Limited Feedback Precoding in Realistic MIMO Channel Conditions

MIMO system design for real applications requires that factors such as channel estimation errors, feedback quantisation and realistic channel responses be taken into account. Limited feedback precoding has been introduced to address the feedback overhead; it is a quantised approximation to equal-power eigenbeamforming. The performance of this technique is evaluated using channel responses obtained from a typical urban microcell. The impact of inaccurate channel state information is considered, in addition to the data rate and feedback requirement. The results of this novel approach clearly show the dependence of the system parameter selection on the local topographical environment, and the importance of codebook size and generation as well as channel estimation.