Method and apparatus for transmitting/receiving feedback information and system supporting the same in a multi-user multi-antenna system

An apparatus for transmitting feedback information in a closed-loop multi-user multi-antenna system, comprising:

• a channel estimator for acquiring Channel Quality Information (CQI) of data streams corresponding to column vectors by performing channel estimation on a received signal;
• and
• a feedback information generator for creating possible combinations using column vectors included in a precoding codebook, correlating column vectors in each of the combinations, designating column vectors comprising correlations exceeding a reference threshold as similar vectors, forming at least two similar vector sets with the similar vectors, generating feedback information based on the at least two similar vector sets, and transmitting the feedback information.

An apparatus for receiving feedback information in a closed-loop multi-user multi-antenna system, comprising:

• a feedback information processor for detecting an index of a selected similar vector set and a data rate of the similar vector set in feedback information received from each user, applying the detected data rate commonly to similar vectors in the selected similar vector set, applying the data rates applied to the similar vectors to column vectors corresponding to the similar vectors in the codebook, and calculating sum rates of unitary matrices included in the codebook using the data rates applied to the column vectors;
• and
• a signal transmitter for performing precoding using a unitary matrix comprising the highest of the sum rates.

A closed-loop multi-user multi-antenna system, comprising:

• a Mobile Station (MS) for creating possible combinations using column vectors included in a precoding codebook, correlating column vectors in each of the combinations, designating column vectors comprising correlations exceeding a reference threshold as similar vectors, forming at least two similar vector sets with the similar vectors, generating feedback information based on the at least two similar vector sets, and transmitting the feedback information;
• and
• a Base Station (BS) for detecting an index of a selected similar vector set and a data rate of the similar vector set in feedback information received from each user, applying the detected data rate commonly to similar vectors in the selected similar vector set, applying the data rates applied to the similar vectors to column vectors corresponding to the similar vectors in the codebook, calculating sum rates of unitary matrices included in the codebook using the data rates applied to the column vectors, and performing precoding using a unitary matrix comprising the highest of the sum rates.