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 scheduling information for an uplink transmission to be made over a plurality of carriers of a shared radio frequency spectrum band;
identifying a carrier of the plurality of carriers for which to perform a first type of listen before talk (LBT) procedure;
performing the first type of LBT procedure for the identified carrier;
performing a second type of LBT procedure for each carrier of the plurality of carriers other than the identified carrier, the second type of LBT procedure having a shorter contention window than the first type of LBT procedure; and
transmitting the uplink transmission over the plurality of carriers based at least in part on the performance of the first type of LBT procedure for the identified carrier and the performance of the second type of LBT procedure for each carrier other than the identified carrier.
2. The method of claim 1 , wherein identifying the carrier comprises identifying the carrier from an indication received from a network access device or independently identifying the carrier.
3. A method for wireless communication at a network access device, comprising:
scheduling an uplink transmission to be made by a user equipment (UE) over a plurality of carriers of a shared radio frequency spectrum band; and
transmitting, to the UE, an indication of a single carrier of the plurality of carriers for which to perform a first type of listen before talk (LBT) procedure.
4. The method of claim 3 , wherein transmitting the indication of the single carrier comprises one or more of:
transmitting the indication of the single carrier in uplink downlink control information (DCI) for the single carrier; or
transmitting the indication of the single carrier in uplink DCI for each carrier of the plurality of carriers.
5. 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 scheduling information for an uplink transmission to be made over a plurality of carriers of a shared radio frequency spectrum band;
identify a carrier of the plurality of carriers for which to perform a first type of listen before talk (LBT) procedure;
perform the first type of LBT procedure for the identified carrier;
perform a second type of LBT procedure for each carrier of the plurality of carriers other than the identified carrier, the second type of LBT procedure having a shorter contention window than the first type of LBT procedure; and
transmit the uplink transmission over the plurality of carriers based at least in part on the performance of the first type of LBT procedure for the identified carrier and the performance of the second type of LBT procedure for each carrier other than the identified carrier.
6. The apparatus of claim 5 , wherein the instructions to identify the carrier are executable by the processor to cause the apparatus to identify the carrier from an indication received from a network access device or independently identifying the carrier.
7. An apparatus for wireless communication at a network access device, 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:
schedule an uplink transmission to be made by a user equipment (UE) over a plurality of carriers of a shared radio frequency spectrum band; and
transmit, to the UE, an indication of a single carrier of the plurality of carriers for which to perform a first type of listen before talk (LBT) procedure.
8. The apparatus of claim 7 , wherein the instructions to transmit the indication of the single carrier are executable by the processor to cause the apparatus to:
transmit the indication of the single carrier in uplink downlink control information (DCI) for the single carrier; or
transmit the indication of the single carrier in uplink DCI for each carrier of the plurality of carriers.