WO2025025388A1 - Delay guarantee method for cloud plc service in 5g-tsn architecture - Google Patents

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 5G-TSN architecture Technical Field

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

The collaboration and integration of 5G and the Industrial Internet has become a hot topic in current academic research. 5G has low-latency and high-reliability 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 guarantees are the basis for the security and controllability of their systems. Therefore, how to achieve collaborative transmission of 5G and TSN to enhance the deterministic bearer capacity of the 5G system has become a key technical issue in the core links of 5G's deep empowerment of the industry.

Time Sensitive Networking (TSN) is a series of standard specifications formed by the IEEE802.1 working group based on standard Ethernet for layer 2 technology enhancements such as time synchronization, resource management, traffic shaping, and network configuration. At the technical level, TSN has the ability to determine delay guarantee and unified carrying capacity for multiple services. On the basis of achieving high-precision time synchronization between nodes in the TSN domain, it can not only ensure the boundedness of end-to-end transmission delay and jitter of time-triggered service flows with strong real-time requirements, but also achieve "one-network transmission" for non-real-time services and best-effort services. At the networking level, TSN is compatible with standard Ethernet protocols, and can achieve collaboration with heterogeneous industrial field communication protocols, and is forward compatible with the coexistence of heterogeneous field communication protocols. However, with the deployment of a large number of 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 difficult to meet the terminal access and data transmission needs of smart factories. The integration and collaboration of 5G and TSN is not only the demand for 5G to extend to the industrial field, but also the driver of the endogenous demand of smart factories.

At present, the IT and OT fields have proposed the concept of cloud PLC, that is, a programmable controller running in the cloud. By standardizing the IoT interface and clouding the application, the software-defined PLC is directly connected to the industrial Internet platform to achieve remote control of the 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, the cloud PLC can be deployed on the MEC server in the industrial park, and the 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 edge computing capabilities to 5G CU, implement the 5G CU protocol stack on a general-purpose architecture server, integrate the diversion function, and deploy cloud PLC to achieve industrial control business data diversion in 5G CU, further shortening the communication link between cloud PLC and industrial field controlled equipment. 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 condition of multi-service carrying has become the key to carrying cloud PLC services under the 5G-TSN architecture. How to reliably transmit in the 5G-TSN network has become the main problem faced by cloud PLC devices based on 5G-TSN.

Summary of the invention

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 equipment terminals. Cloud-based PLC services are given priority resource allocation at the wireless air interface. In a multi-service mixed transmission scenario, the proposed algorithm can obtain lower delay than an algorithm that does not provide guarantees. 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.

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

A latency guarantee method for cloud-based PLC services under a 5G-TSN architecture includes the following contents:

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 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 _pi . The number of data packets is used to count the amount of queue data, and the number of data packets is

(2) Feedback of wireless channel quality: 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 obtained as AMC _i , the more AMC _i there are, the better the quality of the feedback wireless channel is;

(3) Calculate the required wireless resources: According to the wireless channel quality of different cloud-based PLC industrial control service flows, the number of RBs required to carry p _i data packets is obtained. 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. Where 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.

Furthermore, 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.

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 export port.

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.

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 service flows with the same priority. The smaller the delay requirement value, the faster the data of the service flow. The grouping is at the front.

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

1) Reduce the latency of 5G networks, reduce the number of intermediate cables and equipment, and expand the mobility range of equipment terminals;

2) 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 latency than the algorithm that does not provide guarantees;

3) The 5G-TSN network carries multiple services simultaneously and provides latency determinism guarantee for industrial control services, reducing the deployment complexity of industrial site networks.

BRIEF DESCRIPTION OF THE DRAWINGS

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

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.

FIG3 is a delay diagram of the method provided by the present invention and other non-guaranteed methods for Yunhua PLC services.

DETAILED DESCRIPTION

The specific implementation of the present invention will be further described below in conjunction with the accompanying drawings:

See Figure 1, which is a 5G-TSN architecture diagram for cloud-based PLC services of the present invention. The present invention provides a delay guarantee 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, a user terminal UE, and a device-side TSN converter. There are multiple different user terminals in the network, corresponding to different service types. Cloud-based PLC, video services, and other data services are connected to the 5G core network through the user plane function UPF, and the network-side TSN converter NW-TT is used to access the 5G core network. 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.

The present invention provides a delay guarantee method for cloud-based PLC services under a 5G-TSN architecture, comprising the following contents:

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 different service flows according to the flow ID, and maps different service flows to different queues according to priority. For example, the industrial control service flow of the cloud PLC is mapped to the priority queue Q0, and the video service and other mobile service flows with real-time requirements are mapped to the priority queue Q1. Other service flows that do not require latency are mapped to the priority queue Q7. Among them, the Q0 queue is the highest priority queue, and so on. The Q7 queue is the lowest priority queue. The higher the service priority, the smaller the corresponding priority queue number.

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. For queue Q0, data will no longer be queued according to the First In First Out FIFO, but will be queued according to the latency requirement _Di of industrial control service flow i, that is, the smaller _Di , the higher the data packet should be in the queue;

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 give priority to wireless resource scheduling of 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 time 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:

(1) Counting the amount of queue data: 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 . The number of data packets is used to count the amount of queue data, and the number of data packets is

(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 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 . The more AMC _i , the better the feedback 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 number of RBs required to carry p _i data packets is obtained as Among them, _li is the length of the data packet. Therefore, the wireless resources required to transmit m data packets in the current queue are

(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.

Step 1: After passing through the user plane function UPF in the 5G core network, the service data enters the wireless base station side. In order to process different services differently on the air interface, priority tags are given to different service flows according to the characteristics of the service flows. Sign PC, PC values between 0 and 1 are high priority, PC values between 2-4 are medium priority, and PC values between 5-7 are low priority;

Step 2: After the service flow is marked, it enters the base station side and must first be mapped to the service priority. After passing through the network side TSN converter NW-TT, different services will be marked with service priority labels. According to different service priority labels, 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, but queued according to the delay requirements of service flows of the same priority. The smaller the delay requirement value, the data packet of the service flow should be ranked first. In this way, even if the resources cannot fully guarantee the transmission of the high-priority queue, the most urgent service flow can still be guaranteed to transmit data;

Step 3: When allocating wireless resources at 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

Step 3.1: All data packets in the queue will be allocated to the corresponding wireless resources. At this time, the number of wireless resources meets the data packet transmission requirements in 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.

Step 3.2: If The remaining time values of different data packets will be compared and allocated. Where D _i is the required delay 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 it is, the priority will be given to resource allocation until all available wireless resources in the current transmission time interval TT are allocated;

Through this resource allocation method, the same type of industrial control service flow, the higher the time urgency, can get the wireless air interface resource allocation earlier, can ensure the cloud PLC industrial control business to obtain timely transmission.

See Figure 3. Compared with the polling scheduling mechanism, the delay guarantee method for PLC services using the method of the present invention can provide timely wireless resource guarantee for PLC services. Therefore, even with the increase in the number of business flows, the delay change of cloud PLC services does not fluctuate, which reflects 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.

The above embodiments are implemented based on the technical solution of the present invention, and detailed implementation methods and specific operation 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 (5)

A method for ensuring latency of cloud-based PLC services under a 5G-TSN architecture, characterized by comprising the following contents: 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 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 _pi . The number of data packets is used to count the amount of queue data, so the number of data packets is (2) Feedback of wireless channel quality: 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 . The more AMC _i , the better the feedback 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 number of RBs required to carry p _i data packets is obtained. 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 a 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. Where 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. According to a delay guarantee method 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 a 5G+TSN network, and the cloud-based PLC, video services and other data services are transmitted from a server to a client via a 5G-TSN network. According to a delay guarantee method for cloud 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. Cloud 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. According to a delay guarantee method for cloud-based PLC services under a 5G-TSN architecture according to claim 1, it is characterized in that when allocating wireless resources, different service flows are marked with priority tags, and priority tag values of 0 and 1 are high priority, priority tag values of 2, 3 or 4 are medium priority, and priority tag values of 5, 6 or 7 are low priority. According to a delay guarantee method for cloud-based PLC services under a 5G-TSN architecture as described in 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, and the smaller the delay requirement value, the earlier the data packets of the service flow are arranged.