JP5875461B2 - Wireless train control system - Google Patents

Description

  The present invention relates to a wireless communication system and a wireless communication method for performing frequency hopping communication between a base station and a mobile station.

  The present invention also relates to a technique for providing a high-quality communication line by maintaining or updating a high-quality communication line over a long period of time in a wireless train control method, train control system, and wireless communication method. Maintenance of high-quality communication lines over a long period of several decades can also be expected.

  In train control methods and train control systems, there is a movement to reduce the cost of railway communication systems, and the introduction of train control systems using 2.4G-band radio frequencies that do not require licenses worldwide is being considered. Yes.

  However, there are many standards such as IEEE802.11b / g and Bluetooth (registered trademark) using a 2.4G band radio frequency. These standards are used by various devices such as wireless LANs and mobile devices, and are frequency bands where interference problems cannot be avoided.

  Patent Document 1 (Japanese Patent Application Laid-Open No. 2009-171078) discloses a wireless communication system using a frequency hopping method in which wireless communication is performed until a base station transmits a downlink message and receives an uplink message from a mobile station. Data communication is performed twice on different channels to improve the establishment of successful data transmission by frequency and time diversity, and to improve system reliability.

  In the train control method and the train control system, the ground device (base station) calculates the travel permission range indicating the distance to the stop point based on the position information received from the onboard device (mobile station) Notify the device. The on-vehicle device performs brake control based on the travel permission range received from the ground device. Since these processes are performed while the train is running, real-time processing is required.

  For this reason, the ground device secures real-time performance by performing logical calculation of the travel permission range and wireless communication with the on-board device within a predetermined control period.

  As a method for providing a high-quality communication line, for example, there is a method disclosed in Patent Document 1. This method describes a technique for improving the successful establishment of data transmission by performing wireless communication twice within a control period in accordance with a predetermined frequency hopping pattern table.

JP 2009-171078 A

  Frequency diversity and time diversity in which data communication is performed twice by changing a channel in wireless communication are effective methods for improving communication quality. Also in Patent Document 1, communication quality is improved by avoiding interference at a specific frequency by a frequency hopping pattern method and increasing the establishment of successful communication data.

  However, in a system that performs logical processing and wireless communication within a predetermined control cycle, such as a train control system, time is spent for wireless communication of control data, and the time for performing logical processing is under pressure.

  In addition, even if the wireless communication time and logical processing of control data can be scheduled within the control cycle, information that is not directly related to the control data of the train control system, for example, offline information such as communication quality information and control history information It is necessary to provide a communication time separately from the control data, and it is difficult to incorporate it into the schedule within the control cycle.

  In addition, performing communication retransmission between the base station and the mobile station in order to obtain a high communication success rate also increases the time for occupying the frequency, and the influence of interference on peripheral devices can be considered.

  In particular, there is a service using a general-purpose wireless LAN in a station such as a subway, and the influence of interference on the wireless LAN device cannot be ignored.

  With respect to such a problem, the object of the present invention is to ensure communication quality of control data of the train control system and transmit / receive offline information such as control history information, which is different from the control data of the train control system. That is.

  In addition, it is possible to reduce the influence of frequency interference on peripheral devices by canceling unnecessary radio communication.

  In the wireless communication method in which the wireless communication channel is changed based on the frequency hopping pattern table, when communication is normally performed on the channel according to the frequency hopping pattern table, the information to be communicated next is offline from the train control data. It is characterized by switching to information and performing information notification or information collection.

  According to the present invention, it is possible to ensure communication reliability of a train control system and collect or transmit information other than train control data.

  Moreover, the influence on the peripheral device can be reduced by canceling unnecessary wireless communication.

The block diagram of a radio train control system. The basic sequence diagram of a radio train control system. AP functional block diagram. The train control information table structure of Example 1. FIG. 1 is a configuration of a wireless control information table according to the first embodiment. FIG. 3 is a maintenance information collection sequence diagram of the radio train control system according to the first embodiment. 2 is a flowchart of wireless control processing according to the first embodiment. FIG. 3 is an RF reception process flowchart in AP according to the first embodiment.

  Hereinafter, a wireless communication system to which the present invention is applied will be described in detail with reference to the drawings.

  FIG. 1 is a diagram showing a configuration of a wireless communication system according to an embodiment of the present invention.

  In the illustrated wireless communication system, a plurality of base stations 13 a to 13 c are installed on a predetermined route 11. The mobile station 12 changes the base stations 13a, 13b, 13c,... That communicate with each other while moving on the predetermined path 11.

  FIG. 2 is a diagram showing a basic sequence of a wireless communication system performed between the base stations 13a, 13b, 13c... Described in FIG.

  The illustrated basic sequence will be described in order. An access point master (Access Point Master, hereinafter simply referred to as AP) that supervises an access point (hereinafter referred to simply as AP) 22 of a plurality of base stations 13a, 13b, 13c. 21) transmits communication data to the AP 22 at regular intervals.

  As shown in FIG. 2, the AP 22 acquires a transmission channel (one of 16 channels from 0 to 15) from the frequency hopping pattern table 24 stored therein, and transmits communication data to a mobile station station (Station or lower). , Simply described as STA). Further, after a certain time, the next channel is taken out from the frequency hopping pattern table 24, and the communication data is transmitted to the mobile station 23 again after changing the channel. After completing the transmission twice, the response data from the mobile station 23 is transmitted to the APM 21. In the AP 22 of this embodiment, frequency hopping and time diversity are performed twice in one cycle to improve the establishment of successful communication data with the mobile station 23. FIG. 2 shows a state in which channel 0 is taken out at the first transmission frequency, channel 8 is taken out at the second time, channel 4 is taken out at the second cycle, and channel 4 is taken out at the third time. FIG. 2 shows a case where communication on all channels is normal.

  FIG. 3 is a diagram illustrating functional blocks of the AP 22. The Ethernet (registered trademark) unit 31 manages a function of transmitting / receiving communication data to / from the APM 21. The wireless unit 32 manages the function of transmitting and receiving communication data with the STA 23 wirelessly. In the ETH transmission / reception process 33, communication data received from the APM 21 is transferred to the radio control process 34, and communication data received from the RF reception process 35 is transferred to the Ethernet unit 31.

  In the wireless control process 34, when activated from the ETH transmission / reception process 33, a channel is determined from the frequency hopping pattern table 24 based on the serial number included in the communication data, and a transmission request is made to the RF transmission process 36. Also, after a certain time, the channel is changed based on the frequency hopping pattern, and a second transmission request is made.

  In the second transmission request, the reception result from the STA 23 and the permission of the first reception result and the offline data communication permission flag 51 recorded in the wireless control table 38 storing the offline data communication permission flag 51 and the retransmission suspension flag 52 are stored. Referring to the retransmission permission / retransmission prohibition by the / prohibition, retransmission suspension flag 52, it is determined whether the communication data to be transmitted next is control data, offline data, or data retransmission is to be canceled.

  In the RF reception process 35, the rationality of the communication data received from the radio unit 32 is checked, and the result is stored in the radio control table 38 and the online control data in the train control information table 37, and then transferred to the ETH transmission / reception process 33. In the RF transmission process 36, the radio control process 34 is started, and the RF unit is requested to transmit using the channel determined in the radio control process 34.

FIG. 4 is a diagram showing the structure of the train control information table.
Online control data (first page) (second page) 41 and 42 are areas for storing control data received from the mobile station 12. In a normal train control sequence, reception from a mobile station is performed using these two areas. The read pointer 43 indicates a position where the ETH transmission / reception processing 33 reads the offline data 45. The write pointer 44 indicates a position where the RF reception process 35 writes to the offline data 45.

  This is a queue structure using a read pointer and a write pointer so that offline data 45 can be stored on a plurality of surfaces when it cannot fit on one surface.

FIG. 5 is a diagram showing the structure of the radio control table.
When the offline data communication permission flag 51 is “permitted”, when the first control data in the train control sequence is normally performed, it is permitted to transmit the offline information to the data transmitted for the second time. means. When “prohibited”, online control data is always transmitted. By setting the offline data communication permission flag 51 to “permitted”, information different from the control data of the train control system, for example, offline information such as control history information, without affecting the communication quality of the control data of the train control system. Information can be transmitted and received in real time.

  Next, the retransmission stop flag 52 specifies whether the second transmission is permitted or prohibited when the first control data in the train control sequence is normally performed. That is, by setting the retransmission stop flag 52 to “retransmission prohibited”, the second communication can be prohibited when the first control data communication within the control cycle is normal. By such control, it is possible to perform wireless communication of the minimum information necessary for train control, stop unnecessary wireless communication, and reduce the influence of frequency interference on peripheral devices.

  The communication cycle state 53 stores the first transmission cycle and the second transmission cycle. The first reception result 54 and the second reception result 55 store the transmission cycle result in the train control sequence in one control cycle as success or failure.

  FIG. 6 is a sequence for collecting offline data in the train control sequence. When receiving communication data from the APM 61, the AP 62 acquires the transmission channel 0 from the frequency hopping pattern table 24 and transmits it to the STA 23. After receiving the response communication data from the STA 23, the second transmission is performed by changing the transmission channel.

  At the second time, the result of the first reception in the radio control table is checked. If the result is unsuccessful, the control data is transmitted as it is through the channel 8 according to the frequency hopping pattern table 24. When the response from the STA 23 to the control data transmitted on the channel 8 is normally received, the reception result is set to the second reception result case in the radio control table and the received data is recorded in the online control data area of the train control table.

Thereafter, the control data received normally is transmitted to the APM 61.
In the next cycle, the transmission channel 4 is acquired from the frequency hopping pattern table 24 and control data is transmitted to the STA 23. When control data transmission / reception on channel 4 is successful, the first reception result of the wireless control table is checked as processing for collecting offline data. If successful, offline data communication permission is checked and offline request is made. Data is transmitted to the STA 23.

  When the response from the STA 23 to the offline request data is normally received, the reception result is set to the second reception result case in the radio control table and the received data is recorded in the offline data area of the train control table.

  Thereafter, the control data response and the offline data that were successful at the first time are transmitted to the APM 61. Here, as a specific example of offline data, control history information and the like can be considered. It is also possible to transmit display data for display on a display device in the vehicle instead of offline request data.

  In this way, while transmitting twice from the AP 22 to the STA 23, the offline request data is transmitted in the second transmission after the first control data is normal, so that the mobile station is offline without degrading the communication reliability. Data can be collected.

  FIG. 7 is a flowchart of the wireless control process in the first embodiment. After power-on (step 70), the system waits for activation from the ETH transmission / reception process (step 71). After the activation request, a channel is selected from the frequency hopping pattern table 24 based on the serial number included in the communication data (step 72). After the channel selection, the first transmission is requested to the RF transmission process (step 73). Thereafter, the response result of the STA 23 to the control data transmission is determined (step 74). If the first reception result is successful, the retransmission stop flag (step 75) and the offline communication permission flag (step 76) are both permitted. The offline request data is used as transmission data for the second transmission (step 77). Thereafter, a channel is selected from the frequency hopping pattern table 24 (step 78). After the channel selection, the second transmission is requested to the RF transmission processing. After the transmission request, the process returns to the waiting for activation from the ETH transmission / reception process.

  If the first response result is unsuccessful, the second transmission also uses control data as transmission data (step 7a). Thereafter, a channel is selected from the frequency hopping pattern table 24 (step 78). After selecting the channel, the second transmission is requested to the RF transmission processing (step 79). After the transmission request, the process returns to the waiting for activation from the ETH transmission / reception process.

  FIG. 8 is a flowchart of the RF reception process in the first embodiment. After the power is turned on (step 80), the reception data from the RF is waited (step 81). When receiving from the RF, a serial number error, CRC error, etc. are determined in the received data (step 82). Is offline data or offline data (step 83), and if it is offline data, the offline data is recorded in the offline data area of the number indicated by the light pointer in the train control table, and one light pointer is updated (step 84). . Thereafter, the ETH transmission / reception process is started.

  If the received data is online (step 83), the control data is recorded on the corresponding surface of the train control information table (step 86). Thereafter, it is determined whether the communication cycle state is the first time or the second time (step 87). In the first time, the process returns to waiting for received data from the RF. In the second case, TH transmission / reception processing is started.

  If the received data is not normal (step 82), the communication cycle state is determined (step 87), and waiting for received data from RF (step 81) or ETH transmission / reception processing is started (step 85).

  In the first embodiment, a function for determining whether the communication result is normal / abnormal to the base station, a function for selecting either online control data or offline request data as data to be transmitted, or whether the second or subsequent communication is prohibited. Although the example which has the function to determine whether was demonstrated, this invention is not limited to this embodiment.

  For example, in the case of assuming a communication method in which control data is transmitted from the mobile station and the base station responds to the control data, the mobile station can determine whether the communication result is normal / abnormal, and online as the data to be transmitted. It is possible to provide a function for selecting one of the control data and the offline request data, and a function for determining whether to prohibit the second and subsequent communications.

  In this configuration, the mobile station first transmits control data to the base station for the first time within the control period, and the base station returns control data as a response to this control data. Here, the mobile station determines normality / abnormality of the communication result of the return data from the base station. When the communication result is abnormal, the control data is transmitted to the base station again. When the communication result is normal, the offline request data is transmitted to the base station, or the second communication is prohibited. Here, as the offline request data, a display data request command for display on a display device in the vehicle can be considered. Alternatively, control history information recorded in the vehicle can be transmitted to the base station instead of the offline request data.

  In the present embodiment, the configuration of parts not mentioned is the same as that of the first embodiment.

11 Predetermined path 12 Mobile station 13, 13a, 13b, 13c Base station 21, 61 APM
22 AP (base station)
23 STA (mobile station)
24 Frequency hopping pattern table 31 Ethernet section (ETH)
32 Radio section (RF)
33 ETH transmission / reception process 34 Radio control process 35 RF reception process 36 RF transmission process 37 Train control information table 38 Radio control table 41 Online control data (one page)
42 Online control data (2 pages)
43 Read pointer 44 Write pointer 45 Offline data (1st page) to (256th page)
51 Offline data communication permission flag 52 Retransmission stop flag 53 Communication cycle state 54 First reception result 55 Second reception result 62 AP
63 STA

Claims (3)

Wireless communication is performed between the base station and the mobile station using a plurality of channels, the wireless communication channel is changed based on the frequency hopping pattern table, and wireless communication is performed a predetermined number of times at least twice in one control cycle of train control. A radio train control system comprising a radio control processing unit for performing
The wireless control processing unit
Communication result determination means for determining whether or not the communication result for each channel is normal;
A transmission data selection means for transmitting data different from the train control data in the next wireless communication within one control cycle when the communication result determination means determines that the communication result of the train control data is normal. A featured radio train control system. In the radio train control system according to claim 1,
The radio control processing unit is provided in a base station,
The transmission data selection means transmits, as data different from the train control data, a request command for control history information recorded in the vehicle or display data to be displayed on a display device in the vehicle to the mobile station. A featured radio train control system. In the radio train control system according to claim 1,
The radio control processing unit is provided in a mobile station,
The transmission data selection means transmits, as data different from the train control data, a display data request command for display on a display device in a vehicle or control history information recorded in the vehicle to a base station. Wireless train control system characterized by