Abstract: A multiple input multiple output (MIMO) communication system including a base station and at least one terminal may adaptively transform a codebook. The terminal may calculate one or more correlation matrices based on one or more subchannel matrices included in a channel matrix. The terminal may feed back information for the base station to reconstruct the one or more correlation matrices. The terminal may transform a codebook stored in the memory of the terminal, based on the one or more correlation matrices. The base station may verify the one or more correlation matrices using the information for the base station to reconstruct the one or more correlation matrices. The base station may transform a codebook stored in the memory of the base station such that the transformed base station codebook is the same as the transformed terminal codebook.

Abstract: Provided is an apparatus and method for enhancing a demodulation performance of a receiver in a Broadband Wireless Access (BWA) system. A receiving apparatus in a broadband wireless communication system includes an estimator, a first calculator, and a second calculator. The estimator estimates a desired signal. The first calculator calculates a correlation matrix of a signal obtained by eliminating the estimated desired signal from a Received (RX) signal. The second calculator performs an interference elimination using the correlation matrix.