Train radio system

Abstract

This reduces the silent period when a mobile station moves between radio systems while a call is in progress. [Solution] A train radio system according to one embodiment of the present invention comprises a mobile station 50 mounted on a train that travels across the section of radio system A and the section of radio system B, and a line control device 60 that controls the lines of radio system A and radio system B. When the mobile station 50, which is using a call channel of radio system A, reaches the vicinity of the boundary between the section of radio system A and the section of radio system B, the line control device 60 notifies the mobile station 50 of the call channels available in radio system B using the control channel of radio system A. In response to the mobile station 50 receiving notification of the call channels of radio system B from the line control device 60, it switches from the call channel of radio system A to the call channel of radio system B.

Description

Technical Field

[0001] The present invention relates to a train radio system applied to a train running across sections of a plurality of radio systems using different radio systems.

Background Art

[0002] In a train radio system, there is a case where a mobile station moves between radio systems due to relationships such as the entry of trains of different railway operators. Generally, the radio systems adopted by railway operators use different radio systems. Therefore, when it is necessary to continue a call even when the mobile station moves between radio systems, the call is continued by re-performing the call initiation operation in the radio system of the destination.

[0003] FIG. 1 shows an example in which a mobile station moves between radio systems in a conventional train radio system. In the example shown in FIG. 1, a train equipped with a mobile station 40 is running on a route including a section of a radio system A that can use a radio system 10 and a section of a radio system B that can use a radio system 20 different from the radio system 10. Here, it is assumed that the mobile station 40 moves across the radio system boundary 30 while making a call with another radio station using the call channel 11 of the radio system 10 in the section of the radio system A. In this case, the mobile station 40 is out of the range of the radio system A and cannot make a call using the call channel 11 of the radio system 10. Therefore, when it is necessary to continue the call, it is necessary to switch to the radio system 20 available in the radio system B after the movement. Therefore, when the mobile station 40 moves across the radio system boundary 30, it transmits a re-call signal using the radio system 20 to secure the call channel 21 of the radio system B and newly starts a call using the call channel 21.

[0004] Prior art in the field of the present invention includes the following. For example, Patent Document 1 discloses a technology for outputting a switching signal to an interface switching device so as to automatically follow an analog or digital wave. Patent Document 2 discloses a technology for providing a base station device with multiple radios using different frequencies from each other in order to perform wireless communication with an on-board station device mounted on a train. Patent Document 3 discloses a technology for avoiding IP address duplication by introducing a network address translation device when adding a new device that simulates an old device and relays data to other old devices. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2023-47270 [Patent Document 2] Patent No. 6970567 [Patent Document 3] Japanese Patent Publication No. 2017-126844 [Overview of the project] [Problems that the invention aims to solve]

[0006] As described above, when a mobile station in a call moved between radio systems using different radio protocols, it was necessary to initiate the call again, resulting in long periods of silence until a call could be established on the destination radio system. Furthermore, since the design had to be tailored to each radio system used by the railway operator, design costs were high. Moreover, there was the problem of having to redesign the system whenever the radio protocol was changed due to equipment upgrades or other reasons.

[0007] This invention has been made in view of the above-mentioned conventional circumstances, and aims to shorten the silent period when a mobile station in the middle of a call moves across different radio systems using different radio methods. [Means for solving the problem]

[0008] A train radio system according to one aspect of the present invention comprises a mobile station mounted on a train traveling across a section of a first radio system and a section of a second radio system, and a line control device that controls the lines of the first radio system and the second radio system, wherein when the mobile station, which is using a call channel of the first radio system, reaches the vicinity of the boundary between the section of the first radio system and the section of the second radio system, the line control device notifies the mobile station of a call channel available in the second radio system using the control channel of the first radio system, and the mobile station switches from the call channel of the first radio system to the call channel of the second radio system in response to receiving notification of the call channel of the second radio system from the line control device.

[0009] In the above-described train radio system, the mobile station may be configured to transmit its own location information to the line control device using the control channel of the first radio system, and the line control device may be configured to determine, based on the location information received from the mobile station, whether or not the mobile station has reached the vicinity of the boundary between the section of the first radio system and the section of the second radio system.

[0010] Furthermore, in the above-described train radio system, if the mobile station is unable to transmit its own location information to the line control device, it may be configured to transmit its own location information to the line control device using the control channel of the second radio system when it moves to a section of the second radio system, and the line control device may be configured to notify the mobile station of the available communication channels in the second radio system using the control channel of the second radio system in response to receiving the location information from the mobile station.

[0011] Furthermore, the above-mentioned train radio system may be configured to be deployed on lines that include tracks or stations where trains of multiple railway operators run. [Effects of the Invention]

[0012] According to the present invention, when a mobile station in the middle of a call moves across different radio systems using different radio methods, the call can be maintained, and the period of silence can be reduced. [Brief explanation of the drawing]

[0013] [Figure 1] This diagram illustrates an example of a mobile station moving between radio systems in a conventional train radio system. [Figure 2] This figure shows an example of a mobile station moving between radio systems in a train radio system according to one embodiment of the present invention. [Figure 3] This figure shows an example of the processing flow for a mobile station related to call channel switching control. [Figure 4] This figure shows an example of the processing flow of a line control device related to call channel switching control. [Modes for carrying out the invention]

[0014] One embodiment of the present invention will be described with reference to the drawings. Figure 2 shows an example in which a mobile station moves between radio systems in a train radio system according to one embodiment of the present invention. In the example shown in Figure 2, a train equipped with a mobile station 50 is traveling on a route that includes a section of radio system A where radio system 10 can be used and a section of radio system B where radio system 20, which is different from radio system 10, can be used. Radio system 10 is, for example, FDMA (Frequency Division Multiple Access), and radio system 20 is, for example, TDMA (Time Division Multiple Access). The mobile station 50 can communicate with other radio devices through base stations of radio system 10 or radio system 20 arranged along the railway line.

[0015] As described above, the train radio system in this example assumes that the train moves across sections of multiple radio systems with different radio methods. The train radio system in this example is deployed, for example, on a route including a track or a station where trains of multiple railway operators run. The train can be a Shinkansen train. That is, the train radio system in this example can be deployed on a route including a track or a station where the Shinkansen train runs.

[0016] Here, assume that the mobile station 50 is moving across the radio system boundary 30 (in this example, the boundary between the section of radio system A and the section of radio system B) while making a call with another radio station using the call channel of radio method 10 in the section of radio system A. In this case, the mobile station 50 is out of the coverage area of radio system A and cannot make a call using radio method 10, but is configured to be able to quickly switch to a call using radio method 20. The mechanism will be described below.

[0017] In the conventional system, it was common to control the line of radio system A and the line of radio system B with separate line control devices. In contrast, as shown in FIG. 2, this system includes a line control device 60 that controls both the line of radio system A and the line of radio system B. That is, the line control device 60 has a structure adapted to both the radio method 10 related to radio system A and the radio method 20 related to radio system B. [[ID=⑨]]

[0018] The mobile station 50 has a function of periodically transmitting its own position information 71 to the line control device 60. The position information can use, for example, kilometer information obtained from the train system or positioning information obtained from a GPS (Global Positioning System) device. The position information 71 is transmitted using the control channel of the radio system in the section where the mobile station 50 is located. For example, when the mobile station 50 is moving in the section of radio system A, the mobile station 50 transmits the position information 71 using the control channel of radio system A.

[0019] The mobile station 50 also has a function to switch the call channel used for a call to the call channel notified by the call channel information 72 in response to receiving call channel information 72 from the line control device 60. For example, if the mobile station 50 receives notification of a call channel for radio system B while using a call channel for radio system A, it will switch from the call channel for radio system A to the call channel for radio system B. If the mobile station 50 receives notification of a call channel for radio system B before entering the section of radio system B, the call channel switch should be performed after the mobile station 50 has entered the section of radio system B and is able to use the radio method 20 of radio system B.

[0020] The line control device 60 has the function of securing a call channel in the wireless system at the destination of the mobile station 50 when the mobile station 50 reaches the vicinity of the wireless system boundary 30, and transmitting call channel information 72 to the mobile station 50 to notify it of that call channel. Specifically, the line control device 60 in this example first determines whether the mobile station 50 has reached the vicinity of the wireless system boundary 30 based on the current position of the mobile station 50, which is identified by the position information 71. For example, a boundary range including the wireless system boundary 30 is set in advance, and it is determined whether the current position of the mobile station 50 is within the boundary range. The boundary range should be set in advance to a range that allows for smooth switching of call channels, taking into account the speed of the mobile station and the time required to switch call channels.

[0021] As a result, if it is determined that the mobile station 50 has reached the vicinity of the radio system boundary 30, the line control device 60 checks the status of the call channel in the radio system at the destination of the mobile station 50 and secures a call channel if it is available. Subsequently, the line control device 60 transmits call channel information 72 to the mobile station 50 to notify it of the secured call channel. The call channel information 72 is transmitted using the control channel of the radio system in the section where the mobile station 50 is currently located. For example, if the mobile station 50 is moving through a section of radio system A, the line control device 60 transmits the call channel information 72 using the control channel of radio system A.

[0022] Next, the flow of call channel switching control will be described with reference to FIGS. 3 and 4. FIG. 3 shows an example of the processing flow of the mobile station 50 related to call channel switching control. FIG. 4 shows an example of the processing flow of the line control device 60 related to call channel switching control.

[0023] The mobile station 50 periodically transmits its own location information 71 to the line control device 60 (step S11). When the line control device 60 receives the location information 71 from the mobile station 50 (step S21), it determines whether the mobile station 50 has reached the vicinity of the radio system boundary 30 (step S22). If it is determined that the mobile station 50 has not reached the vicinity of the radio system boundary 30 (step S22; No), the line control device 60 returns to the reception of the next location information 71 (step S21). On the other hand, if it is determined that the mobile station 50 has reached the vicinity of the radio system boundary 30 (step S22; Yes), the line control device 60 secures a call channel of the radio system to which the mobile station 50 is moving (step S23) and transmits call channel information 72 to the mobile station 50 (step S24).

[0024] After transmitting the location information 71, the mobile station 50 determines whether it has received the call channel information 72 from the line control device 60 (step S12). If it is determined that the call channel information 72 has not been received from the line control device 60 (step S12; No), the mobile station 50 returns to the transmission of the next location information 71 (step S11). If it is determined that the call channel information 72 has been received from the line control device 60 (step S12; Yes), the mobile station 50 switches the call channel used for the call to the call channel notified by the call channel information 72 (step S13).

[0025] As described above, the train radio system in this example comprises a mobile station 50 mounted on a train that travels across the sections of radio system A and radio system B, and a line control device 60 that controls the lines of radio system A and radio system B. When the mobile station 50, which is using a call channel of radio system A, reaches the vicinity of the boundary between the sections of radio system A and radio system B, the line control device 60 notifies the mobile station 50 of the call channels available in radio system B using the control channel of radio system A. In response to the mobile station 50 receiving notification of the call channels of radio system B from the line control device 60, it switches from the call channel of radio system A to the call channel of radio system B.

[0026] This configuration allows a mobile station to continue a call even when moving across a radio system using a different radio method during a call. While a brief period of call interruption occurs during channel switching, the duration of this interruption is significantly shorter than with conventional methods. Furthermore, changes in the radio method can be addressed simply by modifying the call channel notification. Additionally, the system can communicate the call status of the destination radio system to the mobile station, enabling functional enhancements related to call control.

[0027] In the above explanation, the determination of whether a mobile station has reached the vicinity of the radio system boundary is based on the mobile station's location information, but this determination may be made by other methods. For example, a shared base station compatible with both radio system A and radio system B may be installed at the radio system boundary, and the determination of whether a mobile station has reached the vicinity of the radio system boundary may be made based on whether or not the mobile station is present in the communication area of ​​this shared base station. As another example, a base station immediately before the boundary may be identified in advance, and the determination of whether or not the mobile station has reached the vicinity of the radio system boundary may be made based on whether or not the mobile station is present in the communication area of ​​that base station.

[0028] Here, if the source radio system A is a radio system that cannot use a control channel (for example, an analog system), the mobile station 50 cannot transmit location information 71 to the line control device 60, nor can the line control device 60 transmit call channel information 72 to the mobile station 50. In such cases, when the mobile station 50 moves to a section of radio system B where a control channel is available, it should transmit its own location information 71 to the line control device 60 using the control channel of radio system B, and the line control device 60 should, upon receiving the location information 71 from the mobile station 50, transmit call channel information 72 regarding a call channel available in radio system B to the mobile station 50 using the control channel of radio system B.

[0029] Although embodiments of the present invention have been described above, these embodiments are merely illustrative and do not limit the technical scope of the present invention. The present invention can take many other embodiments, and various modifications such as omissions and substitutions can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention as described herein, and are included in the scope of the invention and its equivalents as described in the claims.

[0030] Furthermore, the present invention can be provided not only as the devices described above or as systems composed of such devices, but also as methods executed by these devices, programs for a processor to realize the functions of these devices, and storage media for storing such programs in a computer-readable manner. [Industrial applicability]

[0031] The present invention can be used in train radio systems applied to trains traveling across sections of multiple radio systems using different wireless methods. [Explanation of symbols]

[0032] 10: Wireless method (Wireless System A), 20: Wireless method (Wireless System B), 11, 21: Communication channel, 30: Wireless system boundary, 40, 50: Mobile station, 60: Line control device, 71: Control channel (location information), 72: Control channel (communication channel information)

Claims

1. A mobile station mounted on a train traveling across the section of the first radio system and the section of the second radio system, The system comprises a line control device that controls the lines of the first wireless system and the second wireless system, When the mobile station using the communication channel of the first wireless system reaches the vicinity of the boundary between the section of the first wireless system and the section of the second wireless system, the line control device notifies the mobile station of the communication channels available in the second wireless system using the control channel of the first wireless system. A train radio system characterized in that the mobile station switches from the call channel of the first radio system to the call channel of the second radio system in response to receiving notification of the call channel of the second radio system from the line control device.

2. In the train radio system according to claim 1, The mobile station transmits its own location information to the line control device using the control channel of the first wireless system. The train radio system is characterized in that the line control device determines, based on location information received from the mobile station, whether or not the mobile station has reached the vicinity of the boundary between the section of the first radio system and the section of the second radio system.

3. In the train radio system according to claim 2, If the mobile station is unable to transmit its own location information to the line control device, when it moves to the section of the second radio system, it transmits its own location information to the line control device using the control channel of the second radio system. A train radio system characterized in that, upon receiving location information from the mobile station, the line control device notifies the mobile station of a call channel available in the second radio system using the control channel of the second radio system.

4. In the train radio system according to any one of claims 1 to 3, A train radio system characterized by being deployed on a line that includes tracks or stations where trains of multiple railway operators run.

Images