Wireless communication system, reception quality display system, and reception quality display method

Abstract

To allow the degradation of reception quality of each mobile station and each base station to be easily ascertained, with respect to a wireless communication system targeted for vehicles traveling along a predetermined route.SOLUTION: A wireless communication system includes: a data server 30 that stores a mobile station side RSSI and a base station side RSSI for each combination of each mobile station 60 and each base station 50; and a monitoring terminal 40 having a display device that displays a reception quality confirmation screen in a matrix format consisting of a first axis allocating each mobile station 60 and a second axis allocating each base station 50, based on the mobile station side RSSI and base station side RSSI stored in the data server 30. Each cell in the reception quality confirmation screen is displayed in a manner determined according to results of comparing the mobile station side RSSI and base station side RSSI corresponding to that cell with predetermined threshold values.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a wireless communication system for performing wireless communication between a mobile station mounted on a vehicle traveling along a predetermined route and a base station installed along the route. [Background technology]

[0002] Conventionally, a wireless communication system (so-called "train radio system") has been put into practical use, which performs wireless communication between a mobile station mounted on a train and a base station installed along the track on which the train runs. In order to ensure stable wireless communication between the mobile station and the base station in such a train radio system, it is necessary to check the reception quality, such as the received signal strength. Therefore, for example, a mobile station mounted on a test train or a train in operation measures the reception quality and records it in a log, and similarly, each base station also measures the reception quality and records it in a log, which are then collected and analyzed.

[0003] The following are examples of prior art related to the present invention: For example, Patent Document 1 discloses an invention in which, when displaying the margin of the reception field strength of an FPU receiving base station on a monitor, the display color is changed according to the margin. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-290580 Summary of the Invention [Problem to be solved by the invention]

[0005] Conventional methods for checking reception quality do not take real-time performance into consideration, making it difficult to check the analysis results of reception quality in real time. Furthermore, even if there is a problem with reception quality, it is difficult to immediately determine whether the problem is on the transmitting side or the receiving side. This problem is not unique to train radio systems; similar concerns exist in radio communication systems for vehicles traveling along a predetermined route, such as buses and highway maintenance vehicles.

[0006] The present invention has been made in consideration of the above-described conventional circumstances, and aims to provide a wireless communication system for vehicles traveling along a predetermined route that makes it possible to easily grasp the degradation of the reception quality of each mobile station and each base station. [Means for solving the problem]

[0007] In order to achieve the above object, a wireless communication system according to one aspect of the present invention is configured as follows. That is, in a wireless communication system comprising a plurality of mobile stations mounted on a plurality of vehicles traveling along a predetermined route and a plurality of base stations installed along the route, each of the plurality of mobile stations has a function of measuring mobile station side reception quality, which is the reception quality of a wireless signal received from a base station with which it is communicating, and each of the plurality of base stations has a function of measuring base station side reception quality, which is the reception quality of a wireless signal received from a mobile station with which it is communicating, and the wireless communication system further comprises a data server that stores the mobile station side reception quality and base station side reception quality for each combination of each mobile station and each base station, and a display device that displays a reception quality confirmation screen in a matrix format consisting of a first axis to which each mobile station is assigned and a second axis to which each base station is assigned, based on the mobile station side reception quality and base station side reception quality stored in the data server, and each square on the reception quality confirmation screen is displayed in a manner determined according to the result of comparing the mobile station side reception quality and base station side reception quality corresponding to that square with a predetermined threshold.

[0008] Here, each square on the reception quality confirmation screen may be displayed differently depending on whether the mobile station side reception quality and base station side reception quality corresponding to that square are both above a threshold, whether the mobile station side reception quality is below the threshold and the base station side reception quality is above the threshold, whether the mobile station side reception quality is above the threshold and the base station side reception quality is below the threshold, or whether both the mobile station side reception quality and the base station side reception quality are below the threshold.

[0009] In addition, if there is a row or column on the reception quality confirmation screen in which the number of squares in which the mobile station side reception quality is below the threshold satisfies a predetermined condition, or if there is a row or column in which the number of squares in which the base station side reception quality is below the threshold satisfies a predetermined condition, the display device may further display a message indicating that there is an abnormality in the mobile station or base station corresponding to that row or column.

[0010] The wireless communication system may further include a wireless central device that transmits a polling request to the mobile station, and when the mobile station receives the polling request via a base station with which it is communicating, it measures the reception quality of the polling request and includes the measurement result in a polling response as mobile station-side reception quality and transmits this to the base station with which it is communicating, and when the base station receives a polling response from the mobile station with which it is communicating, it measures the reception quality of the polling response and adds the measurement result to the polling response as base station-side reception quality and transmits this to the wireless central device, and the wireless central device transmits the mobile station-side reception quality and base station-side reception quality included in the polling response to a data server, and the data server may store the mobile station-side reception quality and base station-side reception quality received from the wireless central device.

[0011] A reception quality display system according to another aspect of the present invention is configured as follows. That is, in a wireless communication system having a plurality of mobile stations mounted on a plurality of vehicles traveling along a predetermined route and a plurality of base stations installed along the route, the reception quality display system for checking the reception quality of wireless communication between each mobile station and each base station includes a data server that stores, for each combination of each mobile station and each base station, the mobile station side reception quality, which is the reception quality of the wireless signal received by the mobile station from the base station, and the base station side reception quality, which is the reception quality of the wireless signal received by the base station from the mobile station, and a display device that displays a reception quality confirmation screen in a matrix format consisting of a first axis to which each mobile station is assigned and a second axis to which each base station is assigned, based on the mobile station side reception quality and base station side reception quality stored in the data server, and each square on the reception quality confirmation screen is displayed in a manner determined according to the result of comparing the mobile station side reception quality and base station side reception quality corresponding to that square with a predetermined threshold.

[0012] A reception quality display method according to yet another aspect of the present invention is configured as follows. That is, in a wireless communication system having a plurality of mobile stations mounted on a plurality of vehicles traveling along a predetermined route and a plurality of base stations installed along the route, a reception quality display method for checking the reception quality of wireless communication between each mobile station and each base station is provided, in which a data server stores, for each combination of each mobile station and each base station, the mobile station side reception quality, which is the reception quality of the wireless signal received by the mobile station from the base station, and the base station side reception quality, which is the reception quality of the wireless signal received by the base station from the mobile station, and a display device displays a reception quality check screen in a matrix format consisting of a first axis to which each mobile station is assigned and a second axis to which each base station is assigned, based on the mobile station side reception quality and base station side reception quality stored in the data server, and each square on the reception quality check screen is displayed in a manner determined according to the result of comparing the mobile station side reception quality and base station side reception quality corresponding to that square with a predetermined threshold. [Effects of the Invention]

[0013] According to the present invention, in a wireless communication system for vehicles traveling on a predetermined route, it becomes possible to easily grasp the degradation of the reception quality of each mobile station and each base station. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a diagram illustrating an example of the configuration of a wireless communication system according to an embodiment of the present invention. [Figure 2] FIG. 10 is a diagram illustrating an example of a processing flow related to collection of reception quality. [Figure 3] FIG. 10 is a diagram illustrating an example of a reception quality accumulation table. [Figure 4] FIG. 10 is a diagram showing an example of a display of a reception quality confirmation screen in a normal state. [Figure 5] 10 is a diagram showing an example of a display on a reception quality confirmation screen when the mobile station side RSSI has decreased. FIG. [Figure 6] 10 is a diagram showing an example of a display on a reception quality confirmation screen when the base station side RSSI has decreased. FIG. [Figure 7] 10 is a diagram showing an example of a display on a reception quality confirmation screen when both the mobile station side RSSI and the base station side RSSI have decreased. FIG. [Figure 8] FIG. 10 is a diagram showing another example of the reception quality confirmation screen when both the mobile station RSSI and the base station RSSI have decreased. DETAILED DESCRIPTION OF THE INVENTION

[0015] A wireless communication system according to an embodiment of the present invention will be described with reference to the drawings. An example of the configuration of a wireless communication system according to an embodiment of the present invention is shown in Fig. 1. The wireless communication system of this example is a train radio system including a train radio central unit 10, a command console 20, a data server 30, a monitoring terminal 40, a base station 50, and a mobile station 60.

[0016] The train radio central unit 10 is a device that connects the command console 20 and the base station 50 and performs overall control of the entire communication system by performing line control, etc. The command console 20 is a terminal device installed at a specific base station (for example, a command room) within the train radio system, and provides calls with mobile stations 60 via the base station 50.

[0017] The base station 50 is a radio communication facility installed on the ground as a relay point for calls between the command console 20 and the mobile station 60, and a plurality of base stations are installed along the tracks on which trains run. Although N base stations 50-1 to 50-N are shown in FIG. 1, the number of base stations 50 is arbitrary. The base station 50 has a function of measuring mobile station reception quality, which is the reception quality of a radio signal received from the mobile station 60. In this example, the base station 50 is configured to measure the received signal strength indicator (RSSI) of the radio signal as the mobile station reception quality, but other values ​​representing the reception quality of the radio signal may also be measured.

[0018] The mobile station 60 is a wireless terminal device that provides communication with the control console 20 via the base station 50 at any position within the wireless communication area covered by the base station 50. The mobile station 60 is also called an on-board station because it is mounted on each running train. Although two mobile stations 60-1 to 60-2 are shown in FIG. 1, the number of mobile stations 60 is arbitrary. The mobile station 60 has a function to measure the base station side reception quality, which is the reception quality of a wireless signal received from the base station 50. In this example, the mobile station 60 is configured to measure the received signal strength indicator (RSSI) of the wireless signal as the base station side reception quality, but other values ​​representing the reception quality of the wireless signal may also be measured.

[0019] The data server 30 is a server device that collects the mobile station side reception quality measured at each base station 50 in the system and the base station side reception quality measured at each mobile station 60, and stores the collected data in a built-in or attached database. The monitoring terminal 40 is installed at a specific location (e.g., a monitoring room) in the train radio system, and has a display device that displays a reception quality confirmation screen based on the data stored in the data server 30.

[0020] Here, the train radio central unit 10 of this example periodically polls the mobile station 60 via the base station 50, and the results are sent to the data server 30 as track location information and displayed on the monitoring terminal 40. In addition to the track location information, the mobile station ID for identifying the mobile station 60, the mobile station side reception quality measured by the mobile station 60, the base station ID for identifying the base station 50, the base station side reception quality measured by the base station 50, and the like are also collected and stored in the data server 30. These operations will be explained below with reference to Fig. 2.

[0021] An example of a processing flow for collecting reception quality is shown in Fig. 2. Here, the received signal strength indicator (RSSI) of the wireless signal is measured as the reception quality on the mobile station side and the reception quality on the base station side. The train radio central unit 10 transmits a polling request for the mobile station 60 to the base station 50 (step S11). The polling request includes a mobile station ID that identifies the destination mobile station 60. The base station 50 transmits the polling request from the train radio central unit 10 to the mobile station 60 (step S12).

[0022] When the mobile station 60 receives a polling request addressed to itself from the base station 50, it measures the RSSI of the polling request and transmits the obtained RSSI and its own mobile station ID in a polling response to the base station 50 (step S13). When the base station 50 receives a polling response from the mobile station 60, it measures the RSSI of the polling response and adds the obtained RSSI and its own base station ID to the polling response and transmits the polling response to the train radio central unit 10 (step S14). Hereinafter, the RSSI measured by the mobile station 60 may be referred to as the "mobile station side RSSI" and the RSSI measured by the base station 50 may be referred to as the "base station side RSSI".

[0023] The train radio central unit 10 includes the data in the received polling response in the track location information and transmits it to the data server 30 (step S15). That is, the data of the mobile station ID, the mobile station side RSSI, the base station ID, and the base station side RSSI are transmitted from the train radio central unit 10 to the data server 30. The data server 30 has a reception quality accumulation table as shown in Fig. 3, and stores the mobile station side RSSI and the base station side RSSI in the reception quality accumulation table using the mobile station ID and base station ID in the track location information as keys (step S16).

[0024] 3 is composed of four items: base station ID, mobile station ID, base station RSSI, and mobile station RSSI, but other data items may be added. For example, by adding a collection time item, it is possible to manage not only the latest mobile station RSSI and base station RSSI, but also past mobile station RSSI and base station RSSI as history.

[0025] The data server 30 transmits a display request including display data for the reception quality check screen to the monitoring terminal 40 in accordance with an instruction from the user operating the monitoring terminal 40 (step S17). The monitoring terminal 40 performs a display process for the reception quality check screen based on the display request received from the data server 30 (step S18).

[0026] The monitoring terminal 40 realizes the display processing of the reception quality check screen by, for example, reading out a display processing program stored in advance in the memory and executing it with a processor. Note that the display processing of the reception quality check screen may be performed by a device other than the monitoring terminal 40, for example, by another device connected to the data server 30 and the monitoring terminal 40 so as to be able to communicate with them.

[0027] The reception quality check screen display process is performed in the following procedure. First, each RSSI stored in the data server 30 is compared with a preset RSSI threshold. The RSSI threshold is set to, for example, a value that allows stable communication to be maintained. Next, the display mode of the reception quality confirmation screen is determined based on the result of comparing each RSSI stored in the data server 30 with the RSSI threshold.

[0028] As shown in Figures 4 to 8, the reception quality confirmation screen in this example is a matrix screen consisting of a first axis (vertical axis in the illustrated example) to which on-board station IDs representing each mobile station are assigned, and a second axis (horizontal axis in the illustrated example) to which base station IDs representing each base station are assigned. The on-board station IDs on the first axis are preferably arranged in an order that makes it easy to understand the relationship between each mobile station, for example, in the same order as the train operation. Similarly, the base station IDs on the second axis are preferably arranged in an order that makes it easy to understand the relationship between each base station, for example, in the same order as the arrangement of base stations along the railway line.

[0029] If a new vehicle enters the on-line state, a row corresponding to the mobile station of that vehicle is added to the reception quality confirmation screen. Furthermore, for mobile stations of vehicles that are no longer on-line, the corresponding row is deleted at the end of business hours (or a certain period of time thereafter). This type of control allows the display on the reception quality confirmation screen to reflect the actual on-line status.

[0030] Each square in the matrix of the reception quality confirmation screen is changed according to the result of comparing the corresponding base station RSSI and mobile station RSSI with the RSSI threshold. In this example, the display color of each square is determined according to the comparison result, and the square is filled with that display color. For example, if both the mobile station RSSI and the base station RSSI are equal to or greater than the RSSI threshold, the square is displayed in "blue." If the mobile station RSSI is less than the threshold and the base station RSSI is equal to or greater than the threshold, the square is displayed in "red." If the mobile station RSSI is equal to or greater than the threshold and the base station RSSI is less than the threshold, the square is displayed in "yellow." If both the mobile station RSSI and the base station RSSI are less than the RSSI threshold, the square is displayed in "gray." Display examples of the reception quality confirmation screen will be described below with reference to FIGS. 4 to 8.

[0031] Figure 4 shows an example of a normal reception quality confirmation screen. In the example in Figure 4, all squares in the matrix are displayed in blue. In this case, it can be confirmed that the mobile station RSSI and base station RISSI are good for all base stations and all mobile stations.

[0032] Figure 5 shows an example of the reception quality confirmation screen display when the mobile station RSSI has decreased. In the example of Figure 5, each square in the column for base station ID = 07 and each square in the row for on-board station ID = 1003 are displayed in red. The red display in the column for base station ID = 07 indicates that a decrease in the mobile station RSSI was observed in downlink communications from the base station with base station ID = 07 to each mobile station. In this case, it is believed that the decrease in the mobile station RSSI was caused by a problem with the transmission system of the base station with base station ID = 07. Furthermore, the red display in the row for on-board station ID = 1003 indicates that a decrease in the mobile station RSSI was observed in downlink communications from each base station to the mobile station with on-board station ID = 1003. In this case, it is believed that the decrease in the mobile station RSSI was caused by a problem with the reception system of the mobile station with on-board station ID = 1003.

[0033] Figure 6 shows an example of the reception quality confirmation screen when the base station RSSI has decreased. In the example of Figure 6, each square in the column for base station ID=07 and each square in the row for on-board station ID=1003 are displayed in yellow. The yellow display in the column for base station ID=07 indicates that a decrease in the base station RSSI was observed in uplink communications from each mobile station to the base station with base station ID=07. In this case, the decrease in the base station RSSI is thought to be due to a problem with the receiving system of the base station with base station ID=07. Furthermore, the yellow display in each square in the row for on-board station ID=1003 indicates that a decrease in the base station RSSI was observed in uplink communications from the mobile station with on-board station ID=1003 to each base station. In this case, the decrease in the base station RSSI is thought to be due to a problem with the transmitting system of the mobile station with on-board station ID=1003.

[0034] Figure 7 shows an example of the reception quality confirmation screen when both the mobile station RSSI and the base station RSSI have decreased. In the example in Figure 7, each square in the column for base station ID = 07 is displayed in red, each square in the row for on-board station ID = 1003 is displayed in yellow, and the squares at the intersections of these rows and columns are displayed in gray. The red display in the column for base station ID = 07 indicates that a decrease in the mobile station RSSI was observed in downlink communications from the base station with base station ID = 07 to each mobile station. In this case, the decrease in the mobile station RSSI is likely due to a problem with the transmission system of the base station with base station ID = 07. Furthermore, the yellow display in each square in the row for on-board station ID = 1003 indicates that a decrease in the base station RSSI was observed in uplink communications from the mobile station with on-board station ID = 1003 to each base station. In this case, the decrease in the base station RSSI is likely due to a problem with the transmission system of the mobile station with on-board station ID = 1003.

[0035] Figure 8 shows another example of the reception quality confirmation screen when both the mobile station RSSI and the base station RSSI have decreased. In the example of Figure 8, the cells in the column for base station ID = 07 and the row for on-board station ID = 1003 are grayed out. The grayed-out column for base station ID = 07 indicates that a decrease in the mobile station RSSI was observed in downlink communications from the base station with base station ID = 07 to each mobile station, and that a decrease in the base station RSSI was observed in uplink communications from each mobile station to the base station with base station ID = 07. In this case, the decrease in the mobile station RSSI and the base station RSSI is likely due to problems with the transmission and reception systems of the base station with base station ID = 07. The grayed-out row for on-board station ID = 1003 indicates that a decrease in the mobile station RSSI was observed in downlink communications from each base station to the mobile station with on-board station ID = 1003, and that a decrease in the base station RSSI was observed in uplink communications from the mobile station with on-board station ID = 1003 to each base station. In this case, it is believed that the degradation of the mobile station RSSI and base station RSSI was due to a problem in the transmission system and reception system of the mobile station with on-board station ID=1003.

[0036] 4 to 8, all the squares in the rows or columns corresponding to mobile stations or base stations with problems in their transmission or reception systems are displayed in red, yellow, or gray, but in actual operation, where communication conditions change from moment to moment due to weather, the presence of temporary interference sources, etc., it is not always possible to perfectly reproduce such displays. Nevertheless, if red, yellow, or gray is distributed horizontally, it can be determined that the problem is on the mobile station side, and if it is distributed vertically, it can be determined that the problem is on the base station side.

[0037] 4 to 8, a decrease in RSSI is represented by red, yellow, or gray, but the degree of decrease in RSSI may be represented by the shade of these colors. For example, the shade of red, yellow, or gray may be changed depending on the degree of deviation between the mobile station RSSI or base station RSSI and the RSSI threshold. Alternatively, multiple RSSI thresholds with different values ​​may be prepared, and the shade of red, yellow, or gray may be changed depending on the results of comparing the mobile station RSSI or base station RSSI with the multiple RSSI thresholds.

[0038] Furthermore, the distribution of red, yellow, or gray squares may be analyzed, and a message reporting an estimated abnormality may be additionally displayed on the reception quality check screen. That is, if a row or column of the reception quality check screen contains a row or column in which the number of squares in which the mobile station RSSI is less than the RSSI threshold satisfies a predetermined condition, or if a row or column contains a row or column in which the number of squares in which the base station RSSI is less than the RSSI threshold satisfies a predetermined condition, a message indicating that an abnormality exists in the mobile station or base station corresponding to that row or column may be additionally displayed. An example of the predetermined condition is that the ratio of the number of squares in the row or column that are less than the RSSI threshold to the total number of squares in the row or column exceeds a reference value (e.g., 50%). This message may be displayed at any position on the reception quality check screen, but is preferably displayed in a position near the corresponding row or column.

[0039] Note that the method of expressing a decrease in RSSI is arbitrary, and the change in display color as shown in Figures 4 to 8 is merely an example. For example, a decrease in RSSI may be expressed by a specific character, symbol, mark, or the like.

[0040] As described above, the wireless communication system of this example includes multiple mobile stations 60 mounted on multiple trains and multiple base stations 50 installed along the tracks on which the trains travel. Each of the multiple mobile stations 60 has a function to measure a mobile station RSSI, which is the RSSI of a wireless signal received from the base station 50 with which it is communicating, and each of the multiple base stations 50 has a function to measure a base station RSSI, which is the RSSI of a wireless signal received from the mobile station 60 with which it is communicating. The wireless communication system further includes a data server 30 that accumulates the mobile station RSSI and base station RSSI for each combination of each mobile station 60 and each base station 50, and a monitoring terminal 40 having a display device that displays a reception quality check screen in a matrix format consisting of a first axis to which each mobile station 50 is assigned and a second axis to which each base station 50 is assigned, based on the mobile station RSSI and base station RSSI accumulated in the data server 30. Each square on the reception quality check screen is configured to be displayed in a manner determined based on the result of comparing the mobile station RSSI and base station RSSI corresponding to that square with a predetermined threshold.

[0041] By using this reception quality confirmation screen, it is easy to grasp the decline in the mobile station RSSI or base station RSSI. Also, just by looking at the distribution of squares indicating declines in the mobile station RSSI or base station RSSI, it is possible to determine whether the problem is on the mobile station side or the base station side, and further whether the problem is in the transmission system or the reception system.

[0042] In the above description, the reception quality check screen is displayed based on the latest mobile station RSSI and base station RSSI, but if past mobile station RSSI and base station RSSI are managed as history, a function may be provided to display the reception quality check screen based on the mobile station RSSI and base station RSSI at a past point in time.It is also possible to provide a function to display the reception quality check screen in chronological order or in reverse chronological order.

[0043] Although the above description has been given of an example of a train radio system to which the present invention is applied, the present invention can be applied to other radio communication systems. For example, the present invention can be applied to a radio communication system that includes a mobile station mounted on a vehicle (such as a bus or a highway service vehicle) that is scheduled to travel a predetermined route, and base stations arranged along that route.

[0044] Although the embodiments of the present invention have been described above, the above embodiments are merely illustrative and do not limit the technical scope of the present invention. The present invention can take various other embodiments, and various modifications such as omissions and substitutions can be made without departing from the spirit of the present invention. These embodiments and modifications are included in the scope and spirit of the invention described in this specification, etc., and are included in the invention described in the claims and their equivalents.

[0045] Furthermore, the present invention can be provided not only as devices such as those described above or as systems composed of these devices, but also as methods executed by these devices, programs for realizing the functions of these devices using a processor, and storage media for storing such programs in a computer-readable manner. [Industrial Applicability]

[0046] The present invention can be used in a wireless communication system that performs wireless communication between a mobile station mounted on a vehicle traveling along a predetermined route and a base station installed along that route. [Explanation of symbols]

[0047] 10: Train radio central unit, 20: Control console, 30: Data server, 40: Monitoring terminal, 50-1 to 50-N: Base stations, 60-1 to 60-2: Mobile stations

Claims

1. A wireless communication system including a plurality of mobile stations mounted on a plurality of vehicles traveling along a predetermined route, and a plurality of base stations installed along the route, each of the plurality of mobile stations has a function of measuring a mobile station side reception quality, which is a reception quality of a radio signal received from a base station with which the mobile stations are communicating; each of the plurality of base stations has a function of measuring a base station side reception quality, which is a reception quality of a radio signal received from a mobile station in communication; The wireless communication system further comprises: a data server that stores the mobile station side reception quality and the base station side reception quality for each combination of each mobile station and each base station; a display device that displays a matrix-type reception quality confirmation screen including a first axis to which each mobile station is assigned and a second axis to which each base station is assigned, based on the mobile station-side reception quality and the base station-side reception quality stored in the data server, a wireless communication system characterized in that each square on the reception quality confirmation screen is displayed in a different manner depending on the result of comparing the corresponding mobile station side reception quality and the corresponding base station side reception quality with predetermined thresholds, in the following cases: when both the mobile station side reception quality and the base station side reception quality are equal to or greater than the threshold; when the mobile station side reception quality is less than the threshold and the base station side reception quality is equal to or greater than the threshold; when the mobile station side reception quality is equal to or greater than the threshold and the base station side reception quality is less than the threshold;

2. 2. The wireless communication system according to claim 1, The display device further displays a message indicating that there is an abnormality in the mobile station or base station corresponding to a row or column when the row or column of the reception quality confirmation screen contains a number of squares in which the mobile station side reception quality is less than the threshold value that satisfies a predetermined condition, or when the row or column contains a number of squares in which the base station side reception quality is less than the threshold value that satisfies a predetermined condition.

3. 2. The wireless communication system according to claim 1, a wireless central unit that transmits a polling request to the mobile station; When the mobile station receives the polling request via a base station with which it is communicating, it measures a reception quality of the polling request, includes the measurement result in a polling response as the mobile station's reception quality, and transmits the polling response to the base station with which it is communicating; when the base station receives the polling response from the mobile station in communication, it measures the reception quality of the polling response, adds the measurement result to the polling response as the base station side reception quality, and transmits the result to the wireless central unit; the wireless central unit transmits the mobile station side reception quality and the base station side reception quality included in the polling response to the data server; The data server stores the mobile station side reception quality and the base station side reception quality received from the wireless central unit.

4. A reception quality display system for confirming reception quality of wireless communication between each mobile station and each base station in a wireless communication system including a plurality of mobile stations mounted on a plurality of vehicles traveling along a predetermined route and a plurality of base stations installed along the route, comprising: a data server that stores, for each combination of each mobile station and each base station, a mobile station side reception quality that is the reception quality of a radio signal received by the mobile station from the base station, and a base station side reception quality that is the reception quality of a radio signal received by the base station from the mobile station; a display device that displays a matrix-type reception quality confirmation screen including a first axis to which each mobile station is assigned and a second axis to which each base station is assigned, based on the mobile station-side reception quality and the base station-side reception quality stored in the data server, a reception quality display system characterized in that each square on the reception quality confirmation screen is displayed in a different manner depending on the result of comparing the corresponding mobile station side reception quality and base station side reception quality with predetermined thresholds, in the following cases: when both the mobile station side reception quality and the base station side reception quality are equal to or greater than the threshold; when the mobile station side reception quality is less than the threshold and the base station side reception quality is equal to or greater than the threshold; when the mobile station side reception quality is equal to or greater than the threshold and the base station side reception quality is less than the threshold;

5. A reception quality display method for confirming reception quality of wireless communication between each mobile station and each base station in a wireless communication system including a plurality of mobile stations mounted on a plurality of vehicles traveling along a predetermined route and a plurality of base stations installed along the route, comprising: a data server stores, for each combination of each mobile station and each base station, a mobile station side reception quality which is the reception quality of a radio signal received by the mobile station from the base station, and a base station side reception quality which is the reception quality of a radio signal received by the base station from the mobile station; a display device displays a reception quality confirmation screen in a matrix format, which is configured with a first axis to which each mobile station is assigned and a second axis to which each base station is assigned, based on the mobile station side reception quality and the base station side reception quality stored in the data server; a reception quality display method characterized in that each square on the reception quality confirmation screen is displayed in a different manner depending on a result of comparing the mobile station side reception quality and the base station side reception quality corresponding to that square with a predetermined threshold, in the following cases: when both the mobile station side reception quality and the base station side reception quality are equal to or greater than the threshold; when the mobile station side reception quality is less than the threshold and the base station side reception quality is equal to or greater than the threshold; when the mobile station side reception quality is equal to or greater than the threshold and the base station side reception quality is less than the threshold;

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