Radio link monitoring and radio resource management measurement procedures for NR-U
Radio resource management measurements for new radio unlicensed are performed that are based on a measurement model where a missed received signal transmission opportunity indicator is provided to higher layers to adapt the measurement functions performed by the radio resource control when a missed received signal transmission opportunity is detected. Radio link monitoring for new radio unlicensed is performed based on in-sync or out-of-sync indications that are based on the estimated radio link quality in combination with missed radio link monitoring reference signal transmission opportunities.
1. A wireless transmit/receive unit (WTRU) for performing a radio link monitoring or radio link failure process, the WTRU comprising:
a processor; and
a memory coupled with the processor, the memory comprising executable instructions stored thereon that when executed by the processor cause the processor to effectuate operations comprising:
monitoring in-sync indications or out-of-sync indications on an unlicensed channel, wherein the in-sync indications or the out-of-sync indications are based on a radio link quality;
monitoring a number of missed radio link monitoring reference signal (RLM-RS) transmission opportunities (TXOPs) on the unlicensed channel, wherein the monitoring of the number of missed RLM-RS TXOPs comprises:
detecting whether the unlicensed channel was acquired during the RLM-RS TXOP based on a channel access indication (CAI) signal, the CAI signal indicating to the WTRU that the unlicensed channel was acquired or, when there is a licensed band downlink available, based on downlink control information (DCI) obtained on the licensed band downlink; and
based on the monitored in-sync indications or out-of-sync indications in combination with the monitored number of missed RLM-RS TXOPs, determining radio link failure (RLF).
2. The WTRU of claim 1 , wherein the monitoring of the number of missed RLM-RS TXOPs is based on a signal transmitted by a base station, wherein the base station is a gNB.
3. The WTRU of claim 1 , wherein the monitoring of the number of missed RLM-RS TXOPs is based on a discovery reference signal.
4. The WTRU of claim 1 , wherein the monitoring the number of missed RLM-RS TXOPs is based on frames of a physical layer in which radio link quality is assessed.
5. The WTRU of claim 1 , wherein the monitoring the number of missed RLM-RS TXOPs is based on detecting N missed_TXOP missed RLM-RS TXOPs within T Evaluate_missed_TXOP period.
6. The WTRU of claim 1 , the operations further comprising when an RLM-RS TXOP is missed, providing an indication that the RLM-RS TXOP was missed to a higher layer.
7. The WTRU of claim 1 , the operations further comprising:
starting timer T Evaluate_missed_TXOP , based on detecting of missed RLM-RS TXOPs while timer T Evaluate_missed_TXOP is not running;
stopping timer T Evaluate_missed_TXOP , based on detecting RLM-RSs during N detected_TXOP consecutive RLM-RS TXOPs, wherein N detected_TXOP is a predetermined threshold number for detected RLM-RS TXOPs; and
when timer T Evaluate_missed_TXOP missed is running, receiving N Missed_TXOP consecutive missed RLM-RS TXOPs indications from lower layers, wherein N missed_TXOP is a predetermined threshold number of missed RLM-RS TXOPs, determining that there is a radio link failure.
8. The WTRU of claim 7 , wherein the T Evaluate_missed_TXOP , N Missed_TXOP , or N detected_TXOP is signaled by RRC signaling.
9. The WTRU of claim 1 , the operations further comprising:
starting timer T Evaluate_missed_TXOP based on receiving N missed_TXOP consecutive missed RLM-RS TXOPs indications from lower layers, wherein N missed_TXOP is a predetermined threshold number of missed RLM-RS TXOPs;
stopping timer T Evaluate_missed_TXOP based on detecting RLM-RSs during N detected_TXOP consecutive RLM-RS TXOPs from lower layers, wherein N detected_TXOP is a predetermined threshold number for detected RLM-RS TXOPs; and
when timer T Evaluate_missed_TXOP is not stopped and timer T Evaluate_missed_TXOP is expired, determining that there is a radio link failure.
10. The WTRU of claim 1 , wherein the determining of the radio link failure is further based on receiving maximum number of consecutive out-of-sync indications for a PCell from lower layers.
11. A method of operating a wireless transmit/receive unit (WTRU) for performing a radio link monitoring or radio link failure process, the method comprising:
monitoring in-sync indications or out-of-sync indications, wherein the in-sync indications or the out-of-sync indications are based on a radio link quality;
monitoring a number of missed radio link monitoring reference signal (RLM-RS) transmission opportunities (TXOPs) on the unlicensed channel, wherein the monitoring of the number of missed RLM-RS TXOPs comprises:
detecting whether the unlicensed channel was acquired during the RLM-RS TXOP based on a channel access indication (CAI) signal, the CAI signal indicating to the WTRU that the unlicensed channel was acquired or, when there is a licensed band downlink available, based on downlink control information (DCI) obtained on the licensed band downlink; and
based on the monitored in-sync indications or out-of-sync indications in combination with the monitored number of missed RLM-RS TXOPs, determining radio link failure (RLF).
12. The method of claim 11 , further comprising:
starting timer T Evaluate_missed_TXOP , based on detecting of a missed RLM-RS TXOPs while timer T Evaluate_missed_TXOP is not running;
stopping timer T Evaluate_missed_TXOP , based on detecting RLM-RSs during N detected_TXOP consecutive RLM-RS TXOPs, wherein N detected_TXOP is a predetermined threshold number for detected RLM-RS TXOPs; and
when timer T Evaluate_missed_TXOP is not stopped and timer T Evaluate_missed_TXOP is expired determining that there is a radio link failure.
13. The method of claim 11 , wherein the monitoring of the number of missed RLM-RS TXOPs is based on a signal transmitted by a base station, wherein the base station is a gNB.
14. The method of claim 11 , wherein the monitoring the number of missed RLM-RS TXOPs is based on frames of a physical layer in which radio link quality is assessed.
15. The method of claim 11 , further comprising when an RLM-RS TXOP is missed, providing an indication that the RLM-RS TXOP was missed to a higher layer.