Interlocking system and ground electronic unit communication method

Abstract

The invention relates to a communication method for an interlocking system and a ground electronic unit. The method comprises the steps that the interlocking system establishes communication connection with the ground electronic unit through a network layer, a security layer and an application layer; in each period, the interlocking system performs legality check on the received first general information packet; if the validity check is passed, the first general information packet is stored, and a second general information packet is sent to the ground electronic unit; and if the legality check is not passed, the interlocking system discards the first general information packet and performs freshness check on the stored third general information packet, if the freshness check is passed, the ground electronic unit is replied according to the stored third general information packet, and if the freshness check is not passed, the application layer is disconnected, and the application layer connection needs to be reestablished. According to the invention, the legality check is carried out during the communication of the interlocking system, and the message is directly sent to the ground electronic unit after the check is passed, so that the input processing process of the message of the ground electronic unit is omitted, and the communication is safe and efficient.

Description

Technical Field

[0001] The present invention relates to the field of rail transit communication, and in particular to a method for communication between an interlocking system and a ground electronic unit. Background Art

[0002] The Lineside Electronic Unit (LEU) is a key device in the balise transmission system. In subway applications, the LEU receives messages from the interlocking and sends them to the active balise. The LEU is responsible for signal transmission between the interlocking and the active balise, and plays an important role in the subway signal control system.

[0003] At present, there are the following problems in the communication between interlocking and LEU:

[0004] (1) Poor scalability. Interlocking and LEUs mostly use serial ports for communication. When the interlocking communicates with multiple LEUs, the hardware of the interlocking needs to reserve multiple serial ports for LEU communication. If the number of interlocking and LEU communications is less than the number of reserved serial ports, hardware resources will be wasted. If the number of interlocking and LEU communications exceeds the number of reserved serial ports, the hardware structure of the interlocking needs to be changed.

[0005] (2) The interlocking process of LEU is time-consuming and wasteful. The main function of LEU is to transmit information such as signal status and switch status received from the interlocking to the transponder. The interlocking does not need to process the received LEU input message. Therefore, the process of interlocking processing LEU can be optimized. Summary of the invention

[0006] The purpose of the present invention is to overcome the defects of the prior art and provide a flexible, efficient and fast communication method between an interlocking system and a ground electronic unit.

[0007] The communication method between the interlocking system and the ground electronic unit includes the following contents:

[0008] The interlocking system establishes a communication connection with the ground electronic unit through the network layer, security layer and application layer;

[0009] In each cycle, the interlocking system performs a legitimacy check on the first general information packet received;

[0010] If the legitimacy check passes, the first general information packet is saved, and the second general information packet is sent to the ground electronic unit based on the first general information packet; if the legitimacy check fails, the interlocking system discards the first general information packet, and determines through a freshness check whether the saved third general information packet is within the freshness time range; if it is within the freshness time range, the ground electronic unit is replied according to the saved third general information packet; if it is not within the freshness range, the application layer connection is re-established.

[0011] Furthermore, at the network layer, the interlocking system is connected to the ground electronic unit via Ethernet; at the safety layer, the RSSP-I protocol (Railway Signal Safety Protocol–I) is used for safety verification; at the application layer, general information packets in a specific format are used for data exchange.

[0012] Furthermore, at the network layer, the ground electronic unit includes two configurations: single-system and dual-system. Each configuration has two networks, red and blue. The two networks are located on different network cards to provide redundant Ethernet.

[0013] Furthermore, at the network layer, the UDP protocol (User Datagram Protocol) is used for data exchange. When the interlocking system receives the first packet of data from the ground electronic unit, the network layer connection state is connected.

[0014] Further, at the safety layer, when the interlocking system receives a data packet that has passed the safety check, the safety layer connection state is connected.

[0015] Furthermore, the general information packet format includes a packet header and application layer data.

[0016] Furthermore, the legality check content includes interface information type, identification information, data version, protocol version number, sequence number, message length and freshness check.

[0017] Furthermore, when the legality check is passed, the message sent by the interlocking system includes the signal lighting status, turnout status and speed limit status.

[0018] Furthermore, the freshness check uses a specific formula, which is as follows:

[0019] F = (Cycle Count-RSN) × PR-(TSN-LTSN) × PT; where F is the message freshness; Cycle Count is the current processing cycle number of the interlocking system; RSN is the message sequence number of the interlocking system in the general information package; PR is the processing cycle of the interlocking system; TSN is the message sequence number of the ground electronic unit in the general information package; LTSN is the message sequence number of the ground electronic unit when the ground electronic unit received the last general information package; PT is the processing cycle of the ground electronic unit.

[0020] Furthermore, if the freshness check fails, during the process of re-establishing the application layer connection, the interlocking system checks whether the received general information packet is the first packet message, and updates the sequence number after confirming that it is the first packet message, and then re-establishes the application layer connection with the ground electronic unit.

[0021] Furthermore, the interlocking system re-establishes the application layer connection including: checking whether the interlocking system message sequence number of the received general information packet and the message sequence number of the ground electronic unit when the ground electronic unit received the previous general information packet are both 0xFFFFFFFF; if both are 0xFFFFFFFF, the general information packet is the first message; the interlocking system updates the message sequence number of the ground electronic unit to the ground electronic unit message sequence number of the received general information packet, updates the message sequence number of the interlocking system to the current cycle number, updates the message sequence number of the interlocking system when the interlocking system received the previous general information packet to the current cycle number, and sends it to the ground electronic unit; the interlocking system is connected to the application layer of the ground electronic unit.

[0022] The present invention also proposes an interlocking system for executing the above-mentioned communication method.

[0023] The present invention has the following beneficial effects:

[0024] 1. The interlocking system communicates with the ground electronic unit through Ethernet. When the interlocking communicates with multiple ground electronic units, there is no need to modify the hardware structure. The interlocking can directly exchange data with the ground electronic units in the same network. Therefore, this method is more flexible and has better scalability.

[0025] 2. The interlocking system and the ground electronic unit realize redundant network through the red and blue networks. The interruption of any network will not lead to the interruption of communication between the interlocking system and the ground electronic unit. Therefore, this method has higher availability.

[0026] 3. After the interlocking receives the message from the ground electronic unit at the application layer, it performs a legitimacy check on the received message. After the check is passed, the information such as signals and switches is directly sent to the ground electronic unit, eliminating the input and processing process of the ground electronic unit message. Therefore, this method speeds up the communication between the interlocking system and the ground electronic unit while ensuring safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A flow chart of a method for communicating between an interlocking system and a ground electronic unit according to the present invention;

[0028] Figure 2 A schematic diagram of the connection between an interlocking system and a single-system ground electronic unit according to an embodiment of the present invention;

[0029] Figure 3 A schematic diagram of the connection between an interlocking system and a dual-system ground electronic unit according to another embodiment of the present invention;

[0030] Figure 4 A general information package definition table of the present invention;

[0031] Figure 5This is the application layer data format definition table of the present invention. DETAILED DESCRIPTION

[0032] The following is a further detailed description of a method for communicating between an interlocking system and a ground electronic unit proposed by the present invention in combination with the accompanying drawings and specific embodiments. According to the following description, the advantages and features of the present invention will be clearer. It should be noted that the accompanying drawings are in a very simplified form and are not in precise proportions, which are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention. In order to make the purposes, features and advantages of the present invention more obvious and easy to understand, please refer to the accompanying drawings. It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention, so they have no technical substantive significance. Any structural modification, change in proportional relationship or adjustment of size, without affecting the effects and purposes that can be achieved by the present invention, should still fall within the scope of the technical content disclosed by the present invention.

[0033] like Figure 1 FIG. 1 is a flow chart of a method for communicating between an interlocking system and a ground electronic unit proposed by the present invention, the method comprising:

[0034] S1. The interlocking system establishes a communication connection with the ground electronic unit through the network layer, security layer and application layer.

[0035] Specifically, at the network layer, the interlocking system and the ground electronic unit use the UDP protocol to exchange data. When the interlocking system receives the first packet of data from the ground electronic unit, the network layer connection status is connected. At the security layer, when the interlocking system receives a data packet that has passed the security check, the security layer connection status is connected. At the application layer, the interlocking system and the ground electronic unit use the format of the general information packet to exchange data. The format of the general information packet is as follows: Figure 4 As shown, a general information packet is roughly divided into two parts: packet header and application layer data. The format of application layer data is as follows Figure 5 shown.

[0036] S2. In each cycle, the interlocking system performs a legitimacy check on the received general information packets; the legitimacy check includes interface information type, identification information, data version, protocol version number, sequence number, message length and freshness check.

[0037] If the legality check passes, save the first general information packet, and send a second general information packet to the ground electronic unit based on the first general information packet

[0038] If the validity check fails, the interlocking system discards the first general information packet and replies to the ground electronic unit according to the third general information packet saved within the freshness time range. The third general information packet comes from the general information packet saved in the previous cycle, and the freshness check is used to determine whether the previously saved general information packet is within the freshness time range.

[0039] S3. If the freshness check passes, it means that the saved general information package is within the freshness time range, and the ground electronic unit is replied according to the saved general information package. If the freshness check fails, it means that the saved general information package is not within the freshness time range, the application layer is disconnected, and the application layer connection needs to be re-established.

[0040] Specifically, the freshness check uses a specific formula, which is as follows:

[0041] F = (Cycle Count – RSN) × PR – (TSN – LTSN) × PT; where F is the message freshness; Cycle Count is the current processing cycle number of the interlocking system; RSN is the interlocking system message sequence number in the general information package; PR is the processing cycle of the interlocking system, usually in seconds or milliseconds; TSN is the ground electronic unit message sequence number in the general information package; LTSN is the message sequence number of the ground electronic unit when the ground electronic unit receives the last general information package; PT is the processing cycle of the ground electronic unit, usually in seconds or milliseconds. When the interlocking system communicates with the ground electronic unit, the freshness will be configured, such as 3s. The freshness of the received message or the stored message is calculated to obtain the freshness F. If F>3s, the check fails. If F<3s or F=3s, the check passes.

[0042] If the freshness check fails, during the process of re-establishing the application layer connection, the interlocking system checks whether the received general information packet is the first packet message, and updates the sequence number after confirming that it is the first packet message, and then re-establishes the application layer connection with the ground electronic unit.

[0043] Furthermore, the interlocking system reestablishes the connection of the application layer including: checking whether the message sequence number of the interlocking system of the received general information packet and the message sequence number of the ground electronic unit when the ground electronic unit received the last general information packet are both 0xFFFFFFFF (hexadecimal number), if both are 0xFFFFFFFF, then the general information packet is the first packet message. The interlocking system updates the message sequence number of the ground electronic unit to the message sequence number of the ground electronic unit of the received general information packet, updates the message sequence number of the interlocking system to the current cycle number, updates the message sequence number of the interlocking system when the interlocking system received the last general message packet to the current cycle number, and sends it to the ground electronic unit; the interlocking system is connected to the application layer of the ground electronic unit.

[0044] Furthermore, at the network layer, the interlocking system is connected to the ground electronic unit via Ethernet; at the security layer, the RSSP-I protocol is used for security verification; at the application layer, a general information packet in a specific format is used for data exchange. Specifically, at the network layer, the ground electronic unit includes two configurations, single-system and dual-system, each of which has two networks, red and blue, and provides Ethernet. Figure 2 As shown in FIG. 1 , it is a schematic diagram of the connection between the interlocking system and the single-system ground electronic unit according to an embodiment of the present invention. The interlocking system includes interlocking system A and interlocking system B, wherein both interlocking system A and interlocking system B are connected to the ground electronic unit through the red and blue networks. Figure 3 As shown, it is a schematic diagram of the connection between the interlocking system and the dual-system ground electronic unit of another embodiment of the present invention. In this embodiment, the interlocking system includes interlocking system A and interlocking system B, and the ground electronic unit includes ground electronic unit A system and ground electronic unit B system, wherein the interlocking system A system and B system are respectively connected to the ground electronic unit A system and B system through the red and blue networks. The red and blue networks are located on different network cards, and a redundant network is realized through the red and blue networks. The interruption of any network will not cause the communication between the interlocking system and the ground electronic unit to be interrupted, so the availability of this method is higher.

[0045] In summary, the interlocking system communicates with the ground electronic unit through Ethernet. When the interlocking system communicates with multiple ground electronic units, there is no need to modify the hardware structure. The interlocking system can directly exchange data with the ground electronic units in the same network. Therefore, this method is more flexible and has better scalability. The interlocking system and the ground electronic unit realize redundant networks through red and blue networks. Any network interruption will not cause the communication between the interlocking system and the ground electronic unit to be interrupted. Therefore, this method has higher availability. After the interlocking system receives the message from the ground electronic unit at the application layer, it checks the legitimacy of the received message. After the check is passed, the signal machine, turnout and other information are directly sent to the ground electronic unit, eliminating the input processing process of the ground electronic unit message. Therefore, this method speeds up the communication between the interlocking system and the ground electronic unit on the basis of ensuring safety.

[0046] Although the content of the present invention has been described in detail through the above preferred embodiments, it should be appreciated that the above description should not be considered as a limitation of the present invention. After reading the above content, it will be apparent to those skilled in the art that various modifications and substitutions of the present invention will occur. Therefore, the protection scope of the present invention should be limited by the appended claims.

Claims

1. A method for communicating between an interlocking system and a ground electronic unit, characterized in that: include: The interlocking system establishes a communication connection with the ground electronic unit through the network layer, security layer and application layer; In each cycle, the interlocking system performs a legitimacy check on the first general information packet received; If the legality check passes, the first general information packet is saved, and a second general information packet is sent to the ground electronic unit based on the first general information packet; If the legitimacy check fails, the interlocking system discards the first general information packet and determines whether the saved third general information packet is within the freshness time range through a freshness check; If it is within the freshness time range, the ground electronic unit is replied according to the saved third general information packet. If it is not within the freshness time range, the application layer connection is re-established.

2. The interlocking system and ground electronic unit communication method according to claim 1, characterized in that: At the network layer, the interlocking system is connected to the ground electronic unit via Ethernet; at the safety layer, the RSSP-I protocol is used for safety verification; at the application layer, general information packets in a specific format are used for data exchange.

3. The interlocking system and ground electronic unit communication method according to claim 1, characterized in that: At the network layer, the ground electronic unit includes two configurations: single-system and dual-system. Each configuration has two networks, red and blue. The two networks are located on different network cards to provide redundant Ethernet.

4. The interlocking system and ground electronic unit communication method according to claim 1, characterized in that: At the network layer, the UDP protocol is used for data exchange. When the interlocking system receives the first packet of data from the ground electronic unit, the network layer connection status is connected.

5. The interlocking system and ground electronic unit communication method according to claim 1, characterized in that: At the safety layer, when the interlocking system receives a safety-verified data packet, the safety layer connection status is connected.

6. The interlocking system and ground electronic unit communication method according to claim 1, characterized in that: The general information packet format includes a packet header and application layer data.

7. The interlocking system and ground electronic unit communication method according to claim 1, characterized in that: The content of the legality check includes: interface information type, identification information, data version, protocol version number, sequence number, message length and freshness check.

8. The interlocking system and ground electronic unit communication method according to claim 1, characterized in that: When the legality check is passed, the interlocking system sends a second general information packet containing the signal lighting status, turnout status and speed limit status to the ground electronic unit.

9. The interlocking system and ground electronic unit communication method according to claim 1, characterized in that: The formula used for freshness check is as follows: F = (Cycle Count-RSN) × PR-(TSN-LTSN) × PT; where F is the message freshness; Cycle Count is the current processing cycle number of the interlocking system; RSN is the message sequence number of the interlocking system in the general information package; PR is the processing cycle of the interlocking system; TSN is the message sequence number of the ground electronic unit in the general information package; LTSN is the message sequence number of the ground electronic unit when the ground electronic unit received the last general information package; PT is the processing cycle of the ground electronic unit.

10. The interlocking system and ground electronic unit communication method according to claim 9, characterized in that: If the freshness check fails, during the process of re-establishing the application layer connection, the interlocking system checks whether the received general information packet is the first packet message, and updates the sequence number after confirming that it is the first packet message, and then re-establishes the application layer connection with the ground electronic unit.

11. The method for communicating between an interlocking system and a ground electronic unit according to claim 9, characterized in that: The interlocking system re-establishes the application layer connection including: checking whether the interlocking system message sequence number of the received general information packet and the message sequence number of the ground electronic unit when the ground electronic unit received the last general information packet are both 0xFFFFFFFF, if both are 0xFFFFFFFF, the general information packet is the first packet message; the interlocking system updates the message sequence number of the ground electronic unit to the message sequence number of the ground electronic unit of the received general information packet, updates the message sequence number of the interlocking system to the current cycle number, updates the message sequence number of the interlocking system when the interlocking system received the last general information packet to the current cycle number, and sends it to the ground electronic unit; the interlocking system is connected to the application layer of the ground electronic unit.

12. An interlocking system, characterized in that: Used to execute the communication method according to any one of claims 1 to 11.

Images