Techniques for communicating on an uplink in a shared radio frequency spectrum band
Techniques are described for wireless communication. One method includes detecting a first reference signal received from a user equipment (UE) in a reference scheduled transmission burst including a plurality of contiguous transmission time intervals (TTIs) received over a shared radio frequency spectrum band; identifying a reference TTI in which the first reference signal is received; determining a contention window size usable by the UE to contend for access to the shared radio frequency spectrum band; and transmitting an indication of the determined contention window size to the UE.
1. A method for wireless communication at a user equipment (UE), comprising:
receiving a first uplink grant for transmitting over a shared radio frequency spectrum band, the first uplink grant associated with a first listen before talk (LBT) priority class;
performing a first LBT procedure based at least in part on the first LBT priority class to contend for access to the shared radio frequency spectrum band, the first LBT procedure concluding at a LBT state;
determining, based at least in part on the LBT state, to not transmit over the shared radio frequency spectrum band in accordance with the first uplink grant;
receiving a second uplink grant for transmitting over the shared radio frequency spectrum band, the second uplink grant associated with a second LBT priority class; and
performing a second LBT procedure based at least in part on the second LBT priority class, the first LBT priority class, and the LBT state to contend for access to the shared radio frequency spectrum band.
2. The method of claim 1 , further comprising:
determining the first LBT priority class and the second LBT priority class are a same LBT priority class; and
initializing the second LBT procedure based at least in part on the LBT state.
3. The method of claim 1 , further comprising:
determining the first LBT priority class and the second LBT priority class are different LBT priority classes;
adjusting the LBT state based at least in part on a difference between the first LBT priority class and the second LBT priority class; and
initializing the second LBT procedure based at least in part on the adjusted LBT state.
4. An apparatus for wireless communication at a user equipment (UE), comprising:
a processor,
memory in electronic communication with the processor; and
instructions stored in the memory and executable by the processor to cause the apparatus to:
receive a first uplink grant for transmitting over a shared radio frequency spectrum band, the first uplink grant associated with a first listen before talk (LBT) priority class;
perform a first LBT procedure based at least in part on the first LBT priority class to contend for access to the shared radio frequency spectrum band, the first LBT procedure concluding at a LBT state;
determine, based at least in part on the LBT state, to not transmit over the shared radio frequency spectrum band in accordance with the first uplink grant;
receive a second uplink grant for transmitting over the shared radio frequency spectrum band, the second uplink grant associated with a second LBT priority class; and
perform a second LBT procedure based at least in part on the second LBT priority class, the first LBT priority class, and the LBT state to contend for access to the shared radio frequency spectrum band.
5. The apparatus of claim 4 , wherein the instructions are further executable by the processor to cause the apparatus to:
determine the first LBT priority class and the second LBT priority class are a same LBT priority class; and
initialize the second LBT procedure based at least in part on the LBT state.
6. The apparatus of claim 4 , wherein the instructions are further executable by the processor to cause the apparatus to:
determine the first LBT priority class and the second LBT priority class are different LBT priority classes;
adjust the LBT state based at least in part on a difference between the first LBT priority class and the second LBT priority class; and
initialize the second LBT procedure based at least in part on the adjusted LBT state.
7. An apparatus for wireless communication at a user equipment (UE), comprising:
means for receiving a first uplink grant for transmitting over a shared radio frequency spectrum band, the first uplink grant associated with a first listen before talk (LBT) priority class;
means for performing a first LBT procedure based at least in part on the first LBT priority class to contend for access to the shared radio frequency spectrum band, the first LBT procedure concluding at a LBT state;
means for determining, based at least in part on the LBT state, to not transmit over the shared radio frequency spectrum band in accordance with the first uplink grant;
means for receiving a second uplink grant for transmitting over the shared radio frequency spectrum band, the second uplink grant associated with a second LBT priority class; and
means for performing a second LBT procedure based at least in part on the second LBT priority class, the first LBT priority class, and the LBT state to contend for access to the shared radio frequency spectrum band.
8. The apparatus of claim 7 , further comprising:
means for determining the first LBT priority class and the second LBT priority class are a same LBT priority class; and
means for initializing the second LBT procedure based at least in part on the LBT state.
9. The apparatus of claim 7 , further comprising:
means for determining the first LBT priority class and the second LBT priority class are different LBT priority classes;
means for adjusting the LBT state based at least in part on a difference between the first LBT priority class and the second LBT priority class; and
means for initializing the second LBT procedure based at least in part on the adjusted LBT state.
10. A non-transitory computer-readable medium storing code for wireless communication at a user equipment (UE), the code comprising instructions executable by a processor to:
receive a first uplink grant for transmitting over a shared radio frequency spectrum band, the first uplink grant associated with a first listen before talk (LBT) priority class;
perform a first LBT procedure based at least in part on the first LBT priority class to contend for access to the shared radio frequency spectrum band, the first LBT procedure concluding at a LBT state;
determine, based at least in part on the LBT state, to not transmit over the shared radio frequency spectrum band in accordance with the first uplink grant;
receive a second uplink grant for transmitting over the shared radio frequency spectrum band, the second uplink grant associated with a second LBT priority class; and
perform a second LBT procedure based at least in part on the second LBT priority class, the first LBT priority class, and the LBT state to contend for access to the shared radio frequency spectrum band.
11. The non-transitory computer-readable medium of claim 10 , wherein the instructions are further executable to:
determine the first LBT priority class and the second LBT priority class are a same LBT priority class; and
initialize the second LBT procedure based at least in part on the LBT state.
12. The non-transitory computer-readable medium of claim 10 , wherein the instructions are further executable to:
determine the first LBT priority class and the second LBT priority class are different LBT priority classes;
adjust the LBT state based at least in part on a difference between the first LBT priority class and the second LBT priority class; and
initialize the second LBT procedure based at least in part on the adjusted LBT state.