Handling gaps in uplink transmission in new radio unlicensed
Methods, systems, and devices for wireless communications are described. A user equipment (UE) may receive a set of one or more uplink grants scheduling at least a first uplink transmission and a second uplink transmission during a channel occupancy time of an unlicensed radio frequency spectrum band. The UE may identify a transmission gap between the first uplink transmission and the second uplink transmission of the plurality of uplink transmissions by the UE during the channel occupancy time, the transmission gap exceeding a threshold time. The UE may determine that the transmission gap corresponds to a lost uplink grant. The UE may modify the first uplink transmission or the second uplink transmission based at least in part on the determination that the transmission gap corresponds to the lost uplink grant.
1. A method for wireless communication at a user equipment (UE), comprising:
receiving an uplink grant scheduling a plurality of uplink transmissions during a plurality of transmission time intervals (TTIs) in an unlicensed radio frequency spectrum band;
modifying, based at least in part on the uplink grant, one or more uplink transmissions of the plurality of uplink transmissions by reordering the one or more uplink transmissions of the plurality of uplink transmissions; and
performing the plurality of uplink transmissions based at least in part on the uplink grant and the modifying.
2. The method of claim 1 , wherein the reordering the one or more uplink transmissions comprises scheduling uplink retransmissions before scheduling new uplink transmissions.
3. The method of claim 1 , wherein modifying the one or more uplink transmissions comprises:
adding padding bits to a subset of the plurality of uplink transmissions for which no data is available.
4. The method of claim 1 , wherein modifying the one or more uplink transmissions comprises:
adding padding bits to each of the plurality of uplink transmissions that are associated with the an empty uplink buffer status.
5. The method of claim 1 , wherein modifying the one or more uplink transmissions comprises:
determining, based at least in part on the uplink grant, that the plurality of uplink transmissions are configured for skipping; and
skipping one or more uplink transmissions associated with a transmission gap of the plurality of uplink transmissions.
6. The method of claim 1 , wherein modifying the one or more uplink transmissions comprises:
detecting, based at least in part on the uplink grant and an uplink buffer status, a transmission gap associated with a lost uplink grant in the plurality of TTIs; and
performing a full listen-before-talk procedure before an uplink transmission following the transmission gap based at least in part on the determination that the transmission gap corresponds to the lost uplink grant.
7. The method of claim 1 , wherein modifying the one or more uplink transmissions comprises:
detecting, based at least in part on the uplink grant and an uplink buffer status, a transmission gap in the plurality of TTIs;
determining that a duration of the transmission gap is within a threshold range; and
performing, based at least in part on the duration being within the threshold range, a short listen-before-talk procedure before an uplink transmission following the transmission gap.
8. The method of claim 1 , wherein modifying the one or more uplink transmissions comprises:
detecting, based at least in part on the uplink grant and an uplink buffer status, a transmission gap in the plurality of TTIs; and
performing a short listen-before-talk procedure before an uplink transmission following the transmission gap based at least in part on the uplink grant configuring the short listen-before-talk procedure or on the uplink transmission being performed during a channel occupancy time associated with the plurality of TTIs.
9. An apparatus for wireless communication at a user equipment (UE), comprising: a processor, memory coupled with the processor; and instructions stored in the memory and executable by the processor to cause the apparatus to:
receive an uplink grant scheduling a plurality of uplink transmissions during a plurality of transmission time intervals (TTIs) in an unlicensed radio frequency spectrum band;
modify, based at least in part on the uplink grant, one or more uplink transmissions of the plurality of uplink transmissions by reordering the plurality of uplink transmissions; and
perform the plurality of uplink transmissions based at least in part on the uplink grant and the modifying.
10. The apparatus of claim 9 , wherein the instructions to reorder the one or more uplink transmissions are executable by the processor to cause the apparatus to:
schedule uplink retransmissions before scheduling new uplink transmissions.
11. The apparatus of claim 9 , wherein the instructions to modify the one or more uplink transmissions are executable by the processor to cause the apparatus to:
add padding bits to a subset of the plurality of uplink transmissions for which no data is available.
12. The apparatus of claim 9 , wherein the instructions to modify the one or more uplink transmissions are executable by the processor to cause the apparatus to:
add padding bits to each of the plurality of uplink transmissions that are associated with the an empty uplink buffer status.
13. The apparatus of claim 9 , wherein the instructions to modify the one or more uplink transmissions are executable by the processor to cause the apparatus to:
determine, based at least in part on the uplink grant, that the plurality of uplink transmissions are configured for skipping; and
skip one or more uplink transmissions that are associated with a transmission gap of the plurality of uplink transmissions.
14. The apparatus of claim 9 , wherein the instructions to modify the one or more uplink transmissions are executable by the processor to cause the apparatus to:
detect, based at least in part on the uplink grant and an uplink buffer status, a transmission gap associated with a lost uplink grant in the plurality of TTIs; and
perform a full listen-before-talk procedure before an uplink transmission following the transmission gap based at least in part on the determination that the transmission gap corresponds to the lost uplink grant.
15. The apparatus of claim 9 , wherein the instructions to modify the one or more uplink transmissions are executable by the processor to cause the apparatus to:
detect, based at least in part on the uplink grant and an uplink buffer status, a transmission gap in the plurality of TTIs;
determine that a duration of the transmission gap is within a threshold range; and
perform, based at least in part on the duration being within the threshold range, a short listen-before-talk procedure before an uplink transmission following the transmission gap.
16. The apparatus of claim 9 , wherein the instructions to modify the one or more uplink transmissions are executable by the processor to cause the apparatus to:
detect, based at least in part on the uplink grant and an uplink buffer status, a transmission gap in the plurality of TTIs; and
perform a short listen-before-talk procedure before an uplink transmission following the transmission gap based at least in part on the uplink grant configuring the short listen-before-talk procedure or on the uplink transmission being performed during a channel occupancy time associated with the plurality of TTIs.