Orthogonal Space-Time Block Codes Over Semi-Identical Channels With Channel Estimation

Assuming the channel gains associated with different receive antennas are not identically distributed, the authors study the orthogonal space-time block codes over non-identical channels with channel estimation. It is shown that the non-identical statistics lead to non-identical channel estimation errors, which make the conventional optimum decoder sub-optimum in this case. A new optimum decoder is derived. They show that it can be simplified to a symbol-by-symbol decoder under certain conditions. Analytical and simulation results show that their new decoder substantially outperforms the conventional decoder.