Adaptive Codebooks for Efficient Feedback Reduction in Cooperative Antenna Systems

This paper presents an adaptive codebook design method, which introduces a transition probability based codeword sorting scheme in an effort to reduce the feedback overhead by exploiting the temporal correlation of the channel. The adaptive codebook sorts the codewords in the increasing order of the chordal distance with respect to the initial codeword, which is the codeword chosen at the previous time step. The adaptive codebook method in conjunction with the lossless data compression scheme requires much less feedback overhead compared with currently available techniques, e.g., the recursive codebook scheme, at the cost of slightly increased memory requirements.