Uplink shared channel repetition for ultra-reliable low latency communications

1. A method of wireless communication performed by a user equipment (UE), comprising:

mapping an ultra-reliable low-latency communication (URLLC) transmission to a set of symbols for uplink transmission,

wherein the mapping of the URLLC transmission relates to a transport block size determination,

wherein a first nominal repetition of the URLLC transmission is used to perform the transport block size determination, and

wherein, when a second nominal repetition of the URLLC transmission is split into two or more orphaned symbol repetitions and the set of symbols is a set of discrete Fourier transform spread orthogonal frequency division multiplexing (DFT-s-OFDM) symbols, the mapping of the URLLC transmission comprises dropping an orphaned symbol repetition, of the two or more orphaned symbol repetitions, having a length of one symbol; and

transmitting the URLLC transmission based at least in part on the mapping of the URLLC transmission.

2. The method of claim 1 , wherein the mapping of the URLLC transmission further comprises postponing another orphaned symbol repetition to an available transmission window.

3. The method of claim 1 , wherein a hybrid automatic repeat request (HARQ) acknowledgment (ACK) is multiplexed with a demodulation reference signal of the orphaned symbol repetition.

4. The method of claim 3 , wherein a Zadoff-Chu sequence is used for the demodulation reference signal.

5. The method of claim 3 , wherein the HARQ ACK is indicated using a cyclic shift of the demodulation reference signal.

6. The method of claim 3 , wherein a pseudo-noise sequence is used for the demodulation reference signal.

7. The method of claim 3 , wherein the HARQ ACK is indicated using a comb index of the demodulation reference signal.

8. The method of claim 1 , wherein a first actual resource or a first actual repetition is used to perform the transport block size determination.

9. The method of claim 1 , wherein one or more repetitions after a first repetition of the URLLC transmission are mapped with a demodulation reference symbol at a first set of symbols of the one or more repetitions.

10. The method of claim 1 , wherein one or more repetitions after a first repetition of the URLLC transmission in a slot are mapped with a demodulation reference symbol at a first set of symbols of the one or more repetitions and the first repetition of the URLLC transmission in the slot is mapped with a demodulation reference signal in a third or fourth symbol of the slot when a condition is satisfied.

11. The method of claim 1 , wherein all repetitions of the URLLC transmission are mapped with a demodulation reference symbol at a first set of symbols.

12. The method of claim 1 , wherein the mapping of the URLLC transmission relates to a priority of an aperiodic sounding reference signal (A-SRS) of the URLLC transmission; and

wherein the A-SRS preempts or cancels an uplink shared channel associated with a best-effort service.

13. The method of claim 1 , wherein the mapping of the URLLC transmission relates to a priority of an aperiodic sounding reference signal (A-SRS) of the URLLC transmission; and

wherein the A-SRS preempts or cancels an uplink shared channel in one or more conflicting symbols.

14. The method of claim 1 , wherein the mapping of the URLLC transmission relates to a priority of an aperiodic sounding reference signal (A-SRS) of the URLLC transmission; and

wherein the priority of the A-SRS is explicitly indicated to the UE.

15. The method of claim 1 , wherein the mapping of the URLLC transmission relates to a priority of an aperiodic sounding reference signal (A-SRS) of the URLLC transmission; and

wherein the priority of the A-SRS is explicitly indicated to the UE using downlink control information.

16. The method of claim 1 , wherein the mapping of the URLLC transmission relates to a priority of an aperiodic sounding reference signal (A-SRS) of the URLLC transmission; and

wherein the priority of the A-SRS is implicitly indicated to the UE.

17. The method of claim 1 , wherein the mapping of the URLLC transmission relates to a priority of an aperiodic sounding reference signal (A-SRS) of the URLLC transmission; and

wherein the priority of the A-SRS is implicitly indicated to the UE based at least in part on a timeline of downlink control information reception of the UE.

18. The method of claim 1 , wherein the mapping of the URLLC transmission relates to a shared channel mapping type of a repetition of the URLLC transmission.

19. The method of claim 1 , wherein a demodulation reference signal and data to be transmitted in the orphaned symbol repetition is frequency division multiplexed.

20. A user equipment (UE) for wireless communication, comprising:

a memory; and

one or more processors coupled to the memory, the one or more processors configured to:

map an ultra-reliable low-latency communication (URLLC) transmission to a set of symbols for uplink transmission,

wherein the mapping of the URLLC transmission relates to a transport block size determination,

wherein a first nominal repetition of the URLLC transmission is used to perform the transport block size determination, and

wherein, when a second nominal repetition of the URLLC transmission is split into two or more orphaned symbol repetitions and the set of symbols is a set of discrete Fourier transform spread orthogonal frequency division multiplexing (DFT-s-ODFM) symbols, the one or more processors, to map the URLLC transmission, are configured to:

drop an orphaned symbol repetition, of the two or more orphaned symbol repetitions, having a length of one symbol; and

transmit the URLLC transmission based at least in part on the mapping of the URLLC transmission.

21. The UE of claim 20 , wherein a first actual resource or a first actual repetition is used to perform the transport block size determination.

22. The UE of claim 20 , wherein one or more repetitions after a first repetition of the URLLC transmission are mapped with a demodulation reference symbol at a first set of symbols of the one or more repetitions.

23. The UE of claim 20 , wherein one or more repetitions after a first repetition of the URLLC transmission in a slot are mapped with a demodulation reference symbol at a first set of symbols of the one or more repetitions and the first repetition of the URLLC transmission in the slot is mapped with a demodulation reference signal in a third or fourth symbol of the slot when a condition is satisfied.

24. The UE of claim 20 , wherein all repetitions of the URLLC transmission are mapped with a demodulation reference symbol at a first one or more symbols.

25. The UE of claim 20 , wherein the mapping of the URLLC transmission relates to a shared channel mapping type of a repetition of the URLLC transmission.

26. The UE of claim 20 , wherein a demodulation reference signal and data to be transmitted in the orphaned symbol repetition is frequency division multiplexed.

27. The UE of claim 20 , wherein the one or more processors, to map the URLLC transmission, are further configured to:

postpone another orphaned symbol repetition to an available transmission window.

28. The UE of claim 20 , wherein a hybrid automatic repeat request (HARQ) acknowledgment (ACK) is multiplexed with a demodulation reference signal of the orphaned symbol repetition.

29. A non-transitory computer-readable medium storing a set of instructions for wireless communication, the set of instructions comprising:

one or more instructions that, when executed by one or more processors of a user equipment (UE), cause the UE to:

map an ultra-reliable low-latency communication (URLLC) transmission to a set of symbols for uplink transmission,

wherein the mapping of the URLLC transmission relates to a transport block size determination,

wherein a first nominal repetition of the URLLC transmission is used to perform the transport block size determination, and

wherein, when a second nominal repetition of the URLLC transmission is split into two or more orphaned symbol repetitions and the set of symbols is a set of discrete Fourier transform spread orthogonal frequency division multiplexing (DFT-s-OFDM) symbols, the one or more instruction, that cause the UE to map the URLLC transmission, cause the UE to:

drop an orphaned symbol repetition, of the two or more orphaned symbol repetitions, having a length of one symbol; and

transmit the URLLC transmission based at least in part on the mapping of the URLLC transmission.

30. An apparatus for wireless communication, comprising:

means for mapping an ultra-reliable low-latency communication (URLLC) transmission to a set of symbols for uplink transmission,

wherein the mapping of the the URLLC transmission relates to a transport block size determination,

wherein a first nominal repetition of the URLLC transmission is used to perform the transport block size determination, and

wherein, when a second nominal repetition is split into two or more orphaned symbol repetitions and the set of symbols is a set of discrete Fourier transform spread orthogonal frequency division multiplexing (DFT-s-ODFM) symbols, the means for mapping the URLLC transmission comprises:

means for dropping an orphaned symbol repetition, of the two or more orphaned symbol repetitions, having a length of one symbol; and

means for transmitting the URLLC transmission based at least in part on mapping the URLLC transmission.