Method and apparatus for selecting pre-coding vectors

A method of transmitting data in a multi-user MIMO system which includes a base station and a plurality of terminals, the method comprising the steps of:

• (a) receiving a plurality of feedback signals from the plurality of terminals, wherein at least one feedback signal includes a plurality of recommended pre-coding vector informations and a plurality of channel status informations, each of the plurality of channel status informations corresponding to a recommended pre-coding vector information, and each of the recommended pre-coding vector informations being used for determining a corresponding pre-coding vector in a predefined pre-coding codebook as a recommended pre-coding vector;
• (b) generating a pre-coding codebook based on the plurality of feedback signals, wherein at least one pre-coding vector in the pre-coding codebook is determined based on a correlation coefficient between at least two recommended pre-coding vectors;
• and
• (c) performing the transmission operation using the pre-coding codebook.

An apparatus for recommending pre-coding vectors in a multi-user MIMO system, comprising:

• a receiver, configured to receive a plurality of signals from abuse station;
• an evaluator, configured to evaluate a channel response matrix corresponding to the plurality of received signals, w′herein each element of the channel response matrix represents a channel response of a channel corresponding to the received signal;
• a calculator, configured to calculate a plurality of channel status informations using a predefined pre-coding codebook and the channel response matrix, wherein each of the channel status informations corresponds to a pre-coding vector in the predefined pre-coding codebook;
• a recommending unit, configured to select a plurality of pre-coding vectors from the predefined pre-coding codebook as a recommended pre-coding codebook, the selection being based on correlation coefficients between pre-coding vectors in the predefined pre-coding codebook and the plurality of channel status informations;
• and
• a transmitter, configured to transmit the recommended pre-coding codebook and a plurality of corresponding channel status informations to the base station, wherein each of the channel status informations corresponds to a recommended pre-coding vector in the recommended pre-coding codebook.

An apparatus for transmitting data in a multi-user MIMO system, comprising:

• a receiver, configured to receive a plurality of feedback signals from a plurality of terminals in the multi-user MIMO system, wherein, at least one feedback signal includes a plurality of recommended pre-coding vector information and a plurality of corresponding channel status information, each of the recommended pre-coding vector information is used for determining a corresponding pre-coding vector in a predefined pre-coding codebook as a recommended pre-coding vector;
• a generator, configured to generate a pre-coding codebook based on the plurality of feedback signals, wherein, at least one pre-coding vector in the pre-coding codebook is determined based on a correlation coefficient between at least two recommended pre-coding vectors;
• and
• a transmitter, configured to perform transmission operation using the pre-coding codebook.