JP7821330B2 - Delay guarantee method for cloud-based PLC services in 5G-TSN architecture - Google Patents

Description

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 delays for cloud-based PLC services in a 5G-TSN architecture.

The integration and collaboration between 5G and the industrial Internet is currently a hot topic of academic research. Because 5G offers low-latency and highly reliable connection capabilities, both the telecommunications and industrial sectors are calling for 5G to enhance industrial applications. However, industrial services place extremely stringent performance requirements on bearer networks. Factory bearer networks require low latency, low jitter, and high reliability, as well as determinism. For industrial control systems, deterministic delay guarantees are the foundation of 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.

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. From a technical perspective, TSN offers deterministic delay guarantees and integrated multi-service transmission capabilities. By achieving high-precision time synchronization between nodes within the TSN domain, it can guarantee end-to-end transmission delay and jitter bounds for time-triggered service flows with strong real-time requirements, as well as realize "one-network transmission" for non-real-time and best-effort services. In terms of networking, TSN is compatible with standard Ethernet protocols, enabling integration with heterogeneous industrial field communication protocols and ensuring coexistence and forward compatibility among heterogeneous field communication protocols. However, as more sensors are introduced into equipment, workshops, and factories, and intelligent terminals such as robotic arms and mobile robots are widely used 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 integration of 5G and TSN is being driven not only by the needs of 5G deployment in the industrial sector, but also by the internal needs of smart factories.

Currently, the IT and OT fields have proposed the concept of cloudified PLCs, programmable controllers that run on the cloud. By standardizing IoT interfaces and cloudifying applications, software-defined PLCs can communicate directly with industrial Internet platforms, enabling remote control of cloudified PLCs. 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, providing factory-specific industrial control services based on the powerful computing capabilities of the MEC. Cloudified PLCs can also further leverage 5G networks to integrate edge computing capabilities into 5G CUs. By implementing the 5G CU protocol stack on a general-purpose server, offloading functions can be integrated into cloudified PLCs, enabling industrial control service data offloading on the 5G CUs and further shortening the communication path between the cloudified PLCs and controlled devices on the industrial site. Meanwhile, when it comes to ensuring the data integrity 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, providing reliable latency guarantees for industrial control services when transmitting multiple services simultaneously is key to transmitting cloud-based PLC services in the 5G-TSN architecture. How to ensure reliable transmission across the 5G-TSN network is a major challenge facing cloud-based PLC devices based on 5G-TSN.

The present invention provides a delay 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 guarantee deterministic latency for industrial control services while simultaneously transmitting multiple services, reducing the complexity of network installation in industrial sites.

In order to achieve the above object, the present invention employs the following technical means.
A method for guaranteeing delay to cloud-based PLC services in a 5G-TSN architecture, comprising:
4) providing a service priority mapping function module in the 5G-TSN network, such that when different service flows arrive at the base station, the base station first identifies the different service flows based on stream IDs, and 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 of wireless resources for 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 n, and the number of data packets corresponding to the same type of industrial control service flow i is p _i . When the data volume of the queue is calculated based on the number of data packets, the number of data packets is:
and
(5) a step of feeding back the quality of the wireless channel, in which the quality of the wireless channel corresponding to the industrial control service flow i is represented as CQI _i , and through adaptive modulation and coding, it is found that the number of bits that each resource block can transmit is AMC _i under the quality of the wireless channel, and the larger AMC _i is, the better the quality of the wireless channel is;
(6) calculating the required wireless resources, and determining the number of RBs required to transmit the p _i data packets according to the quality of the wireless channels of different cloud-based PLC industrial control service flows;
(where l _i is the length of the data packet), which gives the number of radio resources required for transmission of m data packets in the current queue.
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:
Then,
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;
If , the remaining time values of different data packets
(D _i is the delay requirement of the data packet,
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.
The remaining time value of all data packets in the highest priority queue is used to allocate resources preferentially to packets with smaller values.
A method for guaranteeing delay to cloud-based PLC services in a 5G-TSN architecture, comprising: allocating resources according to the

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.

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 terminal UE, and a device-side TSN converter. Cloud-based 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. Allocated resources are sent to the user terminal UE through service priority mapping, priority queue management, and radio resource scheduling. The user terminal UE is connected to the device-side TSN converter to provide a TSN output port.

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

Furthermore, when 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, so that the smaller the delay requirement value, the higher the service flow data is placed.

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 delays 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.

1 is a diagram of a 5G-TSN architecture for cloud-based PLC services according to the present invention; 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. FIG. 10 is a delay diagram for cloud-based PLC services according to the method provided by the present invention and other non-guaranteed methods.

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 a delay guarantee method for cloudified PLC services in a 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 terminal UE, and a device-side TSN converter. There are multiple different user terminals in the network, each bearing a different type of service. 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 terminal UE through service priority mapping, priority queue management, and radio resource scheduling. The user terminal UE is connected to the device-side TSN converter to provide a TSN output port.

The delay guarantee method 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 maps the different service flows to different queues according to their priorities. For example, an industrial control service flow, which includes cloud-based PLC, is mapped to a Q0 priority queue, video service and other mobile service flows with real-time requirements are mapped to a Q1 priority queue, and other service flows without delay requirements are mapped to a 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 priority of a service, the smaller the corresponding priority queue number.

2) A priority queue management function module is provided in the 5G-TSN network. Queueing is performed according to the delay requirements of industrial control service flows, with data packets being placed higher in the queue as the delay requirements become smaller. Among industrial control service flows with different scanning cycles and different delay requirements, priority is given to industrial control service flows with small to large scanning cycles and high to low delay requirements. For other priority queues, queuing is performed using the FIFO rule. For the Q0 queue, data is queued according to the delay requirement D _i of industrial control service flow i, with data packets being placed higher in the queue as D _i becomes smaller.

3) To guarantee the latency of cloud-based PLC industrial control services, a radio resource scheduling function module is provided in the 5G-TSN network. Radio resource scheduling for the high-priority Q0 queue is guaranteed on a priority basis. Radio air interface scheduling is performed every transmission time interval (TTI). A TTI is typically 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 to cloud-based PLC industrial control services includes the following steps:

(1) Calculate the data volume of the queue. Let n be the number of cloud-based PLC industrial control service flows included 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. Calculate the data volume of the queue from the number of data packets. The number of data packets is
is.

(2) Feedback the quality of the wireless channel. Because different cloud-based PLC industrial control service flows are supported by different wireless terminals, when the quality of the wireless channel corresponding to industrial control service flow i is represented by CQI _i , the number of bits that each resource block can transmit is AMC _i according to the quality of the wireless channel through adaptive modulation and coding. The higher the AMC _i , the better the quality of the wireless channel is.

(3) Calculate the required wireless resources: the number of RBs required to transmit p _i data packets according to the quality of the wireless channels of different cloud-based PLC industrial control service flows.
(where l _i is the length of the data packet), which gives the radio resources required for the transmission of m data packets in the current queue.
get.

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

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

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 the different service priority tags. Queues with higher numbers have lower priorities. 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 data transmission for the most urgent service flow, even if resources are insufficient to guarantee transmission for high-priority queues.

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

Step 3.1.
In this case, all data packets in the queue are allocated appropriate radio resources, and since the number of radio resources meets the transmission demand of the data packets in the high-priority Q0 queue, resources are allocated to the high-priority queue first, followed by resources to the medium-priority queue and the low-priority queue.

Step 3.2.
If , the remaining time values of different data packets
(D _i is the delay requirement of the data packet,
is the time value that the data packet has already been waiting, including the transmission time, waiting time and processing time in the non-air interface part.) and allocate it. The remaining time of all data packets in the Q0 queue is compared.
Allocate resources according to the remaining time value.
In this manner, all the allocable radio resources within the current transmission time interval TTI are allocated.

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, ensuring the timely transmission of cloud-based PLC industrial control services.

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 this invention can provide timely radio resource guarantees for PLC services, so even if the number of service flows increases, the delay change of the cloud-based PLC service does not fluctuate, 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 when multiple services are transmitted, it is not possible to provide a service quality guarantee for the cloud-based PLC.

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 (5)

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 calculating the data volume of a 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 . When the data volume of the queue is calculated based on the number of data packets, the number of data packets is:
and
(2) a step of feeding back the quality of a wireless channel, in which the quality of the wireless channel corresponding to the industrial control service flow i is represented as CQI _i , and through adaptive modulation and coding, it is found that the number of bits that each resource block can transmit is AMC _i under the quality of the wireless channel, and the larger AMC _i is, the better the quality of the wireless channel is;
(3) calculating the required wireless resources, and determining the number of RBs required to transmit the p _i data packets according to the quality of the wireless channels of different cloud-based PLC industrial control service flows;
(where l _i is the length of the data packet), which gives the number of radio resources required for transmission of m data packets in the current queue.
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:
Then,
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;
If , the remaining time values of different data packets
(D _i is the delay requirement of the data packet,
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.
The remaining time value of all data packets in the highest priority queue is used to allocate resources preferentially to packets with smaller values.
A method for guaranteeing delay to cloud-based PLC services in a 5G-TSN architecture, comprising: allocating resources according to the 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 via the 5G-TSN network. The method for ensuring delay for cloudified PLC services in a 5G-TSN architecture described in claim 1 is characterized in that: The method for ensuring delay for cloudified PLC services in a 5G-TSN architecture described in claim 1, 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, radio resource scheduling, a user terminal UE, and a device-side TSN converter, and 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 terminal UE through service priority mapping, priority queue management, and radio resource scheduling, and the user terminal UE is connected to the device-side TSN converter to provide a TSN output port. The delay guarantee method for cloud-based PLC services in a 5G-TSN architecture described in claim 1, characterized in that when allocating the radio resources, priority tags are assigned to different service flows, with priority tag values of 0 and 1 being considered high priority, priority tag values of 2, 3, or 4 being considered medium priority, and priority tag values of 5, 6, or 7 being considered low priority. 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.