CU-DU Network Reselection Using UE Context Transfer
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Solution Overview
Problem
In a network sharing scenario with a CU-DU separation architecture, existing technologies face challenges in efficiently reselecting a network for a user equipment (UE) by retrieving UE context from a CU belonging to a previous network to a new CU, especially when the new CU does not support the relocation function.
Innovation Solution
Implementing a series of signaling processes involving rerouting and reallocation messages through F1 and Xn interfaces to facilitate network reselection, including the use of new messages like REROUTE RRC MESSAGE, CU NODE REALLOCATION, and RETRIEVE UE CONTEXT, to transfer UE context between CUs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the new CU does not support relocation function, then the device complexity is reduced, but the network reselection capability is lost
Solution Approach 1:
The patent introduces a distributed unit (DU) as an intermediary component that bridges the gap between CUs with and without relocation functionality. The DU handles the context retrieval and forwarding operations, enabling CUs that lack native relocation support to still participate in network reselection procedures. This allows the system to maintain network reselection capability while keeping individual CU designs simpler.
2Reliability
If context information is transferred between CUs during network reselection, then communication continuity is maintained, but the loss of time increases due to additional signaling
Solution Approach 1:
The patent implements preliminary action by having the source CU proactively retrieve and forward user equipment (UE) context information to the target CU before the actual handover is completed. This advance preparation ensures that when network reselection occurs, the target CU already possesses the necessary context to immediately continue communication, minimizing interruption time while maintaining reliability.
3Reliability
If multiple signaling messages are used for network reselection, then the reliability of context transfer is improved, but the device complexity increases
Solution Approach 1:
The patent segments the context transfer process into distinct, manageable signaling steps: context retrieval from source CU, context forwarding through intermediate nodes, and context confirmation at target CU. Each segment can be independently implemented and verified, improving overall reliability while allowing the complex process to be managed through modular signaling procedures rather than a monolithic operation.
Data Source
AI summary
Methods, systems, and devices related to digital wireless communication, and more specifically, to techniques related to related to reselecting a network in a network sharing split architecture. In one exemplary aspect, a method for wireless communication includes a central node associated with a previous network receiving a rerouting message from a distributed node indicating that a network for the terminal is reselected from the previous network to a new network. The method also includes the central node associated with a previous network transmitting an allocation message to a central node associated with the new network.