Starting offset for new radio-unlicensed (NR-U) uplink transmission

1. A method of wireless communication, comprising:

receiving, by a user equipment (UE) from a base station (BS), a downlink control information (DCI) message scheduling a first communication signal, the DCI message including a cyclic prefix (CP) extension length configuration associated with a gap duration for a listen-before-talk (LBT) to be used for transmitting the scheduled first communication signal; and

transmitting, by the UE to the BS, the first communication signal including a CP extension having a length based on the CP extension length configuration.

2. The method of claim 1 , wherein the first communication signal includes one or more symbols, and wherein a beginning symbol of the one or more symbols is prepended with the CP extension.

3. The method of claim 2 , wherein the transmitting the first communication signal includes:

transmitting, by the UE to the BS, the one or more symbols in an uplink direction based on a first symbol boundary.

4. The method of claim 1 , wherein the CP extension length configuration further indicates that the length of the CP extension corresponds to a symbol duration subtracted by the gap duration of 25 microseconds (μs).

5. The method of claim 4 , wherein the first communication signal is spaced apart from a second communication signal by the gap duration.

6. The method of claim 1 , wherein the CP extension length configuration further indicates that the length of the CP extension corresponds to a symbol duration subtracted by the gap duration and a timing advance, and wherein the gap duration is 16 microseconds (μs) or 25 μs.

7. The method of claim 6 , further comprising:

receiving, by the UE from the BS before the first communication signal, a second communication signal in a downlink direction, the first communication signal and the second communication signal being spaced apart by the gap duration.

8. The method of claim 1 , wherein the CP extension length configuration indicates whether the CP extension is configured to provide the gap duration for no LBT or a category two LBT.

9. The method of claim 1 , wherein the length for the CP extension is based on at least one of a symbol duration or the gap duration.

10. The method of claim 1 , wherein the CP extension length configuration indicates the length of the CP extension corresponds to at least one of:

a symbol duration subtracted by a 25 microseconds (μs) gap duration;

the symbol duration subtracted by the 25 microseconds (μs) gap duration and a timing advance; or

the symbol duration subtracted by a 16 μs gap duration and the timing advance.

11. The method of claim 1 , wherein the transmitting the first communication signal includes:

transmitting, by the UE to the BS, a physical uplink shared channel (PUSCH) signal in response to the DCI message.

12. The method of claim 1 , wherein the transmitting the first communication signal includes:

transmitting, by the UE to the BS, a physical uplink control channel (PUCCH) signal in response to the DCI message and a downlink communication signal associated with the DCI message.

13. The method of claim 1 , further comprising:

receiving, by the UE from the BS, a plurality of scheduling grants for communications in consecutive periods, each scheduling grant of the plurality of scheduling grants including a CP extension length configuration;

determining, by the UE, whether to include a CP extension in a third communication signal based on a signal detection in a first period of the consecutive periods; and

transmitting, by the UE to the BS, the third communication signal during a second period of the consecutive periods, the second period adjacent to the first period.

14. An apparatus comprising:

a transceiver configured to:

receive, from a base station (BS), a downlink control information (DCI) message scheduling a first communication signal, the DCI message including a cyclic prefix (CP) extension length configuration associated with a gap duration for a listen-before-talk (LBT) to be used for transmitting the scheduled first communication signal; and

transmit, to the BS, the first communication signal including a CP extension having a length based on the CP extension length configuration.

15. The apparatus of claim 14 , wherein the transceiver configured to communicate the first communication signal is further configured to:

transmit, to the BS, the first communication signal including one or more symbols in an uplink direction based on a first symbol boundary, wherein a beginning symbol of the one or more symbols is prepended with the CP extension.

16. The apparatus of claim 14 , wherein the CP extension length configuration further indicates that the length of the CP extension corresponds to a symbol duration subtracted by the gap duration of 25 microseconds (μs), and wherein the first communication signal is spaced apart from a second communication signal by the gap duration.

17. The apparatus of claim 14 , wherein the CP extension length configuration further indicates that the length of the CP extension corresponds to a symbol duration subtracted by the gap duration and a timing advance, wherein the gap duration is 16 microseconds (μs) or 25 μs, and wherein the transceiver is further configured to:

receive, from the BS before the first communication signal, a second communication signal in a downlink direction, the first communication signal and the second communication signal spaced apart by the gap duration.

18. The apparatus of claim 14 , wherein the CP extension length configuration indicates whether the CP extension is configured to provide the gap duration for no LBT or a category two LBT.

19. The apparatus of claim 14 , wherein the length for the CP extension is based on at least one of a symbol duration or the gap duration.

20. The apparatus of claim 14 , wherein the CP extension length configuration further indicates that the length of the CP extension corresponds to at least one of:

a symbol duration subtracted by a 25 microseconds (μs) gap duration;

the symbol duration subtracted by the 25 microseconds (μs) gap duration and a timing advance; or

the symbol duration subtracted by a 16 μs gap duration and the timing advance.

21. The apparatus of claim 14 , wherein:

the transceiver is further configured to:

receive, from the BS, a plurality of scheduling grants for communications in consecutive periods, each scheduling grant of the plurality of scheduling grants including a CP extension length configuration; and

transmit, to the BS, a third communication signal during a first period of the consecutive periods, and

the apparatus further comprises:

a processor configured to determine whether to include a CP extension in the third communication signal based on a signal detection in a second period of the consecutive periods, the second period adjacent to the first period.

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

code for causing a user equipment (UE) to receive, from a base station (BS), a downlink control information (DCI) message scheduling a first communication signal, the DCI message including a cyclic prefix (CP) extension length configuration associated with a gap duration for a listen-before-talk (LBT) to be used for transmitting the scheduled first communication signal; and

code for causing the UE to transmit, to the BS, the first communication signal including a CP extension having a length based on the CP extension length configuration.

23. The non-transitory computer-readable medium of claim 22 , wherein the CP extension length configuration further indicates that the length of the CP extension corresponds to a symbol duration subtracted by the gap duration of 25 microseconds (μs), and wherein the first communication signal is spaced apart from a second communication signal by the gap duration.

24. The non-transitory computer-readable medium of claim 22 , wherein the CP extension length configuration further indicates that the length of the CP extension corresponds to a symbol duration subtracted by the gap duration and a timing advance, wherein the gap duration is 16 microseconds (μs) or 25 μs, and wherein the program code further comprises:

code for causing the UE to receive, from the BS before the first communication signal, a second communication signal in a downlink direction, the first communication signal and the second communication signal spaced apart by the gap duration.

25. The non-transitory computer-readable medium of claim 22 , wherein the CP extension length configuration further indicates that the length of the CP extension corresponds to at least one of:

a symbol duration subtracted by a 25 microseconds (μs) gap duration;

the symbol duration subtracted by the 25 microseconds (μs) gap duration and a timing advance; or

the symbol duration subtracted by a 16 μs gap duration and the timing advance.

26. The non-transitory computer-readable medium of claim 22 , further comprising:

code for causing the UE to receive, from the BS, a plurality of scheduling grants for communications in consecutive periods, each scheduling grant of the plurality of scheduling grants including a CP extension length configuration;

code for causing the UE to determine whether to include a CP extension in a third communication signal based on a signal detection in a first period of the consecutive periods; and

code for causing the UE to transmit, to the BS, the third communication signal during a second period of the consecutive periods, the second period adjacent to the first period.