Autonomous uplink transmission techniques using shared radio frequency spectrum
Techniques for autonomous uplink (AUL) transmissions are provided that allow for efficient use of shared radio frequency spectrum band resources. A user equipment (UE) may determine a duration of an AUL transmission and modify an uplink waveform or provide an indication to a base station of one or more channel resources that may be available for base station transmissions, in order to more fully utilize shared radio frequency spectrum band resources within a maximum channel occupancy time (MCOT). A base station may activate or deactivate AUL transmissions through downlink control information (DCI) transmitted to the UE. A UE and base station may exchange various other control information to provide relatively efficient autonomous uplink transmissions and use of the shared radio frequency spectrum band resources.
1. A method for wireless communication, comprising:
receiving, from a base station, radio resource control (RRC) signaling including an autonomous uplink configuration for unscheduled autonomous uplink transmissions in a shared radio frequency spectrum band with the base station;
receiving control information for activating autonomous uplink transmissions;
activating the autonomous uplink transmissions based at least in part on receiving the control information;
based at least in part on activating the autonomous uplink transmissions, sensing, during a configured time duration, for activity on a channel of the shared radio frequency spectrum band to contend for access to the channel of the shared radio frequency spectrum band in accordance with the autonomous uplink configuration; and
transmitting, to the base station, one or more autonomous uplink transmissions over the channel of the shared radio frequency spectrum band in accordance with the autonomous uplink configuration.
2. The method of claim 1 , further comprising:
receiving subsequent control information that deactivates the autonomous uplink transmissions; and
discontinuing contending for access to the channel of the shared radio frequency spectrum band responsive to receiving the subsequent control information.
3. The method of claim 1 , wherein the control information comprises a cyclic redundancy check (CRC) field scrambled with an identifier.
4. The method of claim 3 , wherein a value of the identifier indicates that the control information is associated with the autonomous uplink transmissions.
5. The method of claim 1 , wherein the autonomous uplink configuration enables autonomous uplink transmissions on one or more transmit antennas according to a multiple input multiple output (MIMO) configuration.
6. The method of claim 1 , further comprising:
signaling channel access parameters to the base station in uplink control information (UCI) included in the one or more autonomous uplink transmissions.
7. The method of claim 6 , wherein the UCI comprises:
an indication associated with a gap between the one or more autonomous uplink transmissions and a subsequent downlink transmission by the base station.
8. The method of claim 6 , wherein the UCI comprises:
an indication of a time period used by the base station for a subsequent downlink transmission.
9. The method of claim 6 , wherein the UCI comprises a channel contention procedure priority class.
10. The method of claim 6 , wherein the UCI comprises an indication of the base station to share a UE maximum channel occupancy time.
11. The method of claim 8 , wherein the indication of the time period indicates a quantity of subframes, a quantity of slots, or a quantity of subslots.
12. The method of claim 1 , wherein the control information is downlink control information (DCI).