Transmission path switching system and radio device

Abstract

To provide a transmission path switching system that selects a transmission path suitable for both in-vehicle and ground stations.SOLUTION: A transmission path switching system includes: an in-vehicle station 1 installed in a train; a ground station 2 installed on the ground; and a plurality of transmission paths L1 to Lp for transmitting data between the in-vehicle station 1 and the ground station 2. The transmission path switching system evaluates communications on each of the plurality of transmission paths L1 to Lp using data sent from a transmitting side of either the in-vehicle station 1 or the ground station 2 and received at a receiving side through each of the plurality of transmission paths L1 to Lp. On the basis of the communication evaluation, a transmission path for the transmission side to transmit data is selected from among the plurality of transmission paths L1 to Lp.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a transmission path switching system that switches a transmission path used for communication between an on-board station mounted on a train and a ground station installed on the ground. [Background technology]

[0002] A communication system that selectively uses a plurality of transmission paths for communication is provided with a transmission path switching system that switches between the transmission paths. For example, in a conventional transmission path switching system provided in a train wireless communication system that communicates between an on-board station mounted on a train and a ground station installed on the ground, when data is transmitted from the on-board station to the ground station, the on-board station selects a transmission path based on information on the transmitted data, and when data is transmitted from the ground station to the on-board station, the ground station selects a transmission path based on information on the transmitted data.

[0003] Furthermore, the following Patent Document 1 discloses a transmission path switching system in which a router of a transmitting device calculates a margin indicating the time allowance until the completion of transmission for each frame and for each transmission path based on a predetermined allowable delay time for each frame and the transmission time for each frame for the transmission path, and determines which transmission path to use by selecting for each frame the transmission path with the largest calculated margin time. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2020-195023 A Summary of the Invention [Problem to be solved by the invention]

[0005] As described above, in the conventional transmission path switching system in the train wireless communication system, the transmitting side of the on-board station or the ground station selects a transmission path based only on the information of the transmitting side, so that the selected transmission path may not be appropriate for the receiving side.

[0006] The present disclosure has been made to solve the above-mentioned problems, and has an object to provide a transmission path switching system that selects a transmission path appropriate for both the on-board station and the ground station. [Means for solving the problem]

[0007] The transmission path switching system of the present disclosure comprises an on-board station mounted on a train, a ground station installed on the ground, and a plurality of transmission paths for transmitting data between the on-board station and the ground station, and a transmission path from among the plurality of transmission paths for the transmitting side to transmit data is determined based on a communication evaluation of the plurality of transmission paths using each data transmitted from a transmitting side of the on-board station or the ground station and received at a receiving side through each of the plurality of transmission paths. Effect of the Invention

[0008] According to the transmission path switching system of the present disclosure, a transmission path appropriate for both the on-board station and the ground station is selected. [Brief description of the drawings]

[0009] [Figure 1] 1 is a diagram showing a configuration of a transmission path switching system according to a first embodiment and a data flow when data is transmitted from a ground station to an on-board station. [Diagram 2] 1 is a diagram showing a configuration of a transmission path switching system according to a first embodiment and a data flow when data is transmitted from an on-board station to a ground station. [Diagram 3] 5 is a flowchart showing an operation of the transmission line switching system according to the first embodiment to determine a transmission line. [Figure 4] FIG. 11 is a diagram illustrating an example of communication evaluation data of a transmission path. [Diagram 5] FIG. 11 is a diagram illustrating an example of communication evaluation items of a transmission path. [Figure 6] FIG. 11 is a diagram showing a configuration of a transmission path switching system according to a second embodiment and a data flow when data is transmitted from an on-board station to a ground station. [Figure 7] 10 is a flowchart showing an operation of the transmission line switching system according to the second embodiment to determine a transmission line. [Figure 8] FIG. 11 is a diagram showing the relationship between the on-board station and the ground station in a case where there are no other trains in a new running section of the train in the second embodiment. [Figure 9] FIG. 11 is a diagram showing the relationship between the on-board station and the ground station in a case where another train exists in a new running section of the train in the second embodiment. [Figure 10] 13 is a flowchart showing an operation of the transmission line switching system according to the third embodiment to determine a transmission line. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] <Embodiment 1> The transmission path switching system of the present disclosure switches transmission paths in a train wireless communication system in which data for multiple applications, such as calls, notifications, and passenger services, is transmitted and received between an on-board station, which is a wireless device mounted on a train, and a ground station, which is a wireless device installed on the ground, selectively using multiple transmission paths.

[0011] 1 and 2 are configuration diagrams of a transmission path switching system according to embodiment 1. Fig. 1 shows a data flow when data is transmitted from a ground station 2 to an on-board station 1, and Fig. 2 shows a data flow when data is transmitted from the on-board station 1 to the ground station 2.

[0012] The on-board station 1 includes a plurality of applications a11, a12, a13, ..., a1n (n: natural number), an on-board communication control device c1 that controls the applications a11, a12, a13, ..., a1n, and an on-board gateway g1 that is a relay device for communicating with the ground station 2. The on-board communication control device c1 selects and executes one of the applications a11, a12, a13, ..., a1n of the on-board station 1 depending on the situation. The on-board gateway g1 can transmit and receive data to and from the ground station 2 through a plurality of transmission paths L1, L2, L3, ..., Lp (p: natural number).

[0013] The ground station 2 is composed of a plurality of applications a21, a22, a23, ..., a2m (m: natural number), a ground communication control device c2 that controls the applications a21, a22, a23, ..., a2m, and a ground gateway g2 that is a relay device for communicating with the on-board station 1. The ground communication control device c2 selects and executes one of the applications a21, a22, a23, ..., a2m of the ground station 2 depending on the situation. The ground gateway g2 can transmit and receive data to and from the on-board station 1 through a plurality of transmission paths L1, L2, L3, ..., Lp.

[0014] Communication between the ground station 2 and the on-board station 1 is performed by transmitting and receiving data between the ground station 2 and the on-board station 1 through any one of the transmission paths L1 to Lp. When data is transmitted from the ground station 2 to the on-board station 1, as shown in Fig. 1, the transmission paths L1, L2, L3, ..., Lp contain transmission data T1, T2, T3, ..., Tp transmitted from the ground station 2 to the on-board station 1, and return data R1, R2, R3, ..., Rp transmitted from the on-board station 1 to the ground station 2. When data is transmitted from the on-board station 1 to the ground station 2, as shown in Fig. 2, the transmission paths L1, L2, L3, ..., Lp contain transmission data T1, T2, T3, ..., Tp transmitted from the on-board station 1 to the ground station 2, and return data R1, R2, R3, ..., Rp transmitted from the ground station 2 to the on-board station 1.

[0015] In the drawings, an application is represented as an "app" and a gateway is represented as a "GW". In the following, applications a11, a12, a13, ..., a1n may be represented as "applications a11-a1n", applications a21, a22, a23, ..., a2m as "applications a21-a2m", and transmission paths L1, L2, L3, ..., Lp as "transmission paths L1-Lp".

[0016] The transmission lines L1 to Lp are classified into uses such as private network train radio (400 MHz band), public network 5G, local 5G, and train control. In Fig. 1 and Fig. 2, an example is shown in which the transmission line L1 is a private network train radio line, the transmission line L2 is a public network 5G line, the transmission line L3 is a local 5G line, and the transmission line Lp is a train control line. The private network train radio has the characteristics of being able to communicate even in dead zones and being able to recover quickly even if it cannot be used during communication failure or disaster. The public network 5G has the characteristics of being able to communicate with large capacity and with low latency. The local 5G is a private network independently constructed by companies, local governments, etc., and has the characteristics of being able to communicate with large capacity and with low latency, like the public network 5G. The transmission lines L1 to Lp may include various transmission lines such as lines for train control, and it is assumed that these transmission lines can be switched depending on the situation.

[0017] In the transmission path switching system of embodiment 1, when the ground station 2 transmits data of applications a21 to a2m to the on-board station 1, an appropriate transmission path is selected from among the transmission paths L1 to Lp depending on the position information of the train on which the on-board station 1 is mounted.

[0018] 3 is a flowchart showing an operation of the transmission path switching system according to the embodiment 1 to determine a transmission path. First, the operation of the transmission path switching system when data is transmitted from the ground station 2 to the on-board station 1 will be described with reference to the flowchart in FIG.

[0019] When the ground station 2 transmits data output from the applications a21 to a2m to the on-board station 1, the ground station 2 first transmits the data from the applications a21 to a2m simultaneously using all of the transmission paths L1 to Lp (step S101).

[0020] More specifically, the ground communications control device c2 assigns data to be transmitted to all of the transmission paths L1-Lp, and instructs the ground gateway g2 to transmit data from the applications a21-a2m to the on-board station 1. When the ground gateway g2 transmits the data from the applications a21-a2m simultaneously to all of the transmission paths L1-Lp, the data from the applications a21-a2m are transmitted to all of the transmission paths L1-Lp by radio transceivers (not shown) of the ground station 2 corresponding to each of the transmission paths L1-Lp. The data transmitted through the transmission paths L1-Lp is received by radio transceivers (not shown) of the on-board station 1 corresponding to each of the transmission paths L1-Lp, and is relayed to the on-board gateway g1 and sent to the on-board communications control device c1.

[0021] When the on-board communication control device c1 of the on-board station 1 receives data from the applications a21-a2m of the ground station 2, it performs communication evaluation of each of the transmission paths L1-Lp. In addition, the on-board communication control device c1 holds in advance information indicating the correspondence between the train position and the running section, and determines the running section from the current train position information (step S102).

[0022] Furthermore, the on-board communication control device c1 generates communication evaluation data from the communication evaluation results of the current train running section and each of the transmission paths L1 to Lp, and feeds it back to the ground communication control device c2 of the ground station 2 (step S103).

[0023] At this time, the on-board communication control device c1 assigns the communication evaluation data to all of the transmission paths L1 to Lp and instructs the on-board gateway g1 to transmit the train's running section and the communication evaluation data. When the on-board gateway g1 simultaneously transmits the train's running section and the communication evaluation data to all of the transmission paths L1 to Lp, the train's running section and the communication evaluation data are transmitted to all of the transmission paths L1 to Lp by the radio transceivers of the on-board stations 1 corresponding to each of the transmission paths L1 to Lp. The data transmitted through the transmission paths L1 to Lp is received by the radio transceivers of the ground stations 2 corresponding to each of the transmission paths L1 to Lp, relayed to the ground gateway g2, and sent to the ground communication control device c2.

[0024] An example of communication evaluation data of a transmission path is shown in Fig. 4. The communication evaluation data is a score obtained by converting the results of communication evaluation of each transmission path for each section in which the train runs. In the example of Fig. 4, the best communication evaluation score is 10, and the worst communication evaluation score is 0. Note that, although Fig. 4 shows the communication evaluation data of each transmission path in multiple sections together, the communication evaluation data generated by the on-board communication control device c1 and fed back to the ground station 2 is only the communication evaluation data of each transmission path in the section in which the train runs at that time.

[0025] Figure 5 shows examples of communication evaluation items for a transmission path. The communication evaluation items include the electric field strength on the transmission path, the number of errors (corrections), RSSI (Received Signal Strength Indicator), fading strength, frequency shift (F shift), transmission time, delay time, throughput, line usage status, interference wave level, etc. The on-board communication control device c1 evaluates and scores these items for each transmission path, and for example, sets the average score of all items as the communication evaluation score for the transmission path shown in Figure 4.

[0026] For example, in blind zones, communication failures, and disasters, public network 5G is not capable of communication, so the average score for the communication evaluation of public network 5G is low. However, private network train radio is capable of communication even in blind zones, communication failures, and disasters, so the average score for the communication evaluation of private network train radio is higher in blind zones, communication failures, and disasters. Also, if the section where the train is running is within the communication area of ​​5G and local 5G, 5G and local 5G will receive higher scores than train radio for evaluation results such as delay time and throughput.

[0027] The transmission path switching system repeats the above steps S101 to S103 for a certain period of time (step S104). After the certain period of time has elapsed, the ground communication control device c2 of the ground station 2 totals the scores of the evaluation results of each transmission path in the current train running section from the information on the train running section fed back from the on-board station 1 during that certain period of time and the communication evaluation data of each transmission path in that section, and determines the transmission path with the highest total score as the transmission path to be used in the current train running section. Then, the ground communication control device c2 notifies the on-board communication control device c1 of the determined transmission path using the determined transmission path (step S105).

[0028] Thereafter, data is transmitted from the ground station 2 to the on-board station 1 using the determined transmission path. At this time, even if the on-board communication control device c1 of the on-board station 1 receives data from the ground communication control device c2, it does not need to feed back communication evaluation data. However, when the train advances in position and the running section changes, the flow of FIG. 3 is executed again. In other words, the flow of FIG. 3 is executed every time the running section of the train changes, and the transmission path to be used in each section is re-determined. Note that the ground station 2 constantly receives train position information from the on-board station 1, and can constantly detect when the running section of the train changes.

[0029] Next, the operation of the transmission path switching system when data is transmitted from the on-board station 1 to the ground station 2 will be described with reference to the flowchart of FIG.

[0030] When the on-board station 1 transmits data output from the applications a11 to a1n to the ground station 2, the on-board station 1 first transmits the data from the applications a11 to a1n simultaneously using all of the transmission paths L1 to Lp (step S101).

[0031] More specifically, the on-board communication control device c1 assigns data to be transmitted to all of the transmission paths L1-Lp, and instructs the on-board gateway g1 to transmit data from the applications a11-a1n to the ground station 2. When the on-board gateway g1 transmits data from the applications a11-a1n simultaneously to all of the transmission paths L1-Lp, the data from the applications a11-a1n is transmitted to all of the transmission paths L1-Lp by the wireless transceivers of the on-board station 1 corresponding to each of the transmission paths L1-Lp. The data transmitted through the transmission paths L1-Lp is received by the wireless transceivers of the ground station 2 corresponding to each of the transmission paths L1-Lp, and is relayed to the ground gateway g2 and sent to the ground communication control device c2.

[0032] When the ground communication control device c2 of the ground station 2 receives the data from the applications a11-a1n of the on-board station 1, it performs communication evaluation of each of the transmission paths L1-Lp. In addition, the ground communication control device c2 holds in advance corresponding information of the train position and the running section, and determines the current running section of the train on which the on-board station 1 is mounted from the train position information received from the on-board communication control device c1 (step S102).

[0033] Furthermore, the ground communication control device c2 generates communication evaluation data from the communication evaluation results of the current train running section and each of the transmission paths L1 to Lp, and feeds it back to the on-board communication control device c1 of the on-board station 1 (step S103).

[0034] At this time, the ground communication control device c2 assigns the communication evaluation data to all of the transmission paths L1 to Lp and instructs the ground communication control device c2 to transmit the train's running section and the communication evaluation data. When the ground gateway g2 transmits the communication evaluation data simultaneously to all of the transmission paths L1 to Lp, the train's running section and the communication evaluation data are transmitted to all of the transmission paths L1 to Lp by the radio transceivers of the ground stations 2 corresponding to each of the transmission paths L1 to Lp. The data transmitted through the transmission paths L1 to Lp is received by the radio transceivers of the on-board stations 1 corresponding to each of the transmission paths L1 to Lp, and is relayed to the on-board gateway g1 and sent to the on-board communication control device c1.

[0035] The communication evaluation data sent from the ground communication control device c2 to the on-board communication control device c1 may be the same as that shown in Fig. 4. Also, the communication evaluation items for each transmission path may be those exemplified in Fig. 5. Although Fig. 4 shows the communication evaluation data for each transmission path in multiple sections together, the communication evaluation data generated by the ground communication control device c2 and fed back to the on-board station 1 is only the communication evaluation data for each transmission path in the section in which the train is running at that time.

[0036] The transmission path switching system repeats the above steps S101 to S103 for a certain period of time (step S104). After the certain period of time has elapsed, the on-board communication control device c1 of the on-board station 1 totals the scores of the evaluation results of each transmission path in the current train running section from the communication evaluation data of the train running section and each transmission path in that section fed back from the ground station 2 during that certain period of time, and determines the transmission path with the highest total score as the transmission path to be used in the current train running section. Then, the on-board communication control device c1 notifies the ground communication control device c2 of the determined transmission path using the determined transmission path (step S105).

[0037] Thereafter, data is transmitted from the on-board station 1 to the ground station 2 using the determined transmission path. At this time, even if the ground communication control device c2 of the ground station 2 receives data from the on-board communication control device c1, it does not need to feed back communication evaluation data. However, when the train advances in position and the running section changes, the flow of FIG. 3 is executed again. In other words, the flow of FIG. 3 is executed every time the running section of the train changes, and the transmission path to be used in each section is re-determined. Note that the ground station 2 constantly receives train position information from the on-board station 1, and can constantly detect when the running section of the train changes.

[0038] In the first embodiment, an example has been shown in which the transmission line switching system executes the flow of Fig. 3 when the running section of the train changes, but the flow of Fig. 3 may be executed periodically. Also, when the evaluation score of the communication evaluation data of the selected transmission line becomes lower than a certain value, the transmission line switching system may execute the flow of Fig. 3 to switch to a transmission line with a higher evaluation score.

[0039] In the first embodiment, an example is shown in which the transmission path with the highest evaluation score is selected. However, for example, a priority order of the transmission path to be used may be determined in advance for each piece of data to be transmitted, and the transmission path with the highest priority order may be selected from among those with evaluation scores higher than a certain value.

[0040] In addition, in the first embodiment, when a transmission path for transmitting data from the ground station 2 to the on-board station 1 is determined, an example has been shown in which communication evaluation data is fed back from the on-board communication control device c1, but the communication evaluation data may be fed back from the applications a11 to a1n of the on-board station 1, the on-board gateway g1, or the wireless transceiver of the on-board station 1. Furthermore, the transmission path may also be determined by the applications a21 to a2m of the ground station 2, the ground gateway g2, or the wireless transceiver of the ground station 2, instead of the ground communication control device c2.

[0041] In addition, in the first embodiment, when a transmission path for transmitting data from the on-board station 1 to the ground station 2 is determined, an example has been shown in which communication evaluation data is fed back from the ground communication control device c2, but the communication evaluation data may be fed back from the applications a21-a2m of the ground station 2, the ground gateway g2, or the wireless transceiver of the ground station 2. Furthermore, the transmission path may also be determined by the applications a11-a1n of the on-board station 1, the on-board gateway g1, or the wireless transceiver of the ground station 2, instead of by the on-board communication control device c1.

[0042] In the first embodiment, the communication evaluation data is scored by averaging the communication evaluation results of each item. However, for example, each item may be weighted and a weighted average may be calculated.

[0043] In addition, in the first embodiment, communication evaluation data of each transmission path is fed back from the data receiving side to the data transmitting side, and the transmission path is determined by the transmitting side. However, as shown in the flowchart of FIG. 10 described later, the communication evaluation and the determination of the transmission path may be performed by the receiving side, and the determined transmission path may be notified to the transmitting side.

[0044] In addition, in embodiment 1, an example is shown in which when communication evaluation data is transmitted, information on the train's running section converted from the train's position information is transmitted together with the communication evaluation data. However, it is also possible to transmit the train's position information before conversion, and convert the train's position information into information on the running section when the transmission path is determined.

[0045] As described above, according to the transmission line switching system of the first embodiment, the transmitting side of the ground station 2 and the on-board station 1 transmits data to all transmission lines simultaneously, the transmitting side of the on-board station 1 and the ground station 2 receives the simultaneously transmitted data, and the transmission line through which the transmitting side transmits data is determined based on the communication evaluation data of the data received at the receiving side. Therefore, in the transmission line switching system of the first embodiment, the receiving line quality at the receiving side, which cannot be determined at the transmitting side, can be grasped, and it becomes possible to determine a transmission line with good receiving line quality at the receiving side. In addition, by selecting a transmission line with good receiving line quality at the receiving side for each section in which the train runs, it is also possible to respond to changes in the receiving line quality at the receiving side caused by changes in the position of the train.

[0046] <Embodiment 2> In embodiment 2, a transmission path switching system is described which selects a transmission path by referring to the communication evaluation results of other trains when the running section of a train equipped with an on-board station 1 changes and communication is to be performed from the on-board station 1 to a ground station 2 on the new running section.

[0047] 6 is a configuration diagram of a transmission path switching system according to embodiment 2. FIG 6 shows the flow of data when data is transmitted from the on-board station 1 and the on-board station 3 to the ground station 2.

[0048] The on-board station 1 includes a plurality of applications a11 to a1n, an on-board communication control device c1 that controls the applications a11 to a1n in an integrated manner, and an on-board gateway g1 that is a relay device for communicating with the ground station 2. Similarly to the on-board station 1, the on-board station 3 includes a plurality of applications a31, a32, a33, ..., a3k (k: natural number), an on-board communication control device c3 that controls the applications a31 to a3k in an integrated manner, and an on-board gateway g3 that is a relay device for communicating with the ground station 2. The ground station 2 includes a plurality of applications a21 to a2m, a ground communication control device c2 that controls the applications a21 to a2m in an integrated manner, and a ground gateway g2 that is a relay device for communicating with the on-board station 1 and the on-board station 3.

[0049] Communications between the ground station 2 and the on-board stations 1 and 3 are performed by transmitting and receiving data between the ground station 2 and the on-board stations 1 and 3 through any of the transmission paths L1 to Lp.

[0050] In the transmission path switching system of embodiment 2, when the ground station 2 transmits data of applications a21 to a2m to the on-board station 1, an appropriate transmission path is selected from among the transmission paths L1 to Lp depending on the position information of the train carrying the on-board station 1 and the position information of the train carrying the on-board station 3 running in front of it.

[0051] 7 is a flowchart showing an operation of the transmission line switching system according to the embodiment 2 for determining a transmission line. Hereinafter, the operation of the transmission line switching system according to the embodiment 2 will be described with reference to the flowchart in FIG.

[0052] Ground station 2 monitors the position information of multiple trains, and when it detects that the train's running section has changed, it determines whether there are other trains communicating with ground station 2 in the new running section of the train (step S201).

[0053] For example, as shown in FIG. 8, a case will be described in which a train 11 carrying an on-board station 1 traveling in section s1 moves to the next section s2, and there is no train communicating with the ground station 2 in section s2.

[0054] When transmitting data output from applications a11 to a1n of the on-board station 1 after the train 11 moves to section s2, if there is no train in section s2 communicating with the ground station 2, the on-board station 1 first transmits the data from the applications a11 to a1n simultaneously using all of the transmission paths L1 to Lp (step S202).

[0055] More specifically, the on-board communication control device c1 assigns data to be transmitted to all of the transmission paths L1 to Lp and instructs the on-board gateway g1 to transmit data from the applications a11 to a1n. When the on-board gateway g1 transmits data from the applications a11 to a1n simultaneously to all of the transmission paths L1 to Lp, the data from the applications a11 to a1n is transmitted to all of the transmission paths L1 to Lp by the radio transceivers of the on-board station 1 corresponding to each of the transmission paths L1 to Lp. The data transmitted through the transmission paths L1 to Lp is received by the radio transceivers of the ground stations 2 corresponding to each of the transmission paths L1 to Lp, relayed to the ground gateway g2, and sent to the ground communication control device c2.

[0056] The ground communication control device c2 of the ground station 2 performs communication evaluation of each of the transmission paths L1 to Lp when receiving the data from the applications a11 to a1n of the on-board station 1. The ground communication control device c2 also holds in advance information indicating the correspondence between the train position and the running section, and determines the running section from the current train position information received from the on-board communication control device c1 (step S203).

[0057] Furthermore, the ground communication control device c2 generates communication evaluation data from the communication evaluation results of the current train running section and each of the transmission paths L1 to Lp, and feeds it back to the on-board communication control device c1 of the on-board station 1 (step S204).

[0058] At this time, the ground communication control device c2 assigns the communication evaluation data to all of the transmission paths L1 to Lp and instructs the ground gateway g2 to transmit the train's running section and the communication evaluation data. When the ground gateway g2 transmits the communication evaluation data simultaneously to all of the transmission paths L1 to Lp, the train's running section and the communication evaluation data are transmitted to all of the transmission paths L1 to Lp by the radio transceivers of the ground stations 2 corresponding to each of the transmission paths L1 to Lp. The data transmitted through the transmission paths L1 to Lp is received by the radio transceivers of the on-board stations 1 corresponding to each of the transmission paths L1 to Lp, and is relayed to the on-board gateway g1 and sent to the on-board communication control device c1.

[0059] The communication evaluation data sent from the ground communication control device c2 to the on-board communication control device c1 may be the same as that shown in Fig. 4. Also, the communication evaluation items for each transmission path may be those exemplified in Fig. 5. Although Fig. 4 shows the communication evaluation data for each transmission path in multiple sections together, the communication evaluation data generated by the ground communication control device c2 and fed back to the on-board station 1 is only the communication evaluation data for each transmission path in the section in which the train is running at that time.

[0060] The transmission path switching system repeats the above steps S202 to S205 for a certain period of time (step S205). After the certain period of time has elapsed, the on-board communication control device c1 of the on-board station 1 totals the scores of the evaluation results of each transmission path in the current train running section from the communication evaluation data of the train running section and each transmission path in that section fed back from the ground station 2 during that certain period of time, and determines the transmission path with the highest total score as the transmission path to be used in the current train running section. Then, the on-board communication control device c1 notifies the ground communication control device c2 of the determined transmission path using the determined transmission path (step S211).

[0061] Thereafter, data is transmitted from the on-board station 1 to the ground station 2 using the determined transmission path. At this time, even if the ground communication control device c2 of the ground station 2 receives data from the on-board communication control device c1, it does not need to feed back communication evaluation data. However, when the train advances in position and the running section changes, the flow of FIG. 7 is executed again. In other words, the flow of FIG. 7 is executed every time the running section of the train changes, and the transmission path to be used in each section is re-determined. Note that the ground station 2 constantly receives train position information from the on-board station 1, and can constantly detect when the running section of the train changes.

[0062] 9, a case will be described in which, for example, when a train 11 carrying an on-board station 1 traveling in section s1 moves to the next section s2, a train 32 carrying an on-board station 3 communicating with the ground station 2 is present in section s2. Here, it is assumed that the transmission path used when transmitting data from the on-board station 3 of the train 32 traveling in section s2 to the ground station 2 has already been determined.

[0063] When transmitting data output from the applications a11 to a1n of the on-board station 1 after the train 11 moves to section s2, if there is a train 32 carrying an on-board station 3 that is communicating with the ground station 2, the on-board station 1 first transmits the data from the applications a11 to a1n simultaneously using all of the transmission paths L1 to Lp (step S206).

[0064] More specifically, the on-board communication control device c1 assigns data to be transmitted to all of the transmission paths L1 to Lp and instructs the on-board gateway g1 to transmit data from the applications a11 to a1n. When the on-board gateway g1 transmits data from the applications a11 to a1n simultaneously to all of the transmission paths L1 to Lp, the data from the applications a11 to a1n is transmitted to all of the transmission paths L1 to Lp by the wireless transceivers of the on-board station 1 corresponding to each of the transmission paths L1 to Lp. The data transmitted through the transmission paths L1 to Lp is received by the wireless transceivers of the ground station 2 corresponding to each of the transmission paths L1 to Lp, relayed to the ground gateway g2, and sent to the ground communication control device c2.

[0065] When the ground communication control device c2 of the ground station 2 receives the data from the applications a11-a1n of the on-board station 1, it selects the transmission path used when transmitting data from the on-board station 3 of the train 32 traveling in the section s2 to the ground station 2 as the transmission path to be used when transmitting data from the on-board station 1 to the ground station 2 (step S207). Then, the ground communication control device c2 calls up past communication evaluation data of the transmission path, specifically, the average score of the communication evaluation results of the transmission path when data was transmitted from the on-board station 3 to the ground station 2.

[0066] After that, when data is transmitted from the on-board station 1 to the ground station 2 using the selected transmission path, the ground communication control device c2 performs communication evaluation of the transmission path (steps S208 and S209). The ground communication control device c2 holds information indicating the correspondence between the train position and the running section in advance, and determines the running section from the current train position information received from the on-board communication control device c1. Then, communication evaluation data is generated from the current train running section and the communication evaluation result of the selected transmission path, and is fed back to the on-board communication control device c1 of the on-board station 1 together with the past communication evaluation score of the transmission path (steps S208 and S209).

[0067] At this time, the ground communication control device c2 assigns the data to be transmitted to the selected transmission path, and instructs the ground gateway g2 to transmit the communication evaluation data and past communication evaluation scores of the selected transmission path. When the ground gateway g2 transmits the communication evaluation data and past communication evaluation scores to the selected transmission path, the communication evaluation data and past communication evaluation scores are transmitted to the selected transmission path by the radio transceiver of the ground station 2 corresponding to the selected transmission path. The data transmitted on the selected transmission path is received by the radio transceiver of the on-board station 1 corresponding to the selected transmission path, relayed to the on-board gateway g1, and sent to the on-board communication control device c1.

[0068] The on-board communication control device c1 compares the current communication evaluation score of the selected transmission path contained in the communication evaluation data fed back from the ground station 2 with the past communication evaluation score of the transmission path, and if the current communication evaluation score is equal to or higher than the past communication evaluation score, uses the optimal transmission path used when transmitting data from the on-board station 3 to the ground station 2. On the other hand, if the current communication evaluation score of the transmission path is lower than the past communication evaluation score, the process proceeds to step S202 (step S210), and the transmission path to be used is re-determined by the processes of steps S202 to S205.

[0069] In the second embodiment, an example has been shown in which the transmission line switching system executes the flow of Fig. 3 when the running section of the train changes, but the flow of Fig. 3 may be executed periodically. Also, when the evaluation score of the communication evaluation data of the selected transmission line becomes lower than a certain value, the transmission line switching system may execute the flow of Fig. 3 to switch to a transmission line with a higher evaluation score.

[0070] In the second embodiment, an example has been shown in which the transmission path with the highest evaluation score is selected. However, for example, a priority order of the transmission path to be used may be determined in advance for each piece of data to be transmitted, and the transmission path with the highest priority order may be selected from among those with evaluation scores higher than a certain value.

[0071] In addition, in the second embodiment, when a transmission path for transmitting data from the ground station 2 to the on-board station 1 is determined, an example has been shown in which communication evaluation data is fed back from the on-board communication control device c1, but the communication evaluation data may be fed back from the applications a11 to a1n of the on-board station 1, the on-board gateway g1, or the wireless transceiver of the on-board station 1. Furthermore, the transmission path may also be determined by the applications a21 to a2m of the ground station 2, the ground gateway g2, or the wireless transceiver of the ground station 2, instead of the ground communication control device c2.

[0072] In addition, in the second embodiment, when a transmission path for transmitting data from the on-board station 1 to the ground station 2 is determined, an example has been shown in which communication evaluation data is fed back from the ground communication control device c2, but the communication evaluation data may be fed back from the applications a21-a2m of the ground station 2, the ground gateway g2, or the wireless transceiver of the ground station 2. Furthermore, the transmission path may also be determined by the applications a11-a1n of the on-board station 1, the on-board gateway g1, or the wireless transceiver of the ground station 2, instead of by the on-board communication control device c1.

[0073] In the second embodiment, the communication evaluation data is scored by averaging the communication evaluation results of each item. However, for example, each item may be weighted and a weighted average may be calculated.

[0074] In addition, in the second embodiment, communication evaluation data of each transmission path is fed back from the data receiving side to the data transmitting side, and the transmission path is determined by the transmitting side. However, as shown in the flowchart of FIG. 10 described later, the communication evaluation and the determination of the transmission path may be performed by the receiving side, and the determined transmission path may be notified to the transmitting side.

[0075] In addition, in the second embodiment, an example was shown in which when communication evaluation data is transmitted, information on the train's running section converted from the train's position information is transmitted together with the communication evaluation data. However, it is also possible to transmit the train's position information before conversion, and convert the train's position information into information on the running section when the transmission path is determined.

[0076] As described above, according to the transmission path switching system of the second embodiment, when a train changes its running section, the transmission path used by another train that has already run on the new running section is selected, so that the load of the process for determining the transmission path is reduced. Also, if the current communication evaluation score of the selected transmission path is lower than the past communication evaluation score, the transmission path to be used is re-determined by the same process as in the first embodiment, so that the receiving line quality can be maintained high.

[0077] <Embodiment 3> In the third embodiment, a transmission path switching system is described in which the ground station 2 accumulates and refers to communication evaluations when receiving data from multiple trains, and selects a transmission path for each train to transmit. The configuration of the transmission path switching system according to the third embodiment is the same as that shown in FIG.

[0078] In the transmission path switching system of embodiment 3, when the ground station 2 transmits data of applications a21 to a2m to the on-board station 1, an appropriate transmission path is selected from among the transmission paths L1 to Lp according to the position information of multiple trains each equipped with the on-board station 1 and the on-board station 3.

[0079] 10 is a flowchart showing an operation of determining a transmission path by the transmission path switching system according to the embodiment 3. Hereinafter, the operation of the transmission path switching system according to the embodiment 3 will be described with reference to the flowchart in FIG.

[0080] When the on-board stations 1, 3, ... transmit data output from the applications a11-a1n, a31-a3n, ... to the ground station 2, the on-board communication control devices c1, c3, ... of the on-board stations 1, 3, ... first transmit the data from the applications a11-a1n, a31-a3n, ... simultaneously using all of the transmission paths L1-Lp (step S301).

[0081] More specifically, the on-board communication control devices c1, c3, ... of the on-board stations 1, 3, ... assign the data to be transmitted to all of the transmission paths L1 to Lp, and instruct the on-board gateways g1, g3, ... to transmit the data from the applications a11 to a1n, a31 to a3n, .... When the on-board gateways g1, g3, ... transmit the data from the applications a11 to a1n, a31 to a3n, ... to all of the transmission paths L1 to Lp simultaneously, the data from the applications a11 to a1n, a31 to a3n, ... is transmitted from the wireless transceivers of the on-board stations 1, 3, ... corresponding to each of the transmission paths L1 to Lp to all of the transmission paths L1 to Lp. The data transmitted through the transmission paths L1 to Lp is received by the wireless transceivers of the ground stations 2 corresponding to each of the transmission paths L1 to Lp, relayed to the ground gateway g2, and sent to the ground communication control device c2.

[0082] When the ground communication control device c2 of the ground station 2 receives data from the applications a11-a1n, a31-a3n, ... of the on-board stations 1, 3, ..., it performs communication evaluation of each of the transmission paths L1-Lp. In addition, the ground communication control device c2 holds in advance information indicating the correspondence between the train positions and the running sections, and determines the running section of each train from the train position information received from the on-board communication control devices c1, c3, ... (step S302).

[0083] Furthermore, the ground communication control device c2 generates communication evaluation data from the communication evaluation results of the current running section of each train and each of the transmission paths L1 to Lp, and accumulates the generated communication evaluation data (step S303).

[0084] The communication evaluation data generated and accumulated by the ground communication control device c2 may be the same as that shown in Fig. 4. Also, the communication evaluation items in each transmission path may be those exemplified in Fig. 5. Although Fig. 4 collectively shows the communication evaluation data of each transmission path in a plurality of sections, the communication evaluation data generated and accumulated by the ground communication control device c2 is only the communication evaluation data of each transmission path in the section in which each train is running at that time.

[0085] The transmission path switching system repeats the above steps S301 to S303 for a certain period of time (step S304). After the certain period of time has elapsed, the ground communication control device c2 of the ground station 2 totals the scores of the evaluation results of each transmission path in the current running section of each train from the information on the running section of each train and the communication evaluation data of each transmission path in that section accumulated during that certain period of time, and determines the transmission path with the highest total score for each train as the transmission path to be used in the current running section of each train. Then, the ground communication control device c2 notifies each of the determined transmission paths to each of the on-board communication control devices c1, c3, ... using each determined transmission path (step S305).

[0086] Thereafter, data is transmitted from the on-board stations 1, 3, . . . to the ground station 2 using the determined transmission path.

[0087] The flow of Fig. 10 may be performed periodically. Also, when the evaluation score of the communication evaluation data of the selected transmission path falls below a certain value, the transmission path switching system may perform the flow of Fig. 10 to switch to a transmission path with a higher evaluation score.

[0088] In the third embodiment, an example has been shown in which the transmission path with the highest evaluation score is selected. However, for example, a priority order of the transmission paths to be used may be determined in advance for each piece of data to be transmitted, and the transmission path with the highest priority order may be selected from among those with evaluation scores higher than a certain value.

[0089] In addition, in the embodiment 3, an example has been shown in which the terrestrial communication control device c2 determines the transmission path, but the determination of the transmission path may also be performed by the applications a21 to a2m of the terrestrial station 2, the terrestrial gateway g2, or the radio transceiver of the terrestrial station 2, rather than by the terrestrial communication control device c2.

[0090] In the third embodiment, the communication evaluation data is scored by averaging the communication evaluation results of each item. However, for example, each item may be weighted and a weighted average may be calculated.

[0091] As described above, according to the transmission path switching system of the third embodiment, the on-board stations 1, 3, ... transmit data simultaneously to all transmission paths, the ground station 2 receives the simultaneously transmitted data, and the transmission path through which the on-board stations 1, 3, ... transmit data is determined based on the communication evaluation data of the data received by the ground station 2. Therefore, the transmission path switching system of the third embodiment makes it possible to determine a transmission path with good reception line quality on the receiving side. In addition, by selecting a transmission path with good reception line quality on the receiving side for each running section of the train, it is also possible to respond to a change in reception line quality on the receiving side caused by a change in the position of the train.

[0092] It should be noted that the embodiments can be freely combined, and each embodiment can be modified or omitted as appropriate.

[0093] Various aspects of the present disclosure are summarized below as appendices.

[0094] (Appendix 1) The on-board station installed on the train, A ground station installed on the ground; a plurality of transmission paths for transmitting data between the on-board station and the ground station; Equipped with a transmission path for the transmitter to transmit data is determined from among the plurality of transmission paths based on a communication evaluation of the plurality of transmission paths using each data transmitted from a transmitter of the on-board station or the ground station and received by a receiver through each of the plurality of transmission paths; Transmission line switching system.

[0095] (Appendix 2) The communication evaluation of the plurality of transmission paths is performed for each running section of the train, A transmission path for the transmitter to transmit data is determined based on the communication evaluation of the running section corresponding to the current position of the train. 2. The transmission line switching system according to claim 1.

[0096] (Appendix 3) When the running section of the train changes and another train is present in the new running section, a transmission path used by another on-board station mounted on the other train is selected as the transmission path for the transmitting side to transmit data. 3. The transmission line switching system according to claim 2.

[0097] (Appendix 4) A transmission path for the transmitting side to transmit data is determined based on the multiple communication evaluations of the train. 4. A transmission line switching system according to any one of claims 1 to 3.

[0098] (Appendix 5) a transmission path for the transmitting side to transmit data is determined based on the communication evaluation of the plurality of transmission paths using each of the data transmitted from the plurality of on-board stations mounted on the plurality of trains; 5. A transmission line switching system according to any one of claims 1 to 4. [Explanation of symbols]

[0099] 1,3 on-board station, g1,g3 on-board gateway, c1,c3 on-board communication control device, a11~a1n,a21~a2m,a31~a3k applications, 2 ground station, g2 ground gateway, c2 ground communication control device, L1~Lp transmission path, T1~Tp transmission data, R1~Rp return data, 11,32 train.

Claims

1. An on-board station installed on a train, a ground station installed on the ground; a plurality of transmission paths for transmitting data between the on-board station and the ground station; Equipped with the transmitting side determines a transmission path for transmitting the data from among the plurality of transmission paths based on a communication evaluation of the plurality of transmission paths using each of the data transmitted from a transmitting side of the on-board station or the ground station and received at a receiving side through each of the plurality of transmission paths; Transmission line switching system.

2. An on-board station installed on a train, a ground station installed on the ground; a plurality of transmission paths for transmitting data between the on-board station and the ground station; Equipped with the receiving side determines a transmission path for transmitting the data from among the plurality of transmission paths based on a communication evaluation of the plurality of transmission paths using each of the data transmitted from a transmitting side of the on-board station or the ground station and received at a receiving side through each of the plurality of transmission paths; Transmission line switching system.

3. A transmission path for transmitting the data is determined based on the communication evaluation of the running section corresponding to the current position of the train.

3. The transmission line switching system according to claim 1.

4. When the running section corresponding to the current position of the train changes and another train is present in the new running section, a transmission path used by another on-board station mounted on the other train is selected as the transmission path for transmitting the data.

3. The transmission line switching system according to claim 1.

5. a transmission path for transmitting the data is determined based on the plurality of communication evaluations of the train; 3. The transmission line switching system according to claim 1.

6. a transmission path for transmitting the data is determined based on the communication evaluation of the plurality of transmission paths using each of the data transmitted from the plurality of on-board stations mounted on the plurality of trains; 3. The transmission line switching system according to claim 1.

7. A radio device as an on-board station mounted on a train or a ground station installed on the ground, Data is transmitted between the on-board station and the ground station through a plurality of transmission paths; determining a transmission path for transmitting the data from among the plurality of transmission paths based on a communication evaluation of the plurality of transmission paths transmitted from the other wireless device; Radio equipment.

8. A radio device as an on-board station mounted on a train or a ground station installed on the ground, performing communication evaluation of the plurality of transmission paths using each piece of data transmitted from the other wireless device through each of the plurality of transmission paths; transmitting the communication evaluation results of the plurality of transmission paths to the other wireless device; Radio equipment.

9. A radio device as an on-board station mounted on a train or a ground station installed on the ground, performing communication evaluation of the plurality of transmission paths using each piece of data transmitted from the other wireless device through each of the plurality of transmission paths; determining a transmission path for transmitting the data from among the plurality of transmission paths based on the results of the communication evaluation of the plurality of transmission paths; Radio equipment.

10. A transmission path for transmitting the data is determined based on the communication evaluation of the running section corresponding to the current position of the train.

10. The wireless device according to claim 7 or claim 9.

11. A radio device as the ground station, When the running section corresponding to the current position of the train changes and another train is present in the new running section, a transmission path used by another on-board station mounted on the other train is selected as the transmission path for transmitting the data.

10. The wireless device according to claim 7 or claim 9.

12. A transmission path for transmitting the data is determined based on the multiple communication evaluations of the train.

10. The wireless device according to claim 7 or claim 9.

13. A radio device as the ground station, determining a transmission path for transmitting the data based on the communication evaluation of the plurality of transmission paths using each of the data transmitted from the plurality of on-board stations mounted on the plurality of trains; 10. The wireless device according to claim 7 or claim 9.

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