Wireless communication systems and central stations

Abstract

When a mobile station (150) establishes synchronization with a first base station (130A), the mobile station (150) transmits, to the first base station (130A), first on-rail information that is on-rail information indicating that the mobile station (150) can receive a signal from the first base station (130A), the first base station (130A) transmits the first on-rail information to a first central station (110A), and the first central station (110A) transfers the first on-rail information to a second central station (110B). When the mobile station (150) establishes synchronization with a second base station (130B), the mobile station (150) transmits, to the second base station (130B), second on-rail information that is on-rail information indicating that the mobile station (150) can receive a signal from the second base station (130B), the second base station (130B) transmits the second on-rail information to the second central station (110B), and the second central station (110B) transfers the second on-rail information to the first central station (110A).

Description

wireless communication system

[0001] The present disclosure relates to wireless communication systems.

[0002] As a conventional technology, there is a train wireless communication system that includes a mobile station mounted on a train, a base station installed along the track on which the train runs, and a central station that performs voice communication with the mobile station via the base station (see, for example, Patent Document 1).

[0003] JP 2014-60668 A

[0004] In a train radio communication system that accommodates two different voice communication methods, as in Patent Document 1, a train may move across the communication areas covered by each method. In such a case, when a train crew member in a boundary zone between the two voice communication methods talks to a dispatcher at a control center that manages train operations, etc., it is necessary to consider that the train will move from the area covered by the currently existing voice communication method to an area covered by the other voice communication method.

[0005] However, conventional train radio communication systems have not taken into consideration the fact that the area in which both voice communication methods can be used is wide due to the overreach of highly directional radio waves. As a result, when a train crew member makes a call as described above, the mobile station on the train selects one of the voice communication methods from the radio synchronization state and transmits the call to the central station. However, if the selected voice communication method is different from the voice communication method that should be covered in that area, the voice communication may not be established at the control center that has jurisdiction over that voice communication method, but may be established at the control center that has jurisdiction over the other voice communication method.

[0006] Therefore, one or more aspects of the present disclosure aim to enable appropriate association of the wireless communication method to be used near the boundary between different audio communication methods in a wireless communication system.

[0007] A wireless communication system according to one aspect of the present disclosure includes a mobile station that performs wireless communication using a first wireless communication method and a second wireless communication method different from the first wireless communication method, the mobile station, a first base station that performs wireless communication using the first wireless communication method, the mobile station, a second base station that performs wireless communication using the second wireless communication method, a first central station connected to the first base station, and a second central station connected to the second base station, wherein the first central station and the second central station are capable of communicating with each other, and when the mobile station establishes synchronization with the first base station, the mobile station transmits the wireless communication signal to the first base station. and when the mobile station establishes synchronization with the second base station, the mobile station transmits to the second base station second track information, which is track information indicating that the mobile station can receive signals from the second base station, the first base station transmits the first track information to the first central station, the first central station forwards the first track information to the second central station, and when the mobile station establishes synchronization with the second base station, the mobile station transmits to the second base station second track information, which is track information indicating that the mobile station can receive signals from the second base station, the second base station transmits the second track information to the second central station, and the second central station forwards the second track information to the first central station.

[0008] According to one or more aspects of the present disclosure, in a wireless communication system, it is possible to appropriately link the wireless communication method to be used near the boundary between different voice communication methods.

[0009] FIG. 1 is a block diagram schematically showing the configuration of a train wireless communication system. FIG. 2 is a graph showing characteristics of radio waves used in a first wireless communication method and a second wireless communication method. FIG. 3 is a first example showing a relationship between a boundary where communication can be performed using the first wireless communication method, a boundary where communication can be performed using the second wireless communication method, and a mobile station. FIG. 4 is a block diagram schematically showing the configuration of a central station. FIGS. 1A and 1B are block diagrams showing an example of a hardware configuration. FIG. 5 is a block diagram schematically showing the configuration of a base station. FIG. 6 is a block diagram schematically showing the configuration of a mobile station. FIG. 7 is a sequence diagram showing a first example of handover operation in the first embodiment. FIG. 8 is a second example showing a relationship between a boundary where communication can be performed using the first wireless communication method, a boundary where communication can be performed using the second wireless communication method, and a mobile station. FIG. 9 is a sequence diagram showing a second example of handover operation in the first embodiment. FIG. 10 is a fourth example showing a relationship between a boundary where communication can be performed using the first wireless communication method, a boundary where communication can be performed using the second wireless communication method, and a mobile station. Fig. 10 is a fifth example showing a relationship between a boundary where communication can be performed using a first wireless communication method, a boundary where communication can be performed using a second wireless communication method, and a mobile station. Fig. 11 is a sixth example showing a relationship between a boundary where communication can be performed using a first wireless communication method, a boundary where communication can be performed using a second wireless communication method, and a mobile station. Fig. 12 is a sequence diagram showing a first example of handover operation in embodiment 2. Fig. 13 is a sequence diagram showing a second example of handover operation in embodiment 2.

[0010] First Embodiment. Fig. 1 is a block diagram showing a schematic configuration of a train wireless communication system 100 according to a first embodiment. The train wireless communication system 100 includes a ground station system 101 and a mobile station 150. The ground station system 101 also includes a first central station 110A and first base stations 130A#1 and 130A#2 that use a first wireless communication scheme, and a second central station 110B and second base stations 130B#1 and 130B#2 that use a second wireless communication scheme that conforms to a protocol different from the first wireless communication scheme. The mobile station 150 performs wireless communication using both the first wireless communication scheme and the second wireless communication scheme. Here, the mobile station 150 is mounted on a train (not shown) and moves as the train moves.

[0011] The train wireless communication system 100 uses the first wireless communication method and the second wireless communication method to perform voice calls between the first central station 110A and the second central station 110B and the mobile station 150. The first central station 110A and the second central station 110B are also configured to be able to communicate with each other.

[0012] Hereinafter, when there is no need to particularly distinguish between the first central office 110A and the second central office 110B, each of the first central office 110A and the second central office 110B will be referred to as a central office 110. When there is no need to particularly distinguish between the first base station 130A#1 and the first base station 130A#2, each of the first base station 130A#1 and the first base station 130A#2 will be referred to as a first base station 130A. When there is no need to particularly distinguish between the second base station 130B#1 and the second base station 130B#2, each of the second base station 130B#1 and the second base station 130B#2 will be referred to as a second base station 130B. Furthermore, when there is no need to particularly distinguish between the first base station 130A and the second base station 130B, each of the first base station 130A and the second base station 130B will be referred to as a base station 130.

[0013] The number of the first base stations 130A#1 and the first base stations 130A#2 included in the train wireless communication system 100 is not limited to 2, but may be 1 or more. The number of the second base stations 130B#1 and the second base stations 130B#2 included in the train wireless communication system 100 is also not limited to 2, but may be 1 or more.

[0014] A wireless communication system boundary 102 is set between a first base station 130A#2 that uses a first wireless communication system and a second base station 130B#1 that uses a second wireless communication system. When the mobile station 150 is located on the first base station 130A side of the wireless communication system boundary 102, the first central station 110A is under the control of the command center, and when the mobile station 150 is located on the second base station 130B side of the wireless communication system boundary 102, the second central station 110B is under the control of the command center.

[0015] Fig. 2 is a graph showing the characteristics of radio waves used in the first and second wireless communication methods. Line L1 in Fig. 2 shows the field strength of radio waves used in the first wireless communication method at different distances from the base station, and line L2 in Fig. 2 shows the field strength of radio waves used in the second wireless communication method at different distances from the base station.

[0016] As shown by line L1, the radio waves used in the first wireless communication method have a characteristic that the field strength is almost constant in a communication area and drops sharply near the boundary between the communication area and the non-communication area. For this reason, the wireless communication method boundary 102 is set near the boundary between the communication area and the non-communication area. For example, the first wireless communication method is a wireless communication method using LCX (Leaky CoXial cable).

[0017] On the other hand, as shown by line L2, the radio waves used in the second wireless communication method have a characteristic in which the electric field strength decreases according to the inverse square law as the distance from the source of the radio waves increases. For example, the second wireless communication method is a wireless communication method using an antenna.

[0018] 2, as shown in Fig. 3, a boundary 103 where communication can be performed using the first wireless communication method is located near the wireless communication method boundary 102, and a boundary 104 where communication can be performed using the second wireless communication method is located away from the wireless communication method boundary 102. An area 105 between the boundaries 103 and 104 is an area where communication is possible using both the first and second wireless communication methods. Therefore, the first base station 130A#2 can establish wireless synchronization with the mobile station 150 up to the boundary 103, and the second base station 130B has a large overreach and can establish wireless synchronization with the mobile station 150 up to the boundary 104.

[0019] 4 is a block diagram showing a schematic configuration of the central station 110. The central station 110 includes a communication unit 111, a communication control unit 112, and a command console 113.

[0020] The communication unit 111 communicates with other central stations 110 and base stations 130. For example, the communication unit 111 is connected to other central stations 110 and base stations 130, and communicates with the other central stations 110 and base stations 130 connected thereto.

[0021] The communication control unit 112 controls communication via the communication unit 111. For example, the communication control unit 112 receives track location information from the base station 130 or another central office 110 via the communication unit 111, and provides the track location information to the command console 113. The communication control unit 112 also sends track location information from the base station 130 to another central office 110 via the communication unit 111. The communication control unit 112 also receives call control status information from the base station 130 or another central office 110 via the communication unit 111, and provides the call control status information to the command console 113. The communication control unit 112 also sends call control status information from the base station 130 to another central office 110 via the communication unit 111.

[0022] The command console 113 functions as a central office control unit that controls the central office 110, a display unit that displays the screen, an audio output unit that is a speaker for voice calls, and an audio input unit that is a microphone for voice calls. This allows the command console 113 to check the content of calls. Checking the content of calls means displaying which base station 130 the mobile station 150 is connected to and being able to make and receive calls to and from that mobile station 150.

[0023] Here, the command console 113 of the first central office 110A can use the first call control method but cannot use the second call control method, while the command console 113 of the second central office 110B can use the second call control method but cannot use the first call control method.

[0024] In the following explanation, the communication unit 111, communication control unit 112, and command console 113 of the first central station 110A will also be referred to as the communication unit 111A, communication control unit 112A, and command console 113A, and the communication unit 111, communication control unit 112, and command console 113 of the second central station 110B will also be referred to as the communication unit 111B, communication control unit 112B, and command console 113B.

[0025] As shown in FIG. 5A, part or all of the central office control unit and communication control unit 112 described above can be configured with a memory 10 and a processor 11 such as a CPU (Central Processing Unit) that executes a program stored in the memory 10. Such a program may be provided over a network or may be provided by being recorded on a recording medium. That is, such a program may be provided as a program product, for example.

[0026] 5B, the central office control unit and the communication control unit 112 may be partially or entirely implemented as a processing circuit 12 such as a single circuit, a composite circuit, a programmable processor, a programmable parallel processor, an ASIC (Application Specific Integrated Circuit), or an FPGA (Field Programmable Gate Array). As described above, the central office control unit and the communication control unit 112 may be implemented as a processing circuit network.

[0027] The communication unit 111 can be realized by a communication interface such as a NIC (Network Interface Card).

[0028] 6 is a block diagram showing a schematic configuration of the base station 130. The base station 130 includes a central station side communication unit 131, a mobile station side communication unit 132, and a base station control unit 133.

[0029] The central office side communication unit 131 communicates with the central office 110. The mobile station side communication unit 132 communicates with the mobile station.

[0030] The base station control unit 133 controls processing in the base station 130. For example, the base station control unit 133 outputs a signal received by the central station side communication unit 131 from the mobile station side communication unit 132, and outputs a signal received by the mobile station side communication unit 132 from the central station side communication unit 131.

[0031] As shown in FIG. 5A, part or all of the base station control unit 133 described above can be configured with a memory 10 and a processor 11 such as a CPU that executes a program stored in the memory 10. Such a program may be provided over a network or may be provided by being recorded on a recording medium. That is, such a program may be provided as a program product, for example.

[0032] 5B, a part or all of the base station control unit 133 may be configured by a processing circuit 12 such as a single circuit, a composite circuit, a processor operated by a program, a parallel processor operated by a program, an ASIC, or an FPGA. As described above, the base station control unit 133 can be realized by a processing circuit network.

[0033] The central station communication unit 131 can be realized by a communication interface such as a NIC, and the mobile station communication unit 132 can be realized by a wireless communication interface that performs wireless communication.

[0034] 7 is a block diagram showing a schematic configuration of a mobile station 150. The mobile station 150 performs voice communication with the central office 110 via the base station 130. The mobile station 150 performs voice communication in accordance with both the first and second wireless communication methods. The signal for switching the wireless method can be transmitted using either the first or second wireless communication method. The call control for the voice communication in the mobile station 150 can only be performed using either the first call control method used in the first wireless communication method or the second call control method used in the second wireless communication method, but the voice communication can be dynamically switched between the first and second wireless communication methods depending on the wireless synchronization state.

[0035] The mobile station 150 includes a first wireless communication unit 151 , second wireless communication units 154 A and 154 B, and a mobile station control unit 157 .

[0036] The first wireless communication unit 151 performs wireless communication according to a first wireless communication method, and includes a first receiving unit 152 that receives a wireless signal according to the first wireless communication method, and a first transmitting unit 153 that transmits the wireless signal according to the first wireless communication method.

[0037] The second wireless communication unit 154A performs wireless communication according to a second wireless communication method, and includes a second receiving unit 155A that receives a wireless signal according to the second wireless communication method, and a second transmitting unit 156A that transmits a wireless signal according to the second wireless communication method.

[0038] The second wireless communication unit 154B performs wireless communication according to a second wireless communication method, and includes a second receiving unit 155B that receives wireless signals according to the second wireless communication method, and a second transmitting unit 156B that transmits wireless signals according to the second wireless communication method.

[0039] When there is no need to particularly distinguish between the second wireless communication units 154A and 154B, they are referred to as the second wireless communication units 154. The number of first wireless communication units 151 and second wireless communication units 154 is not limited to the number shown in the figure, and each may be one or more.

[0040] Furthermore, the first wireless communication unit 151 and the second wireless communication unit 154 in the mobile station 150 may be installed in either the leading car or the trailing car of the train, and the installation positions within the train may be, specifically, 400 meters apart.

[0041] The mobile station control unit 157 controls the processing in the mobile station 150 .

[0042] 5A, a part or all of the mobile station control unit 157 described above can be configured by a memory 10 and a processor 11 such as a CPU that executes a program stored in the memory 10. Such a program may be provided over a network or may be provided by being recorded on a recording medium. That is, such a program may be provided as a program product, for example.

[0043] 5B, a part or all of the mobile station control unit 157 may be configured by a processing circuit 12 such as a single circuit, a composite circuit, a programmable processor, a programmable parallel processor, an ASIC, or an FPGA. As described above, the mobile station control unit 157 may be realized by a processing circuit network.

[0044] The first wireless communication unit 151 can be realized by a wireless communication interface compatible with the first wireless communication method, and the second wireless communication unit 154 can be realized by a wireless communication interface compatible with the second wireless communication method.

[0045] Next, the handover operation will be described. Fig. 8 is a sequence diagram showing a first example of the handover operation in the first embodiment. Fig. 8 shows an example of a transition from a state in which the mobile station 150 is located outside the boundary 104 where communication is possible using the second wireless communication method and is only able to communicate using the first wireless communication method, to a state in which the mobile station 150 is located in the area 105 and is only able to communicate using both the first and second wireless communication methods as shown in Fig. 3, and finally to a state in which the mobile station 150 is located outside the boundary 103 where communication is possible using the first wireless communication method and is only able to communicate using the second wireless communication method as shown in Fig. 10.

[0046] First, as shown in FIG. 9, when the mobile station 150 is located outside the boundary 104 where communication can be performed using the second wireless communication method, the first wireless communication unit 151 of the mobile station 150 establishes synchronization with the first base station 130A#2 using the first wireless communication method (S10).

[0047] Then, the mobile station control unit 157 selects the first call control method (S11) and notifies the first wireless communication unit 151 of the call control status under the first call control method (S12). In other words, when synchronization with a new base station 130 is established, the mobile station control unit 157 controls the transmission of call control status information and line location information to the central station 110 via the newly synchronized base station 130.

[0048] The first wireless communication unit 151 transmits call control status information indicating the notified call control status and track location information indicating the track location status to the first base station 130A#2 using the first wireless communication method (S13). The track location information may be information indicating that a wireless signal from the first base station 130A can be received. Note that the call control status information indicating that the first call control method has been selected is also referred to as first call control status information, and the track location information indicating that a wireless signal from the first base station 130A can be received is also referred to as first track location information.

[0049] The first base station 130A#2 transmits the received call control status information and line presence information to the first central office 110A (S14).

[0050] When the communication control unit 112A receives the call control status information and the track location information via the communication unit 111A, the communication control unit 112A sends the call control status information and the track location information to the command console 113A (S15). The command console 113A then displays the track location information of the mobile station 150. In this case, the command console 113A can recognize that the mobile station 150 has selected the first call control method, and can start call control for the mobile station 150 using the first call control method.

[0051] The communication control unit 112A also transfers the call control status information and the line presence information to the second central office 110B via the communication unit 111A (S16).

[0052] When the communication control unit 112B receives the call control status information and the track location information via the communication unit 111B, the communication control unit 112B sends the call control status information and the track location information to the command console 113B (S17). The command console 113B then displays the track location information of the mobile station 150. In this case, the command console 113B can recognize that the mobile station 150 has selected the first call control method, and therefore can understand that call control cannot be started for the mobile station 150 using the second call control method.

[0053] Next, as shown in FIG. 3, if the mobile station 150 is present in the area 105, the second wireless communication unit 154 establishes synchronization with the second base station 130B#1 using the second wireless communication method (S18).

[0054] Then, the mobile station control unit 157 selects the first call control method as the call control method, and notifies the second wireless communication unit 154 of the call control status under the first call control method (S19).

[0055] The second wireless communication unit 154 transmits call control status information indicating the notified call control status and track location information indicating the track location status to the second base station 130B#1 using the second wireless communication method (S20). The track location information may be information indicating that a wireless signal from the second base station 130B can be received. Note that the call control status information indicating that the second call control method has been selected is also referred to as second call control status information, and the track location information indicating that a wireless signal from the second base station 130B can be received is also referred to as second track location information.

[0056] The second base station 130B#1 transmits the received call control status information and line presence information to the second central office 110B (S21).

[0057] When the call control status information and the track location information are received via the communication unit 111B, the communication control unit 112B sends the received call control status information and track location information to the command console 113B (S22). The command console 113B then displays the track location information of the mobile station 150. In this case, the command console 113B can recognize that the mobile station 150 has selected the first call control method, and therefore can grasp that call control cannot be started for the mobile station 150 using the second call control method.

[0058] The communication control unit 112B also transfers the call control status information and the line location information to the first central office 110A via the communication unit 111B (S23).

[0059] Upon receiving the call control status information and the track location information via the communication unit 111A, the communication control unit 112A sends the call control status information and the track location information to the command console 113A (S24). The command console 113A then displays the track location information of the mobile station 150. In this case, the command console 113A can recognize that the mobile station 150 has selected the first call control method, and can start call control for the mobile station 150 using the first call control method. Here, the first central office 110A and the mobile station 150 perform voice communication via the second central office 110B and the second base station 130B. In other words, if the mobile station 150 has established synchronization with multiple base stations 130, the voice communication can be performed via the base station 130 with which synchronization has been newly established.

[0060] 10, when the mobile station 150 is outside the boundary 103 where communication is possible using the first wireless communication method, the mobile station control unit 157 selects the second call control method as the call control method (S25). Specifically, when synchronization with the first wireless communication unit 151 is released, the mobile station control unit 157 selects the second call control method as the call control method.

[0061] As shown in FIG. 10, even if the mobile station 150 is located outside the boundary 103 where communication can be performed using the first wireless communication method, the command console 113A of the first central station 110A and the mobile station 150 can continue voice communication via the second central station 110B and the second base station 130B.

[0062] Then, the mobile station control unit 157 notifies the second wireless communication unit 154 of the call control state according to the second call control method (S26).

[0063] The second wireless communication unit 154 transmits the received call control status information indicating the call control status and the track location information indicating the track location to the second base station 130B#1 using the second wireless communication system (S27). The track location information may be information indicating that a wireless signal from the second base station 130B#1 can be received.

[0064] The second base station 130B#1 transmits the received call control status information and line presence information to the second central office 110B (S28).

[0065] When the call control status information and the track location information are received via the communication unit 111B, the communication control unit 112B sends the received call control status information and track location information to the command console 113B (S29). The command console 113B then displays the track location information of the mobile station 150. In this case, the command console 113B can recognize that the mobile station 150 has selected the second call control method, and can start call control for the mobile station 150 using the second call control method.

[0066] The communication control unit 112B also transfers the call control status information and the line presence information to the first central office 110A via the communication unit 111B (S30).

[0067] When the communication control unit 112A receives the call control status information and the track location information via the communication unit 111A, the communication control unit 112A sends the call control status information and the track location information to the command console 113A (S31). The command console 113A then displays the track location information of the mobile station 150. In this case, the command console 113A can recognize that the mobile station 150 has selected the second call control method, and can therefore understand that call control cannot be started for the mobile station 150 using the first call control method.

[0068] When initiating a voice call to the mobile station 150, the command console 113B designates the second wireless communication method and sends a mobile station call to the communication control unit 112B to be made using the second call control method (S32).

[0069] The communication control unit 112B transmits a mobile station call according to the second call control method to the second base station 120B#1 (S33).

[0070] The second base station 120B#1 transmits the mobile station call to the mobile station 150 in the second wireless communication system, and the second wireless communication unit 154 receives the wireless signal (S34).

[0071] Then, the second wireless communication unit 154 passes the mobile station call to the mobile station control unit 157 (S35), and the mobile station control unit 157 performs call control, thereby enabling voice communication between the central station 110 and the mobile station 150.

[0072] Fig. 11 is a sequence diagram showing a second example of handover operation in embodiment 1. Fig. 11 shows an example of a transition from a state in which the mobile station 150 is located outside the boundary 104 where communication is possible using the first wireless communication scheme and is able to communicate only using the second wireless communication scheme, to a state in which the mobile station 150 is located in an area 105 and is able to communicate using both the first and second wireless communication schemes, as shown in Fig. 13, to a state in which the mobile station 150 is located outside the boundary 104 where communication is possible using the second wireless communication scheme and is able to communicate only using the first wireless communication scheme, as shown in Fig. 14.

[0073] First, as shown in FIG. 12, when the mobile station 150 is located outside the boundary 103 where communication can be performed using the first wireless communication method, the first wireless communication unit 151 of the mobile station 150 establishes synchronization with the second base station 130B#1 using the second wireless communication method (S40).

[0074] Then, the mobile station control unit 157 selects the second call control method as the call control method (S41), and notifies the second wireless communication unit 154 of the call control status in the second call control method (S42).

[0075] The second wireless communication unit 154 transmits call control status information indicating the notified call control status and track presence information indicating the track presence status to the second base station 130B#1 using the second wireless communication system (S43). The track presence information may be information indicating that a wireless signal from the second base station 130B#1 can be received.

[0076] The second base station 130B#1 transmits the received call control status information and line presence information to the second central office 110B (S44).

[0077] When the communication control unit 112B receives the call control status information and the track location information via the communication unit 111B, the communication control unit 112B sends the received call control status information and track location information to the command console 113B (S45). The command console 113B then displays the track location information of the mobile station 150. In this case, the command console 113B can recognize that the mobile station 150 has selected the second call control method, and can start call control for the mobile station 150 using the second call control method.

[0078] The communication control unit 112B also transfers the call control status information and the line presence information to the first central office 110A via the communication unit 111B (S46).

[0079] When the communication control unit 112A receives the call control status information and the track location information via the communication unit 111A, the communication control unit 112A sends the call control status information and the track location information to the command console 113A (S47). The command console 113A then displays the track location information of the mobile station 150. In this case, the command console 113A can recognize that the mobile station 150 has selected the second call control method, and can therefore understand that call control cannot be started for the mobile station 150 using the first call control method.

[0080] Next, as shown in FIG. 13, if the mobile station 150 is present in the area 105, the first wireless communication unit 151 establishes synchronization with the first base station 130A#2 using the first wireless communication method (S48).

[0081] Then, the mobile station control unit 157 selects the second call control method as the call control method, and notifies the first wireless communication unit 151 of the call control status information according to the second call control method (S49).

[0082] The first wireless communication unit 151 transmits the received call control status information and on-track information, which is information indicating the on-track status, to the first base station 130A#2 by the first wireless communication method (S50). The on-track information may be information indicating that a wireless signal from the first base station 130A can be received.

[0083] The first base station 130A#2 transmits the received call control status information and line presence information to the first central office 110A (S51).

[0084] When the communication control unit 112A receives the call control status information and the track location information via the communication unit 111A, the communication control unit 112A sends the call control status information and the track location information to the command console 113A (S52). The command console 113A then displays the track location information of the mobile station 150. In this case, the command console 113A can recognize that the mobile station 150 has selected the second call control method, and can therefore understand that call control cannot be started for the mobile station 150 using the first call control method.

[0085] The communication control unit 112A also transfers the call control status information and the line location information to the second central office 110B via the communication unit 111A (S53).

[0086] When the communication control unit 112B receives the call control status information and the track location information via the communication unit 111B, the communication control unit 112B sends the call control status information and the track location information to the command console 113B (S54). The command console 113B then displays the track location information of the mobile station 150. In this case, the command console 113B can recognize that the mobile station 150 has selected the second call control method, and can start call control for the mobile station 150 using the second call control method.

[0087] 14, when the mobile station 150 is outside the boundary 104 where communication is possible using the second wireless communication method, the mobile station control unit 157 selects the first call control method as the call control method (S55). Specifically, when synchronization of the second wireless communication unit 154 is released, the mobile station control unit 157 selects the first call control method as the call control method.

[0088] As shown in FIG. 14, even if the mobile station 150 is located outside the boundary 104 where communication can be performed using the second wireless communication method, the first command console 113A of the first central station 110A and the mobile station 150 can continue voice communication via the second central station 110B and the second base station 130B#1.

[0089] Then, the mobile station control unit 157 notifies the first wireless communication unit 151 of the call control state in the first call control method (S56).

[0090] The first wireless communication unit 151 transmits call control status information indicating the notified call control status and track presence information indicating the track presence status to the first base station 130A#2 by the first wireless communication system (S57). The track presence information may be information indicating that a wireless signal from the first base station 130A can be received.

[0091] The first base station 130A#2 transmits the received call control status information and line presence information to the first central office 110A (S58).

[0092] When the call control status information and the track location information are received via the communication unit 111A, the communication control unit 112A sends the received call control status information and track location information to the command console 113A (S59). The command console 113A then displays the track location information of the mobile station 150. In this case, the command console 113A can recognize that the mobile station 150 has selected the first call control method, and can start call control for the mobile station 150 using the first call control method.

[0093] The communication control unit 112A also transfers the call control status information and the line presence information to the second central office 110B via the communication unit 111A (S60).

[0094] When the communication control unit 112B receives the call control status information and the track location information via the communication unit 111B, the communication control unit 112B sends the call control status information and the track location information to the command console 113B (S61). The command console 113B then displays the track location information of the mobile station 150. In this case, the command console 113B can recognize that the mobile station 150 has selected the first call control method, and therefore can understand that call control cannot be started for the mobile station 150 using the second call control method.

[0095] When starting a voice call to the mobile station 150, the command console 113A designates the first wireless communication method and issues a mobile station call to the communication control unit 112A using the first call control method (S62).

[0096] The communication control unit 112A transmits a mobile station call according to the first call control method to the first base station 120A#2 (S63).

[0097] The first base station 120A#2 transmits the mobile station call to the mobile station 150 in the first wireless communication system, and the first wireless communication unit 151 receives the wireless signal (S64).

[0098] Then, the first wireless communication unit 151 passes the mobile station call to the mobile station control unit 157 (S65), and the mobile station control unit 157 performs call control, thereby enabling voice communication between the central station 110 and the mobile station 150.

[0099] As described above, when the mobile station 150 establishes synchronization with the first base station 130A, the mobile station 150 transmits to the first base station 130A first track location information indicating that the mobile station 150 can receive signals from the first base station 130A. The first base station 130A then transmits the first track location information to the first central station 110A, and the first central station 110A forwards the first track location information to the second central station 110B. Furthermore, when the mobile station 150 establishes synchronization with the second base station 130B, the mobile station 150 transmits second track location information to the second base station 130B, which is track location information indicating that the mobile station 150 can receive signals from the second base station 130B. The second base station 130B then transmits the second track location information to the second central station 110B, which then forwards the second track location information to the first central station 110A. This allows both the first central station 110A and the second central station 110B, which use different communication methods, to know with which base station 130 the mobile station 150 can communicate.

[0100] Furthermore, if the mobile station 150 releases synchronization with the first base station 130A after establishing synchronization with the second base station 130B, it switches from the first call control method to the second call control method and transmits second call control status information indicating that the second call control method has been selected to the second central station 110B via the second base station 130B. The second central station 110B forwards the second call control status information to the first central station 110A. Furthermore, if the mobile station 150 releases synchronization with the first base station 130A after establishing synchronization with the second base station 130B, it switches from the second call control method to the first call control method and transmits first call control status information indicating that the first call control method has been selected to the first central station 110A via the first base station 130A. The first central office 110A transfers the first call control status information to the second central office 110B, so that both the first central office 110A and the second central office 110B can know which call control method the mobile station 150 has selected.

[0101] Furthermore, if the mobile station 150 establishes synchronization with the second base station 130B while in voice communication with the first central office 110A, the first central office 110A and the mobile station 150 continue voice communication via the second central office 110B and the second base station 130B. Also, if the mobile station 150 establishes synchronization with the first base station 130A while in voice communication with the second central office 110B, the second central office 110B and the mobile station 150 continue voice communication via the first central office 110A and the first base station 130A. This allows the central office 110 to continue voice communication with the mobile station 150 even if the mobile station 150 is connected to a base station 130 that uses a different communication method.

[0102] As described above, according to the first embodiment, the mobile station 150 and the central station 110 can use the first wireless communication scheme and the second wireless communication scheme, and can agree on whether to use the first wireless communication scheme or the second wireless communication scheme when performing voice communication. Therefore, even when a handover occurs between base stations 130 that use different wireless communication schemes, the wireless communication schemes used between the mobile station 150 and the central station 110 are linked, and the content of the call can be confirmed at the central station 110.

[0103] Second Embodiment In the first embodiment, the mobile station 150 transmits the line location information including the call control status information to the central station 110, but in the second embodiment, the line location information and the call control status information are transmitted as separate signals.

[0104] 1, the train wireless communication system 200 according to the second embodiment includes a ground station system 201 and a mobile station 250. The ground station system 201 also includes a first central station 210A, first base stations 130A#1 and 130A#2, and a second central station 210B, and second base stations 130B#1 and 130B#2.

[0105] The first base stations 130A#1, 130A#2 and the second base stations 130B#1, 130B#2 in the second embodiment are similar to the first base stations 130A#1, 130A#2 and the second base stations 130B#1, 130B#2 in the first embodiment.

[0106] In the following description, unless there is a need to particularly distinguish between the first central station 210A and the second central station 210B, each of the first central station 210A and the second central station 210B will be referred to as the central station 210.

[0107] 4 is a block diagram showing a schematic configuration of a central station 210 according to the second embodiment. The central station 210 includes a communication unit 111, a communication control unit 212, and a command console 113. The communication unit 111 and the command console 113 of the central station 210 according to the second embodiment are similar to the communication unit 111 and the command console 113 of the central station 110 according to the first embodiment.

[0108] The communication control unit 212 controls communication via the communication unit 111. In the second embodiment, the communication control unit 212 receives the track presence information and the call control status information separately from the base station 130 or another central office 210, and processes these separately. The processing method is the same as in the first embodiment.

[0109] In the following explanation, the communication unit 111, communication control unit 212, and command console 113 of the first central station 210A will also be referred to as the communication unit 111A, communication control unit 212A, and command console 113A, and the communication unit 111, communication control unit 212, and command console 113 of the second central station 210B will also be referred to as the communication unit 111B, communication control unit 212B, and command console 113B.

[0110] 7 is a block diagram schematically showing the configuration of a mobile station 250 according to the second embodiment. The mobile station 250 includes a first wireless communication unit 251, second wireless communication units 254A and 254B, and a mobile station control unit 157. The mobile station control unit 157 of the mobile station 250 according to the second embodiment is similar to the mobile station control unit 157 of the mobile station 150 according to the first embodiment.

[0111] The first wireless communication unit 251 performs wireless communication according to a first wireless communication method. The first wireless communication unit 251 includes a first receiving unit 152 that receives a wireless signal according to the first wireless communication method, and a first transmitting unit 253 that transmits a wireless signal according to the first wireless communication method.

[0112] The first transmitting unit 253 transmits the line location information to the base station 130 separately from the call control information from the mobile station control unit 157 .

[0113] The second wireless communication unit 254A performs wireless communication according to a second wireless communication method, and includes a second receiving unit 155A that receives wireless signals according to the second wireless communication method, and a second transmitting unit 256A that transmits wireless signals according to the second wireless communication method.

[0114] The second transmitting unit 256A transmits the track location information to the base station 130 separately from the call control information from the mobile station control unit 157.

[0115] The second wireless communication unit 154B performs wireless communication according to a second wireless communication method, and includes a second receiving unit 155B that receives wireless signals according to the second wireless communication method, and a second transmitting unit 156B that transmits wireless signals according to the second wireless communication method.

[0116] The second transmitting unit 256B transmits the track location information to the base station 130 separately from the call control information from the mobile station control unit 157.

[0117] When there is no need to particularly distinguish between the second wireless communication unit 254A and the second wireless communication unit 254B, they will be referred to as the second wireless communication unit 254.

[0118] Next, a handover operation in the second embodiment will be described. Fig. 15 is a sequence diagram showing a first example of the handover operation in the second embodiment. Fig. 15 shows an example of a transition from a state in which the mobile station 250 is located outside the boundary 104 where communication is possible using the second wireless communication scheme and is able to communicate only using the first wireless communication scheme, to a state in which the mobile station 250 is located in the area 105 and is able to communicate using both the first and second wireless communication schemes, as shown in Fig. 3, to a state in which the mobile station 250 is located outside the boundary 103 where communication is possible using the first wireless communication scheme and is able to communicate only using the second wireless communication scheme, as shown in Fig. 10.

[0119] First, as shown in FIG. 9, when the mobile station 250 is located outside the boundary 104 where communication can be performed using the second wireless communication method, the first wireless communication unit 251 of the mobile station 250 establishes synchronization with the first base station 130A#2 using the first wireless communication method (S70).

[0120] Then, the first wireless communication unit 251 transmits the track location information to the first base station 130A#2 using the first wireless communication method (S71). In other words, in the second embodiment, when the first wireless communication unit 251 and the second wireless communication unit 254 establish synchronization with a new base station 130, they transmit the track location information to the base station 130 with which they have newly established synchronization.

[0121] The first base station 130A#2 transmits the received track location information to the first central office 210A (S72).

[0122] When the train location information is received via the communication unit 111A, the communication control unit 212A sends the train location information to the command console 113A (S73).The command console 113A then displays the train location information of the mobile station 250.

[0123] The communication control unit 212A also transfers the track location information to the second central office 210B via the communication unit 111A (S74).

[0124] When the train location information is received via the communication unit 111B, the communication control unit 212B sends the train location information to the command console 113B (S75).The command console 113B then displays the train location information of the mobile station 250.

[0125] Furthermore, the mobile station control unit 157 selects the first call control method as the call control method (S76) and notifies the first wireless communication unit 251 of the call control status under the first call control method (S77). In other words, in the second embodiment, when the mobile station control unit 157 newly establishes synchronization with the base station 130, the mobile station control unit 157 performs control so as to transmit call control information to the base station 130 with which the synchronization has been newly established.

[0126] The first wireless communication unit 251 transmits call control status information indicating the notified call control status to the first base station 130A#2 using the first wireless communication system (S78).

[0127] The first base station 130A#2 transmits the received call control status information to the first central office 210A (S79).

[0128] When the call control status information is received via the communication unit 111A, the communication control unit 212A sends the received call control status information to the command console 113A (S80). As a result, the command console 113A can recognize that the mobile station 250 has selected the first call control method, and can start call control for the mobile station 250 using the first call control method.

[0129] The communication control unit 212A also transfers the call control status information to the second central exchange 210B via the communication unit 111A (S81).

[0130] When the communication control unit 212B receives the call control status information via the communication unit 111B, the communication control unit 212B sends the call control status information to the command console 113B (S82). As a result, the command console 113B recognizes that the mobile station 250 has selected the first call control method, and is able to grasp that call control for the mobile station 150 cannot be started using the second call control method.

[0131] Next, as shown in FIG. 3, if the mobile station 250 is present in the area 105, the second wireless communication unit 254 establishes synchronization with the second base station 130B#1 using the second wireless communication method (S83).

[0132] Then, the mobile station control unit 157 selects the first call control method as the call control method, and notifies the second wireless communication unit 254 of the call control status in the first call control method (S84).

[0133] The second wireless communication unit 254 transmits call control status information indicating the notified call control status to the second base station 130B#1 using the second wireless communication system (S85).

[0134] The second base station 130B#1 transmits the received call control status information to the second central office 210B (S86).

[0135] When the call control status information is received via the communication unit 111B, the communication control unit 212B sends the received call control status information to the command console 113B (S87). As a result, the command console 113B recognizes that the mobile station 250 has selected the first call control method, and is able to grasp that call control for the mobile station 150 cannot be started using the second call control method.

[0136] The communication control unit 212B also transfers the call control status information to the first central exchange 210A via the communication unit 111B (S88).

[0137] When the call control status information is received via the communication unit 111A, the communication control unit 212A sends the call control status information to the command console 113A (S89). As a result, the command console 113A recognizes that the mobile station 250 has selected the first call control method, and can start call control with the mobile station 250 using the first call control method.

[0138] Also, since synchronization with the second base station 130B#1 is established in step S83, the second wireless communication unit 254 transmits the track location information to the second base station 130B#1 using the second wireless communication method (S90).

[0139] The second base station 130B#1 transmits the received track location information to the second central office 210B (S91).

[0140] When the train location information is received via the communication unit 111B, the communication control unit 212B sends the train location information to the command console 113B (S92).The command console 113B then displays the train location information of the mobile station 250.

[0141] The communication control unit 212B also transfers the track location information to the first central office 210A via the communication unit 111B (S93).

[0142] When the train location information is received via the communication unit 111A, the communication control unit 212A sends the train location information to the command console 113A (S94).The command console 113A then displays the train location information of the mobile station 250.

[0143] 10, when the mobile station 250 is located outside the boundary 103 where communication is possible using the first wireless communication method, the mobile station control unit 157 of the mobile station 250 selects the second call control method as the call control method (S95). Specifically, when synchronization with the first wireless communication unit 151 is released, the mobile station control unit 157 selects the second call control method as the call control method.

[0144] As shown in FIG. 10, even if the mobile station 250 is located outside the boundary 103 where communication can be performed using the first wireless communication method, the mobile station 250 and the command console 113A of the first central station 210A can continue voice communication via the second central station 210B and the second base station 130B.

[0145] Then, the mobile station control unit 157 notifies the second wireless communication unit 254 of the call control status according to the second call control method (S96).

[0146] The second wireless communication unit 254 transmits call control status information indicating the notified call control status to the second base station 130B#1 using the second wireless communication system (S97).

[0147] The second base station 130B#1 transmits the received call control status information to the second central office 210B (S98).

[0148] When the call control status information is received via the communication unit 111B, the communication control unit 212B sends the received call control status information to the command console 113B (S99). As a result, the command console 113B can recognize that the mobile station 250 has selected the second call control method, and can start call control for the mobile station 250 using the second call control method.

[0149] The communication control unit 212B also transfers the call control status information to the first central exchange 210A via the communication unit 111B (S100).

[0150] When the communication control unit 212A receives the call control status information via the communication unit 111A, the communication control unit 212A sends the call control status information to the command console 113A (S101). This allows the command console 113A to recognize that the mobile station 250 has selected the second call control method, and to understand that call control for the mobile station 150 cannot be started using the first call control method.

[0151] When starting a voice call to the mobile station 250, the command console 113B designates the second wireless communication method and issues a mobile station call to the communication control unit 212B using the second call control method (S102).

[0152] The communication control unit 212B transmits a mobile station call according to the second call control method to the second base station 120B#1 (S103).

[0153] The second base station 120B#1 transmits the mobile station call to the mobile station 250 in the second wireless communication system, and the second wireless communication unit 254 receives the wireless signal (S104).

[0154] Then, the second wireless communication unit 254 passes the mobile station call to the mobile station control unit 157 (S105), and the mobile station control unit 157 performs call control, thereby enabling voice communication between the central station 210 and the mobile station 250.

[0155] Fig. 16 is a sequence diagram showing a second example of handover operation in embodiment 2. Fig. 16 shows an example of a transition from a state in which the mobile station 250 is located outside the boundary 104 where communication is possible using the first wireless communication scheme and is able to communicate only using the second wireless communication scheme, to a state in which the mobile station 250 is located in the area 105 and is able to communicate using both the first and second wireless communication schemes, as shown in Fig. 13, to a state in which the mobile station 250 is located outside the boundary 104 where communication is possible using the second wireless communication scheme and is able to communicate only using the first wireless communication scheme, as shown in Fig. 14.

[0156] First, as shown in FIG. 12, when the mobile station 250 is located outside the boundary 103 where communication can be performed using the first wireless communication method, the first wireless communication unit 251 of the mobile station 250 establishes synchronization with the second base station 130B#1 using the second wireless communication method (S110).

[0157] Then, the second wireless communication unit 254 transmits the track location information to the second base station 130B#1 using the second wireless communication system (S111).

[0158] The second base station 130B#1 transmits the received track location information to the second central office 210B (S112).

[0159] When the train location information is received via the communication unit 111B, the communication control unit 212B sends the train location information to the command console 113B (S113). Then, the command console 113B displays the train location information of the mobile station 250.

[0160] The communication control unit 212B also transfers the track location information to the first central office 210A via the communication unit 111B (S114).

[0161] When the train location information is received via the communication unit 111A, the communication control unit 212A sends the train location information to the command console 113A (S115).The command console 113A then displays the train location information of the mobile station 250.

[0162] The mobile station control unit 157 selects the second call control method as the call control method (S116), and notifies the second wireless communication unit 154 of the call control status under the second call control method (S117).

[0163] The second wireless communication unit 254 transmits call control status information indicating the notified call control status to the second base station 130B#1 using the second wireless communication system (S118).

[0164] The second base station 130B#1 transmits the received call control status information to the second central office 110B (S119).

[0165] When the call control status information is received via the communication unit 111B, the communication control unit 212B sends the received call control status information to the command console 113B (S120). As a result, the command console 113B can recognize that the mobile station 250 has selected the second call control method, and can start call control for the mobile station 250 using the second call control method.

[0166] The communication control unit 212B also transfers the call control status information to the first central exchange 210A via the communication unit 111B (S121).

[0167] When the communication control unit 212A receives the call control status information via the communication unit 111A, it sends the call control status information to the command console 113A (S122). This allows the command console 113A to recognize that the mobile station 250 has selected the second call control method, and to understand that call control for the mobile station 150 cannot be started using the first call control method.

[0168] Next, as shown in FIG. 13, if the mobile station 250 is present in the area 105, the first wireless communication unit 251 establishes synchronization with the first base station 130A#2 using the first wireless communication method (S123).

[0169] Then, the first wireless communication unit 251 transmits the track location information to the first base station 130A#2 using the first wireless communication system (S124).

[0170] The first base station 130A#2 transmits the received track location information to the first central office 210A (S125).

[0171] When the train location information is received via the communication unit 111A, the communication control unit 212A sends the train location information to the command console 113A (S126).The command console 113A then displays the train location information of the mobile station 250.

[0172] The communication control unit 212A also transfers the track location information to the second central office 210B via the communication unit 111A (S127).

[0173] When the train location information is received via the communication unit 111B, the communication control unit 212B sends the train location information to the command console 113B (S128).The command console 113B then displays the train location information of the mobile station 250.

[0174] Furthermore, the mobile station control unit 157 selects the second call control method as the call control method, and notifies the first wireless communication unit 251 of the call control status in the second call control method (S129).

[0175] The first wireless communication unit 251 transmits the received call control status information to the first base station 130A#2 using the first wireless communication method (S130).

[0176] The first base station 130A#2 transmits the received call control status information to the first central office 210A (S131).

[0177] When the communication control unit 212A receives the call control status information and the line presence information via the communication unit 111A, the communication control unit 212A sends the received call control status information to the command console 113A (S132). As a result, the command console 113A recognizes that the mobile station 250 has selected the second call control method, and can grasp that call control for the mobile station 150 cannot be started using the first call control method.

[0178] The communication control unit 212A also sends the received call control status information to the second central office 210B (S133).

[0179] When the call control status information is received via the communication unit 111B, the communication control unit 212B sends the received call control status information to the command console 113B (S134). As a result, the command console 113B can recognize that the mobile station 250 has selected the second call control method, and can start call control for the mobile station 250 using the second call control method.

[0180] 14, when the mobile station 250 is outside the boundary 104 where communication is possible using the second wireless communication method, the mobile station control unit 157 selects the first call control method as the call control method (S135). Specifically, when synchronization of the second wireless communication unit 254 is released, the mobile station control unit 157 selects the first call control method as the call control method.

[0181] As shown in FIG. 14, even when the mobile station 250 is located outside the boundary 104 where communication is possible using the second wireless communication system, the mobile station 250 and the second central station 210B can continue voice communication via the first central station 210A and the first base station 130A.

[0182] Then, the mobile station control unit 157 notifies the first wireless communication unit 251 of the call control state in the first call control method (S136).

[0183] The first wireless communication unit 251 transmits call control state information indicating the notified call control state to the first base station 130A#2 using the first wireless communication scheme (S137).

[0184] The first base station 130A#2 transmits the received call control status information to the first central office 210A (S138).

[0185] When the call control status information is received via the communication unit 111A, the communication control unit 212A sends the received call control status information to the command console 113A (S139). As a result, the command console 113A can recognize that the mobile station 250 has selected the first call control method, and can start call control for the mobile station 250 using the first call control method.

[0186] The communication control unit 212A also transfers the call control status information to the second central office 210B via the communication unit 111A (S140).

[0187] When the communication control unit 212B receives the call control status information via the communication unit 111B, the communication control unit 212B sends the call control status information to the command console 113B (S141). This allows the command console 113B to recognize that the mobile station 250 has selected the first call control method, and to understand that call control for the mobile station 150 cannot be started using the second call control method.

[0188] When starting a voice call to the mobile station 250, the command console 113A designates the first wireless communication method and issues a mobile station call to the communication control unit 212A using the first call control method (S142).

[0189] The communication control unit 212A transmits a mobile station call according to the first call control method to the first base station 120A#2 (S143).

[0190] The first base station 120A#2 transmits the mobile station call to the mobile station 250 in the first wireless communication system, and the first wireless communication unit 251 receives the wireless signal (S144).

[0191] Then, the first wireless communication unit 251 passes the mobile station call to the mobile station control unit 157 (S145), and the mobile station control unit 157 performs call control, thereby enabling voice communication between the central station 210 and the mobile station 250.

[0192] As described above, according to the second embodiment, there is no need to add call control status information to the line location information, and control can be performed using the call control itself, so there is no need to change the existing protocol. Therefore, even if there is no spare area to extend the existing protocol, the effect can be obtained.

[0193] 100, 200 Train radio communication system, 101, 201 Ground station system, 110A, 210A First central station, 110B, 210B Second central station, 111 Communication unit, 112, 212 Communication control unit, 113 Command console, 130A First base station, 130B Second base station, 131 Central station side communication unit, 132 Mobile station side communication unit, 133 Base station control unit, 150, 250 Mobile station, 151, 251 First radio communication unit, 154A, 154B, 254A, 254B Second radio communication unit, 157 Mobile station control unit.

Claims

1. a mobile station that performs wireless communication using a first wireless communication scheme and a second wireless communication scheme different from the first wireless communication scheme; a first base station that performs wireless communication with the mobile station by using the first wireless communication scheme; a second base station that performs wireless communication with the mobile station using the second wireless communication scheme; a first central office connected to the first base station; a second central office connected to the second base station; the first central station and the second central station are adapted to communicate with each other; When the mobile station has established synchronization with the first base station, the mobile station transmits to the first base station first location information, which is location information indicating that the mobile station can receive a signal from the first base station, the first base station transmits the first location information to the first central station, and the first central station transfers the first location information to the second central station; When the mobile station has established synchronization with the second base station, the mobile station transmits to the second base station second track information indicating that the mobile station can receive a signal from the second base station, the second base station transmits the second track information to the second central station, and the second central station transfers the second track information to the first central station; the first central station indicates, based on the first track information or the second track information, from which of the first base station or the second base station the mobile station can receive a radio signal; The second central station indicates, from the first track information or the second track information, from which of the first base station or the second base station the mobile station can receive a radio signal. A wireless communication system comprising:

2. the mobile station selects, as a method for performing call control, either a first call control method or a second call control method different from the first call control method, and performs call control; the first central office is capable of performing call control using the first call control method but is not capable of performing call control using the second call control method; the second central office is capable of performing call control using the second call control method but is not capable of performing call control using the first call control method; when the mobile station releases synchronization with the first base station after establishing synchronization with the second base station, the mobile station switches from the first call control method to the second call control method and transmits second call control status information indicating that the second call control method has been selected to the second central station via the second base station, and the second central station transfers the second call control status information indicating that call control cannot be started for the mobile station using the first call control method to the first central station; When the mobile station releases synchronization with the second base station after establishing synchronization with the first base station, the mobile station switches from the second call control method to the first call control method and transmits first call control status information indicating that the first call control method has been selected to the first central station via the first base station, and the first central station transfers the first call control status information indicating that call control cannot be started for the mobile station using the second call control method to the second central station.

2. The wireless communication system according to claim 1,

3. A mobile station that performs wireless communication using a first wireless communication method and a second wireless communication method different from the first wireless communication method; a first base station that performs wireless communication with the mobile station by using the first wireless communication scheme; a second base station that performs wireless communication with the mobile station using the second wireless communication scheme; a first central office connected to the first base station; a second central office connected to the second base station; the first central station and the second central station are adapted to communicate with each other; the mobile station selects, as a method for performing call control, either a first call control method or a second call control method different from the first call control method, and performs call control; the first central office is capable of performing call control using the first call control method but is not capable of performing call control using the second call control method; the second central office is capable of performing call control using the second call control method but is not capable of performing call control using the first call control method; when the mobile station releases synchronization with the first base station after establishing synchronization with the second base station, the mobile station switches from the first call control method to the second call control method and transmits second call control status information indicating that the second call control method has been selected to the second central station via the second base station, and the second central station transfers the second call control status information indicating that call control cannot be started for the mobile station using the first call control method to the first central station; When the mobile station releases synchronization with the second base station after establishing synchronization with the first base station, the mobile station switches from the second call control method to the first call control method and transmits first call control status information indicating that the first call control method has been selected to the first central station via the first base station, and the first central station transfers the first call control status information indicating that call control cannot be started for the mobile station using the second call control method to the second central station. A wireless communication system comprising:

4. A mobile station that performs wireless communication using a first wireless communication method and a second wireless communication method different from the first wireless communication method; a first base station that performs wireless communication with the mobile station by using the first wireless communication scheme; a second base station that performs wireless communication with the mobile station using the second wireless communication scheme; a first central office connected to the first base station; a second central station connected to the second base station, the first central station of the wireless communication system having the central station, the first central station and the second central station are adapted to communicate with each other; When the mobile station has established synchronization with the first base station, the mobile station transmits to the first base station first location information, which is location information indicating that the mobile station can receive a signal from the first base station, the first base station transmits the first location information to the first central station, and the first central station transfers the first location information to the second central station; When the mobile station has established synchronization with the second base station, the mobile station transmits to the second base station second track information indicating that the mobile station can receive a signal from the second base station, the second base station transmits the second track information to the second central station, and the second central station transfers the second track information to the first central station; The first central station includes a communication control unit that receives the first track information or the second track information and transfers the first track information to the second central station, and a command console that notifies the mobile station from which the mobile station can receive a radio signal, the first base station or the second base station, based on the first track information or the second track information. A central station characterized by:

5. The mobile station selects, as a method for performing call control, either a first call control method or a second call control method different from the first call control method, and performs call control; the first central office is capable of performing call control using the first call control method but is not capable of performing call control using the second call control method; the second central office is capable of performing call control using the second call control method but is not capable of performing call control using the first call control method; when the mobile station releases synchronization with the first base station after establishing synchronization with the second base station, the mobile station switches from the first call control method to the second call control method and transmits second call control status information indicating that the second call control method has been selected to the second central station via the second base station, and the second central station transfers the second call control status information indicating that call control cannot be started for the mobile station using the first call control method to the first central station; The first central station includes a communication control unit that receives the second call control state information, and a command console that notifies the mobile station that call control cannot be started using the first call control method based on the second call control state information.

5. The central station of claim 4,

6. A mobile station that performs wireless communication using a first wireless communication method and a second wireless communication method different from the first wireless communication method; a first base station that performs wireless communication with the mobile station by using the first wireless communication scheme; a second base station that performs wireless communication with the mobile station using the second wireless communication scheme; a first central office connected to the first base station; a second central station connected to the second base station, the first central station of the wireless communication system having the central station, the first central station and the second central station are adapted to communicate with each other; the mobile station selects, as a method for performing call control, either a first call control method or a second call control method different from the first call control method, and performs call control; the first central office is capable of performing call control using the first call control method but is not capable of performing call control using the second call control method; the second central office is capable of performing call control using the second call control method but is not capable of performing call control using the first call control method; when the mobile station releases synchronization with the first base station after establishing synchronization with the second base station, the mobile station switches from the first call control method to the second call control method and transmits second call control status information indicating that the second call control method has been selected to the second central station via the second base station, and the second central station transfers the second call control status information indicating that call control cannot be started for the mobile station using the first call control method to the first central station; The first central station includes a communication control unit that receives the second call control state information, and a command console that notifies the mobile station that call control cannot be started using the first call control method based on the second call control state information. A central station characterized by:

7. The command console is provided with a display unit for notifying the user. A central station according to any one of claims 4 to 6, characterized in that