Construction and mapping of compact uplink control information (UCI) over physical uplink shared channel (PUSCH)

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

determining to transmit uplink control information (UCI) that identifies one or more parameters associated with a transmission of a physical uplink shared channel (PUSCH) communication in a PUSCH resource unit (PRU),

wherein the PUSCH communication includes a payload of a msgA communication in a contention-free two-step RACH procedure;

transmitting the UCI in the PRU based at least in part on determining to transmit the UCI; and

receiving an indication of the PRU in at least one of a compact downlink control information (DCI) communication or a group-common DCI communication.

2. The method of claim 1 , wherein determining to transmit the UCI comprises:

determining to transmit the UCI based at least in part on determining that a combination of the PRU and a preamble of the msgA communication is associated with a plurality of different combinations of the one or more parameters.

3. The method of claim 1 , wherein the one or more parameters comprise at least one of:

a modulation coding scheme index associated with the PUSCH communication,

a redundancy version associated with the PUSCH communication, or

a transport block size associated with the PUSCH communication.

4. The method of claim 1 , wherein determining to transmit the UCI comprises:

determining to transmit the UCI based at least in part on determining that a plurality of PRUs, included in a PRU group in which the PRU is included, are mapped to a shared set of time-domain resources and frequency-domain resources.

5. The method of claim 4 , wherein the plurality of PRUs are of a same time-domain resource size and a same frequency-domain resource size.

6. The method of claim 4 , wherein at least a subset of the plurality of PRUs are of at least one of different time-domain resource sizes or different frequency-domain resource sizes.

7. The method of claim 1 , wherein determining to transmit the UCI comprises:

determining to transmit the UCI based at least in part on determining that a plurality of PRUs, included in a PRU group in which the PRU is included, are nested in a time domain and a frequency domain such that the plurality of PRUs share a same starting time-domain resource and a same starting frequency-domain resource.

8. The method of claim 1 , wherein the one or more parameters are indicated in the UCI by a plurality of bits,

wherein the plurality of bits are encoded by a channel code to form coded bits.

9. The method of claim 8 , further comprising:

attaching, prior to channel coding the UCI, one or more cyclic redundancy check (CRC) bits to the plurality of bits.

10. The method of claim 9 , further comprising:

determining that a quantity of bits, of the plurality of bits, does not satisfy a bit quantity threshold; and

reducing the quantity of bits to a reduced quantity of bits based at least in part on determining that the quantity of bits does not satisfy the bit quantity threshold.

11. The method of claim 10 , further comprising at least one of:

masking the one or more CRC bits based at least in part on a first pseudo random sequence that is based at least in part on the reduced quantity of bits, or

scrambling the coded bits using a second pseudo random sequence that is based at least in part on the reduced quantity of bits,

wherein scrambling the UCI based at least in part on the reduced quantity of bits comprises:

initializing a scrambling sequence generator based at least in part on the reduced quantity of bits; and

scrambling the UCI based at least in part on the scrambling sequence.

12. The method of claim 1 , wherein transmitting the UCI in the PRU comprises:

transmitting one or more modulation symbols of the UCI in one or more orthogonal frequency division multiplexing (OFDM) symbols adjacent to a transmission of a demodulation reference signal in the PRU and in one or more subcarriers that start at a semi-persistent sub carrier index of the PRU.

13. The method of claim 12 , wherein a quantity of the one or more subcarriers is a same quantity of subcarriers for each PRU included in a PRU group in which the PRU is included; and

wherein modulation symbols of the PUSCH communication are punctured or rate matched in the PRU around the one or more subcarriers.

14. The method of claim 1 , wherein the transmission of the PUSCH communication is scheduled by a configured grant; and

wherein determining to transmit the UCI comprises:

determining to transmit the UCI based at least in part on determining that a signaling communication, that indicates the configured grant, permits the UE to select the one or more parameters from a plurality of different combinations of the one or more parameters.

15. The method of claim 1 , wherein the transmission of the PUSCH communication is triggered by a contention based random access event; and

wherein determining to transmit the UCI comprises:

determining to transmit the UCI based at least in part on the contention based random access event.

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

a memory; and

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

determine to transmit uplink control information (UCI) that identifies one or more parameters associated with a transmission of a physical uplink shared channel (PUSCH) communication in a PUSCH resource unit (PRU) based at least in part on determining that a plurality of PRUs, included in a PRU group in which the PRU is included, are mapped to a shared set of time-domain resources and frequency-domain resources; and

transmit the UCI in the PRU based at least in part on determining to transmit the UCI.

17. The UE of claim 16 , wherein the one or more parameters comprise at least one of:

a modulation coding scheme index associated with the PUSCH communication,

a redundancy version associated with the PUSCH communication, or

a transport block size associated with the PUSCH communication.

18. The UE of claim 16 , wherein the plurality of PRUs are of a same time-domain resource size and a same frequency-domain resource size.

19. The UE of claim 16 , wherein at least a subset of the plurality of PRUs are of at least one of different time-domain resource sizes or different frequency-domain resource sizes.

20. A non-transitory computer-readable medium storing one or more instructions for wireless communication, the one or more instructions comprising:

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

determine to transmit uplink control information (UCI) that identifies one or more parameters associated with a transmission of a physical uplink shared channel (PUSCH) communication in a PUSCH resource unit (PRU) based at least in part on determining that a plurality of PRUs, included in a PRU group in which the PRU is included, are nested in a time domain and a frequency domain such that the plurality of PRUs share a same starting time-domain resource and a same starting frequency-domain resource; and

transmit the UCI in the PRU based at least in part on determining to transmit the UCI.

21. The non-transitory computer-readable medium of claim 20 , wherein the one or more parameters are indicated in the UCI by a plurality of bits,

wherein the plurality of bits are encoded by a channel code to form coded bits.

22. The non-transitory computer-readable medium of claim 21 , wherein the one or more instructions, when executed by the one or more processors, further cause the one or more processors to:

attach, prior to channel coding the UCI, one or more cyclic redundancy check (CRC) bits to the plurality of bits.

23. The non-transitory computer-readable medium of claim 22 , wherein the one or more instructions, when executed by the one or more processors, further cause the one or more processors to:

determine that a quantity of bits, of the plurality of bits, does not satisfy a bit quantity threshold; and

reduce the quantity of bits to a reduced quantity of bits based at least in part on determining that the quantity of bits does not satisfy the bit quantity threshold.

24. The non-transitory computer-readable medium of claim 23 , wherein the one or more instructions, when executed by the one or more processors, further cause the one or more processors to at least one of:

mask the one or more CRC bits based at least in part on a first pseudo random sequence that is based at least in part on the reduced quantity of bits, or

scramble the coded bits using a second pseudo random sequence that is based at least in part on the reduced quantity of bits,

wherein scrambling the UCI based at least in part on the reduced quantity of bits comprises:

initializing a scrambling sequence generator based at least in part on the reduced quantity of bits; and

scrambling the UCI based at least in part on the scrambling sequence.

25. An apparatus for wireless communication, comprising:

means for determining to transmit uplink control information (UCI) that identifies one or more parameters associated with a transmission of a physical uplink shared channel (PUSCH) communication in a PUSCH resource unit (PRU) based at least in part on determining that a plurality of PRUs, included in a PRU group in which the PRU is included, are nested in a time domain and a frequency domain such that the plurality of PRUs share a same starting time-domain resource and a same starting frequency-domain resource; and

means for transmitting the UCI in the PRU based at least in part on determining to transmit the UCI.

26. The apparatus of claim 25 , wherein the means for transmitting the UCI in the PRU comprises:

means for transmitting one or more modulation symbols of the UCI in one or more orthogonal frequency division multiplexing (OFDM) symbols adjacent to a transmission of a demodulation reference signal in the PRU and in one or more subcarriers that start at a semi-persistent subcarrier index of the PRU.

27. The apparatus of claim 25 , wherein the PUSCH communication includes a payload of a msgA communication in a two-step random access channel (RACH) procedure.

28. The apparatus of claim 27 , wherein the two-step RACH procedure is a contention-free two-step RACH procedure; and

wherein the apparatus further comprises:

means for receiving an indication of the PRU in a downlink control information (DCI) communication,

wherein the DCI communication is at least one of:

a compact DCI communication, or

a group-common DCI communication.

29. The apparatus of claim 27 , wherein the means for determining to transmit the UCI comprises:

means for determining to transmit the UCI based at least in part on determining that a combination of the PRU and a preamble of the msgA communication is associated with a plurality of different combinations of the one or more parameters.

30. The apparatus of claim 25 , wherein the one or more parameters are indicated in the UCI by a plurality of bits,

wherein the plurality of bits are encoded by a channel code to form coded bits.