Abstract:

For MIMO beamforming systems over temporallycorrelated channels, a novel limited feedback approach based on neighborhood is proposed. In the approach, exploiting the correlation of beamforming codewords corresponding to adjacent frames, the new codebook of current frame consists of the codewords within in the neighborhood of previous beamforming codeword, thereby the number of feedback bits can be reduced. Then both periodic feedback scheme and autoadaptive feedback scheme are presented. The simulation results show that the presented schemes can reduce efficiently the feedback rate compared to common feedback approach. The periodic feedback can reduce remarkably feedback amount with some performance loss, while the autoadaptive feedback can reduce moderately feedback amount without any performance loss.