Methods, apparatuses, and systems for performing analog CSI feedback

A method for obtaining an analog Channel State Information (CSI) matrix corresponding to a user equipment in a base station, comprising:

• receiving dominated element information corresponding to an analog CSI matrix from the user equipment;
• obtaining the analog CSI matrix according to predetermined index information and the dominated element information;
• wherein the analog CSI matrix satisfies a condition below:
• X XH=D
• where X denotes the analog CSI matrix, H denotes conjugate transpose of matrix, and D denotes a diagonal matrix, and
• wherein the predetermined index information includes any predetermined index information that can indicate respective elements which need to be transmitted to the base station,
• wherein the dominated element information includes all non-zero elements in a matrix resulting from transforming the analog CSI matrix, and the obtaining comprises:
• determining a matrix resulting from transforming the analog CSI according to predetermined index information and the dominated element information, wherein other elements in the transformed matrix except the dominated element information are zero;
• performing singular value decomposition to the transformed matrix to obtain singular values and right singular vectors corresponding to the transformed matrix, and obtaining the analog CSI matrix according to the singular values and the right singular vectors.

A first apparatus for performing analog Channel State Information (CSI) feedback in a user equipment, comprising:

• at least one processor;
• and
• at least one memory including computer program code;
• the at least one memory and the computer program code configured to, with the at least one processor, cause the first apparatus at least to perform:
• obtaining an analog CSI matrix corresponding to the user equipment, the analog CSI matrix satisfies a condition below:
• X XH=D
• where X denotes the analog CSI matrix, H denotes conjugate transpose of matrix, and D denotes a diagonal matrix;
• obtaining dominated element information corresponding to the analog CSI matrix according to predetermined index information, and transmit the dominated element information to a base station,
• wherein the predetermined index information includes any predetermined index information that can indicate respective elements which need to be transmitted to the base station,
• wherein the dominated element information includes all non-zero elements in a matrix resulting from transforming the analog CSI matrix and the analog CSI matrix is obtained by:
• determining a matrix resulting from transforming the analog CSI according to predetermined index information and the dominated element information, wherein other elements in the transformed matrix except the dominated element information are zero;
• performing singular value decomposition to the transformed matrix to obtain singular values and right singular vectors corresponding to the transformed matrix, and obtaining the analog CSI matrix according to the singular values and the right singular vectors.

A second apparatus for obtaining an analog Channel State Information (CSI) matrix corresponding to a user equipment in a base station, comprising:

• at least one processor;
• and
• at least one memory including computer program code;
• the at least one memory and the computer program code configured to, with the at least one processor, cause the second apparatus at least to perform:
• receiving dominated element information corresponding to an analog CSI matrix from the user equipment;
• obtaining the analog CSI matrix according to predetermined index information and the dominated element information;
• wherein the analog CSI matrix satisfies a condition below:
• X XH=D
• where X denotes the analog CSI matrix, H denotes conjugate transpose of matrix, and D denotes a diagonal matrix,
• wherein the predetermined index information includes any predetermined index information that can indicate respective elements which need to be transmitted to the base station,
• wherein the dominated element information includes all non-zero elements in a matrix resulting from transforming the analog CSI matrix and the obtaining comprises:
• determining a matrix resulting from transforming the analog CSI according to predetermined index information and the dominated element information, wherein other elements in the transformed matrix except the dominated element information are zero;
• performing singular value decomposition to the transformed matrix to obtain singular values and right singular vectors corresponding to the transformed matrix, and obtaining the analog CSI matrix according to the singular values and the right singular vectors.