UE QoS Context Transfer Across 4G-to-5G Handover
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Solution Overview
Problem
User Equipment (UE) cannot seamlessly transition from a 4G network to a 5G network due to the lack of a one-to-one mapping relationship between EPS bearers and QoS flows, which is not present in 5G networks, unlike the direct mapping in 4G to 3G transitions.
Innovation Solution
UE pre-stores QoS flow information upon receiving a message in the 4G network, allowing it to maintain consistent QoS context during the transition to 5G by using stored QoS flow information, and communicates with core network entities to ensure seamless handover.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If UE uses direct mapping method for network transition, then transition simplicity is improved, but applicability deteriorates due to lack of one-to-one mapping in 5G
Solution Approach 1:
The UE pre-stores QoS flow information corresponding to each EPS bearer before leaving the 4G network. This preliminary action enables the UE to quickly restore QoS context in the 5G network without real-time negotiation, resolving the contradiction by maintaining simplicity while enabling cross-generation network compatibility
Solution Approach 2:
The UE creates a copy of the QoS flow information from the 4G network and stores it locally. This copied information serves as a template that the UE can reference during 5G network transition, allowing the UE to reconstruct QoS context without establishing one-to-one mappings, thus achieving both simplicity and adaptability
2Reliability
If UE restores QoS context after handover, then service continuity is improved, but handover time increases due to information processing
Solution Approach 1:
QoS flow information is pre-stored in the UE before handover occurs. When the UE transitions to the 5G network, it can immediately retrieve and restore the QoS context from stored information without waiting for network signaling exchanges, thereby maintaining service continuity while minimizing handover time
Solution Approach 2:
The UE autonomously restores its own QoS context using pre-stored information without requiring extensive network assistance. This self-service capability reduces dependency on network signaling during handover, cutting down handover time while ensuring reliable service continuity through accurate QoS context restoration
Data Source
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AI summary
Embodiments of this application relate to the field of communications technologies, and provide a method for moving between communications systems and an apparatus, so as to move user equipment from a first communications system to a second communications system. The method includes: receiving, by the UE, a first message, where the first message is used to set up or modify a first EPS bearer for the UE in the first communications system, and the first message includes first quality of service QoS flow information that is of the second communications system and that is corresponding to the first EPS bearer; storing, by the UE, the first QoS flow information; moving, by the UE, from the first communications system to the second communications system; and determining, by the UE based on a first condition, QoS flow information used by the UE in the second communications system, where the first condition includes the first QoS flow information.