AMF Node Caching NSSF Slice Data to Reduce Signaling Overhead
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Solution Overview
Problem
In 5G networks, when a user equipment (UE) moves and changes its registration area, the existing system experiences repeated queries and interactions between the Access and Mobility Management Function (AMF) and the Network Slice Selection Function (NSSF) nodes, leading to increased signaling and overheads due to outdated slice selection assistance information.
Innovation Solution
The proposed method involves the AMF node sending a request to the NSSF node to obtain allowed Network Slice Selection Assistance Information (NSSAI) and service area information, which are then stored to avoid repeated queries and interactions, improving signaling efficiency and reducing system overheads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the AMF node queries slice information from the NSSF node every time the UE changes registration area, then the slice selection assistance information remains updated, but the signaling overhead and system overheads increase
Solution Approach 1:
The NSSF node pre-determines and provides slice information for multiple registration areas in advance during the initial attach process. When the UE moves to a new registration area, the AMF node can directly use the pre-provided slice information without needing to query the NSSF node again, thus reducing signaling overhead while maintaining information accuracy.
2Loss of energy
If the AMF node stores slice selection assistance information locally, then repeated queries are avoided and signaling overhead is reduced, but the information may become outdated when the UE moves to a new registration area
Solution Approach 1:
The NSSF node performs preliminary action by determining and providing slice information for all possible registration areas in advance. The AMF node stores this pre-determined information locally, which remains valid when the UE moves within the same registration area, thus avoiding repeated queries while maintaining information accuracy.
3Reliability
If the NSSF node provides slice information for the current registration area only, then the information is accurate for the current area, but the AMF node must query again when the UE moves, causing repeated interactions
Solution Approach 1:
The NSSF node extends its preliminary action to provide slice information not only for the current registration area but also for other possible registration areas where the UE might move. This allows the AMF node to handle UE mobility without repeated queries to the NSSF node, improving processing efficiency while maintaining information accuracy.
Data Source
AI summary
The present disclosure relates to a slice-based communications method. In one example method, an access and mobility management function (AMF) node sends a first request message to a network slice selection function (NSSF) node. The AMF node receives a response message from the NSSF node. The AMF node obtains, based on the response message, allowed network slice selection assistance information (NSSAI).