Techniques and apparatuses for enhanced phase feedback in millimeter wave multi-user beamforming

A method of wireless communication performed by a base station, comprising:

• receiving feedback information from a user equipment (UE) identifying phase estimates for a plurality of beams transmitted to the UE,
• wherein the feedback information relates to a selected beam for the UE and one or more other beams of the plurality of beams;
• and
• determining an estimated channel matrix for the UE based at least in part on the feedback information.

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

• a memory;
• and
• one or more processors operatively coupled to the memory, the memory and the one or more processors configured to:
• determine at least one phase estimate for at least one beam received by the UE during a beam training or channel estimation procedure;
• and
• provide the at least one phase estimate to a base station from which the at least one beam is received for the base station to reconstruct an estimated channel matrix of the UE, wherein the at least one phase estimate is provided with at least one of:
• at least one beam index corresponding to the at least one beam,
• at least one measurement associated with the at least one beam, or
• information identifying a cross-correlation associated with the at least one beam.

A base station for wireless communication, comprising:

• a memory;
• and
• one or more processors operatively coupled to the memory, the memory and the one or more processors configured to:
• receive feedback information from a user equipment (UE) identifying phase estimates for a plurality of beams transmitted to the UE,
• wherein the feedback information relates to a selected beam for the UE and one or more other beams of the plurality of beams;
• and
• determine an estimated channel matrix for the UE based at least in part on the feedback information.