Anchor Node Context Transfer for 5G Resume Latency
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Solution Overview
Problem
The existing XnAP Retrieve UE AS context procedure in 5G wireless communications suffers from significant resume latency, particularly due to Xn-interface latency, which adversely affects time-sensitive applications, and current workarounds like broadcasting the UE AS context to all cells in the RAN/RNA increase signaling and storage overheads, especially in massive IoT and mMTC applications.
Innovation Solution
An anchor network node proactively transfers the access context to predicted target network nodes based on UE mobility and traffic profiles, using processor-executable instructions to determine when and where the UE will exit the current cell, thereby minimizing latency and overhead by avoiding the legacy retrieval procedure and reducing unnecessary context transfers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the XnAP Retrieve UE AS context procedure is used to transfer access context from the last serving gNB to the target gNB, then the UE AS context is successfully transferred, but the resume latency increases significantly due to Xn-interface latency
Solution Approach 1:
The patent applies preliminary action by having the last serving gNB proactively transfer the UE AS context to the target gNB before the UE actually needs to resume the connection. This is achieved by monitoring UE mobility information and predicting when the UE will move to a new cell, allowing the context to be pre-positioned at the target gNB, thus avoiding the latency of on-demand retrieval procedures.
Solution Approach 2:
The patent implements dynamics by making the context transfer mechanism adaptive based on UE mobility patterns. The system dynamically decides whether to transfer context proactively or use traditional retrieval based on predicted UE movement, creating a flexible system that optimizes latency while maintaining reliability for different UE behaviors.
2Loss of time
If the UE AS context is pushed to all cells in the RAN/RNA to reduce resume latency, then the resume latency is reduced, but the Xn signalling overhead and storage capacity overhead increase significantly
Solution Approach 1:
The patent applies local quality by transferring the UE AS context only to specific target gNBs that are predicted to serve the UE, rather than broadcasting to all cells in the RAN/RNA. This selective approach uses UE mobility information to identify only the relevant target cells, thereby reducing unnecessary signaling overhead and storage capacity consumption while still achieving low latency for actual UE resumption.
Solution Approach 2:
The patent uses partial action by performing context transfer to a subset of target gNBs based on predicted UE movement patterns, rather than the excessive action of transferring to all possible gNBs. This optimized partial transfer reduces resource consumption while maintaining the benefit of reduced resume latency.
Data Source
AI summary
The present disclosure relates generally to the field of wireless communications, and in particular to techniques for efficiently transferring, among network nodes, an access context required to initiate data transfer when a user equipment (UE) is in an active or suspended Radio Access Network (RAN) connection state. The techniques disclosed herein involve identifying, based on UE-specific data (such, for example, as mobility information, a traffic profile), one or more relevant network nodes where the UE in the suspended RAN connection state could be located at the time when next data transfer needs to be initiated. After that, the access context is sent from an anchor network node to said one or more relevant network nodes. By sending the access context in this manner, network signalling overhead and storage capacity overhead may be significantly reduced.