RRC Redirection Failure Handling via LBT Timeout Mechanisms

The patent applies preliminary action by introducing a timeout mechanism that limits the duration of random access attempts during redirection. The UE monitors whether the random access procedure completes within a predetermined time threshold, and if not, proactively triggers a failure recovery procedure. This prevents the UE from indefinitely attempting access to cells with persistent LBT failures, thereby reducing service interruption time while maintaining redirection success through alternative targets.

The patent implements feedback by having the UE monitor the outcome of each random access attempt during redirection and use this information to control subsequent attempts. The timeout mechanism provides feedback on whether access attempts are succeeding within acceptable time frames, and the failure recovery procedure uses this feedback to switch to alternative redirection targets. This feedback-driven approach ensures the UE performs redirection attempts only when likely to succeed, optimizing the balance between redirection success rate and power consumption.

The patent applies dynamics by making the redirection target selection adaptive rather than static. While the network provides indicated redirection targets, the UE dynamically adjusts its behavior based on real-time LBT failure detection. When the timeout mechanism detects that random access to an indicated target is failing, the UE dynamically switches to alternative targets from the available set, rather than rigidly persisting with the original indicated targets. This dynamic adaptation maintains procedural definition while enabling flexibility in response to LBT failures.