RLM and beam failure detection based on a mix of different reference signals

1. A method, in a user equipment (UE) comprising:

performing measurements based on a plurality of radio link management (RLM) measurement sources received in beam-formed downlink signals, wherein the measurements indicate a quality of a given cell or beam, and wherein the plurality of RLM measurement sources comprises two or more of: one or more first reference signals (RSs); one or more second RSs of a different type than the first one or more RSs; and one or more physical channel quality indicators obtained from non-reference-signal data in the beam-formed downlink signals;

for each of a plurality of evaluation periods and for each of the plurality of RLM measurement sources used to perform measurements, determining whether a measurement for the respective RLM measurement source indicates an out-of-sync event in response to the measurement being below a first threshold; and

performing one or more RLM actions based on determined occurrences of out-of-sync events.

2. The method of claim 1 , wherein the plurality of RLM measurement sources comprises one or more channel-state information reference signals (CSI-RSs) and reference signals from one or more synchronization signal blocks (SSBs).

3. The method of claim 1 , wherein performing the one or more RLM actions based on the determined occurrences of out-of-sync events comprises performing a first RLM action in response to determining that a threshold number of consecutive out-of-sync events has occurred.

4. The method of claim 3 , wherein the first RLM action comprises starting a timer.

5. The method of claim 3 , wherein the first RLM action comprises one of: providing higher layer notifications; declaring radio link failure (RLF); and declaring beam failure.

6. The method of claim 3 , wherein the threshold number of consecutive out-of-sync events is established separately for each source of the plurality of RLM measurement sources.

7. The method of claim 3 , wherein the threshold number of consecutive out-of-sync events for one or more of the plurality of RLM measurement sources is shared by a different RLM measurement source.

8. The method of claim 1 , wherein performing the measurements based on the plurality of RLM measurement sources comprises:

monitoring a control channel region of one or more of the beam-formed downlink signals and associated with a control channel message for the UE; and

in response to determining that data is scheduled in a given subframe of the control channel region:

determining, during an evaluation period, a first measurement by computing a first quality estimate using one or more first RSs, wherein the first RSs are demodulation reference symbols (DMRS) in the control channel region; and

determining, during the evaluation period, a second measurement by computing a second quality estimate using the one or more second RSs, wherein the one or more second RSs are one of: one or more primary synchronization signals (PSSs); one or more secondary synchronization signals (SSSs); one or more tertiary synchronization signals (TSSs); one or more DMRSs used for a physical broadcast channel (PBCH); one or more of channel state information-reference signals (CSI-RSs); one or more mobility reference signals (MRSs); and one or more beam measurement reference signals (BRSs).

9. The method of claim 8 , wherein the first quality estimate is computed as an average of first radio signal metrics measured from the one or more first RSs over the evaluation period, and wherein the second quality estimate is computed as an average of second radio signal metrics measured from the one or more second RSs over the evaluation period.

10. A method in a base station of a wireless communications system, the method comprising:

transmitting, in beam-formed downlink signals, a plurality of radio link management (RLM) measurement sources, wherein the plurality of RLM measurement sources comprises one or more first reference signals RSs), and one or more second RSs of a different type than the first one or more RSs; and

configuring a user equipment (UE) to perform measurements based on a plurality of RLM measurement sources received in the beam-formed downlink signals, wherein the measurements indicate a quality of a given cell or beam, thereby enabling the UE to perform one or more RLM actions based on occurrences of in-sync and out-of-sync events for each of the RLM measurement sources, determined from the measurements.

11. A user equipment (UE) comprising:

transceiver circuitry configured to receive beam-formed downlink signals; and

processing circuitry operatively associated with the transceiver circuitry and configured to:

perform measurements based on a plurality of radio link management (RLM) measurement sources received in the beam-formed downlink signals, wherein the measurements indicate a quality of a given cell or beam, and wherein the plurality of RLM measurement sources comprises two or more of: one or more first reference signals (RSs); one or more second RSs of a different type than the first one or more RSs; and one or more physical channel quality indicators obtained from non-reference-signal data in the beam-formed downlink signals;

for each of a plurality of evaluation periods and for each of the plurality of RLM measurement sources used to perform measurements, determine whether a measurement for the respective RLM measurement source indicates an out-of-sync event in response to the measurement being below a first threshold; and

perform one or more RLM actions based on determined occurrences of out-of-sync events.

12. The UE of claim 11 , wherein the plurality of RLM measurement sources comprises one or more channel-state information reference signals (CSI-RS s) and reference signals from one or more synchronization signal blocks (SSBs).

13. The UE of claim 11 , wherein the processing circuitry is configured to perform the one or more RLM actions based on the determined occurrences of out-of-sync events by performing a first RLM action in response to determining that a threshold number of consecutive out-of-sync events has occurred.

14. The UE of claim 13 , wherein the first RLM action comprises starting a timer.

15. The UE of claim 13 , wherein the first RLM action comprises one of: providing higher layer notifications; declaring radio link failure (RLF); and declaring beam failure.

16. The UE of claim 13 , wherein the threshold number of consecutive out-of-sync events is established separately for each source of the plurality of RLM measurement sources.

17. The UE of claim 13 , wherein the threshold number of consecutive out-of-sync events for one or more of the plurality of RLM measurement sources is shared by a different RLM measurement source.

18. The UE of claim 11 , wherein the processing circuitry is configured to perform the measurements based on the plurality of RLM measurement sources by:

monitoring a control channel region of one or more of the beam-formed downlink signals and associated with a control channel message for the UE; and

in response to determining that data is scheduled in a given subframe of the control channel region:

determining, during an evaluation period, a first measurement by computing a first quality estimate using one or more first RSs, wherein the first RSs are demodulation reference symbols (DMRS) in the control channel region; and

determining, during the evaluation period, a second measurement by computing a second quality estimate using the one or more second RSs, wherein the one or more second RSs are one of: one or more primary synchronization signals (PSSs); one or more secondary synchronization signals (SSSs); one or more tertiary synchronization signals (TSSs); one or more DMRSs used for a physical broadcast channel (PBCH); one or more of channel state information-reference signals (CSI-RSs); one or more mobility reference signals (MRSs); and one or more beam measurement reference signals (BRSs).

19. The UE of claim 18 , wherein the first quality estimate is computed as an average of first radio signal metrics measured from the one or more first RSs over the evaluation period, and wherein the second quality estimate is computed as an average of second radio signal metrics measured from the one or more second RSs over the evaluation period.

20. The UE of claim 11 , wherein the processing circuitry is configured to:

receive configuration information for one or more of the plurality of RLM measurement sources; and

perform the measurements based on the configuration information.

21. A base station of a wireless communications system, the base station comprising:

transceiver circuitry configured to transmit beam-formed downlink signals and communicate with a user equipment, UE; and

processing circuitry operatively associated with the transceiver circuitry and configured to:

transmit, in beam-formed downlink signals via the transceiver circuitry, a plurality of radio link management (RLM) measurement sources, wherein the plurality of RLM measurement sources comprises two or more of: one or more first reference signals (RSs), and one or more second RSs of a different type than the first one or more RSs; and

configure the UE to perform measurements based on a plurality of RLM measurement sources received in the beam-formed downlink signals, wherein the measurements indicate a quality of a given cell or beam, thereby enabling the UE to perform one or more RLM actions based on occurrences of in-sync and out-of-sync events for each of the RLM measurement sources, determined from the measurements.

22. The base station of claim 21 , wherein the processing circuitry is configured to:

transmit configuration information for one or more of the plurality of RLM measurement sources; and

configure the UE to perform the measurements based on the configuration information.

23. The base station of claim 22 , wherein the processing circuitry is configured to:

transmit additional RSs in time-frequency resources corresponding to those that would be used if a control channel message for the UE were included in the physical control channel region; and

transmit configuration information corresponding to the additional RSs.

24. The base station of claim 23 , wherein the processing circuitry is configured to deactivate the transmitting of the additional RS s in the time-frequency resources when a control channel message is to again be included in the physical control channel region.

25. A non-transitory computer-readable medium comprising, stored thereupon, a computer program comprising computer program code that, when run on a user equipment (UE) causes the UE to:

perform measurements based on a plurality of radio link management (RLM) measurement sources received in beam-formed downlink signals, wherein the measurements indicate a quality of a given cell or beam, and wherein the plurality of RLM measurement sources comprises two or more of: one or more first reference signals (RSs); one or more second RSs of a different type than the first one or more RSs; and one or more physical channel quality indicators obtained from non-reference-signal data in the beam-formed downlink signals; and

for each of a plurality of evaluation periods and for each of the plurality of RLM measurement sources used to perform measurements:

determine whether a measurement for the respective RLM measurement source indicates an out-of-sync event in response to the measurement being below a first threshold; and

perform one or more RLM actions based on determined occurrences of out-of-sync events.

26. A non-transitory computer-readable medium comprising, stored thereupon, a computer program comprising computer program code that, when run on a base station causes the base station to:

transmit, in beam-formed downlink signals, a plurality of radio link management (RLM) measurement sources, wherein the plurality of RLM measurement sources comprises one or more first reference signals (RSs), and one or more second RSs different than the first one or more RSs; and

configure a user equipment (UE) to perform measurements based on a plurality of RLM measurement sources received in the beam-formed downlink signals, wherein the measurements indicate a quality of a given cell or beam, thereby enabling the UE to perform one or more RLM actions based on occurrences of in-sync and out-of-sync events for each of the RLM measurement sources, determined from the measurements.