Method for precoding matrix indicator feedback and apparatus

A communication device, comprising:

• a receiver, the receiver configured to receive a rank indication, a first precoding matrix indicator, a second precoding matrix indicator, and a third precoding matrix indicator from a terminal device;
• and
• a processor, the processor configured to determine a precoding matrix W based on the rank indication, the first precoding matrix indicator, the second precoding matrix indicator, and the third precoding matrix indicator,
• wherein W satisfies W=W1×W2×W3, W is a matrix of Nt rows and R columns, Nt is a quantity of antenna ports, R is a rank value corresponding to the rank indication, Nt is greater than or equal to R;
• W1 is a matrix of Nt rows and 2M columns, W2 is a matrix of 2M rows and 2K columns, W3 is a matrix of 2K rows and R columns, K is less than M;
• Nt, R, M, and K are all positive integers, M is greater than or equal to 2, Nt is an even number, none of W1, W2, and W3 is an identity matrix, and the 2M columns in W1 comprise every column in W1×W2;
• wherein the first precoding matrix indicator corresponds to the first precoding matrix W1, the second precoding matrix indicator corresponds to the second precoding matrix W2, and the third precoding matrix indicator corresponds to the third precoding matrix W3.