Delay guarantee method for cloud PLC service in 5g-TSN architecture

Abstract

The present invention relates to a delay guarantee method for a cloud PLC service in a 5G-TSN architecture, comprising: adding a service priority mapping function, a priority queue management function and a radio resource scheduling function in a 5G-TSN network, wherein a method for priority allocation of radio resources for a cloud PLC industrial control service comprises: collecting statistics about queue data volume, feeding back wireless channel quality, calculating required radio resources and allocating the radio resources. According to the present invention, a 5G network delay is reduced, intermediate cables and devices are reduced, the moving range of a device terminal is expanded, a cloud PLC service is given priority allocation of resources at a radio air interface, and in a multi-service hybrid transmission scenario, the proposed algorithm can obtain lower delay compared with an algorithm which does not provide guarantee. A virtual communication interface is flexibly connected to multiple protocols, multi-manufacturer device interconnection is supported, cloud cooperative control is achieved, the production efficiency is improved, a 5G-TSN network bears multiple services at the same time, delay deterministic guarantee is provided for industrial control services, and the deployment complexity of an industrial field network is reduced.

Description

A latency guarantee method for cloud-based PLC services under the 5G-TSN architecture Technical Field

[0001] The present invention relates to the technical field of collaborative integration of 5G and industrial Internet, and in particular to a latency guarantee method for cloud-based PLC services under a 5G-TSN architecture. Background Art

[0002] The collaboration and integration of 5G and the Industrial Internet has become a hot topic in current academic research. 5G has low-latency and highly reliable connection capabilities. 5G-enabled industry applications have become a common demand of the communications and industrial sectors. However, industrial services have extremely strict requirements on the performance of the bearer network. The factory bearer network not only needs to have low latency, low jitter and high reliability capabilities, but also should have deterministic characteristics. For industrial control systems, deterministic latency guarantee is the basis for the security and controllability of its system. Therefore, how to achieve coordinated transmission of 5G and TSN to enhance the deterministic carrying capacity of the 5G system has become a key technical issue in the deep empowerment of the core links of the industry by 5G.

[0003] Time Sensitive Networking (TSN) is a series of standards and specifications developed by the IEEE 802.1 working group based on standard Ethernet, enhancing Layer 2 technologies such as time synchronization, resource management, traffic shaping, and network configuration. Technically, TSN offers deterministic latency guarantees and the ability to uniformly carry multiple services. By achieving high-precision time synchronization between nodes within a TSN domain, it not only ensures bounded end-to-end transmission latency and jitter for time-triggered services with strong real-time requirements, but also enables single-network transmission of non-real-time and best-effort services. At the networking level, TSN, due to its compatibility with standard Ethernet protocols, can collaborate with heterogeneous industrial field communication protocols and achieve forward compatibility with these protocols. However, with the deployment of numerous sensors in equipment, workshops, and factories, and the widespread use of intelligent terminals such as robotic arms and mobile robots on production lines, wired TSN networks are struggling to meet the terminal access and data transmission requirements of smart factories. The convergence and collaboration of 5G and TSN is not only a requirement for the expansion of 5G into the industrial sector, but also a driving force for the inherent needs of smart factories.

[0004] Currently, the IT and OT fields have proposed the concept of cloud PLC, which is a programmable controller running in the cloud. By standardizing the IoT interface and applying cloud-based applications, software-defined PLC is directly connected to the industrial Internet platform to achieve remote control of cloud PLC. The emergence of cloud PLC makes the deployment location of PLC more flexible, and can realize functions such as rapid creation, flexible migration, and secure backup of industrial control tasks. On the one hand, cloud PLC can be deployed on the MEC server in the industrial park, and industrial control business data can be diverted on the 5G UPF, providing industrial control services for the factory based on the powerful computing power of MEC. On the other hand, cloud PLC can further penetrate the 5G network, sink the edge computing capability to the 5G CU, implement the 5G CU protocol stack on the general architecture server, integrate the diversion function, and deploy cloud PLC. CU realizes the offloading of industrial control business data, further shortening the communication link between cloud PLC and controlled equipment in the industrial field. However, how to ensure the industrial control business data of cloud PLC? In the entire 5G-TSN network, the 5G air interface has the greatest impact on the determinism of data transmission. Due to the shortage of 5G air interface resources, how to provide reliable latency guarantee for industrial control services under the conditions of multi-service carrying has become the key to carrying cloud PLC services under the 5G-TSN architecture. How to ensure reliable transmission in the 5G-TSN network has become the main problem facing cloud PLC devices based on 5G-TSN.

[0005] Summary of the Invention

[0006] The present invention provides a delay guarantee method for cloud-based PLC services under the 5G-TSN architecture, which reduces the 5G network delay, reduces intermediate cables and equipment, and expands the mobility range of device terminals. Cloud-based PLC services are given priority resource allocation on the wireless air interface. In the scenario of multi-service mixed transmission, the proposed algorithm can achieve lower delay than the algorithm that does not provide guarantee. The 5G-TSN network carries multiple services simultaneously and provides delay determinism guarantee for industrial control services, reducing the deployment complexity of industrial field networks.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] A latency assurance method for cloud-based PLC services in a 5G-TSN architecture includes the following:

[0009] 1) Set up a service priority mapping function module in the 5G-TSN network: When different service flows arrive at the base station, the base station first identifies the different service flows based on the flow ID and maps them to different queues according to their priority;

[0010] 2) Set up a priority queue management function module in the 5G-TSN network: Queuing is performed based on the latency requirements of industrial control service flows. The lower the latency requirement, the higher the data packet is placed in the queue. Among industrial control service flows with different scan cycles and latency requirements, those with shorter scan cycles and shorter latency requirements are prioritized. For other priority queues, the FIFO rule is used for queuing.

[0011] 3) Setting up a wireless resource scheduling function module in the 5G-TSN network. The wireless resource priority allocation method for cloud-based PLC industrial control services includes the following steps:

[0012] (1) Counting the queue data volume: The number of cloud-based PLC industrial control business flows involved in the current queue is n, and the number of data packets corresponding to the same type of industrial control business flow i is p. i , using the number of data packets to count the amount of queue data, we have the number of data packets

[0013] (2) Feedback on wireless channel quality: The wireless channel quality indicator corresponding to industrial control service flow i is CQI i According to the adaptive modulation and coding rule, the number of bits that each resource block can carry under the wireless channel quality is AMC i , AMC i The more feedback, the better the wireless channel quality;

[0014] (3) Calculate the required wireless resources: According to the wireless channel quality of different cloud-based PLC industrial control service flows, the bearer p i The number of RBs required for a data packet Among them, l i is the length of the data packet, so the number of wireless resources required to transmit m data packets in the current queue can be obtained

[0015] (4) Allocating wireless resources: When allocating wireless resources on the air interface, the highest priority queue is allocated first. The total number of wireless resources that can be allocated in the transmission time interval TTI is

[0016] when All packets in the queue will be allocated to the corresponding wireless resources. Only after all packets in the highest priority queue have been allocated resources, wireless resources will be allocated to other queues.

[0017] like The remaining time values ​​of different data packets will be compared and allocated. Among them, Di is the delay requirement value of the data packet, The time value for which the data packet has been waiting will be calculated based on the remaining time value of all data packets in the highest priority queue. Allocate resources and remaining time value The smaller the value is, the higher the priority of resource allocation will be until all current wireless resources are allocated.

[0018] Furthermore, the 5G-TSN architecture for cloud-based PLC services includes cloud-based PLC, video services, other data services, and a 5G+TSN network. The cloud-based PLC, video services, and other data services are transmitted from the server to the client via the 5G-TSN network.

[0019] Furthermore, the 5G+TSN network includes a network-side TSN converter NW-TT, a user plane function UPF, service priority mapping, priority queue management, wireless resource scheduling, a user terminal UE, and a device-side TSN converter. Clouded PLC, video services, and other data services pass through the user plane function UPF and access the 5G core network using the network-side TSN converter NW-TT. Service priority mapping, priority queue management, and wireless resource scheduling transmit the allocated resources to the user terminal UE. The user terminal UE is connected to the device-side TSN converter to provide a TSN egress port.

[0020] Furthermore, when allocating wireless resources, different service flows are marked with priority tags. Priority tags with values ​​of 0 and 1 are high priority, priority tags with values ​​of 2, 3 or 4 are medium priority, and priority tags with values ​​of 5, 6 or 7 are low priority.

[0021] Furthermore, in the allocation of wireless resources, for queues with the same priority, when service flow data with the same priority arrives, they are queued according to the delay requirements of the service flows with the same priority. The smaller the delay requirement value, the higher the data packets of the service flow are ranked.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1) Reduce 5G network latency, reduce intermediate cables and equipment, and expand the mobility range of device terminals;

[0024] 2) Cloud-based PLC services receive priority resource allocation on the wireless air interface. In multi-service mixed transmission scenarios, the proposed algorithm can achieve lower latency than algorithms that do not provide guarantees.

[0025] 3) The 5G-TSN network carries multiple services simultaneously and provides latency determinism guarantees for industrial control services, reducing the deployment complexity of industrial field networks. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] FIG1 is a diagram of the 5G-TSN architecture for cloud-based PLC services according to the present invention.

[0027] FIG2 is a flow chart of wireless resource allocation for different service flows by a base station under the 5G-TSN architecture described in the present invention.

[0028] FIG3 is a time delay diagram of the method provided by the present invention and other non-guaranteed methods for Yunhua PLC services. DETAILED DESCRIPTION

[0029] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings:

[0030] Figure 1 is a diagram of the 5G-TSN architecture for cloud-based PLC services according to the present invention. The present invention provides a latency assurance method for cloud-based PLC services under a 5G-TSN architecture. The 5G-TSN architecture for cloud-based PLC services includes cloud-based PLC, video services, other data services, and a 5G+TSN network. The 5G+TSN network includes a network-side TSN converter (NW-TT), a user plane function (UPF), service priority mapping, priority queue management, wireless resource scheduling, user terminals (UEs), and a device-side TSN converter. The network includes multiple user terminals, each carrying a different service type. Cloud-based PLC, video services, and other data services access the 5G core network via the user plane function (UPF) and the network-side TSN converter (NW-TT). Service priority mapping, priority queue management, and wireless resource scheduling transmit allocated resources to the user terminals (UEs). The user terminals (UEs) are connected to the device-side TSN converter, providing a TSN egress port.

[0031] The present invention provides a method for ensuring latency for cloud-based PLC services under a 5G-TSN architecture, including the following:

[0032] 1) Set up a service priority mapping function module in the 5G-TSN network: Different service flows have different flow IDs to distinguish different services. When different service flows arrive at the base station, the base station first identifies the different service flows based on the flow ID and maps them to different queues according to their priorities. For example, industrial control service flows belonging to cloud PLC are mapped to priority queue Q0, video services and other mobile service flows with real-time requirements are mapped to priority queue Q1, and other service flows without latency requirements are mapped to priority queue Q7. Among them, queue Q0 is the highest priority queue, and queue Q7 is the lowest priority queue. The higher the service priority, the smaller the corresponding priority queue number.

[0033] 2) Set up a priority queue management function module in the 5G-TSN network: Queue according to the latency requirements of industrial control service flows. The smaller the latency requirement, the higher the data packet is in the queue. Among industrial control service flows with different scan cycles and different latency requirements, the industrial control service flows with scan cycles from small to large and latency requirements from high to low are prioritized. For other priority queues, FIFO rules are used for queuing. For queue Q0, data will no longer use First In First Out FIFO, but will be queued according to the latency requirement D of industrial control service flow i. i Queue up, i.e. D i The smaller it is, the higher up in the queue the packet should be placed;

[0034] 3) A wireless resource scheduling function module is set up in the 5G-TSN network to ensure the latency of cloud-based PLC industrial control services and prioritize wireless resource scheduling for the Q0 high-priority queue. Since wireless air interface scheduling is performed according to the transmission time interval (TTI), which is generally 0.5ms or 1ms, wireless air interface resources need to be dynamically scheduled every TTI to meet the transmission requirements of different services. The wireless resource priority allocation method for cloud-based PLC industrial control services includes the following steps:

[0035] (1) Counting the queue data volume: When the number of cloud-based PLC industrial control business flows involved in the current queue Q0 is n, the number of data packets corresponding to the same type of industrial control business flow i is p. i , using the number of data packets to count the amount of queue data, we have the number of data packets

[0036] (2) Feedback on wireless channel quality: Since different cloud-based PLC industrial control service flows are carried by different wireless terminals, when the wireless channel quality indicator corresponding to the industrial control service flow i is CQI i According to the adaptive modulation and coding rule, the number of bits that each resource block can carry under the wireless channel quality is AMC i , AMC i The more feedback, the better the wireless channel quality;

[0037] (3) Calculate the required wireless resources: According to the wireless channel quality of different cloud-based PLC industrial control service flows, the bearer p i The number of RBs required for a data packet is Among them, l i is the length of the data packet, so the wireless resources required to transmit m data packets in the current queue are

[0038] (4) Allocating wireless resources: The wireless resource guarantee process for high-priority cloud-based PLC and other industrial control services is shown in Figure 2.

[0039] Step 1: After passing through the user plane function (UPF) in the 5G core network, service data enters the wireless base station side. In order to process different services differently on the air interface, different service flows are marked with priority tags (PC) based on their characteristics. PC values ​​between 0 and 1 are high priority, PC values ​​between 2 and 4 are medium priority, and PC values ​​between 5 and 7 are low priority.

[0040] Step 2: After the service flow is marked, it enters the base station side and first undergoes service priority mapping. After passing through the network-side TSN converter NW-TT, different services will be marked with service priority identifiers. Based on the different service priority identifiers, different service flows will be mapped to different queues on the base station side. The higher the queue number, the lower its priority. For high-priority queues, when service flow data of the same priority arrives, the first-in-first-out (FIFO) rule is not adopted. Instead, it is queued according to the latency requirements of service flows of the same priority. The smaller the latency requirement value, the data packet of the service flow should be ranked first. This ensures that even if resources cannot fully guarantee the transmission of the high-priority queue, the most urgent service flow can still be guaranteed to transmit data;

[0041] Step 3: When allocating wireless resources on the air interface, queue Q0 will be allocated first. Since the queuing mechanism used by queue Q0 is arranged according to the service delay requirements, the data packets with higher delay requirements will be allocated resources earlier. Assume that the total number of wireless resources that can be allocated in the current transmission time interval TTI is

[0042] Step 3.1: When All packets in the queue will be allocated to the corresponding wireless resources. At this time, the number of wireless resources meets the packet transmission requirements of the high-priority queue Q0. After allocating resources to the high-priority queue, resources will be allocated to the medium-priority and low-priority queues.

[0043] Step 3.2: If The remaining time values ​​of different data packets will be compared and allocated. Among them, D i is the delay requirement value of the data packet, is the time value that the data packet has been waiting for, Including the transmission time, waiting time and processing time in the non-air interface part, the remaining time of all packets in queue Q0 will be calculated. Allocate resources and remaining time value The smaller the value, the higher the priority of resource allocation will be, until all available radio resources in the current transmission time interval TT are allocated;

[0044] Through this resource allocation method, the more urgent the time of the same type of industrial control business flow, the earlier the wireless air interface resources can be allocated, which can ensure the timely transmission of cloud-based PLC industrial control services.

[0045] As shown in Figure 3, the delay guarantee method for PLC services using the method of the present invention is compared with the polling scheduling mechanism. Since the mechanism proposed by the present invention can provide timely wireless resource guarantee for PLC services, even with the increase in the number of business flows, the delay change of cloud PLC services does not fluctuate, reflecting the delay determinism of the method of the present invention. The delay of the polling scheduling mechanism increases with the increase in the number of business flows, and cannot provide service quality guarantee for cloud PLC under multi-business transmission conditions.

[0046] The above embodiments are implemented under the premise of the technical solution of the present invention, and detailed implementation methods and specific operating processes are given, but the protection scope of the present invention is not limited to the above embodiments. The methods used in the above embodiments are conventional methods unless otherwise specified.

Claims

1. A latency guarantee method for cloud-based PLC services under a 5G-TSN architecture, characterized in that: Includes the following: 1) Set up a service priority mapping function module in the 5G-TSN network: When different service flows arrive at the base station, the base station first identifies different service flows according to the flow ID and maps different service flows to different queues according to their priorities; 2) Set up a priority queue management function module in the 5G-TSN network: Queue according to the latency requirements of industrial control service flows. The smaller the latency requirement, the higher the data packet is in the queue. Among industrial control service flows with different scanning cycles and different latency requirements, the industrial control service flows with scanning cycles from small to large and latency requirements from high to low are prioritized. For other priority queues, the FIFO rule is used for queuing; 3) A wireless resource scheduling function module is set in the 5G-TSN network. The wireless resource priority allocation method for cloud-based PLC industrial control services includes the following steps: (1) Counting the amount of queue data: The number of cloud-based PLC industrial control service flows involved in the current queue is n, and the number of data packets corresponding to the same type of industrial control service flow i is p. i , using the number of packets to count the amount of queue data, the number of packets (2) Feedback of wireless channel quality: The wireless channel quality indicator corresponding to industrial control service flow i is CQI i According to the adaptive modulation and coding rule, the number of bits that each resource block can carry under the wireless channel quality is AMC i , AMC i The more feedback, the better the wireless channel quality; (3) Calculate the required wireless resources: According to the wireless channel quality of different cloud-based PLC industrial control service flows, the bearer p i The number of RBs required for a data packet Among them, l i is the length of the data packet, so the number of wireless resources required to transmit m data packets in the current queue can be obtained (4) Allocating wireless resources: When allocating wireless resources on the air interface, the highest priority queue is allocated first. The total number of wireless resources that can be allocated in the transmission time interval TTI is when Then all packets in the queue will be allocated to the corresponding wireless resources. Only after all packets in the highest priority queue have been allocated resources, wireless resources will be allocated to other queues. like The remaining time values ​​of different data packets will be compared and allocated. Among them, D i is the required delay value of the data packet, The time value for which the packet has been waiting will be calculated based on the remaining time value of all packets in the highest priority queue. Allocate resources and remaining time value The smaller it is, the priority will be given to resource allocation until all current wireless resources are allocated.

2. According to a method for delay guarantee for cloud-based PLC services under a 5G-TSN architecture according to claim 1, it is characterized in that: The 5G-TSN architecture for cloud-based PLC services includes cloud-based PLC, video services, other data services and 5G+TSN network. The cloud-based PLC, video services and other data services are transmitted from the server to the client via the 5G-TSN network.

3. According to a method for delay guarantee for cloud-based PLC services under a 5G-TSN architecture according to claim 1, it is characterized in that: The 5G+TSN network includes a network-side TSN converter NW-TT, a user plane function UPF, service priority mapping, priority queue management, wireless resource scheduling, a user terminal UE and a device-side TSN converter. Clouded PLC, video services and other data services pass through the user plane function UPF and access the 5G core network using the network-side TSN converter NW-TT. Service priority mapping, priority queue management and wireless resource scheduling transmit the allocated resources to the user terminal UE. The user terminal UE is connected to the device-side TSN converter to provide a TSN export port.

4. According to claim 1, a latency guarantee method for cloud-based PLC services under a 5G-TSN architecture is characterized in that: When allocating wireless resources, different service flows are marked with priority tags. Priority tags with values ​​of 0 and 1 are high priority, priority tags with values ​​of 2, 3 or 4 are medium priority, and priority tags with values ​​of 5, 6 or 7 are low priority.

5. According to a method for delay guarantee for cloud-based PLC services under a 5G-TSN architecture according to claim 1, it is characterized in that: In the allocation of wireless resources, for queues with the same priority, when service flow data with the same priority arrives, they are queued according to the delay requirements of the service flows with the same priority. The smaller the delay requirement value, the earlier the data packets of the service flow are ranked.

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