Frequency selective uplink precoding for new radio

A method for wireless communication at a network entity, comprising:

• transmitting, to a user equipment (UE), a first configuration of one or more reference signal resource sets comprising one or more reference signal resources, the first configuration identifying a reference signal resource of the one or more reference signal resources, the reference signal resource comprising a plurality of sub-bands;
• receiving a first reference signal during a first symbol period of a first sub-band of the plurality of sub-bands and receiving a second reference signal during a second symbol period of a second sub-band of the plurality of sub-bands, wherein the first reference signal and the second reference signal comprise precoded reference signals;
• computing respective channel estimates of the first sub-band and the second sub-band based at least in part on receiving the first reference signal and the second reference signal;
• selecting a reference signal resource set based at least in part on the respective channel estimates;
• and
• transmitting, to the UE, a second configuration comprising at least a sounding resource indicator (SRI) based at least in part on the respective channel estimates, wherein the SRI indicates the selected reference signal resource set.

An apparatus for wireless communication, comprising:

• a processor;
• memory in electronic communication with the processor;
• and
• instructions stored in the memory and operable, when executed by the processor, to cause the apparatus to:
• receive, from a network entity, a configuration of one or more reference signal resource sets comprising one or more reference signal resources, the one or more reference signal resources comprising a reference signal resource comprising a plurality of sub-bands;
• apply a first precoding matrix to a reference signal to obtain a first precoded reference signal, the first precoding matrix associated with a first sub-band of the plurality of sub-bands;
• apply a second precoding matrix to the reference signal to obtain a second precoded reference signal, the second precoding matrix associated with a second sub-band of the plurality of sub-bands;
• transmit the first precoded reference signal during a first symbol period of the first sub-band and transmit the second precoded reference signal during a second symbol period of the second sub-band;
• and
• receive, from the network entity, a second configuration comprising at least a sounding resource indicator (SRI) at least in part in response to the first precoded reference signal and the second precoded reference signal, wherein the SRI indicates a reference signal resource set selected based at least in part on the first precoded reference signal and the second precoded reference signal.

An apparatus for wireless communication at a network entity, comprising:

• a processor;
• memory in electronic communication with the processor;
• and
• instructions stored in the memory and operable, when executed by the processor, to cause the apparatus to:
• transmit, to a user equipment (UE), a first configuration of one or more reference signal resource sets comprising one or more reference signal resources, the first configuration identifying a reference signal resource of the one or more reference signal resources, the reference signal resource comprising a plurality of sub-bands;
• receive a first reference signal during a first symbol period of a first sub-band of the plurality of sub-bands and receive a second reference signal during a second symbol period of a second sub-band of the plurality of sub-bands, wherein the first reference signal and the second reference signal comprise precoded reference signals;
• compute respective channel estimates of the first sub-band and the second sub-band based at least in part on receiving the first reference signal and the second reference signal;
• selecting a reference signal resource set based at least in part on the respective channel estimates;
• and
• transmit, to the UE, a second configuration comprising at least a sounding resource indicator (SRI) based at least in part on the respective channel estimates, wherein the SRI indicates the selected reference signal resource set.