Coherence indication for demodulation reference signal bundling
Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may receive a configuration that indicates to the UE to apply demodulation reference signal (DMRS) bundling to physical uplink shared channel (PUSCH) transmissions. The UE may maintain phase coherence across multiple PUSCH transmissions, to which the DMRS bundling is applied, to enable joint channel estimation across the multiple PUSCH transmissions. The UE may transmit, based at least in part on the configuration, uplink control information (UCI) that includes a coherence indication. The UE may multiplex the UCI with a PUSCH transmission of the multiple PUSCH transmissions to which the DMRS bundling is applied. The coherence indication may indicate whether the PUSCH transmission is coherent with one or more other PUSCH transmissions, of the multiple PUSCH transmissions, transmitted by the UE. Numerous other aspects are described.
1 . An apparatus for wireless communication at a user equipment (UE), comprising:
at least one processor; and
at least one memory communicatively coupled with the at least one processor and storing processor-readable code that, when executed by the at least one processor, is configured to cause the apparatus to:
transmit an indication of a capability of the UE to support transmission of a coherence indication for demodulation reference signal (DMRS) bundling, the DMRS bundling applied to a set of PUSCH transmissions; and
transmit, in accordance with the capability, an uplink transmission that includes the coherence indication, the coherence indication indicating whether a physical uplink shared channel (PUSCH) transmission, of the set of PUSCH transmissions, is coherent with one or more other PUSCH transmissions across which the UE is to maintain phase coherence.
2 . The apparatus of claim 1 , wherein the one or more other PUSCH transmissions include a single PUSCH transmission that immediately precedes the PUSCH transmission, the coherence indication indicating whether the PUSCH transmission is coherent with the single PUSCH transmission that immediately precedes the PUSCH transmission.
3 . The apparatus of claim 1 , wherein the one or more other PUSCH transmissions include a single PUSCH transmission that immediately follows the PUSCH transmission, the coherence indication indicating whether the PUSCH transmission is coherent with the single PUSCH transmission that immediately follows the PUSCH transmission.
4 . The apparatus of claim 1 , wherein the one or more other PUSCH transmissions occur in a time window, the coherence indication indicating whether the PUSCH transmission is coherent with all of the one or more other PUSCH transmissions that occur in the time window.
5 . The apparatus of claim 4 , wherein the processor-readable code is further configured to cause the UE to receive an indication that defines the time window.
6 . The apparatus of claim 4 , wherein the time window is defined with respect to the PUSCH transmission.
7 . The apparatus of claim 1 , wherein the one or more other PUSCH transmissions satisfy a set of conditions with respect to the PUSCH transmission, the coherence indication indicating whether the PUSCH transmission is coherent with all of the one or more other PUSCH transmissions that satisfy the set of conditions.
8 . The apparatus of claim 7 , wherein the set of conditions includes at least one of:
the one or more other PUSCH transmissions having a same resource block allocation as the PUSCH transmission,
the one or more other PUSCH transmissions being transmitted on a same uplink beam as the PUSCH transmission,
the one or more other PUSCH transmissions being transmitted with a same transmit power as the PUSCH transmission,
the one or more other PUSCH transmissions having a same precoding as the PUSCH transmission, or
a combination thereof.
9 . The apparatus of claim 1 , wherein the coherence indication consists of a single bit.
10 . The apparatus of claim 1 , wherein an absolute value of the coherence indication indicates whether the PUSCH transmission is coherent with the one or more other PUSCH transmissions transmitted by the UE.
11 . The apparatus of claim 1 , wherein a relative value of the coherence indication, compared to a value of another transmitted coherence indication, indicates whether the PUSCH transmission is coherent with the one or more other PUSCH transmissions transmitted by the UE.
12 . The apparatus of claim 1 , wherein the coherence indication is appended to at least one of hybrid automatic repeat request acknowledgement (HARQ-ACK) information, channel state information (CSI), or a scheduling request (SR) if the at least one of the HARQ-ACK information, the CSI, or the SR is present in the uplink transmission, or
the coherence indication is transmitted independent of the HARQ-ACK information, the CSI, or the SR if the HARQ-ACK information, the CSI, and the SR are not present in the uplink transmission.
13 . The apparatus of claim 1 , wherein the PUSCH transmission is rate-matched around the uplink transmission or is punctured with the uplink transmission.
14 . The apparatus of claim 1 , wherein the PUSCH transmission and the one or more other PUSCH transmissions include at least one of:
different PUSCH transmissions carrying different transport blocks,
different repetitions of a particular PUSCH transmission, or
a combination thereof.
15 . The apparatus of claim 1 , wherein the processor-readable code is further configured to cause the UE to receive an instruction to transmit the coherence indication for the DMRS bundling, and the processor-readable code, that causes the UE to transmit the uplink transmission, is configured to cause the UE to transmit the uplink transmission based at least in part on the instruction to transmit the coherence indication for the DMRS bundling.
16 . A method of wireless communication performed at a user equipment (UE), comprising:
transmitting an indication of a capability of the UE to support transmission of a coherence indication for demodulation reference signal (DMRS) bundling, the DMRS bundling applied to a set of PUSCH transmissions; and
transmitting, in accordance with the capability, an uplink transmission that includes the coherence indication, the coherence indication indicating whether a physical uplink shared channel (PUSCH) transmission, of the set of PUSCH transmissions, is coherent with one or more other PUSCH transmissions across which the UE is to maintain phase coherence.
17 . The method of claim 16 , wherein the one or more other PUSCH transmissions include a single PUSCH transmission that immediately precedes the PUSCH transmission, the coherence indication indicating whether the PUSCH transmission is coherent with the single PUSCH transmission that immediately precedes the PUSCH transmission.
18 . The method of claim 16 , wherein the one or more other PUSCH transmissions include a single PUSCH transmission that immediately follows the PUSCH transmission, the coherence indication indicating whether the PUSCH transmission is coherent with the single PUSCH transmission that immediately follows the PUSCH transmission.
19 . The method of claim 16 , wherein the one or more other PUSCH transmissions occur in a time window, the coherence indication indicating whether the PUSCH transmission is coherent with all of the one or more other PUSCH transmissions that occur in the time window.
20 . An apparatus for wireless communication at a network entity, comprising:
at least one processor; and
at least one memory communicatively coupled with the at least one processor and storing processor-readable code that, when executed by the at least one processor, is configured to cause the apparatus to:
receive an indication of a capability of a user equipment (UE) to support transmission of a coherence indication for demodulation reference signal (DMRS) bundling;
transmit, based at least in part on the indication, a configuration that indicates to a user equipment (UE) to apply the DMRS bundling to physical uplink shared channel (PUSCH) transmissions; and
receive, based at least in part on the configuration, an uplink transmission that includes a coherence indication, the uplink transmission being multiplexed with a PUSCH transmission of the multiple PUSCH transmissions to which the DMRS bundling is applied, and the coherence indication indicating whether the PUSCH transmission is coherent with one or more other PUSCH transmissions, of the multiple PUSCH transmissions, transmitted by the UE.