Channel access with conditional variable energy detection thresholds in shared frequency bands

1. A method of wireless communication performed by a first wireless communication device, the method comprising:

performing, during a deferral period of a listen-before talk (LBT) procedure, a first clear channel assessment (CCA) in a shared radio frequency band based on a first energy detection threshold, wherein performing the first CCA comprises obtaining at least one signal energy measurement;

performing, during a countdown period of the LBT procedure subsequent to the deferral period, a second CCA in the shared radio frequency band based on a second energy detection threshold, wherein the second energy detection threshold is higher than the first energy detection threshold, and wherein the performing the second CCA based on the second energy detection threshold is based on the at least one signal energy measurement satisfying a measurement threshold that is lower than the first energy detection threshold; and

transmitting, to a second wireless communication device in the shared radio frequency band based on the second CCA, a communication signal.

2. The method of claim 1 , further comprising determining a duration of the deferral period based on a priority class associated with the communication signal.

3. The method of claim 1 , further comprising determining a duration of the countdown period based on a random back-off.

4. The method of claim 1 , further comprising determining the second energy detection threshold based on a comparison of the at least one signal energy measurement to the measurement threshold.

5. The method of claim 4 , wherein the determining the second energy detection threshold further comprises:

assigning a first reference energy detection threshold to the second energy detection threshold in response to the at least one signal energy measurement failing to satisfy the measurement threshold; or

assigning a second reference energy detection threshold to the second energy detection threshold in response to the at least one signal energy measurement satisfying the measurement threshold, the second reference energy detection threshold being greater than the first reference energy detection threshold.

6. The method of claim 5 , wherein the first reference energy detection threshold is the same as the first energy detection threshold.

7. The method of claim 1 , wherein the first energy detection threshold is approximately −72 dBm.

8. The method of claim 1 , wherein the first wireless communication device comprises a base station.

9. The method of claim 1 , wherein the first wireless communication device comprises a user equipment.

10. An apparatus comprising:

a processor configured to:

perform, during a deferral period of a listen-before talk (LBT) procedure, a first clear channel assessment (CCA) in a shared radio frequency band based on a first energy detection threshold, wherein performing the first CCA comprises obtaining at least one signal energy measurement; and

perform, during a countdown period of the LBT procedure subsequent to the deferral period, a second CCA in the shared radio frequency band based on a second energy detection threshold, wherein the second energy detection threshold is higher than the first energy detection threshold, and wherein the performing the second CCA based on the second energy detection threshold is based on the at least one signal energy measurement satisfying a measurement threshold that is lower than the first energy detection threshold; and

a transceiver configured to:

transmit, to a wireless communication device in the shared radio frequency band based on the second CCA, a communication signal.

11. The apparatus of claim 10 , wherein the processor is further configured to:

determine a duration of the deferral period based on a priority class associated with the communication signal.

12. The apparatus of claim 10 , wherein the processor is further configured to:

determine a duration of the countdown period based on a random back-off.

13. The apparatus of claim 10 , wherein the processor is further configured to:

determine the second energy detection threshold based on a comparison of the at least one signal energy measurement to the measurement threshold.

14. The apparatus of claim 13 , wherein the processor configured to determine the second energy detection threshold is further configured to:

assign a first reference energy detection threshold to the second energy detection threshold in response to the at least one signal energy measurement failing to satisfy the measurement threshold; or

assign a second reference energy detection threshold to the second energy detection threshold in response to the at least one signal energy measurement satisfies the measurement threshold, the second reference energy detection threshold being greater than the first reference energy detection threshold.

15. The apparatus of claim 14 , wherein the first reference energy detection threshold is the same as the first energy detection threshold.

16. The apparatus of claim 10 , wherein the first energy detection threshold is approximately −72 dBm.

17. A non-transitory computer-readable medium having program code recorded thereon, the program code comprising:

code for causing a first wireless communication device to perform, during a deferral period of a listen-before talk (LBT) procedure, a first clear channel assessment (CCA) in a shared radio frequency band based on a first energy detection threshold, wherein performing the first CCA comprises obtaining at least one signal energy measurement;

code for causing the first wireless communication device to perform, during a countdown period of the LBT procedure subsequent to the deferral period, a second CCA in the shared radio frequency band based on a second energy detection threshold, wherein the second energy detection threshold is higher than the first energy detection threshold, and wherein the performing the second CCA based on the second energy detection threshold is based on the at least one signal energy measurement satisfying a measurement threshold that is lower than the first energy detection threshold; and

code for causing the first wireless communication device to transmit, to a second wireless communication device in the shared radio frequency band based on the second CCA, a communication signal.

18. The non-transitory computer-readable medium of claim 17 , wherein the program code further comprises code for causing the first wireless communication device to determine a duration of the deferral period based on a priority class associated with the communication signal.

19. The non-transitory computer-readable medium of claim 17 , wherein the program code further comprises code for causing the first wireless communication device to determine a duration of the countdown period based on a random back-off.

20. The non-transitory computer-readable medium of claim 17 , wherein the program code further comprises code for causing the first wireless communication device to determine the second energy detection threshold based on a comparison of the at least one signal energy measurement to the measurement threshold.

21. The non-transitory computer-readable medium of claim 20 , wherein the code for causing the first wireless communication device to determine the second energy detection threshold is further configured to:

assign a first reference energy detection threshold to the second energy detection threshold in response to the at least one signal energy measurement failing to satisfy the measurement threshold; or

assign a second reference energy detection threshold to the second energy detection threshold in response to the at least one signal energy measurement satisfies the measurement threshold, the second reference energy detection threshold being greater than the first reference energy detection threshold.

22. The non-transitory computer-readable medium of claim 21 , wherein the first reference energy detection threshold is the same as the first energy detection threshold.

23. An apparatus comprising:

means for performing, during a deferral period of a listen-before talk (LBT) procedure, a first clear channel assessment (CCA) in a shared radio frequency band based on a first energy detection threshold, wherein performing the first CCA comprises obtaining at least one signal energy measurement;

means for performing, during a countdown period of the LBT procedure subsequent to the deferral period, a second CCA in the shared radio frequency band based on a second energy detection threshold, wherein the second energy detection threshold is higher than the first energy detection threshold, and wherein the performing the second CCA based on the second energy detection threshold is based on the at least one signal energy measurement satisfying a measurement threshold that is lower than the first energy detection threshold; and

means for transmitting, to a wireless communication device in the shared radio frequency band based on the second CCA, a communication signal.

24. The apparatus of claim 23 , further comprising means for determining a duration of the deferral period based on a priority class associated with the communication signal.

25. The apparatus of claim 23 , further comprising means for determining a duration of the countdown period based on a random back-off.

26. The apparatus of claim 23 , further comprising means for determining the second energy detection threshold based on a comparison of the at least one signal energy measurement to the measurement threshold.

27. The apparatus of claim 26 , wherein the means for determining the second energy detection threshold is further configured to:

assign a first reference energy detection threshold to the second energy detection threshold in response to the at least one signal energy measurement failing to satisfy the measurement threshold; or

assign a second reference energy detection threshold to the second energy detection threshold in response to the at least one signal energy measurement satisfies the measurement threshold, the second reference energy detection threshold being greater than the first reference energy detection threshold.

28. The apparatus of claim 27 , wherein the first reference energy detection threshold is the same as the first energy detection threshold.

29. The apparatus of claim 23 , wherein the wireless communication device comprises a base station.

30. The apparatus of claim 23 , wherein the wireless communication device comprises a user equipment.