Coupled multiple-unit train set and wireless communication system thereof

Abstract

The present disclosure relates to a coupled multiple-unit train set and a wireless communication system thereof. The coupled multiple-unit train set comprises at least two train formations; each train formation in the coupled multiple-unit train set is provided with a backbone network node, a plurality of terminal nodes, and at least one virtual backbone network node; once the train formations in the coupled multiple-unit train set have been connected by means of couplers, a wireless connection is established between the virtual backbone network nodes of the train formations connected by means of the couplers, so that respective train numbers and device identifiers are exchanged between the virtual backbone network nodes; a topology discovery protocol is run between another virtual backbone network node and the backbone network node of the local train formation, so as to establish mutually addressable routing tables.

Description

Reconnection train set and wireless communication system thereof

[0001] Cross-reference to Related Applications

[0002] The present disclosure claims priority to Chinese Patent Application CN202411372160.9 entitled "Reconnection train set and wireless communication system thereof" filed on September 29, 2024, the entire contents of which are incorporated by reference into the present disclosure. TECHNICAL FIELD

[0003] The present disclosure relates to the field of rail transit on-board communication, in particular to a reconnection train set and a wireless communication system thereof. BACKGROUND

[0004] Early on, train-to-train communication was mainly carried out through wired backbone networks. Wireless backbone networks gradually replaced wired backbone networks. Wireless communication has a large delay, which easily triggers the timeout mechanism of the backbone network communication protocol, leading to the failure of backbone network communication and further leading to the failure of reconnection. Therefore, it is urgent to solve the existing communication timeout problem to improve the communication reliability of the reconnection train set. SUMMARY

[0005] The present disclosure provides a reconnection train set and a wireless communication system thereof to solve the problem of 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 reconnection train set, the reconnection train set comprising at least two train formations, each train formation in the reconnection train set being provided with a backbone network node, a plurality of terminal nodes and at least one virtual backbone network node, the virtual backbone network node being wiredly connected to the backbone network node of the local train formation, the backbone network node being wiredly connected to each terminal node of the local train formation; after the train formations in the reconnection train set establish a coupler connection, a wireless connection is established between the virtual backbone network nodes of the train formations connected by the coupler, for interacting the train numbers and device identifiers of the virtual backbone network nodes with each other; a topology discovery protocol is run between the virtual backbone network nodes and the backbone network nodes of the local train formation, and topology discovery protocol data packets are transmitted to each other to obtain the train numbers and device identifiers of the opposite train formations connected to the local train formation, and the network topology is calculated accordingly to establish a routing table that can be addressed to each other.

[0007] In a second aspect, the present disclosure provides a reconnection train set comprising at least two train formations, which is wirelessly reconnected by using the wireless communication system of the above aspect. BRIEF DESCRIPTION OF DRAWINGS

[0008] The present disclosure will be described in more detail below based on embodiments and with reference to the accompanying drawings:

[0009] Fig. 1 is a schematic diagram of a network topology of a train wired backbone network according to the prior art;

[0010] Fig. 2 is a schematic diagram of a network topology of a train wireless backbone network according to the prior art;

[0011] Fig. 3 is a schematic diagram of a network topology of a wireless communication system of a reconnected train consist according to an embodiment of the present disclosure;

[0012] Fig. 4 is a schematic diagram of a network topology of a wireless communication system of a reconnected train consist according to another embodiment of the present disclosure;

[0013] Fig. 5 is a schematic diagram of a network topology of a wireless communication system of a reconnected train consist according to another embodiment of the present disclosure.

[0014] In the drawings, the same components have the same reference numbers, and the drawings are not drawn to scale. DETAILED DESCRIPTION

[0015] In order to better understand the technical solutions of the present disclosure for those skilled in the art, and to fully understand and implement the implementation process of the present disclosure for applying technical means to solve technical problems and achieve corresponding technical effects, the technical solutions in the embodiments of the present disclosure will be described clearly and completely below in conjunction with the drawings in the embodiments of the present disclosure. Obviously, the described embodiments are only a part of the embodiments of the present disclosure, not all the embodiments. The embodiments of the present disclosure and various features in the embodiments can be combined with each other without conflict, and the technical solutions formed thereby are all within the protection scope of the present disclosure. Based on the embodiments in the present disclosure, all other embodiments obtained by those skilled in the art without creative labor should be within the protection scope of the present disclosure.

[0016] It should be noted that the terms "first", "second", and the like in the specification and claims of the present disclosure and the above-described drawings are used to distinguish similar objects, and do not necessarily have to describe a specific order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, 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 "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product, or device that includes a series of steps or units does not have to be limited to only those steps or units clearly listed, but can include other steps or units that are not clearly listed or inherent to these processes, methods, products, or devices.

[0017] It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described herein can be executed in an order different from that shown.

[0018] The IEC61375 international standard divides the train communication network (TCN) into a two-level network architecture, i.e., a train backbone network and a train consist network. Among them, the train backbone network is used for train-to-train communication between train consists, to realize the interaction of control instructions and state information between train consists, so as to recombine multiple train consists into a train for operation.

[0019] Early, wired backbone networks are mainly used for train-to-train communication, which requires establishing a coupler connection between the recombined trains, and connecting the backbone network cables. If the recombination and decoupling of the train consists need to be established frequently, repeated physical connection and disconnection need to be performed at the coupler connection between the backbone network nodes, which will exacerbate the wear of the connector, thereby affecting the communication quality of the train backbone network, and even causing communication interruption. With the development of wireless communication technology, the safety, reliability and throughput of wireless communication are continuously improved, and wireless backbone networks gradually replace wired backbone networks and obtain more and more applications. Under the premise of retaining the physical coupler between the trains, wireless communication technology is used to replace the cable connector, to realize wireless recombination and complete wireless transmission of the backbone network data between the trains.

[0020] Although the wireless backbone network can effectively solve the problem that the cable connector is easily worn and causes poor contact, due to the large delay of wireless communication, the timeout mechanism of the backbone network communication protocol is easily triggered, which leads to the failure of the backbone network communication, and further leads to the failure of the recombination. Therefore, it is urgent to solve the existing communication timeout problem to improve the communication reliability of the recombined train set.

[0021] First, the technical terms involved in the present disclosure are explained:

[0022] Train consist: a minimum train unit that can run independently.

[0023] Wired recombination: connecting multiple train consists with couplers to recombine multiple trains into a train for operation, and the trains interact train control instructions and state information through wired communication.

[0024] Wireless recombination: connecting multiple train consists with couplers to recombine multiple trains into a train for operation, and the trains interact train control instructions and state information through wireless communication.

[0025] Backbone node: gateway node used for exchanging control instructions and state information between trains when multiple train consist reconnection.

[0026] Cross-train data packet: data packet sent by the terminal of the train to other trains through the backbone node of the train when multiple train consist reconnection.

[0027] Topology discovery protocol: protocol used to obtain the car number, backbone node ID and other information of other trains, so as to calculate the entire backbone network topology and establish the routing table that can be addressed between train consists.

[0028] Figure 1 is a schematic diagram of the network topology of the existing wired backbone network of the train. As shown in Figure 1, the backbone nodes of two trains are connected by a cable. The wired backbone network mainly includes bus type twisted train bus (Wire Train Bus, WTB) and switched Ethernet train backbone (Ethernet Train Backbone, ETB). WTB has lower speed, but good real-time performance and low communication delay; ETB uses real-time Ethernet, has high communication speed, but higher communication delay than WTB. Referring to Figure 1, the initialization process of the wired backbone network of the train is as follows:

[0029] (1) Train 1 and train 2 establish a coupler connection and connect the backbone cable;

[0030] (2) The backbone nodes of train 1 and train 2 run the topology discovery protocol, send topology discovery protocol data packets to each other to discover each other, obtain the car number, identity document (Identity Document, ID) and other information of the other party, calculate the network topology, and establish a routing table that can be addressed to each other;

[0031] (3) After the backbone addressing routing table is established, the terminal node in the train can first send the data packet that needs to be sent across the train to the backbone node of the local end, and the local backbone node sends the data packet to the corresponding backbone node according to the addressing routing table. After the corresponding backbone node receives the data packet, it forwards the data packet to the corresponding terminal node of the train.

[0032] If the reconnection and disconnection between train formations need to be established frequently, repeated physical connection and disconnection at the coupler connection between the backbone nodes will exacerbate the wear and tear of the connector, thereby affecting the communication quality of the train backbone network, and even causing communication interruption. In order to solve the problem that the cable connector is easy to wear and tear and easy to cause poor contact, the scheme of replacing the wired backbone network with a wireless backbone network has been applied more and more. Fig. 2 is a schematic diagram of the network topology of the existing train wireless backbone network. As shown in Fig. 2, the backbone nodes of two trains are connected through a wireless communication link. The initialization process of the train wireless backbone network (such as Fig. 2) is almost the same as that of the train wired backbone network, and the main difference includes: establishing a wireless connection instead of connecting a cable in the first step; in the second step, a wireless communication link is used to send topology discovery protocol packets to each other. In the scheme of replacing the wired backbone network shown in Fig. 1 with the wireless backbone network shown in Fig. 2, 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 the wireless link is directly used to replace the cable connection between the WTB nodes, the timeout mechanism of the WTB communication protocol will be triggered. This is because the delay of wireless communication is larger than that of wired communication, and the topology discovery protocol of the train backbone network has a timeout mechanism. If a topology discovery protocol packet of a train backbone node is not received within a certain time interval (such as 2ms), it is considered that the node is offline, and the node is deleted from the addressing routing table, resulting in that the backbone node cannot communicate normally with other nodes.

[0033] In order to solve the problem that the communication delay of the wireless backbone network is large and easy to trigger the timeout mechanism of the backbone network communication protocol, resulting in the problem of communication failure. The present disclosure proposes a scheme based on a virtual backbone node, which increases a virtual backbone node in two wireless reconnected train formations, and connects the virtual backbone node with the local train backbone node in a wired manner to simulate the backbone node of the opposite train, thereby solving the timeout problem of the WTB communication protocol. At the same time, the virtual backbone nodes in the two wireless reconnected train formations interact with each other through wireless communication to transmit cross-train backbone data, and then transmit the data to the destination terminal through the respective connected local backbone nodes, thereby realizing the wireless reconnection of the two trains without changing the original function of the backbone node and the WTB protocol. The scheme provided by the present disclosure will be described in detail through specific embodiments.

[0034] Embodiment one

[0035] Fig. 3 is a network topology diagram of a wireless communication system of a reconnected train set according to an embodiment of the present disclosure. The wireless communication system of the reconnected train set according to the embodiment is applied to a reconnected train set including at least two train formations. As shown in Fig. 3, each train formation in the reconnected train set is provided with a backbone node, a plurality of terminal nodes, and at least one virtual backbone node. The virtual backbone node is wiredly connected to the backbone node of the local train formation, and the backbone node is wiredly connected to each terminal node of the local train formation. After the train formations in the reconnected train set are connected by couplings, wireless connections are established between the virtual backbone nodes of the train formations connected by the couplings, and configured to exchange the respective train numbers and device identifiers between the virtual backbone nodes. A topology discovery protocol is run between the virtual backbone nodes and the backbone node of the local train formation, and topology discovery protocol data packets are transmitted to each other to obtain the train numbers and device identifiers of the opposite train formations connected to the local train formation, and to calculate the network topology and establish a routable table accordingly. The wireless communication mode between the virtual backbone nodes includes, but is not limited to, WiFi, ZigBee, LoRa, and Bluetooth.

[0036] Taking the reconnected train set including two train formations (train 1 and train 2) shown in Fig. 3 as an example, in order to solve the timeout problem, virtual backbone nodes are added in train 1 and train 2, which are wiredly connected to the local train backbone nodes to simulate the backbone nodes of the opposite train. The virtual backbone nodes in train 1 and train 2 exchange cross-train backbone data through wireless communication, and then transmit the data to the destination terminal through the respective connected local backbone nodes. The initialization process of the train wireless backbone based on the virtual nodes is as follows:

[0037] (1) Train 1 and train 2 are connected by couplings, and wireless connections are established between the virtual backbone nodes of train 1 and train 2;

[0038] (2) The virtual backbone nodes of train 1 and train 2 exchange their respective train numbers, device IDs, and other information;

[0039] (3) The topology discovery protocol is run between the backbone node and the virtual backbone node of train 1, and topology discovery protocol data packets are transmitted to each other to discover the opposite party, obtain the train number, device ID, and other information of the opposite party, calculate the network topology, and establish a routable table. Among them, the virtual backbone node of train 1 simulates the backbone node of train 2 according to the train number, device ID, and other information of train 2 obtained in the previous step;

[0040] (4) The topology discovery protocol is run between the backbone nodes and the virtual backbone nodes of the train 2, and topology discovery protocol data packets are transmitted between each other to discover each other, obtain the train number, equipment ID and other information of each other, calculate the network topology, and establish a route table that can be addressed to each other. The virtual backbone node of the train 2 simulates the backbone node of the train 1 according to the train number, equipment ID and other information of the train 1 obtained in the previous step.

[0041] The wireless communication system for the recombined train set provided in the embodiment increases the virtual backbone node in the two wireless recombined train sets, and connects the virtual backbone node with the backbone node of the local train set by wire to simulate the backbone node of the opposite train set. Since the topology discovery protocol is only run between the backbone node and the virtual backbone node of the local train set, the timeout mechanism of the topology discovery protocol is not triggered, thereby effectively solving the problem of the timeout of the topology discovery protocol of the wireless backbone network of the train. Moreover, the problem of easy wear of the cable connector and easy contact failure is effectively solved, the operation of the cable connection is saved, and the time for establishing and disengaging the recombination between the trains is shortened.

[0042] Embodiment two

[0043] It can be understood that the wireless backbone network is used to replace the wired backbone network. Since the performance requirements of different wired backbone network communication protocols are different, different wireless technologies need to be adopted, and the functions and communication protocols of the backbone node need to be modified, which will result in great difficulty in the modification of the old train. In order to facilitate the modification of the old train, in the wireless communication system for the recombined train set provided in the embodiment, the terminal node of the local train set sends the data packet that needs to be transmitted across the train to the backbone node of the local train set, the backbone node of the local train set sends the data packet to the virtual backbone node of the local train set according to the established route table, and the virtual backbone node of the local train set sends the data packet to the virtual backbone node of the opposite train set through the wireless link. After receiving the data packet, the virtual backbone node of the opposite train set sends the data packet to the backbone node of the local train set according to the established route table, and the backbone node forwards the data packet to the corresponding terminal node in the local train.

[0044] Still taking the recombined train set including two train sets (train 1 and train 2) shown in FIG. 3 as an example, (5) the terminal node in the train 1 and the train 2 sends the data packet that needs to be transmitted across the train to the backbone node of the local train set first, the backbone node of the local train set sends the data packet to the virtual backbone node of the local train set according to the addressing route table, the virtual backbone node receives the data packet and then sends the data packet to the virtual backbone node of the corresponding train through the wireless link, the corresponding virtual backbone node receives the data packet and then sends the data packet to the backbone node of the local train according to the addressing route table, and the backbone node forwards the data packet to the corresponding terminal node in the local train.

[0045] The wireless communication system for the reconnected train set provided by the embodiment adopts a virtual backbone node to simulate a backbone node of a peer train, runs a topology discovery protocol with a backbone node of the local train, and interacts with a cross-train data terminal node, so that the original backbone node function and communication protocol can remain unchanged, which is beneficial to the modification of old trains. The wireless networking between the virtual backbone nodes of the two trains interacts with the cross-train data, and the virtual backbone node isolates the wired and wireless networks, so that the wireless communication performance does not affect the availability of the entire network, only affects the update frequency of the cross-train data, and the applicability is improved.

[0046] Embodiment three

[0047] On the basis of the above-mentioned embodiments, in order to further improve the communication reliability of the wireless communication system for the reconnected train set, the wireless communication system for the reconnected train set provided by the embodiment periodically (such as 20 ms) transmits a state data packet between the virtual backbone nodes after establishing a wireless connection, so as to monitor the connection state of the wireless link, and re-establishes the wireless connection when the wireless link is monitored to be interrupted. By periodically transmitting the state data packet, the connection state of the wireless link between the virtual backbone nodes can be monitored, and the abnormality of the wireless link can be found in time. So that when the wireless link is interrupted, the wireless connection is re-established, and the communication reliability is ensured.

[0048] In an exemplary embodiment, two redundant wireless links can also be established between the virtual backbone nodes. Please refer to FIG. 4, which is a network topology schematic diagram of a wireless communication system for a reconnected train set provided by another embodiment of the disclosure. As shown in FIG. 4, considering that the wireless communication can be disturbed by the surrounding environment, two redundant wireless links can be established between the virtual backbone nodes of train 1 and train 2, and the virtual backbone nodes simultaneously transmit the cross-train data packet to the virtual backbone node of the peer train through the two wireless links. The virtual backbone node of the peer train transmits the data packet received earlier to the backbone node of the local train according to the receiving time of the data packet. Through the redundant wireless links, the communication reliability of the wireless communication system for the reconnected train set is further improved.

[0049] Embodiment four

[0050] On the basis of the above-mentioned embodiments, in order to further improve the utilization rate of the wireless link resources of the wireless communication system of the reconnected train set, the wireless communication system of the reconnected train set provided in the embodiment adjusts the period of sending the state data packet according to the performance parameter of the wireless link, and adopts a first period during the initialization process of the train backbone network and a second period after the initialization of the train backbone network is completed, the first period being smaller than the second period. For example, when the performance of the wireless link is good, a smaller sending period can be adopted to send the state data packet; and when the performance of the wireless link is poor, a larger sending period can be adopted to send the state data packet. The smaller first period is adopted to send the state data packet during the initialization process of the train backbone network, so as to establish the wireless connection as soon as possible; and the larger second period is adopted to send the state data packet after the initialization of the train backbone network is completed, so as to save the wireless link resources.

[0051] In some optional embodiments, when the cross-car data packet sending period of the terminal node is smaller than the cross-car data packet sending period of the virtual backbone network node of the local train consist, the virtual backbone network node of the local train consist sends the latest received cross-car data packet to the virtual backbone network node of the opposite train consist, instead of sending all the received cross-car data packets, thereby greatly saving the wireless link resources and improving the utilization rate of the wireless link resources of the wireless communication system of the reconnected train set. Specifically, if the virtual backbone network node receives the cross-car data packet sent by the train backbone network node, the virtual backbone network node sends the data packet to the virtual backbone network node of the opposite train. If the cross-car data sending period of the terminal node is small, for example, 10 ms, when the virtual backbone network node sends the cross-car data packet to the virtual backbone network node of the opposite train, the virtual backbone network node receives multiple cross-car data packets. Since the cross-car data packets of the backbone network are periodic data, the virtual backbone network node only sends the latest received cross-car data packet to the virtual backbone network node of the opposite train.

[0052] In an exemplary embodiment, after the wireless communication connection is established between the virtual backbone network nodes, the cross-car data packets of the terminal nodes sent by each other are merged into the state data packet of the wireless link and sent together, so as to save the wireless link resources.

[0053] Embodiment Five

[0054] It should be noted that although the above embodiments are all described by taking the re-connection train set including two train formations as an example, the present disclosure is also applicable to the case of re-connection of more than two train formations, please refer to FIG. 5. FIG. 5 is a network topology diagram of a wireless communication system of a re-connection train set according to another embodiment of the present disclosure. As shown in FIG. 5, the re-connection train set in the present embodiment includes multiple train formations, and the train formation located at the middle part needs to establish wireless connection with the two train formations adjacent thereto, thus two virtual backbone nodes need to be arranged on the train formation located at the middle part.

[0055] Embodiment six

[0056] On the basis of the above embodiments, an application example is provided in the present embodiment.

[0057] In order to solve some problems existing in some cases (such as communication timeout, difficulty in old car modification, etc.), the present disclosure increases virtual backbone nodes (such as FIG. 3) in train 1 and train 2, which are connected with the backbone node of the local train by wire to simulate the backbone node of the opposite train. The virtual backbone nodes in train 1 and train 2 interact with each other through wireless communication to cross the train backbone network data, and then transmit the data to the destination terminal through the respective connected local backbone nodes. Since the train backbone node and the virtual backbone 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 based on the virtual node is as follows:

[0058] (1) Train 1 and train 2 establish the coupling connection, and the virtual backbone nodes of train 1 and train 2 establish wireless connection.

[0059] (2) The virtual backbone nodes of train 1 and train 2 interact with each other's train number, equipment ID and other information.

[0060] (3) The topology discovery protocol is run between the backbone node and the virtual backbone node of train 1, and the topology discovery protocol data packets are sent to each other to discover each other, obtain the train number, equipment ID and other information of the other party, so as to calculate the network topology and establish the routing table that can be addressed to each other. Among them, the virtual backbone node of train 1 simulates the backbone node of train 2 according to the train number, equipment ID and other information of train 2 obtained in the above step.

[0061] (4) The topology discovery protocol is run between the backbone node and the virtual backbone node of train 2, and the topology discovery protocol data packets are sent to each other to discover each other, obtain the train number, equipment ID and other information of the other party, so as to calculate the network topology and establish the routing table that can be addressed to each other. Among them, the virtual backbone node of train 2 simulates the backbone node of train 1 according to the train number, equipment ID and other information of train 1 obtained in the above step.

[0062] (5) The terminal nodes in train 1 and train 2 first send the data packets that need to be sent across trains to their local backbone network nodes. The local backbone network nodes send the data packets to their local virtual backbone network nodes according to the addressing routing table. After receiving the data packets, the virtual backbone network nodes send the data packets to the virtual backbone network nodes of the corresponding trains through the wireless link. After receiving the data packets, the corresponding virtual backbone network nodes send the data packets to the backbone network nodes of their own trains according to the addressing routing table. The backbone network nodes then forward the data packets to the corresponding terminal nodes of their own trains.

[0063] (6) After the virtual backbone network nodes of train 1 and train 2 establish a wireless communication connection, they periodically (e.g., every 20ms) send status data packets to each other to monitor the connection status of the wireless link. If the wireless link is found to be interrupted, the connection should be re-established.

[0064] (7) If a virtual backbone node receives a cross-train data packet from the backbone node of its own train, it will forward the data packet to the virtual backbone 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 node sends the cross-train data packet to the virtual backbone node of the opposite train, it will receive multiple cross-train data packets. Since the backbone network cross-train data packets are all periodic data, the virtual backbone node will only send the latest received cross-train data packet to the virtual backbone node of the opposite train.

[0065] (8) Since the backbone network nodes of train 1 and train 2 both run the topology discovery protocol with the virtual backbone network nodes of their respective trains, 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. Cross-train data packets of terminal nodes can be transmitted to the terminal nodes of the opposite train through the wireless link between the virtual backbone network nodes, realizing cross-train transmission of terminal data.

[0066] (9) Considering that wireless communication may be affected by the surrounding environment, two redundant wireless links can be established between the virtual backbone network nodes of train 1 and train 2 (as shown in Figure 4). The virtual backbone network nodes simultaneously send cross-train data packets 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 packets received earlier to the backbone network node of its own train according to the data packet reception time.

[0067] In this disclosure, the wireless communication technology between virtual backbone network nodes is not limited to a certain standard, and can be any feasible wireless technology such as WiFi, ZigBee, LoRa, and Bluetooth.

[0068] After the wireless communication connection between the virtual backbone network nodes is established, the period of sending the state data packet can be adjusted according to the performance parameters of the wireless communication technology, and a smaller sending period is used in the initialization process of the train backbone network, and a larger sending period is used after the initialization is completed.

[0069] After the wireless communication connection between the virtual backbone network nodes is established, the cross-car data packet of the terminal node sent by each other can be sent in a separate message, or can be merged into the wireless link state data packet and sent together, saving the wireless link resources.

[0070] In the technical solution description of the present disclosure, two trains are connected as an example, and in fact, the disclosed scheme is also applicable to the connection of more than two trains, as shown in FIG. 5.

[0071] In summary, the recombined train set and the wireless communication system thereof provided by the present disclosure can effectively solve the problem that the cable connector is easily worn and causes poor contact, and the operation of the cable connection is saved, and the time for establishing and disengaging the recombination between trains is shortened; by increasing the virtual backbone network node in the two wireless recombined trains and connecting it with the local train backbone network node, the backbone network node of the opposite train is simulated, which can solve the problem that the train wireless backbone network topology discovery protocol runs out of time; the virtual backbone network node is used to simulate the backbone network node of the opposite train, the topology discovery protocol is run with the local train backbone network node, and the cross-car data of the terminal node is interacted, which can keep the original backbone network node function and communication protocol unchanged, and is beneficial to the modification of old trains; the wireless networking between the virtual backbone network nodes of the two trains interacts the cross-car data, the wired and wireless networks are isolated by the virtual backbone network node, the wireless communication performance does not affect the availability of the entire network, only affects the update frequency of the cross-car data, and the applicability of the wireless backbone network technical scheme is improved.

[0072] The disclosure provides a heavy train set and a wireless communication system thereof. The heavy train set comprises at least two train formations. Each train formation in the heavy train set is provided with a backbone node, a plurality of terminal nodes and at least one virtual backbone node. The virtual backbone node is wiredly connected to the backbone node of the local train formation. The backbone node is wiredly connected to each terminal node of the local train formation. After the train formations in the heavy train set are connected by couplings, wireless connections are established between the virtual backbone nodes of the train formations connected by the couplings, for exchanging the train numbers and equipment identifiers of the virtual backbone nodes. A topology discovery protocol is run between the virtual backbone nodes and the backbone node of the local train formation, and topology discovery protocol data packets are transmitted to obtain the train numbers and equipment identifiers of the opposite train formations connected to the local train formation, and the network topology is calculated to establish a routable table. By adding the virtual backbone node in the two wireless heavy train formations and wiredly connecting the virtual backbone node to the backbone node of the local train formation, the backbone node of the opposite train formation is simulated. Since the topology discovery protocol is only run between the backbone node and the virtual backbone node of the local train formation, the timeout mechanism of the topology discovery protocol is not triggered, and the problem of timeout of the topology discovery protocol of the train wireless backbone network is effectively solved.

[0073] In the embodiments of the present disclosure, it should be understood that the disclosed apparatus and method can also be implemented in other manners. The above-described apparatus embodiments are merely exemplary. For example, the flowcharts and block diagrams in the accompanying drawings show the possible implementation architectures, functions and operation of the apparatus, method and computer program product according to the embodiments of the present disclosure. In this regard, each block in the flowcharts or block diagrams can represent a module, a program segment or a part of code, which contains one or more executable instructions for implementing the specified logical function. It should also be noted that, in some alternative implementations, the functions noted in the blocks can occur in different orders from those noted in the accompanying drawings. For example, two consecutive blocks can actually be executed substantially in parallel, and sometimes they can be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagrams and / or flowcharts, and the combination of blocks in the block diagrams and / or flowcharts, can be implemented by a dedicated hardware-based system for executing the specified functions or actions, or can be implemented by a combination of special-purpose hardware and computer instructions.

[0074] It should be noted that in the present disclosure, the terms "comprising", "containing" or any other variant thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements, but can also include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without more limitations, the element limited by the statement "comprising a" does not exclude the presence of additional identical elements in the process, method, article, or apparatus comprising the element.

[0075] Although the embodiments disclosed in the present disclosure are as described above, the above description is only for the purpose of facilitating understanding of the embodiments adopted by the present disclosure, and is not intended to limit the present disclosure. Any person skilled in the art of the present disclosure can make any modification and change in the form and details of the implementation without departing from the spirit and scope of the present disclosure, but the patent protection scope of the present disclosure shall be subject to the scope defined by the appended claims.

Claims

1. A wireless communication system for a consist of a heavy-haul train, the consist comprising at least two train units, each train unit being provided with a backbone node, a plurality of terminal nodes and at least one virtual backbone node, the virtual backbone node being wired to the backbone node of the local train unit, the backbone node being wired to the terminal nodes of the local train unit; After the train units of the consist are connected by couplings, wireless connections are established between the virtual backbone nodes of the train units connected by the couplings for exchanging train numbers and equipment identifiers between the virtual backbone nodes; A topology discovery protocol is run between the virtual backbone nodes and the backbone nodes of the local train units, topology discovery protocol packets are exchanged to obtain the train numbers and equipment identifiers of the opposite train units connected to the local train units, and a network topology is calculated based on which a routing table is established for addressable routing. 2.The wireless communication system of claim 1, wherein The terminal nodes of the local train unit send data packets to be transmitted across the train to the backbone node of the local train unit, the backbone node of the local train unit sends the data packets to the virtual backbone node of the local train unit according to the established routing table, and the virtual backbone node of the local train unit sends the data packets to the virtual backbone node of the opposite train unit through the wireless link; Upon receiving the data packets, the virtual backbone node of the opposite train unit sends the data packets to the backbone node of the local train unit according to the established routing table, and the backbone node forwards the data packets to the corresponding terminal nodes in the local train unit.

3. The wireless communication system of claim 1, wherein, After the wireless connections are established between the virtual backbone nodes, status packets are periodically exchanged for monitoring the connection status of the wireless links, and the wireless connections are re-established when a wireless link is detected to be interrupted.

4. The wireless communication system of claim 3, wherein, The period for exchanging the status packets is adjusted according to the performance parameters of the wireless links, 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, the first period being smaller than the second period.

5. The wireless communication system of claim 1, wherein, When the period for transmitting the cross-train data packets of the terminal nodes is smaller than the period for transmitting the cross-train data packets of the virtual backbone node of the local train unit, the virtual backbone node of the local train unit sends the latest received cross-train data packets to the virtual backbone node of the opposite train unit.

6. The wireless communication system of claim 1, wherein, Two redundant wireless links are established between the virtual backbone nodes.

7. The wireless communication system of claim 1, wherein, The cross-train data packets of the terminal nodes are merged into the status packets of the wireless links and are transmitted together.

8. The wireless communication system of claim 1, wherein, When the consist comprises a plurality of train units, two virtual backbone nodes are provided on the train unit located at the middle part.

9. The wireless communication system of any of claims 1-9, wherein, The wireless communication between the virtual backbone nodes includes WiFi, ZigBee, LoRa and Bluetooth. 10.A consist of a heavy-haul train, comprising at least two train units, the consist being wirelessly connected by the wireless communication system of any one of claims 1-9.

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