Remote UE Cell Change Reporting for Multi-Path Relay Connections
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Solution Overview
Problem
The challenge lies in managing operations of a remote user equipment (UE) when a relay UE in the IDLE/INACTIVE state, selected by a serving base station, accesses a target cell different from the expected target cell during multi-path operations in wireless communication systems.
Innovation Solution
The remote UE reports measurement results to a base station, receives an RRCReconfiguration message with a target relay UE ID, and establishes a PC5 connection. It informs the base station of camping cell changes or cell reselection by the target relay UE through a discovery message, allowing it to release or skip RRC reestablishment and report new candidate relay UEs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the remote UE follows the target relay UE to a target cell during multi-path operations, then the connection reliability is improved, but the operation complexity increases due to cell reselection mismatches
Solution Approach 1:
The remote UE performs cell reselection independently and proactively before the relay UE completes its handover, based on measurement results reported to the network. This preliminary action ensures the remote UE is already positioned in the correct target cell when the relay UE arrives, avoiding connection failures and reducing the need for complex recovery procedures.
Solution Approach 2:
The remote UE monitors and detects cell reselection events of the relay UE through discovery messages and provides feedback to the network about cell changes. This feedback mechanism enables the network to track the relay UE's movement and maintain accurate routing information, simplifying the overall operation by enabling coordinated mobility management rather than complex independent handling.
2Productivity
If the remote UE performs cell reselection independently based on measurement results, then the connection establishment speed is improved, but the risk of cell mismatch increases
Solution Approach 1:
The remote UE performs cell reselection in advance based on measurement results, establishing its connection to the target cell before the relay UE completes handover. This preliminary positioning accelerates connection establishment while the network coordinates to ensure the selected target cell matches the relay UE's destination.
Solution Approach 2:
The remote UE provides feedback to the network about detected cell reselection events through discovery messages. This feedback allows the network to verify and coordinate the cell matching between remote UE and relay UE, ensuring reliability while maintaining the speed benefits of independent cell reselection.
3Measurement precision
If the remote UE monitors discovery messages to detect relay UE cell changes, then the mobility management accuracy is improved, but the energy consumption increases
Solution Approach 1:
The discovery message mechanism serves multiple functions simultaneously: it enables the relay UE to announce its cell reselection events to remote UEs, allows remote UEs to detect and track relay UE mobility, and provides network coordination capability. This multi-functionality consolidates mobility management into a single mechanism, improving accuracy without proportionally increasing energy consumption compared to dedicated monitoring schemes.
Data Source
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AI summary
An embodiment pertains to an operation method of a remote user equipment (UE) related to a multi-path relay in a wireless communication system, the method comprising: the remote UE reporting, to a base station, the result of a candidate relay UE measurement; the remote UE receiving, from the base station, an RRCReconfiguration message including the ID of a target relay UE; and the remote UE attempting to establish PCS connection with the target relay UE, wherein the remote UE transmits, to the base station, information notifying the change in the camping cell of the target relay UE, on the basis of the remote UE detecting, through a discovery message transmitted by the candidate relay UE, that the camping cell of the target relay UE has changed or that the target relay UE has performed cell reselection upon RRC connection.