Sidelink Relay Communication: Local ID Allocation During Path Switching
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Solution Overview
Problem
The allocation of a local ID for a remote UE in sidelink relay communication, particularly during path switches when the target relay UE is in an idle or inactive state, is unclear in existing 3GPP Release 17 specifications.
Innovation Solution
A remote UE obtains its local ID from either the target relay UE or the base station, and the target relay UE obtains the local ID from either the remote UE or the base station, facilitating data transmission through the target relay UE.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the target relay UE is in idle or inactive state during path switch, then the switching flexibility is improved, but the local ID allocation becomes unclear and complex
Solution Approach 1:
The base station acts as an intermediary to allocate and manage local IDs during path switching. When the target relay UE is in idle or inactive state, the base station receives the path switch request, determines the appropriate local ID, and provides it to the target relay UE. This intermediary approach simplifies the ID allocation process while maintaining switching flexibility.
Solution Approach 2:
The base station performs preliminary allocation of local IDs before the path switch is executed. By determining and assigning the local ID in advance (before the actual path switching occurs), the system avoids the complexity of real-time ID allocation during the transition, ensuring seamless switching while maintaining clear ID management.
2Speed
If local ID allocation is performed without clear procedures, then the path switch speed is improved, but ID collisions may occur reducing reliability
Solution Approach 1:
The base station implements a feedback mechanism where it receives path switch requests from remote UEs, processes the request to determine appropriate local IDs, and provides confirmation to both the remote UE and target relay UE. This feedback loop ensures that local IDs are uniquely assigned and tracked, preventing collisions while maintaining efficient path switching.
Solution Approach 2:
The target relay UE autonomously uses the local ID provided by the base station for subsequent communications. Once the base station allocates the local ID, the target relay UE self-manages its use in relay communications without requiring continuous network intervention, thus maintaining both speed and reliability.
3Adaptability or versatility
If the remote UE obtains local ID from multiple sources, then the system flexibility is improved, but the ID management complexity increases
Solution Approach 1:
The base station serves multiple functions: it acts as the central authority for local ID allocation, path switch coordination, and communication partner for both remote UEs and target relay UEs. This universal role simplifies the overall system by having a single point of control for ID management, even though the remote UE can conceptually obtain IDs through different interaction paths.
Data Source
AI summary
Embodiments of the present disclosure relate to communication for sidelink relay. According to embodiments of the present disclosure, a first UE receives, from a network, a first message indicating that the first UE is switched to communicate with the network via a second UE in an idle or inactive state, and obtains, from the second UE or the network, a local ID of the first UE. Then the first UE performs, based on the local ID of the first UE, a data transmission with the network via the second UE. In this way, allocation of a local ID of a remote UE is clarified.