Low-delay communication method based on wired and wireless unified time slot scheduling

Abstract

The invention discloses a low-latency communication method based on wired and wireless unified time slot scheduling, which is applied to the technical field of communication and aims at solving the problem that time slice distribution and scheduling are not carried out on wired transmission and wireless transmission in a traditional system, so that data are transmitted from a plurality of wired terminals of one system to a wired terminal of another system at the same time. In order to solve the problem that key data are prone to network congestion and packet loss in the wired and wireless fusion network, the problems can be effectively solved by unifying a protocol stack, unifying a time synchronization reference and unifying network data time slot division and scheduling in the wired and wireless fusion network, the uncertainty of the key data in the transmission process of the wired and wireless fusion network is reduced, and the transmission efficiency of the wired and wireless fusion network is improved. And under the condition that the original network architecture is not changed, the key data transmission delay and jitter are reduced, so that the data transmission reliability of the wired and wireless fusion network is improved.

Description

Technical Field

[0001] The present invention belongs to the field of communication technologies, and particularly relates to a low-latency communication technology. Background Art

[0002] In an interconnected communication system composed of multiple systems, a wired network is often used inside the system, and a wireless network is used between systems. For cross-system device communication, it is necessary to go through the wired communication inside the system and the wireless communication between systems. In traditional systems, there is no unified time slice allocation and unified scheduling for wired transmission and wireless transmission, which may lead to network congestion and packet loss of low-priority or same-priority data when transmitting data simultaneously from multiple wired terminals of one system to a wired terminal of another system.

[0003] For the above congestion and packet loss problems, on the one hand, because the standard Ethernet transmission technology is usually adopted inside the network terminal, it is impossible to achieve the mixed transmission of high and low bandwidth traffic; on the other hand, since the bandwidth of the wireless network link is usually not higher than 100 Mbps, which is quite different from the link bandwidth of 1 Gbps and above of the wired link, when data is transmitted from the wired link to the wireless link, it is easy to cause congestion of the wireless link.

[0004] How to achieve congestion-free data transmission from multiple network terminals inside a system to a network terminal of another system in multiple systems and improve the real-time performance and certainty of data transmission is the problem to be solved by the present invention. Summary of the Invention

[0005] The purpose of the present invention is to overcome the deficiencies of the prior art, and provide a low-latency communication method based on unified time slot scheduling of wired and wireless, which can effectively improve the delay performance and jitter performance of data in a wired and wireless converged network system and reduce network congestion and packet loss problems by implementing a unified network protocol stack, unified time synchronization, and unified time slot allocation and scheduling.

[0006] The technical solution adopted by the present invention is: a low-latency communication method based on unified time slot scheduling of wired and wireless, the application scenario includes multiple converged network systems, each converged network system includes a converged gateway and multiple TNS terminals, and wired transmission is used for communication inside each converged network system, and wireless links are used for communication between each converged network system;

[0007] Inside each converged network system:

[0008] The application layer and the network layer are deployed on the TSN terminal, and the data link layer and the physical layer are deployed in the converged gateway;

[0009] The application layer includes a programming interface and a network control and management module. The source address and destination address of the information flow are set in the programming interface of the application layer, and a Qos feature identifier is added;

[0010] The network control and management module is used to plan the number and positions of time slots for each node;

[0011] The network layer uses the IP layer of the TCP / IP protocol stack to implement a routing forwarding protocol based on IP addresses and maintain dynamic and static routing tables;

[0012] The data link layer implements unified timing scheduling based on TSN, wired-wireless protocol mapping, and autonomous sending and receiving of link negotiation frames;

[0013] The physical layer realizes the sending and receiving of wireless links through a wireless module;

[0014] The low-latency communication method specifically includes the following steps:

[0015] S1. Use a certain TNS terminal inside the converged network system as the master node of the converged network system; terminals inside each converged network system that need to execute tasks report their traffic volume, sending period, source MAC, and destination MAC information to the network control and management module of each autonomous node;

[0016] S2. The network control and management module of the master node analyzes and models the relationship between wired link and wireless link resources and terminal delay, constructs an optimization target with the minimum average end-to-end delay of time-sensitive services across the network, and solves the TSN Qbv gating parameter, Qav bandwidth reservation parameter mapping parameter;

[0017] S3. The network control and management module of the master node distributes the scheduling strategy obtained in step S2 to each TSN terminal inside the converged network system;

[0018] S4. TNS terminals perform data transmission in their respective time slot resources.

[0019] Advantages of the present invention: The present invention provides a low-latency communication method based on unified time slot scheduling of wired and wireless. Aiming at the problem that in the traditional system, no unified time slice allocation and scheduling are made for wired transmission and wireless transmission, which may lead to network congestion and packet loss of key data when multiple wired terminals in one system transmit data to wired terminals in another system simultaneously. By unifying the protocol stack, unified time synchronization benchmark, and unified network data time slot division and scheduling in the wired-wireless converged network, the above problems can be effectively solved, reducing the uncertainty of key data during the transmission in the wired-wireless converged network. Without changing the original network architecture, the transmission delay and jitter of key data are reduced, thereby improving the reliable performance of data transmission in the wired-wireless converged network. The present invention first proposes the idea of unified protocol stack, unified time synchronization benchmark, and unified network data time slot division and scheduling for wireless and wired converged networks. All processes can be implemented using the existing hardware framework, which is conducive to engineering implementation. Brief Description of the Drawings

[0020] Figure 1 It is a flowchart for implementing the low-latency communication method of the present invention;

[0021] Figure 2 It is a wired and wireless network integration diagram;

[0022] Figure 3 It is a hierarchical structure diagram of the wired-wireless unified network protocol stack;

[0023] Figure 4 It is a schematic diagram of TSN time slot division for the mixed flow transmission of periodic and aperiodic data in a wired network;

[0024] Figure 5 It is a functional architecture diagram of the time slot resource negotiation mechanism for a wired and wireless integrated network;

[0025] Figure 6 It is a schematic diagram of unified time slot division for a wired and wireless integrated network;

[0026] Figure 7 It is a schematic diagram of the time slot distribution after the network control and management module calculates under wired and wireless integrated transmission. Detailed Implementation Manner

[0027] To facilitate those skilled in the art to understand the technical content of the present invention, the content of the present invention will be further explained below with reference to the accompanying drawings.

[0028] The data flow transmission path of the wired and wireless integration described in the method of the present invention is as Figure 2 shown. The TSN 1 inside the system generates a TSN service flow, and this flow passes through the TSN switch inside the system, the integration gateway 1, and the inter-system wireless link to reach the TSN terminal 5 inside the destination system. Those skilled in the art should note that in actual applications, one TSN switch can be connected to multiple TSN terminals, and similarly, one integration gateway can also be connected to multiple TSN terminals.

[0029] As Figure 1 shown, a low-latency communication method based on unified time slot scheduling of wired and wireless in the present invention includes the following steps:

[0030] S1. Unify the integrated network system protocol stack: To achieve efficient wired-wireless interoperability, network scheduling and management, all protocol processing does not pass through the application layer and is implemented by the unified network protocol stack. The protocol stack provides a programming interface for the application layer to implement hardware-independent data transceiver operations;

[0031] The hierarchical structure of the wired-wireless unified network protocol stack described in the method of the present invention is as Figure 3As shown, the application layer and the network layer are deployed on the TSN terminal, and the data link layer and the physical layer are deployed in the convergence gateway. The main functions of each layer of the protocol are as follows:

[0032] 1) Application layer

[0033] The application layer is Figure 3 the software shown as follows. The unified interface and network control management functions of the application layer can provide hardware-independent data transceiver and network parameter setting for application software.

[0034] By setting the source address and destination address of the information flow in the application layer programming interface and adding Qos feature identifiers, end-to-end path constraints and delay feature constraints of the information flow are realized. Devices inside and outside the system have different communication address vectors of information flows composed of {IP, MAC, VLAN, port number}. Therefore, according to the communication address vector, the wired and wireless types of the current data stream transmission can be determined. The distinction of this transmission type is realized in the "protocol mapping" module of the data link layer. The Qos feature parameters indicate the indicators of service quality. At the time slot negotiation stage before data sending by each node (including TSN terminals in System 1 and System 2), the Qos parameters are reported to the master node. The master node (the node running the network control management module is called the master node. Figure 2 Among them, TSN terminals 1..5 can all be master nodes, but there can only be one master node in a wired and wireless convergence network system) The "network control management" module of the application layer plans the number and position of time slots of each node according to the QoS feature parameters, network transmission delay model and network planning algorithm. The network transmission delay model and network planning algorithm are existing known technologies. For the network transmission delay model, specific reference can be made to: "Research on Traffic Scheduling Technology in Time-Sensitive Networks" by Pei Jinchuan; for the network planning algorithm, specific reference can be made to "Research and Implementation of Time-Sensitive Network Planning Algorithm" by Zhao Jiayi.

[0035] 2) Network layer

[0036] The network layer directly uses the IP layer of the TCP / IP protocol stack to implement the routing forwarding protocol based on the IP address and maintain dynamic and static routing tables.

[0037] 3) Data link layer

[0038] The data link layer mainly realizes unified timing scheduling based on TSN, wired-wireless protocol mapping, and autonomous sending and receiving of link negotiation frames. Among them, for the unified timing scheduling, the "network control management" module of the application layer schedules and plans according to the Qos attributes marked by the application layer and the execution period of the transmission task, and maps them into TSN Qbv gating parameters and Qav bandwidth reservation parameters respectively to realize low-delay transmission of periodic and aperiodic data streams.

[0039] The wired-wireless mapping feature directly encapsulates payload data into wireless link data by the data link layer logic according to the address vector composed of {IP, MAC, VLAN, port number}.

[0040] All devices in the network will periodically send Link Layer Discovery Protocol (LLDP) frames. When the link layer of the master node receives an LLDP frame, it will report to the network control and management module of the terminal application layer. The network control and management module detects and manages the topology of the entire network and the online and offline status based on the content of the LLDP frame, realizing the dynamic management of network nodes.

[0041] 4) Physical layer

[0042] The physical layer realizes the transceiver of the wireless link, which is implemented by the wireless module. The wireless module and the convergence gateway are arranged in the same integrated processor. The physical layer also has the function of transparent transmission of the wired link, which can enhance the backbone network access ability within the system of the integrated processor.

[0043] S2. Unify the fusion network time reference to achieve system time synchronization: Through the 1PPS+TOD signal, the wireless transceiver module provides the time reference for the internal wired network of System 1 or System 2. The internal wired network of System 1 or System 2 realizes time synchronization through IEEE802.1AS, and System 1 or System 2 realizes wireless network time synchronization between wireless transceiver modules based on the RTT time synchronization mechanism;

[0044] The specific implementation method is as follows: The TSN wired network realizes high-precision time synchronization within 30ns based on the IEEE 1588 two-way time synchronization mechanism suitable for static scenarios, and the wireless network realizes high-precision time synchronization at the 10ns level suitable for mobile scenarios based on the RTT time synchronization mechanism. Since the time synchronization accuracy of the wireless is higher, the 1PPS+TOD time information is input by the wireless module to achieve fusion network time synchronization, and the time synchronization of the network within the system is realized through TSN message interaction. In addition, in order to achieve a unified network-wide time reference, the master clock system as the reference is elected according to the interaction of time messages inside and outside the system. According to the master clock election mechanism of the wireless, the master clock system role (master system) is selected in units of the system; according to the master clock election mechanism of the wired TSN network, the master clock role (master device) within the master system is selected, and the master device of the master system is the master clock device of the entire network.

[0045] S3. In the wired network within the converged network system, the TSN technology is adopted to achieve deterministic transmission of periodic and aperiodic data: for the periodic data stream, time-aware queues in accordance with the IEEE 802.1Qbv specification are used for time slot division and transmission; for the aperiodic data stream, queues and forwarding protocols in accordance with the IEEE 802.1Qav specification are adopted to achieve bandwidth reservation transmission; for the scenario of mixed transmission of periodic and aperiodic traffic flows, different types of traffic flows and different-priority traffic flows of the same type within the TSN network of the system are arranged in different time slots to ensure that there are no time slot conflicts among the traffic flows, so as to ensure the delay determinacy of each data stream under the coexistence of services.

[0046] Figure 4 The TSN time slot division situation of the mixed transmission of the periodic data stream and the aperiodic data stream in the wired network described by the method of the present invention is shown. The following steps are included:

[0047] S31. In the system, a wired TSN network is adopted to achieve deterministic transmission of periodic and aperiodic data. For the periodic data stream, time-aware queues in accordance with the IEEE 802.1Qbv specification are used for time slot division and transmission; for the aperiodic data stream, queues and forwarding protocols in accordance with the IEEE 802.1Qav specification are adopted to achieve bandwidth reservation transmission; for the scenario of mixed transmission of periodic and aperiodic traffic flows, different types of traffic flows and different-priority traffic flows of the same type within the TSN network of the system are arranged in different time slots to try to ensure that there are no time slot conflicts among the traffic flows, so as to ensure the delay determinacy of each data stream under the coexistence of services.

[0048] S32. TSN performs timing scheduling based on priorities. To meet the requirements of different service types for service quality, it is necessary to perform priority mapping for each service type. The following table shows the corresponding relationship between typical service types and priorities. The larger the priority number, the higher the corresponding priority. As shown in Table 1, in the Ethernet protocol, up to 8 levels of priority queues are supported, but considering hardware resources and costs, sometimes only implementing 4 levels of priority queues can also meet better service quality requirements. The priorities of each service type are arranged from high to low as periodic flow, event-triggered flow Class A, event-triggered flow Class B, and best-effort flow. It should be noted that the frame preemption function can be set to a higher priority as needed to further shorten the transmission delay of the event-triggered flow.

[0049] Table 1 Corresponding relationship table between service types and priorities

[0050] Traffic type Delay jitter range (10Gbps link rate) 8-level priority queue 4-level priority queue Periodic flow <5μs 6，7 3 Event-triggered flow Class A <200μs 4，5 2 Event-triggered flow Class B <5ms 3，2 1 Best-effort flow / 1，0 0

[0051] S33. For the mixed flow transmission, TSN adopts the method of global timing planning to distribute the sending moments of each traffic flow in different time slots, so as to avoid data transmission congestion. The time slot division method of TSN for the mixed flow transmission is asFigure 4 As shown, the specific time slot division process is elaborated in detail in step S4.

[0052] S4. Wireless transmission between converged network systems adopts a dynamic time slot allocation strategy to achieve wireless time slot division and scheduling: The dynamic time slot allocation strategy is adopted to achieve wireless time slot division and scheduling between systems, and the transmission process is divided into a time slot negotiation phase and a data transmission phase. In the time slot negotiation phase, the slave nodes in the network report the data volume in their queues to the master node, and then the master node issues the number of time slots for each slave node according to the reported data volumes of the slave nodes. Then, each node conducts data interaction in the data transmission phase. When the terminal traffic in the network changes, the dynamic time slot allocation algorithm can also dynamically adjust the time slot allocation strategy. When the traffic of a slave node increases or decreases, it will use the idle time slots to report its own traffic situation to the master node, and then the master node recalculates the time slot resources and issues them to each slave node in the next time slot negotiation phase;

[0053] Figure 5 shows the dynamic time slot allocation of wireless network data in the method of the present invention. The specific implementation method is as follows:

[0054] The length of the time slot negotiation phase is T0, and the length of the data transmission phase is T L , and the length of the data transmission phase is determined by the number of slave nodes. Assuming there are n TSN terminal nodes in the system, in order to improve the utilization rate of the bandwidth, the time slot unit length T P of the system data transmission phase is divided according to the least common multiple of the time-sensitive data flow periods T n of the slave nodes, and at the same time, it is required that the end-to-end average delay of the system time-sensitive data is as low as possible. Then the length of the data transmission cycle:

[0055]

[0056] Considering that the traffic of different TSN terminals is different, if the division of the T P length is only based on the own traffic of each terminal, due to the large difference in the data lengths of the terminal nodes, the data of the TSN terminal nodes with short data will not be scheduled for a long time, resulting in fragmentation of the time slots. Therefore, the unit length T P of the data transmission phase needs to meet the following conditions:

[0057] 1) Let the transmission rate of data in the wireless link be v, the total amount of time-sensitive data flow in the system be B, and the data flow packet length of the i-th TSN terminal node be The minimum length is The maximum length is Then the T P length satisfies:

[0058]

[0059] 2) The total slot duration should be greater than the actual data transmission time:

[0060]

[0061] 3) Considering the channel delay, the following requirements need to be met:

[0062]

[0063] Through the constraints of the above three conditions, the unit time slot T P length can be determined.

[0064] Specifically, the number of time slots required for the TSN terminal node is:

[0065]

[0066] In step S4, since the wired rate is much greater than the wireless rate, the proportion of the wired transmission time in the time slot can be ignored, and only the wireless rate is considered during the time slot allocation process.

[0067] S5. Unify the time slot allocation and scheduling of the converged network data transmission to achieve low-delay, low-jitter, and congestion-free transmission of key data in the wired and wireless converged network environment: Construct a unified network time slot scheduling method inside and outside the system. By constructing a unified protocol stack, map the wired and wireless protocols, and perform unified time slot allocation and scheduling to enable key data in the wired and wireless converged network environment to have low-delay and low-jitter transmission, and at the same time, the data is congestion-free.

[0068] Figure 6 The implementation architecture of the scheduling time slot resource negotiation mechanism of the wired and wireless converged network according to the method of the present invention is shown. The specific implementation method is as follows: The wired and wireless convergence scheduling mechanism includes a time slot resource negotiation mechanism and a flow scheduling strategy. The process of the time slot resource negotiation mechanism is as follows:

[0069] 1) Terminals that need to execute tasks inside multiple converged network systems report information such as their traffic volume, transmission period, source MAC, and destination MAC to the network control and management module of the master node;

[0070] 2) The flow scheduling strategy analyzes and models the relationship between the wired and wireless link resources and the terminal delay, constructs an optimization target with the minimum average end-to-end delay of the time-sensitive services in the whole network, and solves the mapping parameters of TSN Qav and Qbv;

[0071] 3) The network control and management module of the master node distributes the scheduling strategy (i.e., the mapping parameters of TSN Qav and Qbv) to each TSN terminal.

[0072] 4) The TSN devices perform data transmission in their respective time slot resources.

[0073] Figure 7 The figure shows the schematic diagram of the time slot distribution after the network control and management module calculates under the wired and wireless integrated transmission described by the method of the present invention. Considering the wireless resources in the network, the main process of global time slot division is as follows:

[0074] 1) During the idle period of wireless data transmission, the master system sends a link negotiation frame, and each node follows Figure 4 the shown architecture to upload the service information to be transmitted and the network status.

[0075] 2) The master system characterizes the wireless time slots for the time-sensitive terminals on the wired side within each system.

[0076] 3) According to the wireless time boundary, the wired transmission time is characterized. When the wireless time slots are characterized, since the TSN Qbv scheduling mechanism is adopted on the wired side, it can ensure that the time-sensitive services within the system reach the output port of the system deterministically. At this time, the position of the gating list on the wired side can be characterized by the position of the wireless time slots, so that the time-sensitive traffic does not need to generate queuing delay and only queues in the node's own cache queue. Moreover, each node can be allocated a time slot within the transmission cycle to schedule the time-sensitive data packets out. Therefore, the node internal queue only needs to cache the data packets within the current cycle.

[0077] Due to the deterministic low-latency requirement of TSN data, the boundary characterization of wireless time slots needs to consider the data volume of the TSN terminal nodes and the latency of data transmission to the wireless output port. These information are calculated internally by the corresponding TSN terminal nodes and then reported to the convergence gateway. In this implementation process, the TSN terminal nodes need to calculate the switch time of the gating list time slots at the output port according to the data generation time plus the latency time of data transmission to the wireless output port.

[0078] Let the TSN terminal node D i The data volume of a certain TSN data stream of The wired transmission rate within the system is v1. Then the transmission latency of data passing through a node (terminals, switches, and gateways within system 1 or 2 can all be called nodes) is:

[0079]

[0080] Let the number of data bytes that each TSN node can process per unit time be Then the data processing latency of data within the node is:

[0081]

[0082] Let the terminal D i pass through nodes to reach the wireless output port. Then, for the terminal D i the data volume size is the link delay of the data stream reaching the wireless output port is as follows:

[0083]

[0084] For the wired TSN nodes passed through in the data transmission process, the calculation process of the wired time slot gating switch moment is as follows:

[0085] Let the terminal D i generate a data volume size of with a period of Then, the time slot gating opening moment of the k-th node in the data transmission process is as follows:

[0086]

[0087] The time slot gating closing moment is as follows:

[0088]

[0089] When the data is sent to the wireless port, the calculation process of the wireless time slot gating switch moment is as follows:

[0090] The wireless port is the interface for the node data to send to the fusion gateway. The wireless terminal node needs to request the corresponding time slot sending start position and time length Then:

[0091]

[0092] 4) The nodes inside each system trigger an interrupt at the sending moment. The application software inside the node calls the data sending interface function of the unified network protocol stack in the interrupt callback function to send service data.

[0093] 5) The system acting as the data receiving end receives the data in the receiving time slot and transmits the data to the destination TSN terminal through the TSN network inside the system.

[0094] Those of ordinary skill in the art will realize that the embodiments described herein are provided to assist the reader in understanding the principles of the present invention, and it should be understood that the scope of protection of the present invention is not limited to such specific statements and embodiments. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention shall be included within the scope of the claims of the present invention.

Claims

1. A low-latency communication method based on unified wired and wireless time slot scheduling, characterized in that: The application scenario includes multiple systems, each of which includes a TSN switch, a converged gateway, and multiple TSN devices. The system uses wired transmission for communication, and the systems use wireless transmission for communication through their respective converged gateways. These multiple systems are recorded as a converged network system, one of the TSN devices in the converged network system is used as the master node, and the other TSN devices are used as slave nodes; Inside the converged network system: the application layer and network layer are deployed on the TSN terminal, and the data link layer and physical layer are deployed in the converged gateway; The application layer includes a programming interface and a network control management module. The source address and destination address of the information flow are set in the programming interface of the application layer, and the QoS feature identifier is added; the network control management module is used to plan the number and location of time slots of each node; The network layer uses the IP layer of the TCP / IP protocol stack to implement routing forwarding protocols based on IP addresses and maintain dynamic and static routing tables; The data link layer implements unified timing scheduling based on TSN, wired-wireless protocol mapping, and autonomous sending and receiving of link negotiation frames; The physical layer implements the transmission and reception of wireless links, which is achieved through wireless modules; The TSN device that needs to perform tasks reports its service flow information to the network control management module of the master node; The network control management module of the master node divides the time slots according to the reported service flow information of each TSN device that needs to perform tasks; Each TSN device that needs to perform a task transmits data in its own time slot resource.

2. A low-latency communication method based on wired and wireless unified time slot scheduling according to claim 1, characterized in that: It also includes unifying the time base of the integrated network system to achieve system time synchronization; specifically: achieving time synchronization of the wired network within the system through TSN message interaction; based on the interaction of time messages inside and outside the system, according to the master clock election mechanism of wireless transmission, electing the master clock system as the benchmark, and using the TSN equipment of the master clock system as the master node.

3. A low-latency communication method based on wired and wireless unified time slot scheduling according to claim 1, characterized in that: Business flows are divided into periodic data flows and non-periodic data flows. Non-periodic data flows include event-triggered flows Class A, event-triggered flows Class B, and best-effort flows. Each system performs time scheduling based on the priority of each service flow; The priority order from high to low is periodic flow, event-triggered flow Class A, event-triggered flow Class B, and best-effort flow.

4. A low-latency communication method based on wired and wireless unified time slot scheduling according to claim 3, characterized in that: Within each system, periodic data flows use the time-aware queues of the IEEE 802.1Qbv specification for time slot division and transmission; for non-periodic data flows, the queues and forwarding protocols of the IEEE 802.1Qav specification are used to implement bandwidth reservation transmission.

5. A low-latency communication method based on wired and wireless unified time slot scheduling according to claim 4, characterized in that: Within each system, periodic data streams are transmitted in odd-numbered time slots, and non-periodic data streams are transmitted in even-numbered time slots.

6. A low-latency communication method based on wired and wireless unified time slot scheduling according to claim 5, characterized in that: The converged network system adopts a dynamic time slot allocation strategy. The specific implementation process is as follows: The data transmission process is divided into the time slot negotiation phase and the data transmission phase. In the time slot negotiation phase, the slave nodes in the fusion network system report the amount of data in the queue to the master node, and then the master node sends the number of time slots to each slave node according to the amount of data reported by each slave node. Then, each node interacts with data in the data transmission phase. Set the length of the time slot negotiation phase to T0 and the length of the data transmission phase to T L , assuming that there are n TSN terminals in the system, the time slot unit length T in the data transmission phase P According to the time-sensitive data flow period T of the slave node n The lowest common multiple of the system is divided, and the average end-to-end delay of system time-sensitive data is required As low as possible; then T L The calculation formula is: The unit length T of the data transmission phase P , the following conditions must be met: 1) Assume that the data transmission rate in the wireless link is v, the total amount of time-sensitive data flow in the system is B, and the data flow packet length of the i-th TSN terminal is Minimum length is Maximum length is Then T P Length meets: 2) The total time slot duration must be greater than the actual data transmission time: 3) Considering the minimum channel delay: By constraining the above three conditions, we can get the unit time slot T P Length; Then the number of time slots required by the i-th TNS terminal that needs to perform the task is for:

7. A low-latency communication method based on wired and wireless unified time slot scheduling according to claim 6, characterized in that: It also includes the calculation of wired transmission time slot gating time and wireless transmission time slot gating time; the calculation process is: Assume that TSN terminal node D i The data volume of a certain TSN data stream is The wired transmission rate in the system is v1, so the transmission delay of data passing through a node is for: Assume that the number of data bytes that each TSN node can process per unit time is Then the data processing delay within the node for: Assume terminal D i go through Nodes arrive at the wireless output port, then terminal D i The data size is The link delay of the data stream reaching the wireless output port for: For the wired TSN nodes that the data transmission process passes through, the calculation process of the wired time slot gating switch time is as follows: Assume terminal D i The amount of data generated is The period is The time slot gating opening time of the kth node during data transmission is for: Time slot gate closing time for: When data is sent to the wireless port, the calculation process of the wireless time slot gating switch moment is as follows: The wireless port is the interface for node data to be sent to the fusion gateway. The wireless terminal node needs to request the corresponding time slot to send the starting point position from the fusion gateway. and duration but:

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