Method and apparatus for measuring and feeding back channel information

A method for measuring and feeding back channel information, the method comprising: determining, by a first network device, a first codebook from a first codebook set, wherein the first codebook set comprises at least two first codebooks, wherein a sub-vector W x of each first codebook is formed by a zero vector and a non-zero vector, wherein vectors forming the W x are associated with different groups of antenna ports, wherein each first codebook comprises at least one first sub-vector [formula] and/or at least one second sub-vector [formula] and wherein V a 0 and V a 1 are elements in the vector V a , and V b 0 and V b 1 are elements in the vector V b ; and sending a codebook index to a second network device, wherein the codebook index is associated with the first codebook selected from the first codebook set.

A method for measuring and feeding back channel information, the method comprising: sending, by a second network device, a reference signal to a first network device; receiving, by the second network device, a codebook index sent by the first network device, wherein the codebook index indicating a first codebook of a first codebook set, wherein the first codebook set comprises at least two first codebooks, wherein a sub-vector W x of each first codebook is formed by a zero vector and a non-zero vector, wherein vectors forming the W x correspond to different groups of antenna ports, wherein each first codebook comprises at least one first sub-vector [formula] and/or at least one second sub-vector [formula] and wherein V a 0 and V a 1 are elements in the vector V a , and V b 0 and V b 1 are elements in the vector V b ; and determining, by the second network device, the first codebook according to the codebook index.

A terminal apparatus comprising: a processor configured to determine a first codebook from a first codebook set, wherein the first codebook set comprises at least two first codebooks, a sub-vector W x of each first codebook is formed by a zero vector and a non-zero vector, wherein vectors forming the W x are associated with different groups of antenna ports, wherein each first codebook comprises at least one first sub-vector [formula] and/or at least one second sub-vector [formula] wherein V a 0 and V a 1 are elements in the vector V a , and V b 0 and V b 1 are elements in the vector V b ; and a transmitter configured to send a codebook index to a second network device, wherein the codebook index is associated with the first codebook selected from the first codebook set.

A communications apparatus comprising: a transmitter configured to send a reference signal to a first network device; a receiver configured to receive a codebook index sent by the first network device, wherein the codebook index indicates a first codebook in a first codebook set; and a processor configured to determine the first codebook according to the codebook index, wherein the first codebook set comprises at least two first codebooks, wherein a sub-vector W x of each first codebook is formed by a zero vector and a non-zero vector, wherein vectors forming the W x correspond to different groups of antenna ports, wherein each first codebook comprises at least one first sub-vector [formula] and/or at least one second sub-vector [formula] and wherein V a 0 and V a 1 are elements in the vector V a , and V b 0 and V b 1 are elements in the vector V b .