Non-Unitary Matrix Based Differential Phase Control Codebook for Temporally Correlated Channels

In this paper, we propose an adaptive differential phase control codebook for limited feedback system in slowly time varying channels. In limited feedback system, channel state information is quantized with a given codebook. The spherical cap can be considered as the coverage of a given codebook where the overall channel space is multi-dimensional sphere. By changing the spherical cap radius properly according to the channel statistics, the proposed codebook design scheme can generate the codebook online to track the channel well. The spherical cap radius is analyzed mathematically in this paper. Monte-Carlo simulations demonstrate that the achievable throughput performance employing the proposed codebook is always superior to those of the non-adaptive differential codebooks with the same amount of feedback information.