Remote UE Multipath Relay RLF Timing for Stable RRC Recovery
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Solution Overview
Problem
Existing wireless communication systems face challenges in managing radio link failures (RLF) in multipath relays, leading to unnecessary radio resource control (RRC) reestablishments, which can disrupt communication in critical scenarios such as vehicle-to-everything (V2X) applications.
Innovation Solution
Implementing timers for detecting RLFs on direct and indirect paths in remote UEs, preventing unnecessary RRC reestablishments by allowing the remote UE to wait for an RRCReconfiguration message, and triggering reestablishment procedures only when timers expire without receiving the message.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the remote UE immediately initiates RRC reestablishment procedure upon detecting RLF on direct path, then the RRC connection can be quickly reestablished, but unnecessary RRC reestablishments occur in multipath relay scenarios
Solution Approach 1:
The patent applies preliminary action by configuring the remote UE with a timer (e.g., T319) before RLF detection. When RLF is detected on the direct path, the UE first waits for the timer to expire or for an RRCReconfiguration message from the network before initiating RRC reestablishment. This preliminary timing mechanism prevents premature reestablishment attempts and allows the network time to potentially switch to indirect path routing, thereby avoiding unnecessary RRC reestablishments while maintaining the capability for quick recovery when truly needed.
2Reliability
If the remote UE waits for RRCReconfiguration message before initiating reestablishment, then unnecessary reestablishments are prevented, but communication delay increases
Solution Approach 1:
The patent implements dynamics by making the RRC reestablishment initiation conditional and time-dependent. The UE dynamically decides whether to initiate reestablishment based on whether an RRCReconfiguration message is received within a configured timer period (e.g., T319). If the message is received before timer expiration, the UE waits for network-directed path switching. If the timer expires without receiving the message, the UE proceeds with reestablishment. This dynamic approach balances reliability improvement with time loss minimization.
3Reliability
If the network switches from direct path to indirect path for remote UE, then communication reliability is maintained during RLF, but additional path management complexity is introduced
Solution Approach 1:
The patent uses the RRCReconfiguration message as an intermediary mechanism between the network and the remote UE for path management. When the network detects RLF on the direct path, it can send an RRCReconfiguration message to the remote UE (potentially routed through the indirect path) to instruct the UE to switch to indirect path communication. This intermediary message-based approach allows the network to control path switching without requiring complex real-time coordination protocols, thereby maintaining reliability while managing complexity through standardized signaling.
Data Source
AI summary
One embodiment relates 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 features in which: the remote UE establishes a PC5 RRC connection with a relay UE; the remote UE transmits data to a base station through at least one of a direct path and an indirect path; the remote UE detects direct path RLF; the remote UE reports the RLF to the base station; and a first timer is started on the basis of the report of the RLF, wherein on the basis of the remote UE not receiving a RRCReconfiguration message from the base station by the time of the first timer expiring, the remote UE initiates an RRC Reestablishment procedure, wherein the RRCReconfiguration message is related to direct path addition.