, it is necessary to hand over to the mobile base station again. Therefore, radio resources are wasted and wasteful power of the mobile terminal is used.

  The present invention has been made in consideration of such points, and an object of the present invention is to provide a mobile relay system, a mobile relay station, and a mobile relay method capable of efficiently performing communication between terminals in a mobile vehicle.

  A mobile relay system according to the present invention includes a terminal, a plurality of base stations including a first base station and a second base station, and a radio between the terminal and the plurality of base stations that moves with the terminal. In the mobile relay system having a mobile relay station that relays communication, the plurality of base stations perform wireless communication with the mobile relay station and transmit identification information of the terminal to the mobile relay station The mobile relay station includes a base station side communication unit that performs communication with the first base station, and other base stations including the second base station other than the first base station. Communication quality between the base station detection unit for detecting the base station and the first base station communicating with the base station side communication unit, and the second base station detected by the base station detection unit Including a quality confirmation unit for confirming communication quality with other base stations including the quality confirmation unit. When the communication quality of the second base station is higher than the communication quality of the first base station by a predetermined value and is the best among all the base stations, the connection is switched to the second base station. From the connection switching unit and the second base station switched by the connection switching unit, the terminal information acquisition unit that acquires the identification information of the terminal, communicates with the terminal, and acquired by the terminal information acquisition unit It has the terminal side communication part which transmits identification information to the said terminal, It is characterized by the above-mentioned.

  According to the present invention, a mobile relay station moves together with a terminal, a plurality of base stations including a first base station and a second base station, and a radio between the terminal and the plurality of base stations. In a mobile relay station in a mobile relay system having a relay station for relaying communication, a base station side communication unit that performs communication with the first base station, and a second base other than the first base station Communication quality between the base station detection unit for detecting other base stations including the station and the first base station communicating with the base station side communication unit, and detection performed by the base station detection unit A quality confirmation unit for confirming communication quality with other base stations including the second base station, and a communication quality of the second base station confirmed by the quality confirmation unit is the communication of the first base station. If the quality is the best value among all the base stations above the predetermined value, the second A connection switching unit that switches connection to a base station, a terminal information acquisition unit that acquires identification information of the terminal from the second base station switched by the connection switching unit, and communication with the terminal, and the terminal information And a terminal-side communication unit that transmits the identification information acquired by the acquisition unit to the terminal.

  The mobile relay method according to the present invention includes a terminal, a plurality of base stations including a first base station and a second base station, and a radio between the terminal and the plurality of base stations that moves with the terminal. A mobile relay system having a mobile relay station for relaying communication, wherein the plurality of base stations perform wireless communication with the mobile relay station and transmit identification information of the terminal to the mobile relay station The mobile relay station communicates with the first base station, detects other base stations other than the first base station, including the second base station, and performs communication. The communication quality with the first base station and the communication quality with other base stations including the second base station detected by the base station detection unit are confirmed, and the communication of the second base station The quality is equal to or greater than the communication quality of the first base station, When it is the best among the ground stations, the connection is switched to the second base station, the terminal identification information is acquired from the switched second base station, and the terminal is communicated with the terminal. The identification information is transmitted to each of the terminals.

  According to the mobile relay system, mobile relay station, and mobile relay method of the present invention, it is possible to efficiently perform terminal communication within a mobile vehicle.

The block diagram which shows the mobile relay system which concerns on one Embodiment of this invention. The block diagram which shows schematic structure of the mobile relay station in embodiment same as the above. The flowchart which shows operation | movement of the terminal in this embodiment, a mobile relay station, a base station, and an access gateway server. The figure which shows the example of the data block transmitted to a mobile relay station from a base station in the embodiment same as the above, (b) The example of the data block transmitted from a mobile relay station to a terminal.

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

  FIG. 1 is a configuration diagram showing a mobile relay system 100 according to an embodiment of the present invention. The mobile relay system 100 includes a plurality of base stations 4a, 4b, 4c,... And an access gateway server 3, such as the mobile relay station 1 and the plurality of terminals 2a, 2b in the vehicle 5.

  The vehicle 5 is a bus or a train, for example, and moves from the base station 4a side to the base station 4b side. The mobile relay station 1 is installed in the vehicle 5 in the vehicle.

  The terminals 2a, 2b, etc. are owned by passengers in the vehicle 5. The terminals 2a, 2b, etc. are, for example, mobile phones, notebook computers, etc., and can communicate with the outside by connecting to the base station 4 directly or via the mobile relay station 1.

  The mobile relay station 1 is installed in the vehicle 5 and communicates with the terminals 2a, 2b and the like using the inside of the vehicle 5 as a communication area. Further, the mobile relay station 1 is connected to arbitrary external base stations 4a, 4b, 4c. The mobile relay station 1 reproduces the data to be relayed by demodulating the radio waves from the base stations 4a, 4b, 4c... And the terminals 2a, 2b based on a predetermined standard / system, and again. After performing the modulation processing based on the standard / system, radio waves are transmitted to a predetermined frequency and band. A method for reproducing data by performing demodulation and modulation in this way is called a reproduction method. The mobile relay station 1 performs the operation like a terminal when viewed from the base stations 4a, 4b, 4c,... And the operation like the base station when viewed from the terminals 2a, 2b, and the like. When the mobile relay station 1 moves, the mobile relay station 1 communicates with an arbitrary base station 4 having an optimal communication quality every time. When the base station 4 connected to the mobile relay station 1 changes as the vehicle 5 moves, the mobile relay station 1 performs the handover procedure in the same manner as when the terminals 2a, 2b, etc. directly communicate with the base station 4. Need to be implemented.

  FIG. 2 is a block diagram showing a schematic configuration of the mobile relay station 1. The mobile relay station 1 includes a control unit 10, a base station side baseband processing unit 11, a base station side reception unit 13, a base station side transmission unit 15, a base station side transmission / reception signal switching unit 17, a base station side antenna 17a, a terminal side The baseband processing unit 12, the terminal-side receiving unit 14, the terminal-side transmitting unit 16, the terminal-side transmission / reception signal switching unit 18, the terminal-side antenna 18a, the power supply unit 19, and the memory 21 are connected to be communicable with each other. .

  The power supply unit 19 supplies power to each unit from an external power supply source, and enables each unit of the mobile relay station 1 to operate.

  The control unit 10 controls the entire mobile relay station 1, arranges communication data in a radio frame when relaying communication between an arbitrary base station 4 and terminals 2a, 2b, etc., and selects a radio frequency used for relay I do. The control unit 10 includes a base station detection unit 101, a communication quality confirmation unit 102, a connection switching unit 103, and a terminal connection information acquisition unit 104. The base station detection unit 101 detects a communicable base station 4 around the mobile relay station 1. The communication quality confirmation unit 102 confirms the communication quality (radio wave intensity etc.) with the base stations 4a, 4b, 4c. The connection switching unit 103 performs handover to the base station with the best communication quality based on the communication quality of each base station 4 confirmed by the communication quality confirmation unit 102. The terminal connection information acquisition unit 104 acquires connection information such as an encryption key for the mobile relay station 1 to communicate with the terminals 2a, 2b, etc. collectively for all the terminals 2a, 2b, etc. The connection information such as 2a and 2b is decomposed into connection information for each terminal.

  The memory 21 serves as a work area for the control unit 10, a base station side receiving unit 13, a terminal side receiving unit 14, a base station side transmitting unit 15, and a terminal side transmitting unit 16, which will be described later. Can be realized. Also, connection information such as encryption keys necessary for communication with the terminals 2a, 2b, etc., acquired by the terminal connection information acquisition unit 104 is stored.

  The base station side transmission / reception signal switching unit 17 inputs a radio wave from an arbitrary base station 4 received by the base station side antenna 17a to the base station side reception unit 13, and transmits a transmission signal from the base station side transmission unit 15 The data is transmitted to the base station side transmitting / receiving antenna 17a.

  The base station side receiving unit 13 converts the received radio signal into a baseband signal. The base station side transmission unit 15 converts the modulation signal from the base station side baseband processing unit 11 into a high-frequency radio signal, and amplifies the signal power. The base station side baseband processing unit 11 demodulates the baseband signal from the base station side receiving unit 13 and restores communication data, and the terminal side baseband processing unit 12 input via the control unit 10 The communication data is modulated and output to the base station side transmitter 15.

  The terminal-side transmission / reception signal switching unit 18, the terminal-side transmission / reception antenna 18a, the terminal-side reception unit 14, the terminal-side transmission unit 16, and the terminal-side baseband processing unit 12 are not connected to the terminals 2a, 2b, etc. It has the same function as the base station side.

  The access gateway server 3 exists between the base stations 4a, 4b, and the external network N. The access gateway server 3 uses the identification information (authentication information, communication method information, billing information, usable information) of the terminals 2a, 2b, etc., for the terminals 2a, 2b, etc. to connect to the external network N via an arbitrary base station 4. Communication service information (data communication, telephone, etc.) and connection information (encryption key, etc.), and this identification information is sent in response to a request from the base station 4.

  The base stations 4a, 4b, 4c,... Perform wireless communication with the terminals 2a, 2b, etc. or the mobile relay station 1, and acquire identification information of the communicating terminals 2a, 2b, etc. from the access gateway server 3. Also, the base stations 4a, 4b, 4c,... Collect the connection information such as the encryption key of each terminal among the acquired identification information of the terminals 2a, 2b, etc. into one data block and transmit it to the mobile relay station 1. .

<Operation>
Next, the operation of the mobile relay system 100 configured as described above will be described with reference to FIG.

  A mobile relay station 1 is installed in the moving vehicle 5, and a passenger has a terminal 2a and a terminal 2b. Each terminal 2a, 2b, etc. relays the mobile relay station 1 and communicates with the base station 4a outside the vehicle (step S101). The base station 4 a has identification information such as terminals 2 a and 2 b acquired from the access gateway server 3.

  As illustrated in FIG. 1, if the vehicle 5 is moving from the base station 4a side to the base station 4b side, the mobile relay station 1 gradually leaves the base station 4a, and the radio field intensity from the base station 4a decreases. Come on. Therefore, the base station detection unit 101 of the mobile relay station 1 detects a plurality of other base stations (for example, the base stations 4b and 4c) around the mobile relay station 1 that can communicate (step S103). Next, the communication quality confirmation unit 102 of the mobile relay station 1 confirms the communication quality with each of the base stations 4a, 4b, 4c every predetermined time, and the base station 4a currently communicating via the base station side transmission unit 15 In addition, the communication quality information with the base station 4a and the other base stations 4b and 4c is transmitted every predetermined time (step S105). In step S103, the mobile relay station 1 acquires information such as frequencies, base station identification numbers, synchronization timings, and the like regarding a plurality of other base stations 4b and 4c that can communicate with each other from the currently communicating base station 4a. The other base stations 4b and 4c may be detected based on the information, or the mobile relay station 1 may detect the other base stations 4b and 4c by itself.

  Based on the communication quality information of other neighboring base stations 4b and 4c transmitted from the mobile relay station 1 in step S105, the base station 4a determines that the communication quality of the other base stations 4b and 4c is predetermined with respect to the base station 4a. It is confirmed whether or not the communication quality is higher than the value (step S107). If any of the other base stations 4b and 4c has a communication quality higher than the base station 4a by a predetermined value (“Yes” in step S107), the base station 4a determines that the base station with the best communication quality ( For example, a handover request is made to the mobile relay station 1 so as to switch to the base station 4b (step S109). Further, the base station 4a notifies the access gateway server 3 that the handover is performed from the base station 4a to the base station 4b, and requests to switch the connection (step S111).

  Next, the connection switching unit 103 of the mobile relay station 1 receives a connection switching request from the base station 4a in step S109, and allocates a communication area to the base station 4b in order to switch the connection to the base station 4b. An allocation request is made, and the base station 4b returns a response to the mobile relay station 1 (step S113). Next, the connection switching unit 103 of the mobile relay station 1 makes a connection request to the base station 4b (step S115). Next, the base station 4b requests the mobile relay station 1 for an authentication procedure, and the mobile relay station 1 returns a response indicating that it has been authenticated to the base station 4b (step S117).

  At this point, the base station 4b has no information on the terminals 2a, 2b, etc. that are communicating with the mobile relay station 1. Identification information of the terminals 2a, 2b, etc. is stored in the access gateway server 3. Therefore, next, the base station 4b requests the access gateway server 3 for identification information of the terminals 2a, 2b, etc. (step S119). In response to the request in step S119, the access gateway server 3 transmits all identification information such as the terminals 2a and 2b to the base station 4b (step S121).

  The identification information transmitted to the base station 4b in step S121 includes updated connection information such as an encryption key used for communication between the base station 4b and the terminals 2a and 2b. The base station 4b transmits the updated connection information of all the terminals 2a, 2b, etc. to the mobile relay station 1 in a lump (step S123). Here, since the mobile relay station 1 is installed in the vehicle 5 where the passenger happens to ride, it is not necessary to have all of the identification information of the individual terminals 2a, 2b, etc. for security. It is only necessary to have information necessary for communication processing with the terminals 2a, 2b, etc., that is, only connection information. Therefore, the base station 4b only needs to transmit connection information to the mobile relay station 1.

  Next, as a response to the connection request in step S115, the base station 4b notifies the mobile relay station 1 of the completion of connection processing to the base station 4b (step S125).

  Next, the terminal connection information acquisition unit 104 of the mobile relay station 1 disassembles and transmits the updated connection information transmitted and acquired in step S123 to each terminal 2a, 2b, etc. (step S127). If there is a terminal 2 that does not respond, it is assumed that the mobile relay station 1 cannot be notified of communication disconnection due to some connection failure, and the communication is interrupted. The mobile relay station 1 deletes the encryption key of the terminal 2 .

  Here, FIG. 4A shows an example of a data block of the updated connection information of all the terminals 2a and 2b transmitted from the base station 4b to the mobile relay station 1 in step S123, and FIG. 4B shows step S127. An example of a data block of updated connection information transmitted from the mobile relay station 1 to each of the terminals 2a and 2b is shown. In the head portion of the data block in FIG. 4A, an instruction that the information of the terminals 2a and 2b is packed is attached, and then the header and connection information for each terminal are arranged in order. The mobile relay station 1 grasps that the information of the terminals 2a and 2b is included in the header at the head of this data block. And as shown in FIG.4 (b), a data block is decomposed | disassembled for every terminal and it transmits to each terminal 2a, 2b.

  Through the above procedure, the base station 4b handed over by movement and the terminals 2a, 2b, etc. communicate via the mobile relay station 1 (step S129).

  As described above, in the mobile relay station that relays communication between a plurality of terminals and the base station, when the handover of the base station occurs, the mobile relay station communicates with the base station instead of the plurality of terminals. Performs handover processing in a batch. Therefore, in the conventional case, a plurality of terminals and a base station each need to perform a handover process individually, but the process is completed by a single process between the mobile relay station and the base station. The communication traffic spent for handover can be reduced. In addition, since the mobile relay station performs terminal processing in handover, the terminal processing is greatly reduced, and the power consumption of the terminal can be reduced. In addition, since the communication between the mobile relay station and the terminal in the vehicle is stable, the terminal can perform smooth communication even if the vehicle moves.

  As mentioned above, although embodiment of this invention was explained in full detail with reference to drawings, the specific structure is not restricted to this embodiment, The design change etc. of the range which does not deviate from the summary of this invention are included.

  Further, the present invention is applied to a PDA (Personal Digital Assistance) having a wireless communication function, a portable music player, a portable video camera, a portable game machine, etc., instead of the cellular phone or the portable personal computer in the above embodiment. Also good.

  DESCRIPTION OF SYMBOLS 1 ... Mobile relay station, 2a, 2b ... Terminal, 3 ... Access gateway server, 4a, 4b, 4c ... Base station, 5 ... Vehicle, 100 ... Mobile relay system.

Claims (7)

A terminal, a plurality of base stations including a first base station and a second base station, a mobile relay station that moves together with the terminal and relays wireless communication between the terminal and the plurality of base stations; In a mobile relay system having
The plurality of base stations includes a base station communication unit that performs radio communication with the mobile relay station and transmits identification information of the terminal to the mobile relay station,
The mobile relay station is
A base station side communication unit for communicating with the first base station;
A base station detector that detects other base stations other than the first base station, including the second base station;
Communication quality with the first base station communicating with the base station side communication unit, and communication quality with other base stations including the second base station detected by the base station detection unit A quality confirmation department to confirm
When the communication quality of the second base station confirmed by the quality confirmation unit is the predetermined value or higher than the communication quality of the first base station and is the best among all the base stations, the second base station A connection switching unit for switching the connection to the base station;
A terminal information acquisition unit for acquiring identification information of the terminal from the second base station switched by the connection switching unit;
A terminal-side communication unit that communicates with the terminal and transmits the identification information acquired by the terminal information acquisition unit to the terminal;
A mobile relay system characterized by that. A server for storing identification information of the terminal and connected to the base station;
The server is configured to transmit identification information of the terminal to the base station;
The mobile relay system according to claim 1. The base station communication unit of the base station is configured to transmit identification information of all of the plurality of terminals as one data block when there are a plurality of terminals relayed to the mobile relay station,
The terminal information acquisition unit of the mobile relay station is configured to decompose data from the one data block into identification information of each terminal.
The mobile relay system according to claim 1. The base station communication unit of the base station is configured to transmit only information necessary for communication among the identification information of all the terminals to the mobile relay station as one data block.
The mobile relay system according to claim 3. A terminal, a plurality of base stations including a first base station and a second base station, a mobile relay station that moves together with the terminal and relays wireless communication between the terminal and the plurality of base stations; In a mobile relay station in a mobile relay system having
A base station side communication unit that performs communication with the first base station;
A base station detector that detects other base stations other than the first base station, including a second base station;
Communication quality with the first base station communicating with the base station side communication unit, and communication quality with other base stations including the second base station detected by the base station detection unit A quality confirmation department to confirm
When the communication quality of the second base station confirmed by the quality confirmation unit is the predetermined value or higher than the communication quality of the first base station and is the best among all the base stations, the second base station A connection switching unit for switching the connection to the base station;
A terminal information acquisition unit for acquiring identification information of the terminal from the second base station switched by the connection switching unit;
A terminal-side communication unit that communicates with the terminal and transmits the identification information acquired by the terminal information acquisition unit to the terminal;
A mobile relay station characterized by comprising: The terminal information acquisition unit is configured to decompose one data block including identification information of all the plurality of terminals transmitted from the base station into identification information of each terminal.
The mobile relay station according to claim 5. A terminal, a plurality of base stations including a first base station and a second base station, a mobile relay station that moves together with the terminal and relays wireless communication between the terminal and the plurality of base stations; In a mobile relay method in a mobile relay system having
The plurality of base stations perform wireless communication with the mobile relay station, and transmits identification information of the terminal to the mobile relay station;
The mobile relay station is
Communicate with the first base station;
Detecting other base stations other than the first base station, including the second base station,
Confirm communication quality with the first base station that is performing communication, and communication quality with other base stations including the second base station detected by the base station detection unit,
When the communication quality of the second base station is equal to or higher than the communication quality of the first base station and is the best among all the base stations, the connection is switched to the second base station,
Obtaining identification information of the terminal from the switched second base station,
Communicate with the terminal, and transmit the acquired identification information to each of the terminals,
A mobile relay method characterized by the above.

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