Harmonized operation between radio link monitor and beam failure recovery
A method for harmonized operation between radio link monitor and beam failure recovery is proposed. In one example, upon indication of unsuccessful recovery from beam failure, a counter is initiated to count a configured number of OOS indication before RLF is declared due to beam failure. In another example, upon indication of successful recovery from beam failure, a counter is initiated to count a configured number of IS indication before starting over RLM procedure on its previous observations on failed beams. As a result, either early RLF declaration or RLM reset may be triggered based on BFR procedure to more accurately maintain the link quality.
1. A method comprising:
detecting a beam failure condition of a serving beam pair link (BPL) by a user equipment (UE) in a beamforming communication network, wherein the UE initiates a beam failure recovery (BFR) procedure and transmits a beam failure recovery (BFRQ) message when the beam failure condition is met;
initiating a radio link monitor (RLM) procedure by the UE by periodically providing In-Sync (IS) and Out-of-Sync (OOS) indications of the serving BPL;
determining a BFR procedure result based on whether the UE receives a network response to the BFRQ message; and
generating an output to the RLM procedure by counting the IS and OOS indications, wherein the output triggers an RLM procedure reset or triggers a radio link failure (RLF) declaration in accordance with the BFR procedure result.
2. The method of claim 1 , wherein the UE initiates a timer upon determining the BFR procedure is unsuccessful, and wherein the UE declares radio link failure (RLF) when a number of accumulative OOS indications reaches a threshold before the timer expires.
3. The method of claim 1 , wherein the UE starts counting OOS-indications upon determining the BFR procedure is unsuccessful, and wherein the UE declares radio link failure (RLF) when a number of consecutive OOS-indications reaches a threshold.
4. The method of claim 1 , wherein the UE initiates a timer upon determining the BFR procedure is unsuccessful, and wherein the UE restarts the RLM procedure when a number of accumulative IS-indications reaches a threshold before the timer expires.
5. The method of claim 1 , wherein the UE starts counting IS-indications upon determining the BFR procedure is unsuccessful, and wherein the UE restarts the RLM procedure when a number of consecutive IS-indications reaches a threshold.
6. The method of claim 1 , wherein the UE initiates a timer upon determining the BFR procedure is successful, and wherein the UE restarts the RLM procedure when a number of accumulative IS-indications reaches a threshold before the timer expires.
7. The method of claim 1 , wherein the UE starts counting IS-indications upon determining the BFR procedure is successful, and wherein the UE restarts the RLM procedure when a number of consecutive IS-indications reaches a threshold.
8. A User Equipment (UE), comprising:
a receiver that receives reference signals and detects a beam failure condition of a serving beam pair link (BPL) in a beamforming communication network;
a radio link monitor (RLM) handling circuits that initiates an RLM procedure by periodically providing In-Sync (IS) and Out-of-Sync (OOS) indications of the serving BPL;
a beam failure recovery (BFR) handling circuits that initiates a BFR procedure and transmits a beam failure recovery request (BFRQ) message when the beam failure condition is met, wherein the BFR handling circuits determines a BFR procedure result based on whether the UE receives a network response to the BFRQ message; and
a BFR/RLM coordinating circuit that generates an output to the RLM procedure by counting the IS and OOS indications, wherein the output triggers an RLM procedure reset or triggers a radio link failure (RLF) declaration in accordance with the BFR procedure result.
9. The UE of claim 8 , wherein the UE initiates a timer upon determining the BFR procedure is unsuccessful, and wherein the UE declares radio link failure (RLF) when a number of accumulative OOS indications reaches a threshold before the timer expires.
10. The UE of claim 8 , wherein the UE starts counting OOS-indications upon determining the BFR procedure is unsuccessful, and wherein the UE declares radio link failure (RLF) when a number of consecutive OOS-indications reaches a threshold.
11. The UE of claim 8 , wherein the UE initiates a timer upon determining the BFR procedure is unsuccessful, and wherein the UE restarts the RLM procedure when a number of accumulative IS-indications reaches a threshold before the timer expires.
12. The UE of claim 8 , wherein the UE starts counting IS-indications upon determining the BFR procedure is unsuccessful, and wherein the UE restarts the RLM procedure when a number of consecutive IS-indications reaches a threshold.
13. The UE of claim 8 , wherein the UE initiates a timer upon determining the BFR procedure is successful, and wherein the UE restarts the RLM procedure when a number of accumulative IS-indications reaches a threshold before the timer expires.
14. The UE of claim 8 , wherein the UE starts counting IS-indications upon determining the BFR procedure is successful, and wherein the UE restarts the RLM procedure when a number of consecutive IS-indications reaches a threshold.