Uplink codebook and signaling design

A method for wireless communication at a base station, comprising:

• selecting, based at least in part on one or more reference signals received from a user equipment (UE), a precoding matrix indicator and a rank indicator, the precoding matrix indicator and the rank indicator being based at least in part on the UE having at least eight transmit antennas and based at least in part on a phase difference between different subsets of transmit antennas of the at least eight transmit antennas;
• transmitting, to the UE, control signaling indicating the precoding matrix indicator and the rank indicator;
• and
• receiving, from the UE, an uplink transmission configured based at least in part on the precoding matrix indicator and the rank indicator.

An apparatus for wireless communication at a user equipment (UE), comprising:

• a processor;
• memory coupled with the processor;
• and
• instructions stored in the memory and executable by the processor to cause the apparatus to:
• transmit, to a base station, one or more reference signals over a channel;
• receive, from the base station based at least in part on transmitting the one or more reference signals, control signaling indicating a precoding matrix indicator and a rank indicator, the precoding matrix indicator and the rank indicator being based at least in part on the UE having at least eight transmit antennas and based at least in part on a phase difference between different subsets of transmit antennas of the at least eight transmit antennas;
• and
• transmit, to the base station, an uplink transmission configured according to the precoding matrix indicator and the rank indicator.

An apparatus for wireless communication at a base station, comprising:

• a processor;
• memory coupled with the processor;
• and
• instructions stored in the memory and executable by the processor to cause the apparatus to:
• select, based at least in part on one or more reference signals received from a user equipment (UE), a precoding matrix indicator and a rank indicator, the precoding matrix indicator and the rank indicator being based at least in part on the UE having at least eight transmit antennas and based at least in part on a phase difference between different subsets of transmit antennas of the at least eight transmit antennas;
• transmit, to the UE, control signaling indicating the precoding matrix indicator and the rank indicator;
• and
• receive, from the UE, an uplink transmission configured based at least in part on the precoding matrix indicator and the rank indicator.