RLM enhancements for 5G networks

1. An apparatus of a user equipment (UE), the apparatus comprising:

processing circuitry, wherein to configure the UE for radio link monitoring (RLM) in a New Radio-Unlicensed (NR-U) network, the processing circuitry is to:

decode radio resource control (RRC) signaling from a base station, the RRC signaling including configuration information to configure one or more transmission occasions for a plurality of RLM reference signals (RLM-RSs);

perform a primary synchronization signal (PSS) or a secondary synchronization signal (SSS) or a physical broadcast channel (PBCH) detection to determine a number of first RLM-RSs of the plurality of RLM-RSs that are successfully transmitted during the transmission occasions within an evaluation duration;

perform signal measurements on the first RLM-RSs that are successfully transmitted within the evaluation duration to determine a hypothetical block error rate (BLER) for physical downlink control channel (PDCCH) reception, the signal measurements performed during the transmission occasions within the evaluation duration; and

generate based on the signal measurements, one of an in-sync (IS) indicator or an out-of-sync (OOS) indicator for communication to a higher layer;

generate a transmission failure (TXT) indicator when the number of first RLM-RSs of the plurality of RLM-RSs that are successfully transmitted during the transmission occasions within the evaluation duration is zero or is smaller than a threshold number, the threshold number configured by higher layer signaling; and

memory coupled to the processing circuitry and configured to store the signal measurements.

2. The apparatus of claim 1 , wherein the processing circuitry is to:

upon generating a total of N 312 number of consecutive TXF indicators including the TXF indicator, start a radio link failure (RLF) timer T 310 ,

wherein N 312 and the T 310 timer are configured by higher layer signaling.

3. The apparatus of claim 2 , wherein the processing circuitry is to:

initiate an RLF procedure upon expiration of the RLF timer T 310 .

4. The apparatus of claim 2 , wherein the processing circuitry is to:

upon generating a total of N 311 number of consecutive IS indicators without a TXF indicator, stopping the RLF timer T 310 .

5. The apparatus of claim 1 , wherein the evaluation duration comprises a first pre-configured time duration, and wherein the processing circuitry is to:

when the number is higher than the threshold number, perform an evaluation on the BLER for a subset of the RLM-RSs that are successfully transmitted within the first pre-configured time duration within the transmission occasions; and

generate the OOS indicator when the BLER for a number of RLM-RSs of the plurality of RLM-RSs that are successfully transmitted within the first pre-configured time duration is higher than an OOS threshold.

6. The apparatus of claim 5 , wherein the evaluation duration comprises a second pre-configured time duration, and wherein the processing circuitry is to:

when the number is higher than the threshold number, perform an evaluation on the BLER for a subset of the RLM-RSs that are successfully transmitted within the second pre-configured time duration within the transmission occasions; and

generate the IS indicator when the BLER for the number of RLM-RSs of the plurality of RLM-RSs that are successfully transmitted within the second pre-configured time duration is lower than an IS threshold.

7. The apparatus of claim 6 , wherein the threshold number, the OOS threshold, and the IS threshold are configured by the RRC signaling.

8. The apparatus of claim 1 , wherein the processing circuitry is to:

perform a physical broadcast channel (PBCH) detection to determine the number of RLM-RSs of the plurality of RLM-RSs that are successfully transmitted during the transmission occasions.

9. The apparatus of claim 1 , wherein the processing circuitry is to:

for each transmission occasion within the evaluation duration, encode for transmission to the base station at least one of the following: the TXF indicator, an indicator of absence of a TXF during the transmission occasion, and a reference signal received power (RSRP) associated with an RLM-RS of the plurality of RLM-RSs received during the transmission occasion.

10. The apparatus of claim 1 , further comprising transceiver circuitry coupled to the processing circuitry; and, one or more antennas coupled to the transceiver circuitry.

11. A computer-readable non-transitory storage medium that stores instructions for execution by one or more processors of a user equipment (UE), the instructions to configure the UE for radio link monitoring (RLM) in a New Radio-Unlicensed (NR-U) network, and to cause the UE to:

decode radio resource control (RRC) signaling from a base station, the RRC signaling including configuration information to configure transmission occasions for a plurality of RLM reference signals (RLM-RSs);

perform a primary synchronization signal (PSS) or a secondary synchronization signal (SSS) detection to determine a number of first RLM-RSs of the plurality of RLM-RSs that are successfully transmitted during the transmission occasions within an evaluation duration;

perform signal measurements on the first RLM-RSs that are successfully transmitted within the evaluation duration to determine a hypothetical block error rate (BLER) for physical downlink control channel (PDCCH) reception, the signal measurements performed when the number is higher than a threshold number;

generate a transmission failure (TXT) indicator when the number of first RLM-RSs of the plurality of RLM-RSs that are successfully transmitted during the transmission occasions within the evaluation duration is zero or is smaller than a threshold number, the threshold number configured by higher layer signaling; and

generate based on the signal measurements, one of an in-sync (IS) indicator or an out-of-sync (OOS) indicator for communication to a higher layer.

12. The computer-readable non-transitory storage medium of claim 11 , wherein the instructions further cause the UE to:

upon generating a total of N 312 number of consecutive TXF indicators including the TXF indicator, start a radio link failure (RLF) timer T 310 ; and

initiate an RLF procedure upon expiration of the RLF timer T 310 , wherein N 312 and the T 310 timer are configured by higher layer signaling.

13. The computer-readable non-transitory storage medium of claim 12 , wherein the instructions further cause the UE to:

upon generating a total of N 311 number of consecutive IS indicators without a TXF indicator, stopping the RLF timer T 310 .

14. The computer-readable non-transitory storage medium of claim 11 , wherein the evaluation duration comprises a first pre-configured time duration, and wherein the instructions further cause the UE to:

when the number is higher than the threshold number, perform an evaluation on the BLER for a subset of the RLM-RSs that are successfully transmitted within the first pre-configured time duration within the transmission occasions; and

generate the OOS indicator when the BLER for a number of RLM-RSs of the plurality of RLM-RSs that are successfully transmitted within the first pre-configured time duration is higher than an OOS threshold.

15. The computer-readable non-transitory storage medium of claim 14 , wherein the evaluation duration comprises a second pre-configured time duration, and wherein the instructions further cause the UE to:

when the number is higher than the threshold number, perform an evaluation on the BLER for a subset of the RLM-RSs that are successfully transmitted within the second pre-configured time duration within the transmission occasions; and

generate the IS indicator when the BLER for the number of RLM-RSs of the plurality of RLM-RSs that are successfully transmitted within the second pre-configured time duration is lower than an IS threshold.

16. The computer-readable non-transitory storage medium of claim 11 , wherein the instructions further cause the UE to:

perform a physical broadcast channel (PBCH) detection to determine the number of RLM-RSs of the plurality of RLM-RSs that are successfully transmitted during the transmission occasions.

17. A method, comprising:

by a user equipment (UE):

wherein to configure the UE for radio link monitoring (RLM) in a New Radio-Unlicensed (NR-U) network, the processing circuitry is to:

decoding radio resource control (RRC) signaling from a base station, the RRC signaling including configuration information to configure one or more transmission occasions for a plurality of RLM reference signals (RLM-RSs);

performing a primary synchronization signal (PSS) or a secondary synchronization signal (SSS) or a physical broadcast channel (PBCH) detection to determine a number of first RLM-RSs of the plurality of RLM-RSs that are successfully transmitted during the transmission occasions within an evaluation duration;

performing signal measurements on the first RLM-RSs that are successfully transmitted within the evaluation duration to determine a hypothetical block error rate (BLER) for physical downlink control channel (PDCCH) reception, the signal measurements performed during the transmission occasions within the evaluation duration; and

generating based on the signal measurements, one of an in-sync (IS) indicator or an out-of-sync (OOS) indicator for communication to a higher layer;

generating a transmission failure (TXT) indicator when the number of first RLM-RSs of the plurality of RLM-RSs that are successfully transmitted during the transmission occasions within the evaluation duration is zero or is smaller than a threshold number, the threshold number configured by higher layer signaling; and

storing the signal measurements in a non-transitory computer-readable storage medium.

18. The method of claim 17 , further comprising:

upon generating a total of N 312 number of consecutive TXF indicators including the TXF indicator, starting a radio link failure (RLF) timer T 310 ,

wherein N 312 and the T 310 timer are configured by higher layer signaling.

19. The method of claim 18 , further comprising:

initiating an RLF procedure upon expiration of the RLF timer T 310 .

20. The method of claim 18 , further comprising:

upon generating a total of N 311 number of consecutive IS indicators without a TXF indicator, stopping the RLF timer T 310 .