Proactive Access Context Transfer for 5G UE 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 gNBs in the RAN/RNA increase signaling and storage overheads, especially in MIoT and mMTC applications.
Innovation Solution
An anchor network node predicts the target time and location of a UE based on mobility and traffic profiles, proactively sending the access context to predicted target network nodes, thereby minimizing latency and overhead by avoiding the legacy retrieval procedure and reducing unnecessary context transfers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
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 can be successfully relocated, but the resume latency increases significantly due to Xn-interface round-trip time
Solution Approach 1:
The patent applies preliminary action by proactively transferring the UE AS context from the last serving gNB to the target gNB before the UE actually resumes the RRC connection. This is achieved by monitoring UE mobility and predicting potential target gNBs in advance, so that when the UE needs to resume, the context is already available at the target gNB, eliminating the need for the XnAP Retrieve procedure and reducing resume latency while maintaining reliable context relocation
2Loss of time
If the UE AS context is pushed to all gNBs in the RAN/RNA to reduce resume latency, then any target gNB can serve the UE without context retrieval, 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 be relevant based on UE mobility patterns and traffic profiles, rather than broadcasting to all gNBs in the RAN/RNA. This selective approach ensures that context is available at the right location (local quality) when needed, reducing both signalling overhead and storage capacity overhead while maintaining low resume latency
Data Source
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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.