Precoding vector indication method, precoding vector determining method, and communications apparatus

A communication apparatus, comprising:

• a transceiver;
• and
• at least one processor coupled to one or more memories storing programming instructions for execution by the at least one processor to perform operations including:
• generating a channel state information (CSI) report, wherein the CSI report indicates M space-frequency units and a weighting coefficient of a part or all of the M space-frequency units, wherein each of the M space-frequency units corresponds to one space domain vector and one frequency domain vector, and wherein the CSI report comprises an indication of a quantity of non-zero-amplitude weighting coefficients in M weighting coefficients corresponding to the M space-frequency units;
• and
• sending the CSI report, wherein the weighting coefficient indicated by the CSI report is usable for determining a weighted sum of the part or all of the M space-frequency units, and the weighted sum is usable for determining a precoding matrix of a plurality of frequency domain units.