Method for feeding back channel state information, and method and device for obtaining channel state information

A method for obtaining channel state information, comprising:

• receiving, by a base station, a codebook index sent by a user equipment;
• reconstructing, by the base station, according to the codebook index, time domain channel state information compressed by the user equipment;
• and
• obtaining, by the base station, according to the reconstructed time domain channel state information and a recovery matrix, estimated time domain channel state information of the user equipment.

A user equipment, comprising:

• a compression unit, configured to compress original time domain channel state information to obtain compressed time domain channel state information;
• a quantization unit, configured to quantize the compressed time domain channel state information to obtain a codebook index;
• and
• a sending unit, configured to send the codebook index to a base station.

A base station, comprising:

• a receiving unit, configured to receive a codebook index sent by a user equipment;
• a reconstruction unit, configured to reconstruct, according to the received codebook index, time domain channel state information compressed by the user equipment;
• and
• a recovery unit, configured to obtain estimated time domain channel state information of the user equipment according to the reconstructed time domain channel state information and a recovery matrix.