Distributed Unit Network Slice Switching for Low-Latency RAN Access
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Solution Overview
Problem
Existing communication systems face challenges in achieving optimal latency and resource access by placing gateways far from the RAN, leading to increased signaling overhead and latency in local switching operations.
Innovation Solution
Implementing network slices at distributed units (DUs) within a radio access network, allowing local switching by configuring data transmission contexts at the DU, and managing protocol data unit sessions to enable direct user plane termination and interaction with locally available resources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If gateways are placed far from the RAN to provide centralized control, then network management and control is simplified, but latency increases and signaling overhead increases
Solution Approach 1:
The network is segmented into centralized control functions (CU) and distributed user plane functions (DU with network slice gateway capabilities). This segmentation allows control plane operations to remain centralized while user plane traffic is handled locally at the DU, resolving the contradiction between centralized management simplicity and low latency requirements.
Solution Approach 2:
The network slice gateway at the DU acts as an intermediary between the centralized CU and local data networks. It provides local switching and routing capabilities, enabling fast local traffic handling while maintaining centralized control through the CU, thus reducing latency without sacrificing management simplicity.
2Device complexity
If gateways are placed far from the RAN, then centralized network control is achieved, but signaling overhead increases
Solution Approach 1:
User plane routing and switching functions are extracted from the centralized gateway and placed at the DU-level network slice gateway. This extraction allows local traffic to be switched without generating excessive signaling to the centralized controller, reducing signaling overhead while maintaining centralized control architecture.
Solution Approach 2:
The network slice gateway at the DU pre-configures local routing and switching rules based on network slice requirements. This preliminary configuration enables fast local switching decisions without requiring real-time signaling to the centralized CU, thereby reducing signaling overhead.
3Loss of time
If local switching is enabled at distributed units, then latency is reduced and local resource access is improved, but device complexity at the DU increases
Solution Approach 1:
The network slice gateway at the DU is designed with multi-functionality, handling both traditional user plane routing and local switching functions. This universal design allows the DU to provide low-latency local switching without requiring separate dedicated hardware, thus limiting the increase in device complexity.
4Productivity
If network slices with local switching are implemented, then local resource access efficiency is improved, but configuration and management complexity increases
Solution Approach 1:
The system implements feedback mechanisms where the network slice gateway at the DU reports local switching performance and resource usage to the centralized CU. The CU uses this feedback to dynamically adjust network slice configurations and routing policies, simplifying management while maintaining high local resource access efficiency.
Data Source
AI summary
There is provided an apparatus, said apparatus comprising means for receiving, from a distributed unit of a radio access network node at a centralized unit control plane part of the radio access network node, an indication that the distributed unit supports network slices providing local switching at the distributed unit, indicating, from the centralized unit control plane part of the radio access network node to a core network, that the distributed unit of the radio network node supports network slices providing local switching at the distributed unit, receiving a user equipment context from the core network, for a user equipment providing a request for local switching at the distributed unit, the request including an indication the user equipment is allowed to use at least one of the network slices providing local switching at the distributed unit, configuring for each of the network slices providing local switching at the distributed unit, at least one data transmission context at the distributed unit such that the user plane of the user equipment is terminated at the distributed unit and a protocol data unit session associated with the data transmission context becomes available to the user equipment for local switching at the distributed unit and configuring for each of the network slices providing local switching at the distributed unit at least one data transmission context at the user equipment such that the user equipment can use the protocol data unit session for local switching at the distributed unit.