Transmission speed selection system

Abstract

To provide a transmission speed selection system capable of selecting an optimal transmission speed without estimating line quality every time and suppressing an increase in maintenance cost by improving utilization efficiency of an existing communication line.SOLUTION: A transmission speed selection system includes: a base station 11; a mobile station 21 that has a fixed movement range; and a ground management device 13 for selecting an optimal transmission speed from among a plurality of transmission speeds for transmitting data through the communication line between the base station 11 and the mobile station 21. The ground management device 13 acquires line quality information that determines a transmission speed applicable to each spot on the basis of line quality of the communication line at each spot within the movement range, operation diagram information showing a movement plan of the mobile station 21, and train position information showing a current position of the mobile station 21, and selects a spot and a transmission speed at which data can be transmitted fastest on the basis of the line quality information, the operation diagram information, and the train position information.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a transmission rate selection system. [Background technology]

[0002] In wireless communications, the likelihood of bit errors fluctuates depending on the line quality of the propagation path. The line quality of the communication line, which is the wireless transmission line, is affected by changes in surrounding structures and the relative positions of the transmitting and receiving devices. In general, there is a trade-off between transmission speed and the likelihood of bit errors, with faster transmission speeds making bit errors more likely and slower transmission speeds making bit errors less likely. If the transmission speed is fixed so that bit errors fall within a certain range in consideration of possible degradation in the line quality of the communication line, a slower transmission speed will be applied even when the line quality is good, resulting in reduced utilization efficiency of the communication line.

[0003] Therefore, in recent wireless communications, a transmission rate selection system is provided that applies a high transmission rate when the line quality is good and applies a low transmission rate when the line quality deteriorates.For example, Patent Document 1 discloses a communication method that switches between multiple transmission rates depending on the line quality estimated based on an error detection signal. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-199033 Summary of the Invention [Problem to be solved by the invention]

[0005] In a transmission rate selection system that switches the transmission rate according to the line quality as described above, the line quality of the communication line varies depending on surrounding structures and the relative positions of the transmitting and receiving devices, so it was necessary to estimate the line quality each time in order to switch the transmission rate.

[0006] Furthermore, with the development of high-speed, large-capacity communication environments such as 5G, increases in communication volume are also expected for train radio systems. Conventional train radio systems use dedicated lines for each application, so suppressing the increase in the number of facilities and maintenance costs that accompany increases in communication volume has become a challenge. For this reason, there is a need to improve the utilization efficiency of existing communication lines without increasing new facilities.

[0007] Therefore, the present disclosure aims to provide a transmission rate selection system that can select the optimal transmission rate without estimating line quality each time, and that can reduce increases in maintenance costs by improving the utilization efficiency of existing communication lines. [Means for solving the problem]

[0008] The transmission rate selection system according to the present disclosure includes a base station installed on the ground, a mobile station with a fixed movement range, and a ground control device that selects an optimum transmission rate from among a plurality of transmission rates for transmitting data between the base station and the mobile station via a communication line, wherein the ground control device acquires line quality information that defines a transmission rate applicable to each point based on the line quality of the communication line at each point within the movement range, movement plan information that indicates a movement plan for the mobile station, and location information that indicates the current location of the mobile station, and selects a point and transmission rate at which the data can be transmitted most quickly based on the line quality information, the movement plan information, and the location information. [Effects of the Invention]

[0009] According to the present disclosure, it is possible to select an optimal transmission rate without estimating line quality each time, and to suppress increases in maintenance costs by improving the utilization efficiency of existing communication lines. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a configuration diagram of a train radio system equipped with a transmission rate selection system according to a first embodiment. [Figure 2] 1 is a configuration diagram for explaining transmission rate selection in a train radio system equipped with a transmission rate selection system according to a first embodiment. [Figure 3] FIG. 10 is a configuration diagram of a train radio system equipped with a transmission rate selection system according to a second embodiment. [Figure 4] FIG. 10 is a configuration diagram of a train radio system equipped with a transmission rate selection system according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] <First Embodiment> The first embodiment will be described below with reference to the drawings. An example in which the transmission rate selection system according to the first embodiment is applied to a train radio system will be described. Fig. 1 is a configuration diagram of a train radio system equipped with the transmission rate selection system according to the first embodiment.

[0012] 1, the train radio system includes a ground facility and a train 20. The ground facility is made up of a base station 11, a central device 12, and a ground control device 13.

[0013] Base station 11 is installed on the ground and performs wireless communication with mobile stations 21 of trains 20. Central device 12 controls base station 11. Generally, multiple base stations 11 are connected to one central device 12, but only one base station 11 is shown here. Ground control device 13 selects the optimum transmission rate from multiple transmission rates for transmitting data between base station 11 and mobile station 21 via a communication line. Ground control device 13 includes a line quality information database (hereinafter referred to as line quality information DB) 31, a train schedule information database (hereinafter referred to as train schedule information DB) 32, and a train location information database (hereinafter referred to as train location information DB) 33. Details of line quality information DB 31, train schedule information DB 32, and train location information DB 33 will be described later.

[0014] The train 20 includes a mobile station 21 and an on-board control device 22. The mobile station 21 has a fixed movement range and communicates with the base station 11. The on-board control device 22 instructs the mobile station 21 to communicate at a transmission rate instructed by the wayside control device 13.

[0015] Next, the line quality information DB31, the train schedule information DB32, and the train position information DB33 will be described in detail. The line quality information DB31 is a database that stores line quality information in which applicable transmission rates at each point within the travel range are determined based on the line quality of the communication line at each point. Since the travel range of the train 20 is fixed and the communication line does not fluctuate significantly on the same track, the line quality information can be treated as known information. The line quality information DB31 stores line quality information acquired during the daily travel of an inspection train or an operating train. Here, the line quality information is information in which each point within the travel range is associated with an applicable transmission rate at each point. Note that when determining the transmission rate associated with each point within the travel range in the line quality information DB31, the running speed of the train 20 at each point may be taken into consideration.

[0016] The train schedule information DB32 is a database that stores the movement plan of the mobile station 21, such as when and where the train 20 will be located and how long the train will stop at which station, based on the train schedule. Here, the train schedule information corresponds to movement plan information that indicates the movement plan of the mobile station 21.

[0017] The train position information DB 33 is a database that stores train position information indicating the current location of the mobile station 21. The train position information DB 33 collects and stores position information of trains 20 in operation in real time. Here, the train position information corresponds to position information. The train position information is constructed using any one or a combination of information from track circuitry installed on the tracks, latitude and longitude information acquired by a GPS (Global Positioning System) device mounted on the train 20, and kilometer distance information of the train 20. Here, the kilometer distance information of the train 20 is information calculated by sensors attached to the wheels or axles of the train 20 about the travel distance of the train 20 from a specific starting point.

[0018] When data transmission between the trackside equipment and the train 20 is required, the trackside control device 13 acquires line quality information, train schedule information, and train location information from the line quality information DB 31, train schedule information DB 32, and train location information DB 33, respectively, and selects the location and transmission speed at which data can be transmitted most quickly based on the line quality information, train schedule information, and train location information. The trackside control device 13 then instructs the on-board control device 22 of the train 20 to communicate at the selected location at the selected transmission speed, and instructs the base station 11 to communicate at the selected transmission speed at the selected location. The on-board control device 22 instructs the mobile station 21 to communicate at the selected transmission speed at the location specified by the trackside control device 13. When communicating the location and transmission speed instructions from the trackside control device 13 to the on-board control device 22, a communication method using the base station 11 and the mobile station 21 may be predetermined, or a different communication line may be used.

[0019] Next, an example of transmission rate selection will be described with reference to Fig. 2. Fig. 2 is a configuration diagram for explaining transmission rate selection in a train radio system equipped with the transmission rate selection system according to the first embodiment.

[0020] As shown in Figure 2, train 20 is located at point b1 within area a1 of base station 11 and is traveling toward point b2 within area a1 of the same base station 11. Here, point b2 is assumed to be a station where train 20 will stop. When data transmission between base station 11 and train 20 becomes necessary, ground control device 13 acquires train schedule information and train position information from train schedule information DB 32 and train position information DB 33, respectively, and determines that train 20 will stop at the station at point b2 for a certain period of time after a certain period of time.

[0021] In addition, the ground control device 13 acquires line quality information from the line quality information DB 31 and determines that only a slow transmission speed can be applied in the section from point b1 to point b2, and that a fast transmission speed can be applied while the train is stopped at point b2, which is a station.

[0022] Next, the ground control device 13 compares the time the communication line will be occupied when communication is performed at a slow transmission speed while the train 20 is traveling from point b1, which is the current location of the train 20, to point b2, which is a station, with the time the communication line will be occupied when communication is performed at a fast transmission speed while the train arrives at point b2 and stops, and selects the point and transmission speed that allows the fastest data transmission. That is, the ground control device 13 compares the amount of data to be transmitted divided by the slow transmission speed applicable to the section from point b1 to point b2 with the amount of data to be transmitted divided by the fast transmission speed applicable to point b2, plus the travel time of the train 20 from point b1 to point b2, and selects the point and transmission speed that results in the shortest time. As a result, for example, if communication at a fast transmission speed while the train 20 arrives at point b2 and stops, it is possible to free up the communication line while the train 20 travels from point b1 to point b2 without reducing the efficiency of data transmission between the train 20 and the train 20.

[0023] The example in Figure 2 is a simple example in which there is only one train 20 in the area a1 of the base station 11, but if there are multiple trains 20 in the area a1 of the base station 11 and communication with each train 20 is required, the transmission speed applicable to each train 20 is calculated in turn, and the location and transmission speed that can transmit data the fastest in communication with all trains 20 are selected in a round-robin manner.

[0024] The procedure for selecting a transmission rate by round-robin method will be explained below. For example, if three trains A, B, and C are on the line and data transmission is required between the base station 11 and all of these trains A, B, and C, calculations are performed for patterns 1 to 6, namely, pattern 1 (A → B → C), pattern 2 (A → C → B), pattern 3 (B → A → C), pattern 4 (B → C → A), pattern 5 (C → A → B), and pattern 6 (C → B → A), and the location and transmission rate that allows the fastest data transmission among patterns 1 to 6 are selected.

[0025] First, in pattern 1, the location and transmission speed that allows the fastest data transmission for train A are selected. Next, the location and transmission speed that allows the fastest data transmission for train B are selected, excluding the time when the line is occupied for communication with train A. Next, the location and transmission speed that allows the fastest data transmission for train C are selected, excluding the time when the line is occupied for communication with trains A and B.

[0026] As with pattern 1, for patterns 2 to 6, the location and transmission speed that allows the best data transmission is selected for trains A, B, and C. Finally, the pattern that allows the fastest data transmission is selected from patterns 1 to 6. In other words, the pattern that minimizes the total communication time with trains A, B, and C is selected.

[0027] Next, a description will be given of a variation of embodiment 1. The transmission rate selection procedure is performed each time a new data transmission becomes necessary, but it may be performed by canceling the previously determined selection of the transmission rate, including transmissions already in progress, or by excluding transmissions already in progress.

[0028] Furthermore, in the first embodiment, a transmission rate selection system for the area a1 of one base station 11 has been described. However, in order to reduce the load on the entire system, the above-described transmission rate selection procedure may be performed for the areas of multiple base stations 11, targeting multiple trains 20 located within the areas of multiple base stations 11.

[0029] Furthermore, in the first embodiment, an upper or lower limit of the applicable transmission rate may be set depending on the type of data to be transmitted, thereby reducing the amount of calculation required to calculate the applicable transmission rate.

[0030] Furthermore, in the first embodiment, an example has been described in which the transmission rate selection system according to the first embodiment is applied to a train radio system. However, the transmission rate selection system according to the first embodiment can also be applied to a radio communication system in which the line quality information between the mobile station 21 and the base station 11 can be known and the movement plan information and the position information of the mobile station 21 can be grasped.

[0031] As described above, the transmission rate selection system according to the first embodiment includes the base station 11 installed on the ground, the mobile station 21 with a fixed movement range, and the ground control device 13 that selects the optimum transmission rate from among a plurality of transmission rates for transmitting data via a communication line between the base station 11 and the mobile station 21. The ground control device 13 acquires line quality information that determines the transmission rate applicable to each point based on the line quality of the communication line at each point within the movement range, train schedule information that indicates the movement plan of the mobile station 21, and train position information that indicates the current position of the mobile station 21, and selects the point and transmission rate at which data can be transmitted the fastest based on the line quality information, the train schedule information, and the train position information.

[0032] Therefore, it is possible to select an optimum transmission rate without having to estimate the line quality each time, and by improving the utilization efficiency of existing communication lines, it is possible to suppress increases in maintenance costs.

[0033] <Embodiment 2> Next, a description will be given of a transmission rate selection system according to embodiment 2. Fig. 3 is a configuration diagram of a train radio system including a transmission rate selection system according to embodiment 2. In embodiment 2, the same components as those described in embodiment 1 are denoted by the same reference numerals, and description thereof will be omitted.

[0034] In the first embodiment, the location and transmission speed at which data can be transmitted most quickly are selected based on line quality information, train schedule information, and train position information, but in the second embodiment, the transmission priority of the data is also taken into consideration.

[0035] 3, the ground control device 13 further includes a transmission priority information database (hereinafter referred to as transmission priority information DB) 34 that stores transmission priority information that defines the transmission priority of data. The transmission priority information DB 34 is a database that defines the transmission priority of data for each data type.

[0036] In the second embodiment, when selecting a transmission rate, the ground control device 13 acquires transmission priority information from the transmission priority information DB 34, and selects the location and transmission rate at which data with a high transmission priority can be transmitted most quickly based on the transmission priority information, line quality information, train schedule information, and train position information. For transmission of other data (data with a low transmission priority), the ground control device 13 selects the location and transmission rate at which data can be transmitted most quickly for all trains 20 that are located in the area a1 (see FIG. 2) of the same base station 11 and require data transmission, using the same procedure as in the first embodiment, during the time excluding the time when the line is occupied by transmitting data with a high transmission priority. Note that in the second embodiment, multiple data with a high transmission priority may be set.

[0037] As described above, in the transmission rate selection system according to the second embodiment, the ground control device 13 further acquires transmission priority information that defines the transmission priority of data, and selects the location and transmission rate at which data with high transmission priority can be transmitted most quickly based on the transmission priority information, line quality information, train schedule information, and train position information.

[0038] Therefore, data with a high transmission priority can be transmitted preferentially, and the utilization efficiency of existing communication lines can be improved.

[0039] <Third Embodiment> Next, a description will be given of a transmission rate selection system according to embodiment 3. Fig. 4 is a configuration diagram of a train radio system equipped with a transmission rate selection system according to embodiment 3. In embodiment 3, the same components as those described in embodiments 1 and 2 are denoted by the same reference numerals, and description thereof will be omitted.

[0040] In the third embodiment, a function for selecting a transmission rate by user operation is added to the first embodiment. The ground equipment is composed of a base station 11, a central device 12, a ground control device 13, and an operation unit 14. The operation unit 14 is connected to the ground control device 13 and is a device that allows the user to input the data transmission priority by operation. In other words, the operation unit 14 is a device for selecting a transmission rate by operation of the user. The user uses the operation unit 14 to select a data type for which data transmission is to be prioritized or a train 20 for which data transmission is to be prioritized.

[0041] In the third embodiment, when selecting a transmission rate, the ground control device 13 selects a location and a transmission rate that enable the fastest data transmission for the data type specified by user operation and for data transmission with the train 20 specified by user operation, based on the transmission priority, line quality information, train schedule information, and train position information. Here, the data transmission with the data type specified by user operation and the data transmission with the train 20 specified by user operation are data with a high transmission priority. For transmission of other data (data with a low transmission priority), the ground control device 13 selects a location and a transmission rate that enable the fastest data transmission for all trains 20 that are located in the area a1 (see FIG. 2) of the same base station 11 and require data transmission, using the same procedure as in the first embodiment, within the time excluding the time that the line is occupied by the data transmission with the data type specified by user operation and the data transmission with the train 20 specified by user operation.

[0042] In addition, in embodiment 3, multiple data types specified by user operation and multiple trains 20 specified by user operation may be set, or only one of the data types and trains 20 may be set.

[0043] As described above, the transmission rate selection system according to the third embodiment further includes the operation unit 14 that allows the user to input the transmission priority of data. The ground control device 13 selects the location and transmission rate that can transmit data with high transmission priority most quickly based on the transmission priority, line quality information, train schedule information, and train position information.

[0044] Therefore, data with a high transmission priority can be preferentially transmitted by user operation, and the utilization efficiency of existing communication lines can be improved.

[0045] It should be noted that the embodiments can be freely combined, and each embodiment can be modified or omitted as appropriate.

[0046] Various aspects of the present disclosure are summarized below as appendices.

[0047] (Appendix 1) a base station installed on the ground; a mobile station having a fixed range of movement; a ground control device that selects an optimum transmission rate from among a plurality of transmission rates for transmitting data between the base station and the mobile station via a communication line, The ground control device acquires line quality information that determines a transmission rate applicable to each point based on the line quality of the communication line at each point within the movement range, movement plan information that indicates a movement plan of the mobile station, and location information that indicates the current location of the mobile station, and selects a point and transmission rate that can transmit the data most quickly based on the line quality information, the movement plan information, and the location information.

[0048] (Appendix 2) The transmission rate selection system described in Appendix 1, wherein the ground control device further acquires transmission priority information that defines a transmission priority of the data, and selects the location and the transmission rate that can transmit the data with high transmission priority most quickly based on the transmission priority information, the line quality information, the movement plan information, and the location information.

[0049] (Appendix 3) an operation unit that allows a user to input the transmission priority of the data; The transmission rate selection system described in Appendix 1, wherein the ground control device selects the location and the transmission rate at which the data with high transmission priority can be transmitted most quickly based on the transmission priority, the line quality information, the movement plan information, and the location information. [Explanation of symbols]

[0050] 11 base station, 12 central equipment, 13 ground control equipment, 14 operation unit, 20 train, 21 mobile station, 22 on-board control equipment, 31 line quality information DB, 32 operation schedule information DB, 33 train position information DB, 34 transmission priority information DB.

Claims

1. a base station installed on the ground; a mobile station having a fixed range of movement; a ground control device that selects an optimum transmission rate from among a plurality of transmission rates for transmitting data between the base station and the mobile station via a communication line, The ground control device acquires line quality information that determines a transmission rate applicable to each point based on the line quality of the communication line at each point within the movement range, movement plan information that indicates a movement plan of the mobile station, and location information that indicates the current location of the mobile station, and selects a point and transmission rate that can transmit the data most quickly based on the line quality information, the movement plan information, and the location information.

2. 2. The transmission rate selection system according to claim 1, wherein the ground control device further acquires transmission priority information that defines a transmission priority of the data, and selects the location and the transmission rate that can transmit the data with the highest transmission priority most quickly based on the transmission priority information, the line quality information, the movement plan information, and the location information.

3. an operation unit that allows a user to input the transmission priority of the data; 2. The transmission rate selection system according to claim 1, wherein the ground control device selects the location and the transmission rate at which the data with high transmission priority can be transmitted most quickly based on the transmission priority, the line quality information, the movement plan information, and the location information.

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