Reconnection train group and wireless communication system thereof

Abstract

The invention relates to a reconnection train group and a wireless communication system thereof, the reconnection train group comprises at least two train marshalling, and each train marshalling in the reconnection train group is provided with a backbone network node, a plurality of terminal nodes and at least one virtual backbone network node; after train marshalling in the reconnection train group establishes coupler connection, wireless connection is established between virtual backbone network nodes of the train marshalling connected through a coupler, and the wireless connection is used for interacting respective train numbers and device identifiers between the virtual backbone network nodes; and a topology discovery protocol is operated between the virtual backbone network node and the backbone network node of the train marshalling at the home terminal, and a routing table capable of addressing mutually is established. The topology discovery protocol is only operated between the backbone network node and the virtual backbone network node of the local end, so that an overtime mechanism of the topology discovery protocol is not triggered, and the problem of overtime operation of the train wireless backbone network topology discovery protocol is effectively solved.

Description

Technical Field

[0001] The present disclosure relates to the field of rail transit vehicle-mounted communication technology, and in particular to a multiple-unit train set and a wireless communication system thereof. Background Art

[0002] The IEC61375 international standard divides the Train Communication Network (TCN) into two levels of network architecture, namely the Train Backbone and the Consist Network. The Train Backbone is used for vehicle-to-vehicle communication between train marshalings, realizing the interaction of control instructions and status information between train marshalings, so as to reconnect multiple train marshalings into one train for operation.

[0003] In the early days, wired backbone networks were mainly used for train-to-train communication, which required establishing coupler connections between reconnected trains and connecting the backbone network cables. If train marshaling needs to frequently establish and disconnect reconnections, it is necessary to repeatedly physically connect and disconnect at the coupler connections between backbone network nodes, which will increase the wear of the connectors, thereby affecting the communication quality of the train backbone network and even causing communication interruptions. With the development of wireless communication technology, the security, reliability, and throughput of wireless communication have continued to improve, and wireless backbone networks have gradually replaced wired backbone networks and have gained more and more applications. On the premise of retaining the physical couplers between trains, wireless communication technology is used instead of cable connectors to achieve wireless reconnection and complete the wireless transmission of backbone network data between trains.

[0004] Although the wireless backbone network can effectively solve the problem of cable connectors being easily worn and causing poor contact, the large wireless communication delay can easily trigger the timeout mechanism of the backbone network communication protocol, leading to backbone network communication failure and further reconnection failure. Therefore, it is urgent to solve the existing communication timeout problem to improve the communication reliability of the reconnected train set. Summary of the invention

[0005] The present disclosure provides a reconnected train set and a wireless communication system thereof, so as to solve the problem of operation timeout of the existing train wireless backbone network topology discovery protocol.

[0006] In a first aspect, the present disclosure provides a wireless communication system of a multiple train set, wherein the multiple train set includes at least two train sets, each train set in the multiple train set is provided with a backbone network node, a plurality of terminal nodes and at least one virtual backbone network node, the virtual backbone network node is wiredly connected to the backbone network node of the train set at the local end, and the backbone network node is wiredly connected to each terminal node of the train set at the local end;

[0007] After the train sets in the reconnected train set are connected by couplers, a wireless connection is established between the virtual backbone network nodes of the train sets connected by the couplers, for exchanging respective train numbers and equipment identifications between the virtual backbone network nodes;

[0008] A topology discovery protocol is run between the virtual backbone network node and the backbone network node of the local train formation, and topology discovery protocol data packets are sent to each other to obtain the car number and equipment identification of the opposite train formation connected to the local train formation, and the network topology is calculated based on this to establish a mutually addressable routing table.

[0009] In some embodiments, the terminal node of the local train formation sends the data packet that needs to be sent across trains to the backbone network node of the local train formation, the backbone network node of the local train formation sends the data packet to the virtual backbone network node of the local train formation according to the established routing table, and the virtual backbone network node of the local train formation sends the data packet to the virtual backbone network node of the opposite train formation through a wireless link;

[0010] After receiving the data packet, the virtual backbone network node of the opposite train formation sends the data packet to the backbone network node of the train formation according to the established routing table, and the backbone network node forwards the data packet to the corresponding terminal node in the train.

[0011] In some embodiments, after a wireless connection is established between virtual backbone network nodes, status data packets are periodically sent between the nodes to monitor the connection status of the wireless link, and the wireless connection is reestablished when a wireless link interruption is detected.

[0012] In some embodiments, the period of sending status data packets to each other is adjusted according to the performance parameters of the wireless link, and a first period is used during the initialization of the train backbone network, and a second period is used after the initialization of the train backbone network is completed, and the first period is smaller than the second period.

[0013] In some embodiments, when the cross-vehicle data packet sending period of the terminal node is smaller than the cross-vehicle data packet sending period of the virtual backbone network node of the local train formation, the virtual backbone network node of the local train formation sends the latest received cross-vehicle data packet to the virtual backbone network node of the opposite train formation.

[0014] In some embodiments, two redundant wireless links are established between virtual backbone network nodes.

[0015] In some embodiments, the inter-vehicle data packets of the terminal nodes sent to each other are merged into the status data packet of the wireless link and sent together.

[0016] In some embodiments, when the multiple train set includes multiple train sets, two virtual backbone network nodes are set on the train set located in the middle.

[0017] In some embodiments, wireless communication methods between virtual backbone network nodes include WiFi, ZigBee, LoRa and Bluetooth.

[0018] In a second aspect, the present disclosure provides a reconnected train set, including at least two train sets, which are wirelessly reconnected using a wireless communication system as described above.

[0019] The present invention provides a multiple-unit train set and a wireless communication system thereof, wherein the multiple-unit train set comprises at least two train sets, each train set in the multiple-unit train set is provided with a backbone network node, a plurality of terminal nodes and at least one virtual backbone network node, the virtual backbone network node is wiredly connected to the backbone network node of the train set at the local end, and the backbone network node is wiredly connected to each terminal node of the train set at the local end; after the train sets in the multiple-unit train set establish a coupler connection, a wireless connection is established between the virtual backbone network nodes of the train sets connected by the coupler, so as to exchange respective car numbers and device identifications between the virtual backbone network nodes; a topology discovery protocol is run between the virtual backbone network node and the backbone network node of the train set at the local end, and topology discovery protocol data packets are sent to each other to obtain the car number and device identification of the opposite train set connected to the train set at the local end, and the network topology is calculated based on the obtained data, so as to establish a mutually addressable routing table. By adding a virtual backbone network node in two wirelessly reconnected train formations and connecting it to the backbone network node of the local train formation through a wired connection, the backbone network node of the other train formation is simulated. Since the topology discovery protocol is only run between the backbone network node and the virtual backbone network node on the local end, the timeout mechanism of the topology discovery protocol will not be triggered, effectively solving the problem of timeout of the train wireless backbone network topology discovery protocol. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The present disclosure will be described in more detail below based on embodiments and with reference to the accompanying drawings:

[0021] Figure 1 This is a schematic diagram of the existing train wired backbone network topology;

[0022] Figure 2 This is a schematic diagram of the existing train wireless backbone network topology;

[0023] Figure 3 A schematic diagram of a network topology of a wireless communication system of a multiple-unit train set provided in an embodiment of the present disclosure;

[0024] Figure 4 A schematic diagram of a network topology of a wireless communication system of a multiple-unit train set provided in another embodiment of the present disclosure;

[0025] Figure 5A schematic diagram of the network topology of a wireless communication system for a multiple-unit train set provided in accordance with another embodiment of the present disclosure.

[0026] In the drawings, the same reference numerals are used for the same components and the drawings are not drawn to scale. DETAILED DESCRIPTION

[0027] In order to enable those skilled in the art to better understand the technical solution of the present disclosure, and to fully understand and implement how the present disclosure applies technical means to solve technical problems and achieve the corresponding technical effects, the technical solution in the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings in the embodiments of the present disclosure. Obviously, the described embodiments are only embodiments of a part of the present disclosure, not all of the embodiments. The embodiments of the present disclosure and the various features in the embodiments can be combined with each other without conflict, and the technical solutions formed are all within the scope of protection of the present disclosure. Based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in this field without making creative work should fall within the scope of protection of the present disclosure.

[0028] It should be noted that the terms "first", "second", etc. in the specification and claims of the present disclosure and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present disclosure described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product, or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products, or devices.

[0029] It should be noted that the steps shown in the flowcharts of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and that, although a logical order is shown in the flowcharts, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0030] First, the technical terms involved in this application are explained:

[0031] Train formation: the smallest train unit that can operate independently.

[0032] Wired reconnection: Multiple train sets are connected with couplers, and multiple trains are reconnected into one train for operation. Train control instructions and status information are exchanged between trains through wired communication.

[0033] Wireless reconnection: Connect multiple train sets with couplers, reconnect multiple trains into one train, and exchange train control instructions and status information between trains through wireless communication.

[0034] Backbone network node: A gateway node used to exchange control instructions and status information between trains when multiple trains are reconnected.

[0035] Cross-train data packet: When multiple trains are reconnected, the terminal of this train sends the data packet to other trains through the backbone network node of this train.

[0036] Topology discovery protocol: When multiple train sets are reconnected, it is used to obtain information such as the car numbers and backbone network node IDs of other trains, thereby calculating the topology of the entire backbone network and establishing a routing table that can be addressed by each train set.

[0037] Figure 1 The figure below is a schematic diagram of the existing train wired backbone network topology. Figure 1 As shown in the figure, the backbone network nodes of the two trains are connected by cables. There are two main types of wired backbone networks: bus-type twisted train bus (WTB) and switched Ethernet train backbone (ETB). WTB has a lower rate, but good real-time performance and low communication delay; ETB uses real-time Ethernet, with a high communication rate, but a higher communication delay than WTB. Figure 1 ,The initialization process of the train wired backbone network is:

[0038] (1) Train 1 and Train 2 establish a coupler connection and connect the backbone network cables;

[0039] (2) The backbone network nodes of Train 1 and Train 2 run the topology discovery protocol and send topology discovery protocol packets to each other to discover each other, obtain each other's train number, device identification (Identity Document, ID) and other information, calculate the network topology, and establish a mutually addressable routing table;

[0040] (3) After the backbone network addressing routing table is established, the terminal nodes in the train can send the data packets that need to be sent across trains to the backbone network node at the local end. The backbone network node at the local end sends the data packets to the corresponding backbone network node according to the addressing routing table. After the corresponding backbone network node receives the data packets, it forwards the data packets to the corresponding terminal node of the train.

[0041] If train marshaling needs to be frequently reconnected and disconnected, repeated physical connection and disconnection will be required at the coupler connection between backbone network nodes, which will increase the wear of the connectors, thereby affecting the communication quality of the train backbone network and even causing communication interruption. In order to solve the problem of easy wear of cable connectors and poor contact, the solution of replacing wired backbone networks with wireless backbone networks has been increasingly used. Figure 2 Figure 1 is a schematic diagram of the existing train wireless backbone network topology. Figure 2 As shown in Figure 2, the backbone network nodes of the two trains are connected via wireless communication links. Train wireless backbone network (such as Figure 2 The initialization process of the ) is similar to that of the wired backbone network of the train. The main differences include: in the first step, a wireless connection is established instead of connecting cables; in the second step, a wireless communication link is used to send topology discovery protocol packets to each other. Figure 2 The wireless backbone network shown replaces Figure 1 In the wired backbone network solution shown, the communication rate of common wireless communication technologies such as WiFi can meet the requirements of WTB and ETB, but the communication delay cannot meet the requirements of WTB. If wireless links are directly used to replace the cable connection between WTB nodes, the timeout mechanism of the WTB communication protocol will be triggered. This is because the delay of wireless communication is greater than the delay of wired communication, and the topology discovery protocol of the train backbone network has a timeout mechanism. If the topology discovery protocol message of a train backbone network node is not received for more than a certain time interval (such as 2ms), the node is considered to be offline and deleted from the addressing routing table, resulting in the backbone network node being unable to communicate normally with other nodes.

[0042] In order to solve the problem of large communication delay in the wireless backbone network, which is easy to trigger the timeout mechanism of the backbone network communication protocol and cause the problem of communication failure. The present application proposes a solution based on virtual backbone network nodes, which simulates the backbone network nodes of the opposite train by adding virtual backbone network nodes in two wirelessly reconnected train formations and connecting them to the backbone network nodes of the local train by wire, so as to solve the problem of WTB communication protocol timeout. At the same time, wireless communication is used between the virtual backbone network nodes in the two wirelessly reconnected train formations to exchange cross-vehicle backbone network data, and then the data is transmitted to the destination terminal through the local backbone network nodes connected to each other, thereby realizing the wireless reconnection of the two trains without changing the original backbone network node functions and the WTB protocol. The solution provided by the present application will be described in detail below through specific embodiments.

[0043] Embodiment 1

[0044] Figure 3A network topology diagram of a wireless communication system for a multiple train set provided in an embodiment of the present disclosure. The wireless communication system for a multiple train set provided in this embodiment is applied to a multiple train set, and the multiple train set includes at least two train formations. Figure 3 As shown, each train set in the reconnected train set is provided with a backbone network node, a plurality of terminal nodes and at least one virtual backbone network node, the virtual backbone network node is wiredly connected to the backbone network node of the train set at the local end, and the backbone network node is wiredly connected to each terminal node of the train set at the local end; after the train sets in the reconnected train set establish a coupler connection, a wireless connection is established between the virtual backbone network nodes of the train sets connected by the coupler, for exchanging respective vehicle numbers and device identifiers between the virtual backbone network nodes; a topology discovery protocol is run between the virtual backbone network node and the backbone network node of the train set at the local end, and topology discovery protocol data packets are sent to each other to obtain the vehicle number and device identifier of the opposite train set connected to the train set at the local end, and the network topology is calculated accordingly to establish a mutually addressable routing table. Among them, the wireless communication methods between the virtual backbone network nodes include but are not limited to WiFi, ZigBee, LoRa and Bluetooth.

[0045] by Figure 3 The example of a combined train group including two train formations (train 1 and train 2) is shown. In order to solve the timeout problem, virtual backbone network nodes are added in train 1 and train 2, which are wired to the local train backbone network nodes to simulate the backbone network nodes of the opposite train. Wireless communication is used between the virtual backbone network nodes in train 1 and train 2 to exchange cross-train backbone network data, and then the data is transmitted to the destination terminal through the local backbone network nodes connected to each other. The initialization process of the train wireless backbone network based on virtual nodes is as follows:

[0046] (1) Train 1 and Train 2 establish a coupler connection, and a wireless connection is established between the virtual backbone network nodes of Train 1 and Train 2;

[0047] (2) The virtual backbone network nodes of Train 1 and Train 2 exchange their respective train numbers, equipment IDs, and other information;

[0048] (3) The backbone network nodes of Train 1 and the virtual backbone network nodes run the topology discovery protocol and send topology discovery protocol packets to each other to discover each other and obtain each other's car number, device ID and other information, thereby calculating the network topology and establishing a mutually addressable routing table. Among them, the virtual backbone network node of Train 1 simulates the backbone network node of Train 2 based on the car number, device ID and other information of Train 2 obtained in the previous step;

[0049] (4) The backbone network nodes of Train 2 and the virtual backbone network nodes run the topology discovery protocol and send topology discovery protocol packets to each other to discover each other and obtain each other's car number, device ID and other information, thereby calculating the network topology and establishing a mutually addressable routing table. Among them, the virtual backbone network node of Train 2 simulates the backbone network node of Train 1 based on the car number, device ID and other information of Train 1 obtained in the previous step.

[0050] The wireless communication system of the reconnected train set provided in this embodiment simulates the backbone network node of the opposite train set by adding a virtual backbone network node in the two wirelessly reconnected train sets and connecting it to the backbone network node of the train set at the local end. Since the topology discovery protocol is only run between the backbone network node and the virtual backbone network node at the local end, the timeout mechanism of the topology discovery protocol will not be triggered, which effectively solves the problem of the train wireless backbone network topology discovery protocol running timeout. It also effectively solves the problem that the cable connector is easy to wear and cause poor contact, saves the operation of cable connection, and shortens the time to establish and undo the reconnection between trains.

[0051] Embodiment 2

[0052] It is understandable that replacing the wired backbone network with a wireless backbone network will require different wireless technologies and modify the backbone network node functions and communication protocols because different wired backbone network communication protocols have different performance requirements, which will make it difficult to transform old vehicles. In order to facilitate the transformation of old vehicles, in the wireless communication system of the reconnected train set provided in this embodiment, the terminal node of the train set at this end sends the data packet that needs to be sent across the train to the backbone network node of the train set at this end, and the backbone network node of the train set at this end sends the data packet to the virtual backbone network node of the train set at this end according to the established routing table, and the virtual backbone network node of the train set at this end sends the data packet to the virtual backbone network node of the train set at the opposite end through a wireless link; after receiving the data packet, the virtual backbone network node of the train set at the opposite end sends the data packet to the backbone network node of the train set at this end according to the established routing table, and the backbone network node forwards the data packet to the corresponding terminal node in the train.

[0053] Still Figure 3 Taking the example of a coupled train consisting of two train formations (train 1 and train 2), (5) the terminal nodes in train 1 and train 2 first send the data packets that need to be sent across trains to the backbone network node at the local end. The backbone network node at the local end sends the data packets to the virtual backbone network node at the local end according to the addressing routing table. After the virtual backbone network node receives the data packets, it sends the data packets to the virtual backbone network node of the corresponding train through the wireless link. After the corresponding virtual backbone network node receives the data packets, it sends the data packets to the backbone network node of the train according to the addressing routing table. The backbone network node then forwards the data packets to the terminal node corresponding to the train.

[0054] The wireless communication system of the reconnected train set provided in this embodiment adopts a virtual backbone network node to simulate the backbone network node of the opposite train, runs a topology discovery protocol with the backbone network node of the local train, and exchanges cross-train data of the terminal nodes, so as to keep the original backbone network node functions and communication protocols unchanged, which is conducive to the reconstruction of old trains; and the virtual backbone network nodes of the two trains are wirelessly networked and exchange cross-train data, and the wired and wireless networks are isolated by the virtual backbone network nodes. The wireless communication performance does not affect the availability of the entire network, but only affects the update frequency of the cross-train data, thereby improving the applicability.

[0055] Embodiment 3

[0056] On the basis of the above embodiments, in order to further improve the communication reliability of the wireless communication system of the multiple train group. In the wireless communication system of the multiple train group provided in this embodiment, after the wireless connection is established between the virtual backbone network nodes, status data packets are sent periodically (for example, 20ms) to each other to monitor the connection status of the wireless link, and when the wireless link is detected to be interrupted, the wireless connection is re-established. By periodically sending status data packets, the connection status of the wireless link between the virtual backbone network nodes can be monitored, and the abnormality of the wireless link can be discovered in time. So that when the wireless link is interrupted, the wireless connection can be re-established to ensure the reliability of communication.

[0057] Furthermore, two redundant wireless links can be established between the virtual backbone network nodes. Figure 4 , Figure 4 A network topology diagram of a wireless communication system of a multiple train set provided by another embodiment of the present disclosure. Figure 4 As shown in the figure, considering that wireless communication may be interfered by the surrounding environment, two redundant wireless links can be established between the virtual backbone network nodes of train 1 and train 2. The virtual backbone network node simultaneously sends the cross-train data packet to the virtual backbone network node of the opposite train through these two wireless links. The virtual backbone network node of the opposite train sends the data packet received earlier to the backbone network node of the train according to the reception time of the data packet. The communication reliability of the wireless communication system of the reconnected train group is further improved through redundant wireless links.

[0058] Embodiment 4

[0059] On the basis of the above embodiments, in order to further improve the utilization rate of wireless link resources of the wireless communication system of the multiple train group, in the wireless communication system of the multiple train group provided in this embodiment, the period of mutually sending status data packets is adjusted according to the performance parameters of the wireless link, and the first period is adopted during the initialization of the train backbone network, and the second period is adopted after the initialization of the train backbone network is completed, and the first period is smaller than the second period. For example, when the performance of the wireless link is good, a smaller sending period can be used to send the status data packet; and when the performance of the wireless link is poor, a larger sending period can be used to send the status data packet. During the initialization of the train backbone network, a smaller first period is used to send the status data packet so that the wireless connection can be established as soon as possible; after the initialization of the train backbone network is completed, a larger second period is used to send the status data packet to save wireless link resources.

[0060] In some optional implementations, when the cross-car data packet transmission period of the terminal node is less than the cross-car data packet transmission period of the virtual backbone network node of the local train formation, the virtual backbone network node of the local train formation sends the latest received cross-car data packet to the virtual backbone network node of the opposite train formation, instead of sending all received cross-car data packets, which greatly saves wireless link resources and improves the wireless link resource utilization rate of the wireless communication system of the reconnected train group. Specifically, if the virtual backbone network node receives a cross-car data packet sent by the backbone network node of the local train, it sends the data packet to the virtual backbone network node of the opposite train. If the cross-car data transmission period of the terminal node is small, such as 10ms, then when the virtual backbone network node sends the cross-car data packet to the virtual backbone network node of the opposite train, it will receive multiple cross-car data packets. Because the backbone network cross-car data packets are all periodic data, the virtual backbone network node will only send the latest received cross-car data packet to the virtual backbone network node of the opposite train.

[0061] Furthermore, after a wireless communication connection is established between the virtual backbone network nodes, the inter-vehicle data packets of the terminal nodes sent to each other are merged into the status data packet of the wireless link and sent together to save wireless link resources.

[0062] Embodiment 5

[0063] It should be noted that, although the above embodiments are all described by taking a multiple train set including two train sets as an example, the present application is also applicable to the case where more than two train sets are multiple-connected. Figure 5 . Figure 5 A network topology diagram of a wireless communication system for a multiple train set provided by another embodiment of the present disclosure. Figure 5As shown, the multiple-unit train set in this embodiment includes multiple train sets. The train set located in the middle part needs to establish wireless connection with the two adjacent train sets. Therefore, two virtual backbone network nodes need to be set on the train set located in the middle part.

[0064] Embodiment 6

[0065] Based on the above embodiments, this embodiment provides an application example.

[0066] In order to solve the problems existing in the prior art (such as communication timeout, difficulty in remodeling old trains, etc.), the present application adds virtual backbone network nodes (such as Figure 3 ), and is wired to the backbone network node of the local train to simulate the backbone network node of the opposite train. The virtual backbone network nodes in Train 1 and Train 2 use wireless communication to exchange cross-train backbone network data, and then transmit the data to the destination terminal through the local backbone network nodes connected to each other. Since the train backbone network node and the virtual backbone network node of the train run the topology discovery protocol, the timeout mechanism of the topology discovery protocol will not be triggered. The initialization process of the train wireless backbone network based on virtual nodes is as follows:

[0067] (1) Train 1 and Train 2 establish a coupler connection, and a wireless connection is established between the virtual backbone network nodes of Train 1 and Train 2.

[0068] (2) The virtual backbone network nodes of Train 1 and Train 2 exchange their respective train numbers, equipment IDs, and other information.

[0069] (3) The backbone network nodes of Train 1 and the virtual backbone network nodes run the topology discovery protocol and send topology discovery protocol packets to each other to discover each other and obtain each other's car number, device ID and other information, thereby calculating the network topology and establishing a mutually addressable routing table. Among them, the virtual backbone network node of Train 1 simulates the backbone network node of Train 2 based on the car number, device ID and other information of Train 2 obtained in the previous step.

[0070] (4) The backbone network nodes of Train 2 and the virtual backbone network nodes run the topology discovery protocol and send topology discovery protocol packets to each other to discover each other and obtain each other's car number, device ID and other information, thereby calculating the network topology and establishing a mutually addressable routing table. Among them, the virtual backbone network node of Train 2 simulates the backbone network node of Train 1 based on the car number, device ID and other information of Train 1 obtained in the previous step.

[0071] (5) The terminal nodes in Train 1 and Train 2 first send the data packets that need to be sent across trains to the backbone network node at the local end. The backbone network node at the local end sends the data packets to the virtual backbone network node at the local end according to the addressing routing table. After the virtual backbone network node receives the data packets, it sends the data packets to the virtual backbone network node of the corresponding train through the wireless link. After the corresponding virtual backbone network node receives the data packets, it sends the data packets to the backbone network node of the train according to the addressing routing table. The backbone network node then forwards the data packets to the terminal node corresponding to the train.

[0072] (6) After the wireless communication connection is established between the virtual backbone network nodes of Train 1 and Train 2, status data packets are sent to each other periodically (for example, 20 ms) to monitor the connection status of the wireless link. If the wireless link is found to be interrupted, the connection should be reestablished.

[0073] (7) If the virtual backbone network node receives a cross-train data packet sent by the backbone network node of the train, it will send the data packet to the virtual backbone network node of the opposite train. If the cross-train data transmission period of the terminal node is small, such as 10ms, then when the virtual backbone network node sends the cross-train data packet to the virtual backbone network node of the opposite train, it will receive multiple cross-train data packets. Because the backbone network cross-train data packets are periodic data, the virtual backbone network node will only send the latest received cross-train data packet to the virtual backbone network node of the opposite train.

[0074] (8) Since the backbone network nodes of train 1 and train 2 run the topology discovery protocol with the virtual backbone network node of the train, the timeout mechanism of the topology discovery protocol will not be triggered, and there is no need to change the functions of the existing backbone network nodes and the logic of the topology discovery protocol. The cross-train data packets of the terminal node can be transmitted to the terminal node of the opposite train through the wireless link between the virtual backbone network nodes, realizing the cross-train transmission of terminal data.

[0075] (9) Considering that wireless communication may be interfered by the surrounding environment, two redundant wireless links can be established between the virtual backbone network nodes of Train 1 and Train 2 (such as Figure 4 ), the virtual backbone network node simultaneously sends the cross-train data packets to the virtual backbone network node of the opposite train through the two wireless links. The virtual backbone network node of the opposite train sends the data packets received earlier to the backbone network node of the train according to the reception time of the data packets.

[0076] In the present application, the wireless communication technology between the virtual backbone network nodes is not limited to a certain type of standard, and can be feasible wireless technologies such as WiFi, ZigBee, LoRa, Bluetooth, etc.

[0077] After wireless communication connections are established between virtual backbone network nodes, the period of sending status data packets to each other can be adjusted according to the performance parameters of the wireless communication technology, and a smaller sending period is used during the initialization of the train backbone network, and a larger sending period is used after the initialization is completed.

[0078] After wireless communication connections are established between virtual backbone network nodes, the cross-vehicle data packets of terminal nodes sent to each other can be sent as separate messages or merged into wireless link status data packets and sent together, saving wireless link resources.

[0079] In the technical solution description of the present application, two trains are connected in a reconnected manner as an example. In fact, the solution of the present invention is also applicable to the case where more than two trains are connected in a reconnected manner, such as Figure 5 shown.

[0080] In summary, the reconnected train set and its wireless communication system provided by the present application, the train wireless backbone network can effectively solve the problem that the cable connector is easily worn and causes poor contact, and eliminates the operation of cable connection, shortening the time for establishing and disconnecting the reconnection between trains; by adding a virtual backbone network node in the two wirelessly reconnected trains, and connecting it to the backbone network node of the local train by wire, to simulate the backbone network node of the opposite train, the problem of timeout of the train wireless backbone network topology discovery protocol can be solved; the virtual backbone network node is used to simulate the backbone network node of the opposite train, and the topology discovery protocol is run with the backbone network node of the local train, and the cross-train data of the terminal node is exchanged, so that the original backbone network node function and communication protocol can be kept unchanged, which is conducive to the transformation of old cars; the virtual backbone network nodes of the two trains are wirelessly networked and cross-train data is exchanged. The wired and wireless networks are isolated through the virtual backbone network nodes. The wireless communication performance does not affect the availability of the entire network, but only affects the update frequency of the cross-train data, thereby improving the applicability of the wireless backbone network technical solution.

[0081] In the embodiments provided in the present disclosure, it should be understood that the disclosed devices and methods can also be implemented in other ways. The device embodiments described above are merely schematic. For example, the flowcharts and block diagrams in the accompanying drawings show the possible architecture, functions and operations of the devices, methods and computer program products according to multiple embodiments of the present disclosure. In this regard, each box in the flowchart or block diagram can represent a module, a program segment or a part of a code, and the above-mentioned module, program segment or a part of the code contains one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in a different order from the order marked in the accompanying drawings. For example, two consecutive boxes can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram and / or flowchart, and the combination of boxes in the block diagram and / or flowchart can be implemented with a dedicated hardware-based system that performs a specified function or action, or can be implemented with a combination of dedicated hardware and computer instructions.

[0082] It should be noted that in the present disclosure, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element limited by the sentence "includes a ..." does not exclude the existence of other identical elements in the process, method, article or device including the element.

[0083] Although the embodiments disclosed in the present disclosure are as above, the above contents are only embodiments adopted for facilitating the understanding of the present disclosure and are not intended to limit the present disclosure. Any technician in the technical field to which the present disclosure belongs can make any modifications and changes in the form and details of the implementation without departing from the spirit and scope disclosed in the present disclosure, but the scope of patent protection of the present disclosure shall still be subject to the scope defined in the attached claims.

Claims

1. A wireless communication system for a multiple train set, the multiple train set comprising at least two train sets, characterized in that: Each train set in the multiple train set is provided with a backbone network node, a plurality of terminal nodes and at least one virtual backbone network node, the virtual backbone network node is wiredly connected to the backbone network node of the train set at the local end, and the backbone network node is wiredly connected to each terminal node of the train set at the local end; After the train marshaling in the reconnected train set establishes a coupler connection, a wireless connection is established between the virtual backbone network nodes of the train marshaling connected by the coupler, for exchanging respective vehicle numbers and device identifications between the virtual backbone network nodes; A topology discovery protocol is run between the virtual backbone network node and the backbone network node of the local train formation, and topology discovery protocol data packets are sent to each other to obtain the car number and equipment identification of the opposite train formation connected to the local train formation, and the network topology is calculated based on this to establish a mutually addressable routing table.

2. The wireless communication system according to claim 1, characterized in that: The terminal node of the local train set sends the data packet that needs to be sent across trains to the backbone network node of the local train set. The backbone network node of the local train set sends the data packet to the virtual backbone network node of the local train set according to the established routing table. The virtual backbone network node of the local train set sends the data packet to the virtual backbone network node of the opposite train set through a wireless link. After receiving the data packet, the virtual backbone network node of the opposite train formation sends the data packet to the backbone network node of the train formation according to the established routing table, and the backbone network node forwards the data packet to the corresponding terminal node in the train.

3. The wireless communication system according to claim 1, characterized in that: After the wireless connection is established between the virtual backbone network nodes, status data packets are periodically sent to each other to monitor the connection status of the wireless link, and the wireless connection is reestablished when the wireless link is detected to be interrupted.

4. The wireless communication system according to claim 3, characterized in that: The period of mutually sending status data packets is adjusted according to the performance parameters of the wireless link, and a first period is adopted during the initialization of the train backbone network, and a second period is adopted after the initialization of the train backbone network is completed, wherein the first period is smaller than the second period.

5. The wireless communication system according to claim 1, characterized in that: When the inter-vehicle data packet sending period of the terminal node is less than the inter-vehicle data packet sending period of the virtual backbone network node of the local train formation, the virtual backbone network node of the local train formation sends the latest received inter-vehicle data packet to the virtual backbone network node of the opposite train formation.

6. The wireless communication system according to claim 1, characterized in that: Two redundant wireless links are established between the virtual backbone network nodes.

7. The wireless communication system according to claim 1, characterized in that: The cross-vehicle data packets of the terminal nodes sent to each other are merged into the status data packet of the wireless link and sent together.

8. The wireless communication system according to claim 1, characterized in that: When the multiple train set includes multiple train sets, two virtual backbone network nodes are set on the train set located in the middle.

9. The wireless communication system according to any one of claims 1 to 9, characterized in that: Wireless communication methods between virtual backbone network nodes include WiFi, ZigBee, LoRa and Bluetooth.

10. A multiple train set, characterized in that: The invention comprises at least two train formations, and adopts the wireless communication system as described in any one of claims 1 to 9 for wireless reconnection.

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