Multilink communication method and system based on subway train-ground wireless communication

Abstract

The invention discloses a multi-link communication method and system based on subway train-ground wireless communication. The method comprises the following steps: acquiring a to-be-uploaded train-mounted service data packet; the method comprises the following steps: carrying out QoS (Quality of Service) classification on data in a vehicle-mounted service data packet, repackaging the data into a new data packet, distributing the new data packet to a vehicle-mounted wireless unit at a vehicle head and a vehicle-mounted wireless unit at a vehicle tail according to a calculated estimated uploading data volume, and uploading the new data packet to a subway control center through a trackside base station to form two communication links. According to the invention, the dynamic bandwidth of subway wireless communication can be improved, and the congestion probability of subway wireless communication is reduced.

Description

Technical Field

[0001] The present invention relates to the field of wireless communications, and in particular to a multi-link communication method and system based on subway vehicle-to-ground wireless communications. Background Art

[0002] In the subway wireless communication system, the 802.11 technical standard has become a common communication standard for passenger information systems and signal systems. On subway lines that apply this technical standard, a large number of trackside base station equipment (also known as ground AP equipment) are generally deployed in tunnels, and a vehicle-mounted wireless unit (also known as vehicle-mounted AP equipment) is generally installed at the front and rear of the subway train.

[0003] The subway completes system services through the communication between the central service server and the on-board service server. The central service server must communicate with the on-board service server in the on-board exchange network through the wireless link between the trackside base station and the on-board wireless unit. The ground network has relatively strong bandwidth stability due to physical connections such as optical fiber and network cables, while the wireless network between the trackside base station and the on-board wireless unit has relatively large bandwidth changes due to the constant movement of the vehicle. Therefore, how to effectively increase the available bandwidth of the wireless link has become a technical development trend.

[0004] The current mainstream usage method is to use only one end for communication, that is, only one end of the front and rear of the train is working, while the other end is not working or in hot standby state. This will cause the communication service quality of the subway to fluctuate when the bandwidth of the working device fluctuates. Moreover, only one of the two devices at the front and rear of the train is always working, and the equipment working efficiency is not high. Therefore, how to use both the front and rear devices at the same time and use two data paths at the same time has become a new demand. Summary of the invention

[0005] The main purpose of the present invention is to provide a multi-link communication method and system based on subway vehicle-ground wireless communication, so as to improve the efficiency of wireless communication and reduce the congestion probability of wireless signals.

[0006] The technical solution adopted by the present invention is:

[0007] A multi-link communication method based on subway vehicle-ground wireless communication is provided, comprising the following steps:

[0008] Obtain the vehicle-mounted service data packet to be uploaded;

[0009] The data in the on-board business data packets are classified according to their quality of service (QoS), repackaged into new data packets, and distributed to the on-board wireless units at the front and rear of the train according to the calculated estimated upload data volume. The new data packets are then uploaded to the subway control center through the trackside base station to form two communication links.

[0010] Following the above technical solution, the calculation process of estimating the amount of data to be sent is specifically as follows:

[0011] Obtain relevant data information of the on-board wireless unit at the front and rear of the vehicle within a period, including the modulation order MCS, the number of multiple-input multiple-output spatial streams MIMO, the wireless signal signal-to-noise ratio SNR, the wireless signal noise floor NF, whether the wireless signal data frame is successfully received, the amount of data carried in each data frame, and the current cached data stream;

[0012] Calculate the average modulation order, average number of MIMO spatial streams, and data frame error rate within the period, and calculate the maximum estimated bandwidth based on ...

[0013] The actual transmission time ratio of wireless signals within the calculation period;

[0014] Calculate the channel quality coefficient based on the wireless signal signal-to-noise ratio SNR and the wireless signal noise floor NF;

[0015] The estimated amount of data to be sent is calculated based on the calculated maximum estimated bandwidth, the proportion of wireless signal sending time, the channel quality coefficient, and the amount of cached data.

[0016] Following the above technical solution, the wireless signal transmission duration of each data packet is calculated according to the data volume of all data packets in the period, the modulation order MCS and the number of multiple-input multiple-output spatial streams MIMO, and the actual transmission time proportion of the wireless signal is calculated accordingly.

[0017] According to the above technical solution, the data packets sent to the two communication links are different.

[0018] According to the above technical solution, after receiving the data packet, the subway control center analyzes it and sends a retransmission request if it finds that the packet is lost.

[0019] Following the above technical solution, the new data packet is distributed to the front vehicle-mounted wireless unit and the rear vehicle-mounted wireless unit according to the calculated estimated amount of data to be sent, wherein the front vehicle-mounted wireless unit is forwarded to the subway control center via the first trackside base station, and the rear vehicle-mounted wireless unit is forwarded to the subway control center via the second trackside base station.

[0020] The present invention also provides a multi-link communication system based on subway vehicle-to-ground wireless communication, comprising:

[0021] The vehicle communication controller is used to obtain the vehicle service data packets to be uploaded, classify the data in the vehicle service data packets according to the quality of service QoS, repackage them into new data packets, and distribute them according to the calculated estimated data transmission volume;

[0022] The on-board wireless unit at the front of the train is used to connect to the on-board communication controller and form a first communication link with the trackside base station to obtain data packets distributed by the on-board communication controller;

[0023] The on-board wireless unit at the rear of the train is used to connect to the on-board communication controller and form a second communication link with the trackside base station to obtain data packets distributed by the on-board communication controller;

[0024] Trackside base stations are used to obtain distributed data packets and upload them to the subway control center.

[0025] According to the above technical solution, the on-board wireless unit at the front of the train and the on-board wireless unit at the rear of the train respectively establish communication links with the subway control center through different trackside base stations.

[0026] Following the above technical solution, the vehicle communication controller obtains relevant data information statistically collected within a period through the front vehicle wireless unit and the rear vehicle wireless unit, calculates the estimated amount of data to be sent, and then dynamically distributes new vehicle service data packets.

[0027] Following the above technical solution, the subway control center includes a wireless controller, which is communicatively connected to the trackside base station. The wireless controller is used to obtain relevant data information of the front vehicle-mounted wireless unit and the rear vehicle-mounted wireless unit periodically counted by the vehicle-mounted communication controller through the communication link, calculate the estimated amount of data to be sent based on the relevant data information, and then dynamically package the corresponding data packets based on the estimated sent data, and finally send them to the front vehicle-mounted wireless unit and the rear vehicle-mounted wireless unit through the corresponding trackside base station.

[0028] The beneficial effect of the present invention is as follows: the present invention establishes two communication links through the front vehicle-mounted wireless unit and the rear vehicle-mounted wireless unit respectively. When the subway train needs to upload business data, the data packets are dynamically distributed to the front vehicle-mounted wireless unit and the rear vehicle-mounted wireless unit according to the calculated estimated upload data volume, and then uploaded to the subway control center through the trackside base station. Similarly, when the subway control center needs to send data, data is also transmitted through the two communication links, thereby reducing the probability of air interface (i.e., wireless communication) congestion.

[0029] Of course, any product implementing the present invention does not necessarily need to achieve all of the advantages described above at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0031] Figure 1 is a flow chart of a multi-link communication method based on subway vehicle-to-ground wireless communication according to an embodiment of the present invention;

[0032] Figure 2 2 is a schematic diagram of the structure of a multi-link communication system based on subway vehicle-to-ground wireless communication according to an embodiment of the present invention;

[0033] Figure 3 Schematic diagram of switching of onboard wireless units at the front and rear of a subway train according to an embodiment of the present invention;

[0034] Figure 4 is a schematic diagram of two communication links according to an embodiment of the present invention;

[0035] Figure 5 is a data transmission flow chart of two communication links in an embodiment of the present invention;

[0036] Fig. 6A is a data transmission block diagram of two communication links according to an embodiment of the present invention;

[0037] Figure 6B is a data transmission block diagram of a single communication link according to an embodiment of the present invention;

[0038] Figure 7 is a data flow diagram of a vehicle communication controller according to an embodiment of the present invention;

[0039] Figure 8 is a schematic diagram of access of two communication links in an embodiment of the present invention;

[0040] Fig. 9 This is a schematic diagram of a rear-end communication link according to an embodiment of the present invention;

[0041] Fig.10 is a diagram showing the effect of the superimposed bandwidth of the communication link according to an embodiment of the present invention;

[0042] Fig.11 It is a schematic diagram of signal coverage distance of an embodiment of the present invention. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0044] It should be noted that the illustrations provided in the embodiments of the present invention are only used to illustrate the basic concept of the present invention in a schematic manner. Therefore, the drawings only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout type may also be more complicated.

[0045] In the present invention, it is also necessary to explain that, if the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. appear, the orientation or position relationship indicated is based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, if the terms "first" and "second" appear, they are only used for description and distinction purposes, and cannot be understood as indicating or implying relative importance.

[0046] In addition, it should be noted that the features of the various embodiments of the present invention may be combined or combined in part or in whole, and may interact and operate in different ways as will be appreciated by those skilled in the art. Each embodiment may be implemented independently of one another, or in an associated relationship.

[0047] The present invention establishes two communication links between a subway control center and a subway train, wherein the first communication link includes the subway control center, a first trackside base station and a front vehicle-mounted wireless unit, and the second communication link includes the subway control center, a second trackside base station and a rear vehicle-mounted wireless unit.

[0048] like Figure 1 As shown, the multi-link communication method based on subway vehicle-to-ground wireless communication in an embodiment of the present invention includes the following steps:

[0049] S1. Obtain the vehicle-mounted service data packet to be uploaded;

[0050] S2. Classify the data in the vehicle-borne business data packet according to the quality of service (QoS), repackage it into a new data packet, and distribute the new data packet to the front vehicle-borne wireless unit and the rear vehicle-borne wireless unit according to the calculated estimated upload data volume, and then upload it to the subway control center through the trackside base station to form two communication links.

[0051] The calculation process of estimating the amount of data to be sent is as follows:

[0052] (1) Obtain relevant data information of the on-board wireless unit at the front and rear of the vehicle within a period, including the modulation order MCS, the number of multiple-input multiple-output spatial streams MIMO, the wireless signal signal-to-noise ratio SNR, the wireless signal noise floor NF, whether the wireless signal data frame is successfully received, the amount of data carried in each data frame, and the current cached data stream;

[0053] (2) Calculate the average modulation order, average number of MIMO spatial streams, and data frame error rate within the period, and calculate the maximum estimated bandwidth based on these;

[0054] (3) Calculate the percentage of actual wireless signal transmission time within the period;

[0055] (4) Calculate the channel quality coefficient based on the wireless signal signal-to-noise ratio SNR and the wireless signal noise floor NF;

[0056] (5) Calculate the estimated amount of data to be sent based on the calculated maximum estimated bandwidth, the proportion of wireless signal transmission time, the channel quality coefficient, and the amount of cached data.

[0057] Among them, in step (3), the wireless signal transmission duration of each data packet is calculated based on the data volume of all data packets in the period, the modulation order MCS and the number of multiple-input multiple-output spatial streams MIMO, and the actual transmission time proportion of the wireless signal is calculated accordingly.

[0058] In addition, the repackaged new data packets can be the same or different. Generally, different data can be sent through the two wireless communication links at the front and rear of the vehicle to improve the actual working bandwidth. That is, through the bandwidth superposition effect of multi-link communication, the actual dynamic bandwidth of the vehicle can be significantly improved. It is understandable that the efficiency of transmitting highly reliable data can also be improved by sending the same data simultaneously through multiple links.

[0059] If the subway control center receives the data packet and analyzes it, if it finds that the packet is lost, it will send a retransmission request and then resend the data packet through the communication link.

[0060] Furthermore, in step S2, the two communication links formed can be completely independent, that is, the two onboard wireless units at the front and rear of the train form different communication links with the subway control center through different trackside base stations. Specifically, the new data packet is distributed to the onboard wireless unit at the front and rear of the train according to the calculated estimated amount of data to be sent, wherein the onboard wireless unit at the front is forwarded to the subway control center through the first trackside base station, and the onboard wireless unit at the rear is forwarded to the subway control center through the second trackside base station. If communication conditions permit, the two onboard wireless units at the front and rear of the train can also share one trackside base station.

[0061] In order to implement the above method embodiment, the present invention also provides a multi-link communication system based on subway vehicle-to-ground wireless communication, such as Figure 2 , 3 As shown in the figure, the system mainly involves subway control center equipment, tunnel equipment and subway trains, and mainly includes on-board communication controller, front on-board wireless unit, rear on-board wireless unit and trackside base station. Among them:

[0062] The vehicle communication controller is used to obtain the vehicle service data packets to be uploaded, classify the data in the vehicle service data packets according to the quality of service QoS, repackage them into new data packets, and distribute them according to the calculated estimated data transmission volume;

[0063] The on-board wireless unit at the front of the train is used to connect to the on-board communication controller and form a first communication link with the trackside base station to obtain data packets distributed by the on-board communication controller;

[0064] The on-board wireless unit at the rear of the train is used to connect to the on-board communication controller and form a second communication link with the trackside base station to obtain data packets distributed by the on-board communication controller;

[0065] Trackside base stations are used to obtain distributed data packets and upload them to the subway control center.

[0066] The subway control center equipment may include a wireless controller, which is connected to the trackside base station through a ground switch network, and the wireless controller includes a network data module and a wireless bandwidth estimation module, wherein the network data module is mainly used to send and receive business data, and the wireless bandwidth estimation module is mainly used to obtain relevant data information of the front vehicle-mounted wireless unit and the rear vehicle-mounted wireless unit periodically counted by the vehicle-mounted communication controller through a communication link, and calculate the estimated data volume to be sent based on the relevant data information. The network data module dynamically packs the corresponding data packets according to the calculation results of the wireless bandwidth estimation module, and finally sends them to the front vehicle-mounted wireless unit and the rear vehicle-mounted wireless unit through the corresponding trackside base station.

[0067] The on-board communication controller is set on the subway train and can be wirelessly connected to the on-board wireless unit through the on-board switch network. The on-board communication controller specifically includes a network data module and a wireless bandwidth estimation module. The wireless bandwidth estimation module obtains relevant data information statistically within a period through the on-board wireless unit at the front and the on-board wireless unit at the rear of the train, and calculates the estimated amount of data to be sent; the network data module dynamically distributes new on-board business data packets according to the estimated calculation results, and uploads the on-board business personnel data packets through the corresponding communication link.

[0068] Therefore, if Figure 4 As shown, when the subway train starts, the on-board communication controller can establish two different data link tunnels through the two on-board wireless units at the front and rear of the train.

[0069] Specifically, the on-board wireless unit at the front or rear of the vehicle counts the modulation order (MCS), the number of multiple-input and multiple-output spatial streams (MIMO), the signal-to-noise ratio (SNR) of the air interface signal, the noise floor (NF) of the air interface signal, whether the air interface data frame is successfully received, and the length of the data carried in each data frame at a certain time (for example, 50 milliseconds) as a cycle. And all statistical results and the current cache size are sent to the wireless bandwidth estimation module in the on-board communication controller. The air interface is the air interface (indicating wireless communication), which is relative to the concept of "line interface" in wired communication. In wired communication, the "line interface" defines the physical size and a series of electrical or optical signal specifications; in wireless communication technology, the "air interface" defines the technical specifications of the radio wave link between the terminal device and the network device, making wireless communication as reliable as wired communication.

[0070] The wireless bandwidth estimation module in the vehicle communication controller mainly performs the following bandwidth estimation:

[0071] Step 1: Calculate the maximum estimated bandwidth

[0072] After receiving the periodic statistical data, the wireless bandwidth estimation module of the vehicle communication controller calculates the average MCS value, the average effective MIMO number and the data frame error rate (PER) within the period based on the statistical data. The above data can be used to estimate the bandwidth of the air interface.

[0073] The average MCS value and the average effective MIMO number are calculated as follows:

[0074] 1. Based on the data, the PER corresponding to all MCS and MIMO can be calculated.

[0075] 2. Take the MCS and MIMO with the lowest PER as the average MCS and average effective MIMO number.

[0076] Therefore, the currently valid maximum estimated bandwidth calculation formula is as follows:

[0077]

[0078] Step 2: Calculate the actual sending time ratio within the cycle

[0079] The wireless bandwidth estimation module of the vehicle communication controller can calculate the time it takes to send each data packet over the air interface and the actual amount of data sent for each data packet based on the data length of all data packets and the MIMO and MCS information, and can also calculate the proportion of air interface transmission time.

[0080]

[0081] Step 3: Analyze channel quality based on air interface signal-to-noise ratio (SNR) and air interface noise floor (NF)

[0082] First, the wireless bandwidth estimation module of the vehicle communication controller calculates the air interface signal strength (RSSI), and obtains the theoretical MCS value corresponding to the RSSI based on the theoretical correspondence between RSSI and MCS. Then, the channel quality coefficient for the estimated bandwidth is calculated based on the theoretical MCS and the air interface signal noise floor. At the same time, when there is no external interference, the noise floor is generally maintained below -95dBm, and when the noise floor is obviously too high (experienced to be higher than -85dBm), an empirical noise floor coefficient is introduced to calculate the channel quality coefficient.

[0083]

[0084] Step 4: Calculate the estimated amount of data that can be sent in the next cycle.

[0085] Based on the calculation results of the previous three steps and the current amount of cached data, the actual amount of data that can be sent in the next cycle is calculated, and the settlement result is sent to the network data module.

[0086] Estimated amount of data to be sent

[0087] =(maximum estimated bandwidth * air interface transmission time ratio * channel quality coefficient)

[0088] -Amount of cached data

[0089] Based on the above algorithm, it can be ensured that the vehicle wireless unit will not send too much data in a cycle, causing air interface network congestion. At the same time, the use of channel quality coefficient can improve the overall anti-interference ability of the system.

[0090] The wireless communication link between the trackside base station and the onboard wireless unit will have dynamic changes in bandwidth and latency due to the movement of the train. When the data traffic is large, it may cause network congestion. Therefore, in order to reduce the impact of wireless communication quality on bandwidth, the onboard wireless unit not only transmits real-time Ethernet data to the onboard communication controller, but also provides real-time feedback on the wireless channel status and its own cache information. The onboard communication controller estimates how much traffic can pass through the front and rear of the train respectively based on the wireless channel status, and then the onboard communication controller can dynamically allocate the data traffic of the two links, thereby reducing the probability of air interface congestion.

[0091] Furthermore, if Figure 5 , 6AAs shown in Figure 7, the wireless bandwidth estimation module of the wireless controller and the on-board communication controller estimates how much bandwidth can be sent at the front and rear of the train respectively according to the quality of the wireless air interface, and the network data module sends a certain amount of data to the air interface link according to the calculation result of the wireless bandwidth estimation module. When the network data packet to be uploaded passes through this system, the network data module will first classify the data by QoS, and then repackage and number the newly composed data packets, and then distribute the numbered data packets through multiple links at the front and rear of the train. After receiving the packaged numbered data at the receiving end of the subway control center, the data is unpacked and retransmission is requested based on whether the packet is lost. After the unpacking is completed, the reassembled data is sent out through the data export.

[0092] The onboard wireless unit or trackside base station calculates the air interface signal quality by collecting statistics on the receiving and sending status of wireless communications, and sends its own cache size to the wireless bandwidth estimation module of the onboard communication controller or wireless controller. The wireless bandwidth estimation module calculates the estimated air interface bandwidth by analyzing the received data, and decides how much data to send based on the current cache size of the onboard wireless unit or trackside base station.

[0093] Because the entire system is composed of multiple devices, in the event of a wireless device failure or different wireless device startup speeds, the order of wireless device registration may be different. The system can switch between single-link working mode and multi-link working mode. Figure 6B As shown, in the single-link working mode, the system sends data only through a single air interface, and other working principles remain unchanged.

[0094] like Figure 8 As shown, the network data module will enter a waiting state after booting up and will determine whether it has been connected to the network. After connecting to the network, the network data module will wait for the wireless device to register. Then the network data module receives the registration according to the order in which the wireless device initiates the request and enters the single-link working mode. If there are more wireless devices registering, the registration is received and the multi-link working mode is entered.

[0095] After the network data module enters the single-link or multi-link working mode, the wireless device will continuously send the data collected by itself to the wireless bandwidth estimation module.

[0096] In the process of vehicle-to-ground wireless communication, Fig. 9 As shown in the figure, when the vehicle sends data to the ground, the data link bandwidth is limited by three physical connections, namely the vehicle wired bandwidth, the air interface wireless bandwidth, and the ground wired bandwidth. The vehicle wired bandwidth and the ground wired bandwidth are both directly connected by cables, and the communication bandwidth is usually fixed at 1000Mbps. However, due to the rapid movement of the train, the air interface wireless bandwidth will change rapidly between 0Mbps-2400Mbps.

[0097] Common reasons that affect air interface communication quality are as follows: (1) Low signal strength, generally due to long communication distance. The communication distance of general Wi-Fi usage scenarios is about 0-50 meters. In the wireless communication scenario of the subway, the usual communication distance will reach about 400 meters, and considering the condition of redundant backup, the maximum coverage can reach 1.2 kilometers. (2) External signal interference. In the coverage scenario of the elevated section of the subway, there are many situations where it passes through the downtown area. As a public means of communication, Wi-Fi can be expected to encounter a large number of interference signals from ordinary Wi-Fi devices.

[0098] Therefore, if the air interface communication quality is poor, the air interface wireless bandwidth will be significantly lower than the vehicle wired bandwidth. At this time, the vehicle communication controller sends too much data to the vehicle wireless unit, which will cause wireless communication congestion on the air interface, resulting in increased data communication delay and packet loss rate.

[0099] In order to solve the above problems, when the network data module of the vehicle communication controller performs multi-link distribution, it must ensure that the amount of data sent does not exceed the buffer of the vehicle wireless unit and the sending capacity of the air interface wireless bandwidth.

[0100] In normal scenarios, the system can send different data through two wireless air interface links at the front and rear of the vehicle to increase the actual working bandwidth.

[0101] like Fig.10 As shown in the figure, compared with the case where a single device is working, the maximum dynamic bandwidth of a single device can only reach the effect of the dotted line. However, through the bandwidth superposition effect of multi-link communication, the actual dynamic bandwidth of the vehicle can be significantly improved.

[0102] In the actual application scenario of subway communication, the increase in bandwidth brought by multi-link communication can improve the overall coverage distance of vehicles. Fig.11 As shown, since the effective coverage distance of a single-end on-board wireless unit is generally around 400 meters, in order to ensure communication effect and redundant backup requirements, the deployment spacing of ground trackside base stations is generally within 200 meters.

[0103] Under the same dynamic bandwidth coverage requirements, multi-link communication can significantly increase the coverage distance. Therefore, the deployment interval of trackside equipment can be significantly increased. In practical applications, the average deployment interval can be increased to 400-450 meters. Such a deployment distance can significantly reduce the number of trackside equipment installed, thereby reducing the amount of engineering construction and the workload of later trackside equipment maintenance.

[0104] In special scenarios, this system can transmit highly reliable data efficiently by sending the same data simultaneously through multiple links. The network data module of the vehicle communication controller identifies highly reliable data through QoS classification, and then packages two copies of the same data when packaging the data, and sends them out through two links at the same time. At the receiving end, as long as any copy of the data arrives, the receiving end can restore the original data.

[0105] In summary, the present invention establishes two communication links through the front vehicle-mounted wireless unit and the rear vehicle-mounted wireless unit respectively. When the subway train needs to upload business data, the data packets are dynamically distributed to the front vehicle-mounted wireless unit and the rear vehicle-mounted wireless unit according to the calculated estimated upload data volume, and then uploaded to the subway control center through the trackside base station. Similarly, when the subway control center needs to send data, data is also transmitted through the two communication links, thereby reducing the probability of air interface (i.e., wireless communication) congestion.

[0106] It should be pointed out that, according to the needs of implementation, the various steps / components described in this application can be split into more steps / components, and two or more steps / components or partial operations of steps / components can be combined into new steps / components to achieve the purpose of the present invention.

[0107] The order of execution of each step in the above embodiment does not mean the order of execution. The order of execution of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiment of the present application.

[0108] It should be understood that those skilled in the art can make improvements or changes based on the above description, and all these improvements and changes should fall within the scope of protection of the appended claims of the present invention.

Claims

1. A multi-link communication method based on subway vehicle-to-ground wireless communication, characterized in that: The following steps are involved: Obtain the vehicle-mounted service data packet to be uploaded; The data in the on-board business data packets are classified according to their quality of service (QoS), repackaged into new data packets, and distributed to the on-board wireless units at the front and rear of the train according to the calculated estimated upload data volume. The new data packets are then uploaded to the subway control center through the trackside base station to form two communication links.

2. The multi-link communication method based on subway vehicle-to-ground wireless communication according to claim 1, characterized in that: The calculation process of the estimated amount of data to be sent is as follows: Obtain relevant data information of the on-board wireless unit at the front and rear of the vehicle within a period, including the modulation order MCS, the number of multiple-input multiple-output spatial streams MIMO, the wireless signal signal-to-noise ratio SNR, the wireless signal noise floor NF, whether the wireless signal data frame is successfully received, the amount of data carried in each data frame, and the current cached data stream; Calculate the average modulation order, average number of MIMO spatial streams, and data frame error rate within the period, and calculate the maximum estimated bandwidth based on the calculated values; The actual transmission time ratio of wireless signals within the calculation period; Calculate the channel quality coefficient based on the wireless signal signal-to-noise ratio SNR and the wireless signal noise floor NF; The estimated amount of data to be sent is calculated based on the calculated maximum estimated bandwidth, the proportion of wireless signal sending time, the channel quality coefficient, and the amount of cached data.

3. The multi-link communication method based on subway vehicle-to-ground wireless communication according to claim 1, characterized in that: The wireless signal transmission duration of each data packet is calculated based on the data volume, modulation order MCS and multiple-input multiple-output spatial stream number MIMO of all data packets in the period, and the actual transmission time proportion of the wireless signal is calculated accordingly.

4. The multi-link communication method based on subway vehicle-to-ground wireless communication according to claim 1, characterized in that: The packets sent to the two communication links are not identical.

5. The multi-link communication method based on subway vehicle-to-ground wireless communication according to claim 1, characterized in that: After receiving the data packet, the subway control center analyzes it and sends a retransmission request if it finds packet loss.

6. The multi-link communication method based on subway vehicle-to-ground wireless communication according to any one of claims 1 to 5, characterized in that: Specifically, the new data packet is distributed to the front vehicle-mounted wireless unit and the rear vehicle-mounted wireless unit according to the calculated estimated data transmission volume, wherein the front vehicle-mounted wireless unit forwards it to the subway control center through the first trackside base station, and the rear vehicle-mounted wireless unit forwards it to the subway control center through the second trackside base station.

7. A multi-link communication system based on subway vehicle-to-ground wireless communication, characterized in that: include: The vehicle communication controller is used to obtain the vehicle service data packets to be uploaded, classify the data in the vehicle service data packets according to the quality of service QoS, repackage them into new data packets, and distribute them according to the calculated estimated data transmission volume; The on-board wireless unit at the front of the train is used to connect to the on-board communication controller and form a first communication link with the trackside base station to obtain data packets distributed by the on-board communication controller; The on-board wireless unit at the rear of the train is used to connect with the on-board communication controller and form a second communication link with the trackside base station to obtain data packets distributed by the on-board communication controller; Trackside base stations are used to obtain distributed data packets and upload them to the subway control center.

8. The multi-link communication system based on subway vehicle-to-ground wireless communication according to claim 7 is characterized in that: The on-board wireless unit at the front of the train and the on-board wireless unit at the rear of the train establish communication links with the subway control center respectively through different trackside base stations.

9. The multi-link communication system based on subway vehicle-to-ground wireless communication according to claim 7, characterized in that: The vehicle communication controller obtains relevant data information statistically within a cycle through the front vehicle wireless unit and the rear vehicle wireless unit, calculates the estimated amount of data to be sent, and then dynamically distributes new vehicle service data packets.

10. The multi-link communication system based on subway vehicle-to-ground wireless communication according to claim 9, characterized in that: The subway control center includes a wireless controller, which is connected to the trackside base station for communication. The wireless controller is used to obtain relevant data information of the front vehicle-mounted wireless unit and the rear vehicle-mounted wireless unit periodically counted by the vehicle-mounted communication controller through the communication link, calculate the estimated amount of data to be sent based on the relevant data information, and then dynamically package the corresponding data packets based on the estimated sent data, and finally send them to the front vehicle-mounted wireless unit and the rear vehicle-mounted wireless unit through the corresponding trackside base station.

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