Latency Guarantee Method for Cloud-Based PLC Services in 5G-TSN Architecture

Abstract

The present invention provides a latency guarantee method for cloud-based PLC services in a 5G-TSN architecture. This method adds service priority mapping, priority queue management, and wireless resource scheduling functions to the 5G-TSN network. The method prioritizes wireless resource allocation for cloud-based PLC industrial control services, including queue data volume statistics, wireless channel quality feedback, required wireless resource calculation, and wireless resource allocation. This reduces 5G network latency, reduces intermediate cables and devices, and expands the mobility range of device terminals. Because cloud-based PLC services prioritize resource allocation in the wireless air interface, the proposed algorithm can achieve lower latency than algorithms that do not provide guarantees when multiple services are transmitted simultaneously. The virtual communication interface flexibly connects to various protocols, supporting the interconnection of devices from multiple manufacturers, enabling cooperative control on the cloud and improving production efficiency. The 5G-TSN network guarantees latency determinism for industrial control services while simultaneously transmitting multiple services, reducing the complexity of network installation in industrial sites.

Description

[Technical Field]

[0001] The present invention relates to the technical field of collaboration and integration between 5G and the industrial Internet, and in particular to a method for guaranteeing delay for cloud-based PLC services in a 5G-TSN architecture. [Background technology]

[0002] The integration and collaboration of 5G and the industrial Internet has become a hot topic of academic research. Because 5G offers low-latency and highly reliable connection capabilities, 5G's enhancements to industrial applications are highly sought after by both the telecommunications and industrial sectors. However, industrial services place extremely stringent performance requirements on bearer networks. Factory bearer networks require not only low latency, low jitter, and high reliability, but also determinism. For industrial control systems, deterministic delay guarantees are the foundation for system safety and controllability. Therefore, the technical challenge of how to achieve cooperative transmission between 5G and TSN to improve the deterministic transmission capabilities of 5G systems is crucial for the deep enhancement of 5G to industrial core links.

[0003] Time Sensitive Networking (TSN) is a set of standards established by the IEEE 802.1 Working Group to enhance Layer 2 technologies, such as time synchronization, resource management, traffic shaping, and network configuration, based on standard Ethernet. TSN boasts deterministic latency guarantees and integrated multi-service transmission capabilities. By achieving high-precision time synchronization between nodes within the TSN domain, TSN can guarantee end-to-end transmission latency and jitter bounds for time-triggered service flows with strict real-time requirements, while also enabling "one-network transmission" for non-real-time and best-effort services. TSN's compatibility with standard Ethernet protocols allows it to interoperate with heterogeneous industrial field communication protocols, ensuring their coexistence and forward compatibility. However, with the increasing adoption 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 finding it difficult to meet the terminal access and data transmission needs of smart factories. The convergence and collaboration between 5G and TSN is being driven not only by the need to deploy 5G in the industrial sector, but also by the internal needs of smart factories.

[0004] Currently, the IT and OT fields have proposed the concept of cloudified PLC, a programmable controller that runs on the cloud. Through standardization of IoT interfaces and cloudification of applications, software-defined PLCs can communicate directly with industrial Internet platforms, enabling remote control of the cloudified PLC. The emergence of cloudified PLCs increases flexibility in PLC installation location and enables rapid construction of industrial control tasks, smooth migration, and secure backup. By deploying cloudified PLCs on MEC servers in industrial parks, 5G UPF can be used to offload industrial control service data, leveraging the powerful computing capabilities of MEC to provide industrial control services for factories. Cloudified PLCs can also take advantage of 5G networks to integrate edge computing capabilities into 5G CUs. By implementing the 5G CU protocol stack on a general-purpose server, cloudified PLCs can be installed with offloading functions, enabling industrial control service data offloading to the 5G CUs, further shortening the communication path between the cloudified PLC and controlled devices on the industrial site. On the other hand, to guarantee the data of cloud-based PLC industrial control services, the 5G air interface has the greatest impact on the determinism of data transmission across the entire 5G-TSN network. However, due to the limited resources of the 5G air interface, when multiple services are transmitted simultaneously, how to provide reliable delay guarantees for industrial control services is the key to transmitting cloud-based PLC services in the 5G-TSN architecture. How to ensure reliable transmission in the 5G-TSN network is a major challenge facing cloud-based PLC devices based on 5G-TSN. Summary of the Invention [Problem to be solved by the invention]

[0005] This invention provides a latency guarantee method for cloud-based PLC services in a 5G-TSN architecture, thereby reducing 5G network latency, eliminating intermediate cables and devices, and expanding the mobility range of device terminals. Because cloud-based PLC services receive priority resource allocation in the wireless air interface, the proposed algorithm can achieve lower latency than algorithms that do not provide guarantees when multiple services are transmitted simultaneously. 5G-TSN networks can guarantee latency determinism for industrial control services while simultaneously transmitting multiple services, reducing the complexity of network installation in industrial sites. [Means for solving the problem]

[0006] In order to achieve the above object, the present invention employs the following technical means. A method for guaranteeing delay for cloud-based PLC services in a 5G-TSN architecture, comprising: 4) A service priority mapping function module is provided 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 stream ID, and then maps the different service flows to different queues according to their priorities; 5) A priority queue management function module is provided in the 5G-TSN network, and queuing is performed according to the delay requirement of the industrial control service flow, and the smaller the delay requirement, the higher the data packet is placed in the queue. Among the industrial control service flows with different scanning cycles and different delay requirements, the industrial control service flows with small to large scanning cycles and high to low delay requirements are prioritized, and other priority queues are queued using the FIFO rule; 6) providing a radio resource scheduling function module in the 5G-TSN network; The priority allocation method for wireless resources in cloud-based PLC industrial control services is (4) A step of calculating the data volume of the queue. The number of cloud-based PLC industrial control service flows currently included in the queue is defined as n, and the number of data packets corresponding to the same type of industrial control service flow i is defined as p i If we calculate the amount of data in the queue based on the number of data packets, the number of data packets is

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[0007] Furthermore, the 5G-TSN architecture for cloudified PLC services includes cloudified PLC, video services, other data services and a 5G+TSN network, and the cloudified PLC, video services and other data services are transmitted from the server to the client through the 5G-TSN network.

[0008] Furthermore, the 5G+TSN network includes a network-side TSN converter NW-TT, a user plane function UPF, service priority mapping, priority queue management, radio resource scheduling, a user equipment UE, and a device-side TSN converter, where cloudified PLC, video services, and other data services access the 5G core network using the network-side TSN converter NW-TT via the user plane function UPF, and the allocated resources are sent to the user equipment UE through service priority mapping, priority queue management, and radio resource scheduling, and the user equipment UE is connected to the device-side TSN converter to provide a TSN output port.

[0009] Furthermore, when allocating the wireless resources, priority tags are attached to different service flows, with priority tag values ​​of 0 and 1 being high priority, priority tag values ​​of 2, 3 or 4 being medium priority, and priority tag values ​​of 5, 6 or 7 being low priority.

[0010] Furthermore, in allocating the wireless resources, when service flow data of the same priority arrives in queues of the same priority, queuing is performed according to the delay request of the service flows of the same priority such that the smaller the value of the delay request, the higher the service flow data is placed. [Effects of the Invention]

[0011] The present invention has the following advantageous effects compared to the prior art. 1) 5G networks reduce latency, eliminate intermediate cables and devices, and expand the range of device terminal movement. 2) Cloud-based PLC services are given priority in resource allocation in the wireless air interface, so when multiple services are transmitted together, the proposed algorithm can achieve lower delay than algorithms that do not provide guarantees. 3) 5G-TSN networks can simultaneously transmit multiple services while guaranteeing deterministic latency for industrial control services, reducing the complexity of network installation in industrial sites. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a diagram of a 5G-TSN architecture for cloudified PLC services according to the present invention. [Figure 2] 1 is a flowchart illustrating a base station allocating radio resources to different service flows in the 5G-TSN architecture according to the present invention. [Figure 3] FIG. 10 is a diagram showing the delay to the cloud-based PLC service according to the method provided by the present invention and other non-guaranteed methods. DETAILED DESCRIPTION OF THE INVENTION

[0013] Specific embodiments of the present invention will be further described below with reference to the drawings. FIG. 1 is a diagram of a 5G-TSN architecture for cloudified PLC services according to the present invention. In the method for providing latency guarantee for cloudified PLC services in the 5G-TSN architecture according to the present invention, the 5G-TSN architecture for cloudified PLC services includes cloudified 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, radio resource scheduling, a user equipment (UE), and a device-side TSN converter. There are multiple different user equipments in the network, each carrying different types of services. The cloudified PLC, video services, and other data services access the 5G core network using the network-side TSN converter (NW-TT) via the user plane function (UPF). The allocated resources are transmitted to the user equipment (UE) through service priority mapping, priority queue management, and radio resource scheduling. The user equipment (UE) is connected to the device-side TSN converter to provide a TSN output port.

[0014] The method for guaranteeing delay for cloud-based PLC services in the 5G-TSN architecture according to the present invention includes the following: 1) A service priority mapping function module is provided in the 5G-TSN network. Different service flows have different stream IDs to distinguish between different services. When different service flows arrive at the base station, the base station first identifies the different service flows based on the stream IDs and then maps them to different queues according to their priorities. For example, industrial control service flows, including cloud-based PLCs, are mapped to the Q0 priority queue, video service and other mobile service flows with real-time requirements are mapped to the Q1 priority queue, and other service flows without latency requirements are mapped to the Q7 priority queue. Here, the Q0 queue is the highest priority queue, and by analogy, the Q7 queue is the lowest priority queue. The higher the service priority, the smaller the corresponding priority queue number.

[0015] 2) A priority queue management function module is provided in the 5G-TSN network. Queueing is performed according to the delay requirement of the industrial control service flow, with data packets being placed at the top of the queue as the delay requirement decreases. Among industrial control service flows with different scan cycles and delay requirements, priority is given to industrial control service flows with scan cycles ranging from small to large and delay requirements ranging from high to low. For other priority queues, queuing is performed using the FIFO rule. For the Q0 queue, first-in, first-out (FIFO) data is not used, but rather the delay requirement D of industrial control service flow i is used. i Queueing is performed according to the D i The smaller the value, the higher the data packet is placed in the queue.

[0016] 3) To guarantee the latency of cloud-based PLC industrial control services, a radio resource scheduling function module is installed in the 5G-TSN network. Radio resource scheduling for the high-priority Q0 queue is guaranteed preferentially. Radio air interface scheduling is performed every transmission time interval (TTI). TTI is usually 0.5 ms or 1 ms. That is, to meet the transmission needs of different services, radio air interface resources are dynamically scheduled once per TTI. The method for prioritizing radio resource allocation for cloud-based PLC industrial control services includes the following steps:

[0017] (1) Calculate the data volume of the queue. Let n be the number of cloud-based PLC industrial control service flows in the current Q0 queue, and let p be the number of data packets corresponding to the same type of industrial control service flow i. i If we calculate the amount of data in the queue based on the number of data packets, the number of data packets is

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[0018] (2) Feed back the quality of the wireless channel. Since different cloud-based PLC industrial control service flows are supported by different wireless terminals, the quality of the wireless channel corresponding to industrial control service flow i is calculated as CQI i When the quality of the wireless channel is such that the number of bits that each resource block can transmit is determined by adaptive modulation and coding (AMC), i AMC i The higher the number of QoS, the better the quality of the wireless channel will be.

[0019] (3) Calculate the required wireless resources according to the quality of the wireless channels for different cloud-based PLC industrial control service flows. i The number of RBs required to transmit a data packet

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[0020] (4) Allocate wireless resources. Figure 2 shows a flowchart for allocating wireless resources to high-priority industrial control services such as cloud-based PLC.

[0021] Step 1. Service data passes through the user plane function (UPF) in the 5G core network and enters the radio base station. To handle different services differently across the air interface, different service flows are assigned priority tags (PC) according to their characteristics. PC values ​​of 0 and 1 represent high priority, PC values ​​of 2 to 4 represent medium priority, and PC values ​​of 5 to 7 represent low priority.

[0022] Step 2. After being tagged, the service flow enters the base station and first undergoes service priority mapping. After passing through the network-side TSN converter NW-TT, different services are assigned service priority tags. The base station maps different service flows to different queues according to their different service priority tags. The higher the queue number, the lower the priority. For high-priority queues, when service flow data of the same priority arrives, the queueing is performed according to the delay requirements of service flows of the same priority, without adopting the first-in, first-out (FIFO) rule. The smaller the delay requirement value, the higher the service flow data is placed. This ensures the data transmission of the most urgent service flow, even if there are insufficient resources to guarantee the transmission of high-priority queues.

[0023] Step 3. When allocating radio resources on the air interface, the Q0 queue is the first to be allocated. The Q0 queue employs a queuing mechanism that queues resources according to the delay requirements of the service, so resources are allocated preferentially to data packets with high delay requirements. The total number of radio resources that can be allocated within the current transmission time interval (TTI) is

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[0024] Step 3.1.

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[0026] With this resource allocation method, for the same type of industrial control service flow, the higher the time urgency, the earlier the wireless air interface resources are allocated, thereby ensuring the timely transmission of cloud-based PLC industrial control services.

[0027] Referring to Figure 3, the delay guarantee method for PLC services according to the present invention is compared with the round robin method. The method proposed in the present invention can provide timely wireless resource guarantees for PLC services, so the delay change of cloud-based PLC services does not fluctuate even when the number of service flows increases, demonstrating the delay determinism of the method according to the present invention. On the other hand, the delay of the round robin method increases as the number of service flows increases, and it cannot provide service quality guarantees for cloud-based PLC when multiple services are transmitted.

[0028] The above-described embodiments are implemented based on the technical solutions of the present invention, and provide detailed embodiments and specific operation procedures, but do not limit the scope of protection of the present invention. The methods used in the above-described embodiments are conventional methods unless otherwise specified.

Claims

1. A method for guaranteeing delay to cloud-based PLC services in a 5G-TSN architecture, comprising: 1) providing a service priority mapping function module in the 5G-TSN network, such that when different service flows arrive at a base station, the base station first identifies different service flows based on stream IDs, and maps the different service flows to different queues according to their priorities; 2) A priority queue management function module is provided in the 5G-TSN network, and queuing is performed according to the delay requirements of the industrial control service flows, and the smaller the delay requirement, the higher the data packet is placed in the queue. Among the industrial control service flows with different scanning cycles and different delay requirements, the industrial control service flows with small to large scanning cycles and high to low delay requirements are prioritized, and other priority queues are queued using the FIFO rule; 3) providing a radio resource scheduling function module in the 5G-TSN network; The priority allocation method for wireless resources for cloud-based PLC industrial control services is as follows: (1) A step of collecting statistics on the amount of data in the queue. The number of cloud-based PLC industrial control service flows currently included in the queue is n, and the number of data packets corresponding to the same type of industrial control service flow i is p i If we calculate the amount of data in the queue based on the number of data packets, the number of data packets is [Equation 1] and (2) A step of feedbacking the quality of the wireless channel, in which the quality of the wireless channel corresponding to the industrial control service flow i is expressed as CQI i and adaptive modulation and coding determines the number of bits that each resource block can transmit under the quality of the wireless channel. i AMC i feedback that the more the quality of the wireless channel is, the better the quality of the wireless channel is; (3) calculating the required wireless resources according to the quality of the wireless channels of different cloud-based PLC industrial control service flows; i Number of RBs required to transmit data packets [Equation 2] (l i is the length of the data packet. ) and thus the number of radio resources required for transmission of the m data packets in the current queue is obtained. [Equation 3] and (4) A step of allocating radio resources, in which when allocating radio resources on the air interface, the allocation is performed for the queue with the highest priority first, and the total number of radio resources that can be allocated within a transmission time interval (TTI) is calculated as follows: [Equation 4] Then, [Equation 5] In this case, allocate appropriate radio resources to all data packets in the queue, such that resources are allocated to all data packets in the highest priority queue before allocating radio resources to other queues; [Equation 6] If , the remaining time values ​​of different data packets [Equation 7] (D i is the delay requirement of the data packet, [Equation 8] is the time value for which the data packet is already waiting.) and allocates it. The remaining time value is calculated until all the current radio resources are allocated. [Equation 9] The remaining time value of all data packets in the highest priority queue is used to allocate resources preferentially to packets with smaller values. [Equation 10] A method for guaranteeing delay to cloud-based PLC services in a 5G-TSN architecture, comprising: allocating resources according to the

2. The method for ensuring delay for cloudified PLC services in a 5G-TSN architecture according to claim 1, wherein the 5G-TSN architecture for cloudified PLC services includes cloudified PLC, video services, other data services, and a 5G+TSN network, and the cloudified PLC, video services, and other data services are transmitted from a server to a client through the 5G-TSN network.

3. 2. The method for ensuring delay for cloudified PLC services in a 5G-TSN architecture according to claim 1, wherein the 5G+TSN network includes a network-side TSN converter NW-TT, a user plane function UPF, service priority mapping, priority queue management, radio resource scheduling, a user equipment UE, and a device-side TSN converter, wherein cloudified PLC, video services, and other data services access the 5G core network using the network-side TSN converter NW-TT via the user plane function UPF, and allocated resources are sent to the user equipment UE through service priority mapping, priority queue management, and radio resource scheduling, and the user equipment UE is connected to the device-side TSN converter to provide a TSN output port.

4. When allocating the radio resources, priority tags are attached to different service flows, and priority tag values ​​of 0 and 1 are assigned to high priority, priority tag values ​​of 2, 3, or 4 are assigned to medium priority, and priority tag values ​​of 5, 6, or 7 are assigned to low priority. This is the delay guarantee method for cloud-based PLC services in a 5G-TSN architecture described in claim 1.

5. The delay guarantee method for cloud-based PLC services in a 5G-TSN architecture according to claim 1, characterized in that, in allocating the wireless resources, when service flow data of the same priority arrives in queues of the same priority, queuing is performed according to the delay requirements of service flows of the same priority, such that the smaller the delay requirement value, the higher the service flow data is placed.

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