JP5498924B2 - Wireless communication system, wireless base station, and communication control method - Google Patents

Description

  The present invention provides a radio communication system having a first system corresponding to the first radio communication scheme and a second system corresponding to the second radio communication scheme, a radio base station in the radio communication system, and The present invention relates to a communication control method in the wireless communication system.

  In a 3GPP (Third Generation Partnership Project) wireless communication system supporting LTE (Long Term Evolution), which is currently in the process of developing a standard, a wireless base station is connected via a backhaul to an MME (Mobile Management Entity) that is an upper node. ) To communicate with the MME.

  Similarly, in a radio communication system corresponding to CDMA (Code Division Multiple Access), a radio base station is connected to an upper node MSC / VLR (Mobile Switching Center / Visitor Location Register) via a backhaul, Communication is performed between the MSC / VLR.

3GPP TS 36.300 V9.4.0 (2010-06)

  When a failure occurs in the backhaul and the radio base station can no longer communicate with the upper node, the radio base station connects to another adjacent radio base station and passes through the other radio base station. Communicate with the upper node. However, when the radio base station cannot directly communicate with another adjacent radio base station, communication with the upper node is not restored.

  In view of the above problems, an object of the present invention is to provide a radio communication system, a radio base station, and a communication control method that improve the reliability of communication between a radio base station and an upper node.

  In order to solve the above-described problems, the present invention has the following features.

  A feature of the present invention is that the first system includes a first system corresponding to a first wireless communication system (LTE) and a second system corresponding to a second wireless communication system (CDMA). Includes a first radio base station (first LTE base station 10-1) and a second radio base station (second LTE base station 10-2) that can communicate with each other, and the second system includes: A first radio base station including a third radio base station (first CDMA base station 20-1), a fourth radio base station (second CDMA base station 20-2), and an upper node (MSC / VLR 110) capable of communicating; A radio communication system in which a base station and the third radio base station are connected to be able to communicate with each other, and the second radio base station and the fourth radio base station are connected to be able to communicate with each other (Radio communication system 1), wherein the third radio base And the upper radio node, the third radio base station and the fourth radio base station via the first radio base station and the second radio base station when communication between the third radio base station and the upper radio node becomes impossible. The main point is to establish a communication path between the two.

  In such a wireless communication system, a first wireless base station in a first system and a third wireless base station in a second system are connected so as to be able to communicate with each other. When the second radio base station and the fourth radio base station in the second system are connected to be communicable with each other, the first radio base station and the second radio base station are connected via the first radio base station and the second radio base station. A communication path between the third radio base station and the fourth radio base station is established. Therefore, even when the third radio base station and the fourth radio base station in the second system cannot communicate directly, the third radio base station and the fourth radio base station A communication path with the base station is established, and the third radio base station and the upper node can communicate with each other via the communication path.

  A feature of the present invention is that the third radio base station determines whether or not to relay communication between the third radio base station and the upper node, whether the first radio base station or the second radio base station. The gist is to transmit information for inquiring to the base station and the fourth radio base station.

  A feature of the present invention is that the first radio base station, the second radio base station, and the fourth radio base station are configured to relay communication between the third radio base station and the upper node. The gist is to send the information on availability.

A feature of the present invention is that the first system is a data communication system,
The gist of the second system is a system for voice communication.

  A feature of the present invention is that the first radio base station is information for switching the connection destination of the radio terminal to the third radio base station when the connected radio terminal transmits voice communication. Is transmitted to the wireless terminal.

  A feature of the present invention is that the first radio base station is information for switching the connection destination of the radio terminal to the third radio base station when the connected radio terminal receives an incoming voice communication. Is transmitted to the wireless terminal.

  A feature of the present invention is a radio base station in a first system corresponding to a first radio communication system, and a first other radio base station in a second system corresponding to a second radio communication system The second other radio base station, which is communicably connected and via the own radio base station and the second other radio base station in the first system, and the third radio base station in the second system. The gist is to establish a communication path with another radio base station.

  A feature of the present invention is that it has a first system corresponding to the first wireless communication method and a second system corresponding to the second wireless communication method, and the first system can communicate with each other. A first radio base station and a second radio base station, and the second system includes a third radio base station, a fourth radio base station, and an upper node that can communicate with each other, and One radio base station and the third radio base station are communicably connected to each other, and the second radio base station and the fourth radio base station are communicably connected to each other. A communication control method in a radio communication system, the communication path between the third radio base station and the fourth radio base station via the first radio base station and the second radio base station It includes the step of establishing

  ADVANTAGE OF THE INVENTION According to this invention, the certainty of communication with a wireless base station and a high-order node can be improved.

1 is an overall schematic configuration diagram of a wireless communication system according to an embodiment of the present invention. It is a block diagram of the LTE base station which concerns on embodiment of this invention. It is a block diagram of the CDMA base station which concerns on embodiment of this invention. It is a block diagram of UE which concerns on embodiment of this invention. It is a sequence diagram which shows the 1st operation | movement of the radio | wireless communications system which concerns on embodiment of this invention. It is a sequence diagram which shows the 2nd operation | movement of the radio | wireless communications system which concerns on embodiment of this invention.

  Next, an embodiment of the present invention will be described with reference to the drawings. Specifically, the configuration of the wireless communication system, the operation of the wireless communication system, the operation and effect, and other embodiments will be described. In the description of the drawings in the following embodiments, the same or similar parts are denoted by the same or similar reference numerals.

(1) Configuration of Radio Communication System The radio communication system includes a first system corresponding to a first radio communication scheme and a second system corresponding to a second radio communication scheme, and the first system The system includes a first radio base station and a second radio base station that can communicate with each other, and the second system includes a third radio base station, a fourth radio base station, and An upper node is included, the first radio base station and the third radio base station are communicably connected to each other, and the second radio base station and the fourth radio base station are mutually connected. A wireless communication system communicatively coupled to the third wireless base station and the fourth wireless base station via the first wireless base station and the second wireless base station. Establish a communication path for.

  In addition, the third radio base station determines whether the relay of communication between the third radio base station and the upper node is possible, the first radio base station, the second radio base station, and the Information for inquiring to the fourth radio base station is transmitted.

  In addition, the first radio base station, the second radio base station, and the fourth radio base station may determine whether or not to relay communication between the third radio base station and the upper node. Send.

  The first system is a data communication system, and the second system is a voice communication system.

  Further, the first radio base station transmits information for switching the connection destination of the radio terminal to the third radio base station when the connected radio terminal performs voice communication. Send to.

  The first radio base station transmits information for switching the connection destination of the radio terminal to the third radio base station when a connected radio terminal receives an incoming voice communication. Send to.

FIG. 1 is a schematic configuration diagram of a wireless communication system according to the present embodiment. A radio communication system 1 illustrated in FIG. 1 includes a radio communication system compatible with LTE and a radio communication system compatible with CDMA.

  In this embodiment, the wireless communication system corresponding to LTE is a wireless communication system for data communication that does not have a VoIP (Voice over IP) function. The wireless communication system corresponding to LTE includes a first LTE base station 10-1, a second LTE base station 10-2, a router 50, an S-GW (Serving Gateway) 60, a P-GW (Packet data network Gateway) 70, an IMS ( IP Multimedia Subsystem) 80 and MME (Mobile Management Entity) 90 are included. The router 50, the S-GW 60, the P-GW 70, the IMS 80, and the MME 90 are installed in a backhaul (LTE backhaul) in a radio communication system corresponding to LTE.

  In this embodiment, the radio communication system corresponding to CDMA is a radio communication system for voice communication. A radio communication system corresponding to CDMA includes a first CDMA base station 20-1, a second CDMA base station 20-2, a BSC (Base Station Controller) 100, an MSC / VLR (Mobile Switching Center / Visitor Location Register) 110, a GMCS (Generalized). Multi Carrier Subsystem) 120 and switch 130 are included. The BSC 100, the MSC / VLR 110, the GMCS 120, and the exchange 130 are installed in a backhaul (CDMA backhaul) in a wireless communication system that supports CDMA.

  The radio communication system 1 includes an HSS (Home Subscriber Server) 140 shared by a radio communication system compatible with LTE and a radio communication system compatible with CDMA, a radio communication system compatible with LTE, and a radio corresponding to CDMA. And a network 151 connecting the communication system.

  The first LTE base station 10-1 and the first CDMA base station 20-1 are installed in the same position and can communicate with each other via the communication line 150-1. The second LTE base station 10-2 and the second CDMA base station 20-2 are provided in the same position and can communicate with each other via the communication line 150-2.

  In the present embodiment, a radio terminal (UE: User Equipment) 200-1 exists in the cell of the first LTE base station 10-1 and in the cell of the first CDMA base station 20-1, and the first LTE base station 10 -1 and the first CDMA base station are capable of wireless communication. The UE 200-2 and the UE 200-3 exist in the cell of the first LTE base station 10-1 and in the cell of the second LTE base station 10-2, and the first LTE base station 10-1 and the second LTE base station 10- 2 can be wirelessly communicated.

(1.1) Configuration of LTE Base Station The radio base station is a radio base station in the first system corresponding to the first radio communication scheme, and in the second system corresponding to the second radio communication scheme. The second other radio base station, which is communicably connected to the first other radio base station, via the own radio base station and the second other radio base station in the first system, A communication path is established with a third other radio base station in the second system.

  FIG. 2 is a diagram illustrating configurations of the first LTE base station 10-1 and the second LTE base station 10-2. The first LTE base station 10-1 and the second LTE base station 10-2 shown in FIG. 2 include a radio communication processing unit 11, a backhaul side communication processing unit 12, a CDMA base station communication processing unit 13, and a backhaul side line monitoring unit 14. The communication control unit 15 and the terminal relay communication processing unit 16 are included.

  The radio communication processing unit 11 includes an RF circuit, a baseband circuit, an antenna, and the like, performs modulation and demodulation, encoding and decoding, and transmits and receives radio signals to and from the UE 200-1. The backhaul side communication processing unit 12 transmits and receives data to and from the router 50 provided in the LTE backhaul. The CDMA base station communication processing unit 13 in the first LTE base station 10-1 connects the communication line 150-1, and exchanges data with the first CDMA base station 20-1 via the communication line 150-1. Send and receive. The CDMA base station communication processing unit 13 in the second LTE base station 10-2 connects the communication line 150-2, and exchanges data with the second CDMA base station 20-2 via the communication line 150-2. Send and receive.

  The backhaul side line monitoring unit 14, the communication control unit 15, and the terminal relay communication processing unit 16 are configured using, for example, a CPU (Central Processing Unit) or a DSP (Digital Signal Processor).

(1.2) Configuration of CDMA Base Station FIG. 3 is a diagram illustrating the configuration of the first CDMA base station 20-1 and the second CDMA base station 20-2. The first CDMA base station 20-1 and the second CDMA base station 20-2 shown in FIG. 3 include a radio communication processing unit 21, a backhaul side communication processing unit 22, an LTE base station communication processing unit 23, and a backhaul side line monitoring unit 24. The communication control unit 25 and the relay communication processing unit 26 are included.

  The radio communication processing unit 21 includes an RF circuit, a baseband circuit, an antenna, and the like, performs modulation and demodulation, encoding and decoding, and transmits and receives radio signals to and from the UE 200-1. The backhaul side communication processing unit 22 transmits and receives data to and from the BSC 100 provided in the CDMA backhaul. The LTE base station communication processing unit 23 in the first CDMA base station 20-1 connects the communication line 150-1, and exchanges data with the first LTE base station 10-1 via the communication line 150-1. Send and receive. The LTE base station communication processing unit 23 in the second CDMA base station 20-2 connects the communication line 150-2, and exchanges data with the second LTE base station 10-2 via the communication line 150-2. Send and receive.

  The backhaul side line monitoring unit 24, the communication control unit 25, and the relay communication processing unit 26 are configured using, for example, a CPU (Central Processing Unit) or a DSP (Digital Signal Processor).

(1.3) Configuration of UE FIG. 4 is a diagram illustrating a configuration of UE 200-1, UE 200-2, and UE 200-3. UE 200-1 to UE 200-3 illustrated in FIG. 4 include a radio communication processing unit 201, a communication control / processing unit 202, and a relay communication control unit 203.

  The radio communication processing unit 21 includes an RF circuit, a baseband circuit, an antenna, etc., performs modulation and demodulation, encoding and decoding, etc., and transmits and receives radio signals between the LTE base station and the CDMA base station. Do. The communication control / processing unit 202 and the relay communication control unit 203 are configured using, for example, a CPU (Central Processing Unit) or a DSP (Digital Signal Processor).

(1.4) Processing of radio communication system First LTE base station 10-1 and second LTE base station 10-2 constituting a radio communication system corresponding to LTE, and first CDMA base station constituting a radio communication system corresponding to CDMA The 20-1 and the second CDMA base station 20-2 and the UEs 200-1 to 200-3 are disconnected from the CDMA backhaul line in the first CDMA base station 20-1 provided together with the first LTE base station 10-1. If so, the following processing is performed.

  The backhaul side line monitoring unit 14 in the first LTE base station 10-1 monitors the state of the LTE backhaul. Specifically, the backhaul side line monitoring unit 14 in the first LTE base station 10-1 periodically transmits an inquiry message for confirming the line state of the LTE backhaul to the MME 90. Receive a response message from. When the LTE backhaul line is disconnected due to an earthquake or the like, the backhaul side line monitoring unit 14 in the first LTE base station 10-1 transmits a response message to the MME 90, but the response from the MME 90 You will not be able to receive the message. In this case, the backhaul side line monitoring unit 14 in the first LTE base station 10-1 detects disconnection of the LTE backhaul line.

  The terminal relay communication processing unit 16 in the first LTE base station 10-1 performs autonomous recovery processing by a known method when disconnection of the LTE backhaul line is detected. Specifically, the terminal relay communication processing unit 16 exchanges a predetermined message with the terminal relay communication processing unit 16 in the second LTE base station 10-2, so that the terminal relay communication processing unit 16 in the first LTE base station 10-1 The communication path (detour path) from the wireless communication processing unit 11 to the second LTE base station 10-2 is established via the UE 200-2 or the UE 200-3.

  The backhaul side line monitoring unit 24 in the first CDMA base station 20-1 monitors the state of the CDMA backhaul. Specifically, the backhaul side line monitoring unit 24 in the first CDMA base station 20-1 periodically transmits an inquiry message to the MSC / VLR 110 to confirm the line state of the CDMA backhaul. The response message from the MSC / VLR 110 is received. When the CDMA backhaul line is disconnected due to an earthquake or the like, the backhaul side line monitoring unit 24 in the second CDMA base station 20-1 transmits an inquiry message to the MSC / VLR 110, and the MSC / VLR 110 The response message cannot be received. In this case, the backhaul side line monitoring unit 24 in the first CDMA base station 20-1 detects disconnection of the CDMA backhaul line.

  When the disconnection of the CDMA backhaul line is detected, the relay communication processing unit 26 in the first CDMA base station 20-1 detects the first LTE via the LTE base station communication processing unit 23 and the communication line 150-1. A message (first relay inquiry message) for inquiring whether or not relay communication is possible is transmitted to the base station 10-1. The first relay inquiry message includes information indicating that it is a control message.

  The terminal relay communication processing unit 16 in the first LTE base station 10-1 receives the first relay inquiry message via the communication line 150-1 and the CDMA base station communication processing unit 13.

  When the autonomous recovery is not completed, the terminal relay communication processing unit 16 in the first LTE base station 10-1 sends a first response message indicating that relay communication is not possible to the CDMA base station communication processing unit 13. And transmitted to the first CDMA base station 20-1 via the communication line 150-1. The first response message includes information indicating that it is a control message.

  On the other hand, when the autonomous recovery has been completed, the terminal relay communication processing unit 16 in the first LTE base station 10-1 transmits to the second LTE base station 10-2 via the wireless communication processing unit 11 and the detour path. A first relay inquiry message including information (LTE relay determination information) indicating that the message is to be transmitted to the second LTE base station 10-2 is transmitted. In this case, the relay communication control unit 203 in the UE 200-2 or UE 200-3 receives the first relay inquiry message via the radio communication processing unit 201. Furthermore, when the relay communication control unit 203 in the UE 200-2 or the UE 200-3 determines that the first relay inquiry message includes the LTE relay determination information, the relay communication control unit 203 transmits the first relay inquiry message to the wireless communication processing unit 201. To the second LTE base station 10-2.

  When receiving the first relay inquiry message, the terminal relay communication processing unit 16 in the second LTE base station 10-2 determines whether relay communication is possible or not. Specifically, the terminal relay communication processing unit 16 in the second LTE base station 10-2 connects the second LTE base station 10-2 to the second CDMA base station 20-2 via the communication line 150-2. If so, it is determined that relay communication is possible. When the terminal relay communication processing unit 16 in the second LTE base station 10-2 receives the first relay inquiry message, the terminal relay communication processing unit 16 adds LTE relay determination information to the first response message indicating whether relay communication is possible or not. Is included. Further, the terminal relay communication processing unit 16 in the second LTE base station 10-2 sends the first response message including the LTE relay determination information to the first LTE base station 10- via the wireless communication processing unit 11 and the detour path. Send to 1. In this case, the relay communication control unit 203 in the UE 200-2 or the UE 200-3 receives the first response message via the wireless communication processing unit 201. Furthermore, when determining that the first response message includes the LTE relay determination information, the relay communication control unit 203 in the UE 200-2 or the UE 200-3 transmits the first response message via the wireless communication processing unit 201. To the first LTE base station 10-1.

  The terminal relay communication processing unit 16 in the first LTE base station 10-1 receives the first response message. Next, the terminal relay communication processing unit 16 in the first LTE base station 10-1 deletes the LTE relay determination information included in the first response message. Further, the terminal relay communication processing unit 16 in the first LTE base station 10-1 transmits a first response message to the first CDMA base station 20-1 via the CDMA base station communication processing unit 13 and the communication line 150-1. .

  The relay communication processing unit 26 in the first CDMA base station 20-1 receives the first response message via the LTE base station communication processing unit 23.

  When the first response message indicates that relay communication is not possible, the wireless communication system is in a state where a bypass path between the first LTE base station 10-1 and the second LTE base station 10-2 is not established, Alternatively, the second LTE base station 10-2 and the second CDMA base station 20-2 are not connected via the communication line 150-2. When the first response message indicates that relay communication is not possible, the relay communication processing unit 26 in the first CDMA base station 20-1 transmits the first relay inquiry message again after a predetermined time has elapsed.

  On the other hand, when the first response message indicates that relay communication is possible, the relay communication processing unit 26 in the first CDMA base station 20-1 passes through the LTE base station communication processing unit 23, and the second CDMA base station 20- A message (second relay inquiry message) for inquiring whether or not relay communication is possible is transmitted to 2. Information indicating that the second relay inquiry message is a message to be transmitted to the second CDMA base station 20-2 via the first LTE base station 10-1 and the second LTE base station 10-2 (CDMA relay discrimination information) including.

  The terminal relay communication processing unit 16 in the first LTE base station 10-1 receives the second relay inquiry message via the communication line 150-1 and the CDMA base station communication processing unit 13. The terminal relay communication processing unit 16 in the first LTE base station 10-1 should transmit the second relay inquiry message to the second CDMA base station 20-2 based on the CDMA relay determination information included in the second relay inquiry message. It is judged that. Next, the terminal relay communication processing unit 16 in the first LTE base station 10-1 includes LTE relay determination information in the second relay inquiry message. Furthermore, the terminal relay communication processing unit 16 in the first LTE base station 10-1 transmits the second relay inquiry message to the second LTE base station 10-2 via the wireless communication processing unit 11 and the detour path. In this case, the relay communication control unit 203 in the UE 200-2 or UE 200-3 receives the second relay inquiry message via the radio communication processing unit 201. The UE 200-2 or the relay communication control unit 203 in the UE 200-3 should transmit the second relay inquiry message to the second CDMA base station 20-2 based on the LTE relay determination information included in the second relay inquiry message. Judge that there is. Further, the relay communication control unit 203 in the UE 200-2 or UE 200-3 transmits the second relay inquiry message to the second LTE base station 10-2 via the radio communication processing unit 201.

  The terminal relay communication processing unit 16 in the second LTE base station 10-2 receives the second relay inquiry message via the wireless communication processing unit 11. Next, the terminal relay communication processing unit 16 in the second LTE base station 10-2 deletes the LTE relay determination information included in the second relay inquiry message. Further, the terminal relay communication processing unit 16 in the second LTE base station 10-2 transmits the second relay inquiry message to the second CDMA base station 20-2 based on the CDMA relay determination information included in the second relay inquiry message. Judge that it should be. Furthermore, the terminal relay communication processing unit 16 in the second LTE base station 10-2 sends a second relay inquiry message from which the LTE relay determination information has been deleted via the CDMA base station communication processing unit 13 and the communication line 150-2. Transmit to the second CDMA base station 20-2.

  The relay communication processing unit 26 in the second CDMA base station 20-2 receives the second relay inquiry message via the LTE base station communication processing unit 23. When the second CDMA base station 20-2 is connected to the CMDA backhaul, the relay communication processing unit 26 in the second CDMA base station 20-2 sends a second response message indicating that relay communication is possible. When the second CDMA base station 20-2 is not connected to the CMDA backhaul, a second response message indicating that relay communication is not possible is transmitted. The second response message is information indicating that it is a control message, and is a message to be transmitted to the first CDMA base station 20-1 via the second LTE base station 10-2 and the first LTE base station 10-1. Information (CDMA relay determination information).

  The terminal relay communication processing unit 16 in the second LTE base station 10-2 receives the second response message via the communication line 150-2 and the CDMA base station communication processing unit 13. The terminal relay communication processing unit 16 in the second LTE base station 10-2 should transmit the second response message to the first CDMA base station 20-1 based on the CDMA relay determination information included in the second response message. Judge. Next, the terminal relay communication processing unit 16 in the second LTE base station 10-2 includes LTE relay determination information in the second response message. Further, the terminal relay communication processing unit 16 in the second LTE base station 10-2 sends the second response message to the first LTE base station 10-1 via the wireless communication processing unit 11 and the detour path. Send. In this case, the relay communication control unit 203 in the UE 200-2 or the UE 200-3 receives the second response message via the wireless communication processing unit 201. Furthermore, when determining that the second response message includes the LTE relay determination information, the relay communication control unit 203 in the UE 200-2 or the UE 200-3 transmits the second response message via the wireless communication processing unit 201. To the first LTE base station 10-1.

  The terminal relay communication processing unit 16 in the first LTE base station 10-1 receives the second response message via the wireless communication processing unit 11. Next, the terminal relay communication processing unit 16 in the first LTE base station 10-1 deletes the LTE relay determination information included in the second response message. Furthermore, the terminal relay communication processing unit 16 in the first LTE base station 10-1 should transmit the second response message to the first CDMA base station 20-1 based on the CDMA relay determination information included in the second response message. Judge. Furthermore, the terminal relay communication processing unit 16 in the first LTE base station 10-1 sends the second response message from which the LTE relay determination information has been deleted via the CDMA base station communication processing unit 13 and the communication line 150-1. Transmit to the first CDMA base station 20-1.

  The relay communication processing unit 26 in the first CDMA base station 20-1 receives the second response message via the LTE base station communication processing unit 23.

  Through the processing described above, a communication path (CDMA transfer path) from the first CDMA base station 20-1 to the second CDMA base station 20-2 via the first LTE base station 10-1 and the second LTE base station 10-2 is established. Established.

  Thereafter, when the UE 200-1 connected to the first LTE base station 10-1 performs voice transmission, the following first process is performed. In addition, when a voice incoming call is made to the UE 200-1 connected to the first LTE base station 10-1, the following second process is performed. Further, after the first process or the second process, the following third process is performed.

(First process)
The communication control / processing unit 202 in the UE 200-1 transmits a voice call request message to the first LTE base station 10-1 via the wireless communication processing unit 201 in response to an operation of an operation unit (not shown) by the user. .

  The communication control unit 15 in the first LTE base station 10-1 receives the voice call request message via the wireless communication processing unit 11. The communication control unit 15 in the first LTE base station 10-1 outputs a voice call request message to the terminal relay communication processing unit 16 in the first LTE base station 10-1. The terminal relay communication processing unit 16 in the first LTE base station 10-1 includes LTE relay determination information in the input voice call request message. Further, the terminal relay communication processing unit 16 in the first LTE base station 10-1 sends a voice call request message including the LTE relay determination information to the second LTE base station 10- via the wireless communication processing unit 11 and the detour path. 2 to send. In this case, the relay communication control unit 203 in the UE 200-2 or UE 200-3 receives the voice call request message via the wireless communication processing unit 201. Further, when the relay communication control unit 203 in the UE 200-2 or the UE 200-3 determines that the voice call request message includes the LTE relay determination information, the relay communication control unit 203 sends the voice call request message to the radio communication processing unit 201. To the second LTE base station 10-2.

  The terminal relay communication processing unit 16 in the second LTE base station 10-2 receives the voice call request message via the wireless communication processing unit 11. Next, the terminal relay communication processing unit 16 in the second LTE base station 10-2 deletes the LTE relay determination information from the voice call request message. Furthermore, the terminal relay communication processing unit 16 in the second LTE base station 10-2 transmits the voice call request message from which the LTE relay determination information has been deleted to the MME 90 via the backhaul side communication processing unit 12 and the router 50. To do.

  The MME 90 receives the voice call request message. A wireless communication system corresponding to LTE is a wireless communication system for data communication that does not have a VoIP function. For this reason, the MME 90 changes the connection destination of the UE 200-1 from the first LTE base station 10-1 to the first LTE base station 10-1, and configures the first CDMA base station 20 constituting the radio communication system corresponding to CDMA. A handover command message for switching to -1 is transmitted to the second LTE base station 10-2. The handover command message includes information indicating that it is a control message.

  The terminal relay communication processing unit 16 in the second LTE base station 10-2 receives the handover command message via the router 50 and the backhaul side communication processing unit 12. Next, the terminal relay communication processing unit 16 in the second LTE base station 10-2 includes LTE relay determination information in the handover command message. Further, the terminal relay communication processing unit 16 in the second LTE base station 10-2 sends a handover command message including the LTE relay determination information to the first LTE base station 10-1 via the radio communication processing unit 11 and the detour path. Send to. In this case, the relay communication control unit 203 in the UE 200-2 or UE 200-3 receives the handover command message via the wireless communication processing unit 201. Further, when the relay communication control unit 203 in the UE 200-2 or the UE 200-3 determines that the handover command message includes the LTE relay determination information, the relay command control unit 203 transmits the handover command message via the wireless communication processing unit 201. Transmit to the first LTE base station 10-1.

  The terminal relay communication processing unit 16 in the first LTE base station 10-1 receives the handover command message via the wireless communication processing unit 11. Next, the terminal relay communication processing unit 16 in the first LTE base station 10-1 deletes the LTE relay determination information from the handover command message. Further, the terminal relay communication processing unit 16 in the first LTE base station 10-1 outputs a handover command message from which the LTE relay determination information has been deleted to the communication control unit 15 in the first LTE base station 10-1. The communication control unit 15 in the first LTE base station 10-1 transmits the input handover command message to the UE 200-1 via the radio communication processing unit 11.

  The communication control / processing unit 202 in the UE 200-1 receives the handover command message via the wireless communication processing unit 201. Furthermore, the communication control / processing unit 202 in the UE 200-1 connects to the first CDMA base station 20-1 according to the handover message.

  Next, the communication control / processing unit 202 in the UE 200-1 transmits a voice outgoing message to the first CDMA base station 20-1 via the wireless communication processing unit 201.

  The communication control unit 25 in the first CDMA base station 20-1 receives the voice transmission message via the wireless communication processing unit 21, and outputs it to the relay communication processing unit 26 in the first CDMA base station 20-1. The relay communication processing unit 26 in the first CDMA base station 20-1 transmits the voice transmission message to the second CDMA base station 20-2 via the first LTE base station 10-1 and the second LTE base station 10-2. Information indicating that the message should be included (CDMA relay determination information) is included. Further, the relay communication processing unit 26 in the first CDMA base station 20-1 transmits the voice outgoing message including the CDMA relay discrimination information to the first LTE base via the LTE base station communication processing unit 23 and the communication line 150-1. Transmit to station 10-1.

  The terminal relay communication processing unit 16 in the first LTE base station 10-1 receives the voice transmission message via the CDMA base station communication processing unit 13. The terminal relay communication processing unit 16 in the first LTE base station 10-1 determines that the voice outgoing message should be transmitted to the second CDMA base station 20-2 based on the CDMA relay discrimination information included in the voice outgoing message. To do. Next, the terminal relay communication processing unit 16 in the first LTE base station 10-1 includes LTE relay determination information in the voice outgoing message. Further, the terminal relay communication processing unit 16 in the first LTE base station 10-1 transmits a voice transmission message including the LTE relay determination information to the second LTE base station 10-2 via the wireless communication processing unit 11 and the detour path. Send to. In this case, the relay communication control unit 203 in the UE 200-2 or UE 200-3 receives the voice transmission message via the wireless communication processing unit 201. The UE 200-2 or the relay communication control unit 203 in the UE 200-3 determines that the voice call message should be transmitted to the second CDMA base station 20-2 based on the LTE relay determination information included in the voice call message. . Further, the relay communication control unit 203 in the UE 200-2 or the UE 200-3 transmits the voice transmission message to the second LTE base station 10-2 via the radio communication processing unit 201.

  The terminal relay communication processing unit 16 in the second LTE base station 10-2 receives the voice outgoing message via the wireless communication processing unit 11. Next, the terminal relay communication processing unit 16 in the second LTE base station 10-2 deletes the LTE relay determination information included in the voice outgoing message. Further, the terminal relay communication processing unit 16 in the second LTE base station 10-2 should transmit the voice outgoing message to the second CDMA base station 20-2 based on the CDMA relay discrimination information included in the voice outgoing message. Judge. Further, the terminal relay communication processing unit 16 in the second LTE base station 10-2 transmits the voice outgoing message from which the LTE relay determination information has been deleted via the CDMA base station communication processing unit 13 and the communication line 150-2. 2 Transmit to the CDMA base station 20-2.

  The relay communication processing unit 26 in the second CDMA base station 20-2 receives the voice outgoing message via the LTE base station communication processing unit 23. Next, the relay communication processing unit 26 in the second CDMA base station 20-2 deletes the CDMA relay determination information from the voice outgoing message. As a result, the voice transmission message is transmitted from the first CDMA base station 20-1 to the second CDMA base station 20-2 via the CDMA transfer path.

  The relay communication processing unit 26 in the second CDMA base station 20-2 transmits the voice outgoing message from which the CDMA relay determination information is deleted to the MSC / VLR 110 via the backhaul side communication processing unit 22 and the BSC 100. The MSC / VLR 110 receives the voice outgoing message.

(Second process)
When there is an incoming call addressed to the UE 200-1 connected to the first LTE base station 10-1, the MSC / VLR 110 transmits a general call message for calling the UE 200-1 to the MME 90. The MME 90 transmits a general call message via the router 50 to the first LTE base station 10-1 to which the UE 200-1 is connected.

  The backhaul side communication processing unit 12 in the first LTE base station 10-1 includes the first LTE base station 10-2, the UE 200-2 or the UE 200-3, and the radio communication processing unit 11 in the first LTE base station 10-1. A general call message is received through the network. Furthermore, the communication control unit 15 in the first LTE base station 10-1 transmits a general call message via the wireless communication processing unit 11.

  The communication control / processing unit 202 in the UE 200-1 receives the general call message. Furthermore, the communication control / processing unit 202 in the UE 200-1 transmits a CS service request message to the first LTE base station 10-1 in order to perform voice communication using the CS Fallback function.

  The communication control unit 15 in the first LTE base station 10-1 receives the CS service request message via the wireless communication processing unit 11. Further, the communication control unit 15 in the first LTE base station 10-1 connects the UE 200-1 from the first LTE base station 10-1 to the first LTE base station 10-1, and supports CDMA. A handover command message for switching to the first CDMA base station 20-1 configuring the radio communication system is transmitted to the UE 200-1 via the radio communication processing unit 11.

  The communication control / processing unit 202 in the UE 200-1 receives the handover command message via the wireless communication processing unit 201. Furthermore, the communication control / processing unit 202 in the UE 200-1 connects to the first CDMA base station 20-1 according to the handover message.

  Next, the communication control / processing unit 202 in the UE 200-1 transmits a general call response message, which is a response to the general call message, to the first CDMA base station 20-1 via the wireless communication processing unit 201.

  The communication control unit 25 in the first CDMA base station 20-1 receives the simultaneous call response message via the wireless communication processing unit 21. The communication control unit 25 in the first CDMA base station 20-1 outputs a simultaneous call response message to the relay communication processing unit 26 in the first CDMA base station 20-1.

  The relay communication processing unit 26 in the first CDMA base station 20-1 is transmitted to the second CDMA base station 20-2 via the first LTE base station 10-1 and the second LTE base station 10-2 in a simultaneous call response message. Information indicating that the message should be included (CDMA relay determination information) is included. Further, the relay communication processing unit 26 in the first CDMA base station 20-1 sends a general call response message including the CDMA relay discrimination information to the first LTE via the LTE base station communication processing unit 23 and the communication line 150-1. Transmit to the base station 10-1.

  The terminal relay communication processing unit 16 in the first LTE base station 10-1 receives the simultaneous call response message via the CDMA base station communication processing unit 13. The terminal relay communication processing unit 16 in the first LTE base station 10-1 should transmit the paging response message to the second CDMA base station 20-2 based on the CDMA relay determination information included in the paging response message. Judge. Next, the terminal relay communication processing unit 16 in the first LTE base station 10-1 includes LTE relay determination information in the simultaneous call response message. Furthermore, the terminal relay communication processing unit 16 in the first LTE base station 10-1 transmits a general call response message to the second LTE base station 10-2 via the wireless communication processing unit 11 and the detour path. In this case, the relay communication control unit 203 in the UE 200-2 or the UE 200-3 receives the general call response message via the wireless communication processing unit 201. The relay communication control unit 203 in the UE 200-2 or the UE 200-3 should transmit the paging response message to the second LTE base station 10-2 based on the LTE relay determination information included in the paging response message. to decide. Furthermore, the relay communication control unit 203 in the UE 200-2 or the UE 200-3 transmits a paging response message to the second LTE base station 10-2 via the radio communication processing unit 201.

  The terminal relay communication processing unit 16 in the second LTE base station 10-2 receives the simultaneous call response message via the wireless communication processing unit 11. Next, the terminal relay communication processing unit 16 in the second LTE base station 10-2 deletes the LTE relay determination information from the simultaneous call response message. The terminal relay communication processing unit 16 in the second LTE base station 10-2 should transmit the general call response message to the second CDMA base station 20-2 based on the CDMA relay determination information included in the general call response message. Judge. Furthermore, the terminal relay communication processing unit 16 in the second LTE base station 10-2 transmits a general call response message to the second CDMA base station 20-2 via the CDMA base station communication processing unit 13 and the communication line 150-2. To do.

  The relay communication processing unit 26 in the second CDMA base station 20-2 receives the simultaneous call response message via the LTE base station communication processing unit 23. Next, the relay communication processing unit 26 in the second CDMA base station 20-2 deletes the CDMA relay determination information from the simultaneous call response message. As a result, the paging response message is transmitted from the first CDMA base station 20-1 to the second CDMA base station 20-2 via the CDMA transfer path.

  Further, the relay communication processing unit 26 in the second CDMA base station 20-2 transmits a general call response message from which the CDMA relay determination information is deleted to the MSC / VLR 110 via the backhaul side communication processing unit 22 and the BSC 100. To do.

  MSC / VLR 110 receives the paging response message. The MSC / VLR 110 transmits a voice outgoing message to the second CDMA base station 20-2 via the BSC 100.

  The relay communication processing unit 26 in the second CDMA base station 20-2 receives the voice outgoing message via the backhaul side communication processing unit 22. The relay communication processing unit 26 in the second CDMA base station 20-2 transmits the voice outgoing message to the first CDMA base station 20-1 via the second LTE base station 10-2 and the first LTE base station 10-1. Information indicating that the message should be included (CDMA relay determination information) is included. Further, the relay communication processing unit 26 in the second CDMA base station 20-2 sends the voice outgoing message including the CDMA relay discrimination information to the second LTE base via the LTE base station communication processing unit 23 and the communication line 150-2. Transmit to station 10-2.

  The terminal relay communication processing unit 16 in the second LTE base station 10-2 receives the voice transmission message via the CDMA base station communication processing unit 13. The terminal relay communication processing unit 16 in the second LTE base station 10-2 determines that the voice outgoing message should be transmitted to the first CDMA base station 20-1 based on the CDMA relay discrimination information included in the voice outgoing message. To do. Next, the terminal relay communication processing unit 16 in the second LTE base station 10-2 includes LTE relay determination information in the voice outgoing message. Furthermore, the terminal relay communication processing unit 16 in the second LTE base station 10-2 transmits a voice transmission message to the first LTE base station 10-1 via the wireless communication processing unit 11 and the detour path. In this case, the relay communication control unit 203 in the UE 200-2 or UE 200-3 receives the voice transmission message via the wireless communication processing unit 201. The UE 200-2 or the relay communication control unit 203 in the UE 200-3 determines that the voice transmission message should be transmitted to the first LTE base station 10-1 based on the LTE relay determination information included in the voice transmission message. . Furthermore, the relay communication control unit 203 in the UE 200-2 or the UE 200-3 transmits a voice transmission message to the first LTE base station 10-1 via the radio communication processing unit 201.

  The terminal relay communication processing unit 16 in the first LTE base station 10-1 receives the voice outgoing message via the wireless communication processing unit 11. Next, the terminal relay communication processing unit 16 in the first LTE base station 10-1 deletes the LTE relay determination information from the voice call message. The terminal relay communication processing unit 16 in the first LTE base station 10-1 determines that the voice outgoing message should be transmitted to the first CDMA base station 20-1 based on the CDMA relay discrimination information included in the voice outgoing message. To do. Furthermore, the terminal relay communication processing unit 16 in the first LTE base station 10-1 transmits a voice transmission message to the first CDMA base station 20-1 via the CDMA base station communication processing unit 13 and the communication line 150-1. .

  The relay communication processing unit 26 in the first CDMA base station 20-1 receives the voice outgoing message via the LTE base station communication processing unit 23. Further, the relay communication processing unit 26 in the first CDMA base station 20-1 deletes the relay discrimination information from the voice transmission message and outputs it to the communication control unit 25 in the first CDMA base station 20-1. As a result, the voice transmission message is transmitted from the second CDMA base station 20-2 to the first CDMA base station 20-1 via the CDMA transfer path.

  The communication control unit 25 in the first CDMA base station 20-1 transmits the voice transmission message from which the relay determination information is removed to the UE 200-1 via the radio communication processing unit 21.

  The communication control / processing unit 202 in the UE 200-1 receives the voice outgoing message via the wireless communication processing unit 201.

(Third process)
After the first process or the second process, the communication control / processing unit 202 in the UE 200-1 transmits an audio signal via the wireless communication processing unit 201.

  The relay communication processing unit 26 in the first CDMA base station 20-1 receives the audio signal via the wireless communication processing unit 21. The relay communication processing unit 26 in the first CDMA base station 20-1 converts the voice signal into a voice packet and then sends the voice packet to the first LTE base station 10-1 and the second LTE base station 10-2. Information (CDMA relay determination information) indicating that the packet is to be transmitted to the second CDMA base station 20-2 is included. Further, the relay communication processing unit 26 in the first CDMA base station 20-1 transmits the voice packet including the CDMA relay determination information to the first LTE base station via the LTE base station communication processing unit 23 and the communication line 150-1. Send to 10-1.

  The terminal relay communication processing unit 16 in the first LTE base station 10-1 receives the voice packet via the CDMA base station communication processing unit 13. The terminal relay communication processing unit 16 in the first LTE base station 10-1 determines that the voice packet should be transmitted to the second CDMA base station 20-2 based on the CDMA relay discrimination information included in the voice packet. Next, the terminal relay communication processing unit 16 in the first LTE base station 10-1 includes LTE relay determination information in the voice packet. Furthermore, the terminal relay communication processing unit 16 in the first LTE base station 10-1 transmits the voice packet to the second LTE base station 10-2 via the wireless communication processing unit 11 and the detour path. In this case, the relay communication control unit 203 in the UE 200-2 or UE 200-3 receives the voice packet via the wireless communication processing unit 201. The relay communication control unit 203 in the UE 200-2 or the UE 200-3 determines that the voice packet should be transmitted to the second LTE base station 10-2 based on the LTE relay determination information included in the voice packet. Furthermore, the relay communication control unit 203 in the UE 200-2 or the UE 200-3 transmits the voice packet to the second LTE base station 10-2 via the radio communication processing unit 201.

  The terminal relay communication processing unit 16 in the second LTE base station 10-2 receives the voice packet via the wireless communication processing unit 11. Next, the terminal relay communication processing unit 16 in the second LTE base station 10-2 deletes the LTE relay determination information from the voice packet. Further, the terminal relay communication processing unit 16 in the second LTE base station 10-2 determines that the voice packet should be transmitted to the second CDMA base station 20-2 based on the CDMA relay discrimination information included in the voice packet. To do. Further, the terminal relay communication processing unit 16 in the second LTE base station 10-2 transmits the voice packet to the second CDMA base station 20-2 via the CDMA base station communication processing unit 13 and the communication line 150-2.

  The relay communication processing unit 26 in the second CDMA base station 20-2 receives the voice packet via the LTE base station communication processing unit 23. Further, the relay communication processing unit 26 in the second CDMA base station 20-2 deletes the CDMA relay discrimination information from the voice packet and generates voice data. As a result, the voice data is transmitted from the first CDMA base station 20-1 to the second CDMA base station 20-2 via the CDMA transfer path.

  The relay communication processing unit 26 in the second CDMA base station 20-2 transmits voice data to the MSC / VLR 110 via the backhaul side communication processing unit 22 and the BSC 100. The MSC / VLR 110 receives audio data.

  On the other hand, the MSC / VLR 110 transmits voice data addressed to the UE 200-1 to the second CDMA base station 20-2 via the BSC 100.

  The relay communication processing unit 26 in the second CDMA base station 20-2 receives the voice data via the backhaul side communication processing unit 22. The relay communication processing unit 26 in the second CDMA base station 20-2 generates a voice packet from the voice data. The relay communication processing unit 26 in the second CDMA base station 20-2 should transmit the voice packet to the first CDMA base station 20-1 via the second LTE base station 10-2 and the first LTE base station 10-1. Information indicating that it is a packet (CDMA relay discrimination information) is included. Further, the relay communication processing unit 26 in the second CDMA base station 20-2 transmits the voice packet including the CDMA relay determination information to the second LTE base station via the LTE base station communication processing unit 23 and the communication line 150-2. Send to 10-2.

  The terminal relay communication processing unit 16 in the second LTE base station 10-2 receives the voice packet via the CDMA base station communication processing unit 13. The terminal relay communication processing unit 16 in the second LTE base station 10-2 determines that the voice packet should be transmitted to the first CDMA base station 20-1 based on the CDMA relay discrimination information included in the voice packet. Next, the terminal relay communication processing unit 16 in the second LTE base station 10-2 includes LTE relay determination information in the voice packet. Further, the terminal relay communication processing unit 16 in the second LTE base station 10-2 transmits the voice packet to the first LTE base station 10-1 via the wireless communication processing unit 11 and the detour path. In this case, the relay communication control unit 203 in the UE 200-2 or UE 200-3 receives the voice packet via the wireless communication processing unit 201. The relay communication control unit 203 in the UE 200-2 or the UE 200-3 determines that the voice packet should be transmitted to the first LTE base station 10-1 based on the LTE relay determination information included in the voice packet. Furthermore, the relay communication control unit 203 in the UE 200-2 or UE 200-3 transmits the voice packet to the first LTE base station 10-1 via the radio communication processing unit 201.

  The terminal relay communication processing unit 16 in the first LTE base station 10-1 receives the voice packet via the wireless communication processing unit 11. Next, the terminal relay communication processing unit 16 in the first LTE base station 10-1 deletes the LTE relay determination information from the voice packet. Further, the terminal relay communication processing unit 16 in the first LTE base station 10-1 determines that the voice packet should be transmitted to the first CDMA base station 20-1 based on the CDMA relay discrimination information included in the voice packet. To do. Further, the terminal relay communication processing unit 16 in the first LTE base station 10-1 transmits the voice packet to the first CDMA base station 20-1 via the CDMA base station communication processing unit 13 and the communication line 150-1.

  The relay communication processing unit 26 in the first CDMA base station 20-1 receives the voice packet via the LTE base station communication processing unit 23. Next, the relay communication processing unit 26 in the first CDMA base station 20-1 deletes the CDMA relay discrimination information from the voice packet, and converts the voice packet into a voice signal. As a result, the voice signal is transmitted from the second CDMA base station 20-2 to the first CDMA base station 20-1 via the CDMA transfer path. Further, the relay communication processing unit 26 in the first CDMA base station 20-1 transmits a voice signal to the UE 200-1 via the radio communication processing unit 21.

  The communication control / processing unit 202 in the UE 200-1 receives the audio signal via the wireless communication processing unit 201.

(2) Operation of Radio Communication System (2.1) First Operation FIG. 5 is a sequence diagram showing a first operation of the radio communication system 1. The first operation corresponds to the case where the first process and the third process described above are performed.

  In step S101, the first CDMA base station 20-1 detects disconnection of the CDMA backhaul line.

  In step S102, the first LTE base station 10-1 detects disconnection of the LTE backhaul line. In step S103, the first LTE base station 10-1 and the second LTE base station 10-2 establish a bypass route.

  In step S104, the first CDMA base station 20-1 transmits a first relay inquiry message to the first LTE base station 10-1. The first LTE base station 10-1 receives the first relay inquiry message and transmits the first inquiry message to the second LTE base station 10-2. The second LTE base station 10-2 receives the second inquiry message.

  In step S105, the second LTE base station 10-2 transmits a first response message to the first LTE base station 10-1. The first LTE base station 10-1 receives the first response message and transmits the first response message to the first CDMA base station 20-1. The first CDMA base station 20-1 receives the first response message.

  In step S106, the first CDMA base station 20-1 transmits a second relay inquiry message to the second CDMA base station 20-2. The second CDMA base station 20-2 receives the second relay inquiry message.

  In step S107, the second CDMA base station 20-2 transmits a second response message to the first CDMA base station 20-1. The first CDMA base station 20-1 receives the second response message. In step S108, a CDMA transfer path is established between the first CDMA base station 20-1 and the second CDMA base station 20-2 via the first LTE base station 10-1 and the second LTE base station 10-2.

  In step S109, the UE 200-1 transmits a voice call request message to the first LTE base station 10-1. The first LTE base station 10-1 receives the voice call request message and transmits the voice call request message to the second LTE base station 10-2. The second LTE base station 10-2 receives the voice call request message and transmits the voice call request message to the MME 90. The MME 90 receives the voice call request message.

  In step S111, the MME 90 transmits a handover command message to the second LTE base station 10-2. The second LTE base station 10-2 receives the handover command message and transmits the handover command message to the first LTE base station 10-1. The first LTE base station 10-1 receives the handover command message and transmits the handover command message to the UE 200-1. The UE 200-1 receives the handover command message.

  In step S112, the UE 200-1 connects to the first CDMA base station 20-1.

  In step S113, the UE 200-1 transmits a voice transmission message to the first CDMA base station 20-1. The first CDMA base station 20-1 receives the voice transmission message and transmits the voice transmission message to the second CDMA base station 20-2. The second CDMA base station 20-2 receives the voice call message and transmits the voice call message to the MSC / VLR 110. The MSC / VLR 110 receives the voice outgoing message.

  In step S114, the UE 200-1 transmits a voice signal to the first CDMA base station 20-1. The first CDMA base station 20-1 receives an audio signal. In step S115, the first CDMA base station 20-1 transmits a voice packet to the second CDMA base station 20-2. The second CDMA base station 20-2 receives the voice packet. In step S116, the second CDMA base station 20-2 transmits the voice data to the MSC / VLR 110. The MSC / VLR 110 receives audio data.

  In step S117, the MSC / VLR 110 transmits voice data to the second CDMA base station 20-2. The second CDMA base station 20-2 receives the voice data. In step S118, the second CDMA base station 20-2 transmits a voice packet to the first CDMA base station 20-1. The first CDMA base station 20-1 receives the voice packet. In step S119, the first CDMA base station 20-1 transmits an audio signal to the UE 200-1. The UE 200-1 receives an audio signal.

(2.2) Second Operation FIG. 6 is a sequence diagram showing a second operation of the wireless communication system 1. The second operation corresponds to the case where the above-described second process and third process are performed.

  Since the operations from step S201 to step S208 are the same as the operations from step S101 to step S108 of FIG.

  In step S209, the MSC / VLR 110 transmits a general call message to the MME 90. The MME 90 receives the general call message and transmits the general call message to the first LTE base station 10-1. The first LTE base station 10-1 receives the general call message and transmits the general call message to the UE 200-1. The UE 200-1 receives the general call message.

  In step S210, the UE 200-1 transmits a CS service request message to the first LTE base station 10-1. The first LTE base station 10-1 receives the CS service request message.

  In step S211, the first LTE base station 10-1 transmits a handover command message to the UE 200-1. The UE 200-1 receives the handover command message.

  In step S212, the UE 200-1 connects to the first CDMA base station 20-1.

  In step S213, the UE 200-1 transmits a general call response message to the first CDMA base station 20-1. The first CDMA base station 20-1 receives the paging response message and transmits the paging response message to the second CDMA base station 20-2. The second CDMA base station 20-2 receives the general call response message and transmits the general call response message to the MSC / VLR 110. MSC / VLR 110 receives the paging response message.

  In step S214, the MSC / VLR 110 transmits a voice transmission message to the second CDMA base station 20-2. The second CDMA base station 20-2 receives the voice transmission message and transmits the voice transmission message to the first CDMA base station 20-1. The first CDMA base station 20-1 receives the voice call message and transmits the voice call message to the UE 200-1. The UE 200-1 receives the voice outgoing message.

  The operations in steps S215 to S220 are the same as the operations in steps S114 to S119 in FIG.

(3) Operation and Effect The wireless communication system 1 according to the present embodiment includes a first LTE base station 10-1 in a wireless communication system compatible with LTE, and a first CDMA base station 20- in a wireless communication system compatible with CDMA. 1 are communicably connected to each other via a communication line 150-1, and the second LTE base station 10-2 in the radio communication system corresponding to LTE and the second CDMA base station 20 in the radio communication system corresponding to CDMA are connected. -2 are communicably connected to each other via a communication line 150-2. When disconnection of the CDMA backhaul line is detected in the first CDMA base station 20-1, the radio communication system 1 transmits the first CDMA base station via the first LTE base station 10-1 and the second LTE base station 10-2. A communication path (CDMA transfer path) between 20-1 and the second CDMA base station 20-2 is established. Therefore, even if the first CDMA base station 20-1 and the second CDMA base station 20-2 cannot communicate directly, by establishing a CDMA transfer path, The first CDMA base station 20-1 and the MSC / VLR 110 can communicate with each other.

  Further, when the UE 200-1 connected to the first LTE base station 10-1 in the wireless communication system corresponding to LTE for data communication performs voice communication, the first LTE base station 10-1 1, a handover command message is transmitted to switch the connection destination of the UE 200-1 to the first CDMA base station 20-1 in the system corresponding to CDMA for voice communication. For this reason, when a radio communication system compatible with LTE and a radio communication system compatible with CDMA are provided together, it is possible to select an appropriate radio communication system according to the communication content.

(4) Other Embodiments As described above, the present invention has been described according to the embodiment. However, it should not be understood that the description and drawings constituting a part of this disclosure limit the present invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art.

  In the above-described embodiment, the first LTE base station 10-1 and the second LTE base station 10-2 have established a detour path via the UE 200-2 or the like. However, the first LTE base station 10-1 and the second LTE base station 10-2 may establish a bypass route via a wireless communication device (for example, a relay node) other than the UE. Alternatively, the first LTE base station 10-1 and the second LTE base station 10-2 may establish a detour path using the X2 interface without going through another wireless communication device.

  In the embodiment described above, the CDMA transfer path is established when the CDMA backhaul line is disconnected. However, the CDMA transfer path may be established when a predetermined condition regarding the CDMA backhaul, for example, the amount of traffic on the CDMA backhaul line is equal to or greater than a predetermined threshold.

  In the above-described embodiment, when relaying is performed by the UE 200-2 or the like, the cell formed by the first LTE base station 10-1 and the cell formed by the second LTE base station 10-2 are different. Although it is assumed that frequency channels are used, interference can be suppressed by using SDMA or OFDM subchannels even when the same frequency channel is used. Also, the UE 200-2 or the like can suppress interference by switching the connection-destination LTE base station in time division by TDMA. Furthermore, when there are a plurality of UEs, the UEs can perform transfer via a plurality of UEs by performing communication using another method such as Bluetooth (registered trademark) communication or infrared communication.

  In the above-described embodiment, the radio communication system 1 is configured by a radio communication system compatible with LTE and a radio communication system compatible with CDMA. In this case, the present invention can be similarly applied.

  Thus, it should be understood that the present invention includes various embodiments and the like not described herein. Therefore, the present invention is limited only by the invention specifying matters in the scope of claims reasonable from this disclosure.

  DESCRIPTION OF SYMBOLS 1 ... Wireless communication system 10-1 ... 1st LTE base station, 10-2 ... 2nd LTE base station, 11 ... Wireless communication processing part, 12 ... Communication control / processing part, 13 ... CDMA communication processing part, 14 ... Backhaul side Line monitoring unit, 15 ... terminal relay communication control unit, 16 ... terminal relay communication processing unit 16, 20-1 ... first CDMA base station, 20-2 ... second CDMA base station, 21 ... radio communication processing unit, 22 ... backhaul Side communication processing unit, 23 ... LTE relay communication processing unit, 24 ... backhaul side line monitoring unit, 25 ... LTE relay communication control unit, 50 ... router, 60 ... S-GW, 70 ... P-GW, 80 ... IMS, 90 ... MME, 100 ... BSC, 110 ... MSC / VLR, 120 ... GMCS, 130 ... switch, 140 ... HSS, 150-1, 150-2 ... communication line, 151 ... network, 200- , 200-2,200-3 ... UE

Claims (8)

A first wireless base having a first system corresponding to a first wireless communication system and a second system corresponding to a second wireless communication system, the first system being capable of communicating with each other A second radio base station, and the second system includes a third radio base station, a fourth radio base station, and an upper node that can communicate with each other, and the first radio base station A wireless communication system in which the third wireless base station is connected to be able to communicate with each other, and the second wireless base station and the fourth wireless base station are connected to be able to communicate with each other. ,
A wireless communication system for establishing a communication path between the third wireless base station and the fourth wireless base station via the first wireless base station and the second wireless base station. The third radio base station is
Information for inquiring of the first radio base station, the second radio base station, and the fourth radio base station whether or not the relay of communication between the third radio base station and the upper node is possible The wireless communication system according to claim 1, which transmits The first radio base station, the second radio base station, and the fourth radio base station are:
The wireless communication system according to claim 2, wherein information on whether to relay communication between the third wireless base station and the upper node is transmitted. The first system is a system for data communication,
The wireless communication system according to claim 1, wherein the second system is a voice communication system. The first radio base station is
5. The wireless communication according to claim 4, wherein, when a connected wireless terminal transmits voice communication, information for switching the connection destination of the wireless terminal to the third wireless base station is transmitted to the wireless terminal. system. The first radio base station is
5. The wireless communication according to claim 4, wherein, when a connected wireless terminal makes an incoming voice communication, information for switching the connection destination of the wireless terminal to the third wireless base station is transmitted to the wireless terminal. system. A wireless base station in a first system corresponding to a first wireless communication method,
Connected to the first other radio base station in the second system corresponding to the second radio communication system in a communicable manner;
The second other radio base station via the own radio base station and the second other radio base station in the first system, and the third other radio base station in the second system; A wireless base station that establishes a communication path between. A first wireless base having a first system corresponding to a first wireless communication system and a second system corresponding to a second wireless communication system, the first system being capable of communicating with each other A second radio base station, and the second system includes a third radio base station, a fourth radio base station, and an upper node that can communicate with each other, and the first radio base station Communication control in a radio communication system in which the third radio base station is connected to be communicable with each other, and the second radio base station and the fourth radio base station are connected to be communicable with each other. A method,
A communication control method including a step of establishing a communication path between the third radio base station and the fourth radio base station via the first radio base station and the second radio base station.

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