In the existing network of operators, GWs are deployed in a centralized way. The media-plane data transmission distance is long, and the forwarding delay is long too, which result in poor user experience. To solve this problem, 3GPP proposed the solution of C/U separation (CUPS). Based on 3GPP standards, ZTE firstly launched its own commercial solutions. The C/U separation solution separates the GW-C plane (control plane) from the GW-U plane (user plane) , and deploys them independently to realize CUPS network. The GW-C plane is deployed in the central data center in a centralized way. The GW-U is deployed in a lightweight way, with plug-and-play, where and where are required. The GW-U is usually deployed in the data center close to the user.
5G CUPS Design Concept
With the commercial development of 5G, the eMBB/URLLC application requirements such as 4K/8K HD video, cloud game, remote driving and industrial control are increasingly urgent. They impose ultra-low delay and ultra-large bandwidth requirements upon the network. These performance requirements are closely related to the network user plane, which needs to provide highly-efficient data processing and forwarding. Therefore, 5GC adopted the natural CUPS network architecture at the beginning of its design. Combined with the SBA concept, in the 5GC standard architecture defined by 3GPP, 5G CUPS network designed the user plane as an independent UPF service, while the control plane is further divided into various types of services. The UPF service can be deployed one or more as needed. Its deployment location is planned based on service traffic, and can be deployed in a centralized way or deployed on the edge in a distributed way. In this way, the 5G application scenarios with large bandwidth and low latency can be satisfied.
ZTE C/U separation solution introduces the 5G CUPS network concept to the EPC network, and CUPS network further improves the service experience of 4G users through the distributed user plane.
CUPS Network Improves User Plane Performance
The end-to-end performance improvement of the user plane involves many aspects.
Firstly, analyze and optimize the overall network architecture design and deployment to shorten user-plane transmission paths.
Secondly, the NE/network functions that forward user-plane data in the network need to be optimized to improve the processing performance of the single node.
This is a performance improvement process involving both aspects and points.
CUPS Network Shortens the Forwarding Path and Optimizes Service Experience
After a mobile terminal accesses the core network through a base station, if the core network is not distributed, the service data accessed by the terminal needs to be forwarded through a centralized DC. When the user is located in a remote town, the delay is huge.
To improve the forwarding performance of the user plane, the core network should adopt CUPS network concept, user plane must be distributed. Compared with central DCs, edge DCs and access DCs are closer to terminal users. Control-plane signaling is still transmitted to central DCs, and user-plane data is directly processed and distributed at edge or access DCs, greatly reducing end-to-end network transmission paths and service delay, saving transmission costs, ,and providing better service experience for mobile users.