Method and apparatus for determining precoding matrix indicator, user equipment, and base station

A method for determining a precoding matrix indicator, comprising:

• receiving a precoding matrix indicator PMI sent by user equipment;
• and
• determining a corresponding precoding matrix W according to the PMI, wherein the precoding matrix W satisfies a first condition, a second condition, or a third condition, wherein
• the first condition is that the precoding matrix W satisfies W=DV;
• the second condition is that the precoding matrix W comprises one or more column vectors of a block diagonal matrix W1, or the precoding matrix W is obtained by performing weighted combination on one or more column vectors of a block diagonal matrix W1, wherein W1=diag{X1, . . . , XNB}, and NB≧1, wherein at least one block matrix X is a product X=DV of a matrix D and a matrix V, and X∈{X1,X2, . . . , XNB};
• and
• the third condition is that the precoding matrix W comprises one or more column vectors of a block diagonal matrix W1, or the precoding matrix W is obtained by performing weighted combination on one or more column vectors of a block diagonal matrix W1, wherein W1=diag{X1, . . . , XNB}, and NB≧1, wherein at least one block matrix X is a Kronecker product of a matrix A and a matrix B, X=A{circle around (×)}B, and X∈{X1,X2, . . . , XNB};
• the matrix A or the matrix B is a product of a matrix D and a matrix V, the matrix D is a diagonal matrix, i=1, . . . , n, and n is a quantity of rows of the matrix A or the matrix B, wherein
• the matrix D is a diagonal matrix, D=α·diag{u1,u2, . . . , un,u*n,u*n-1, . . . , u*1}, α is a complex factor, a complex number u*i is a conjugate complex number of a complex number ui, and n is determined by a quantity of antenna ports;
• and the matrix V is a constant modulus matrix.

User equipment, comprising:

• a first processor, configured to determine a precoding matrix indicator PMI, wherein the PMI corresponds to a precoding matrix W, and the precoding matrix W satisfies a first condition, a second condition, or a third condition;
• and
• a first transmitter, configured to send the PMI to a base station, wherein
• the first condition is that the precoding matrix W satisfies W=DV, wherein the matrix D is a diagonal matrix, D=α·diag{u1,u2, . . . , un,u*n,u*n-1, . . . , u*1}, α is a complex factor, a complex number u*i is a conjugate complex number of a complex number ui, and n is determined by a quantity of antenna ports;
• and the matrix V is a constant modulus matrix;
• the second condition is that the precoding matrix W comprises one or more column vectors of a block diagonal matrix W1, or the precoding matrix W is obtained by performing weighted combination on one or more column vectors of a block diagonal matrix W1, wherein W1=diag{X1, . . . , XNB}, and NB≧1, wherein at least one block matrix X is a product X=DV of a matrix D and a matrix V, and X∈{X1,X2, . . . , XNB};
• the matrix D is a diagonal matrix, D=α·diag{u1,u2, . . . , un,u*n,u*n-1, . . . , u*1}, α is a complex factor, a complex number u*i, is a conjugate complex number of a complex number ui, and n is determined by a quantity of antenna ports;
• and the matrix V is a constant modulus matrix;
• and
• the third condition is that the precoding matrix W comprises one or more column vectors of a block diagonal matrix W1, or the precoding matrix W is obtained by performing weighted combination on one or more column vectors of a block diagonal matrix W1, wherein W1=diag {X1, . . . , XNB}, and NB≧1, wherein at least one block matrix X is a Kronecker product of a matrix A and a matrix B, X=A{circle around (×)}B, X∈{X1,X2, . . . , XNB};
• the matrix A or the matrix B is a product of a matrix D and a matrix V;
• the matrix D is a diagonal matrix, D=α·diag{u1,u2, . . . , un,u*n,u*n-1, . . . , u*1}, α is a complex factor, a complex number u*i is a conjugate complex number of a complex number ui, i=1, . . . , n, and n is a quantity of rows of the matrix A or the matrix B ;
• and the matrix V is a constant modulus matrix.

A base station, comprising:

• a second receiver, configured to receive a precoding matrix indicator PMI sent by user equipment;
• and
• a second processor, configured to:
• determine a corresponding precoding matrix W according to the PMI, wherein the precoding matrix W satisfies a first condition, a second condition, or a third condition, wherein
• the first condition is that the precoding matrix W satisfies W=DV;
• the second condition is that the precoding matrix W comprises one or more column vectors of a block diagonal matrix W1, or the precoding matrix W is obtained by performing weighted combination on one or more column vectors of a block diagonal matrix W1, wherein W1=diag{X1, . . . , XNB}, and NB≧1, wherein at least one block matrix X is a product X=DV of a matrix D and a matrix V, and X∈{X1,X2, . . . , XNB};
• and
• the third condition is that the precoding matrix W comprises one or more column vectors of a block diagonal matrix W1, or the precoding matrix W is obtained by performing weighted combination on one or more column vectors of a block diagonal matrix W1, wherein W1=diag{X1, . . . , XNB}, and NB≧1, wherein at least one block matrix X is a Kronecker product of a matrix A and a matrix B, X=A{circle around (×)}B, and X∈{X1,X2, . . . , XNB};
• the matrix A or the matrix B is a product of a matrix D and a matrix V;
• the matrix D is a diagonal matrix, i=1, . . . , n, and n is a quantity of rows of the matrix A or the matrix B, wherein
• the matrix D is a diagonal matrix, D=α·diag{u1,u2, . . . , un,u*n,u*n-1, . . . , u*1}, α is a complex factor, a complex number u*i is a conjugate complex number of a complex number ui, and n is determined by a quantity of antenna ports;
• and the matrix V is a constant modulus matrix.