A low-complexity differential space-time transmission scheme for large numbers of receive antennas

We propose a new unitary matrix code for differential space-time modulation that is useful for two transmit antennas and a large number of receive antennas. We optimize the design of this code with respect to the Euclidean distance criterion. To reduce decoding complexity, we derive two suboptimal low-complexity receivers that allow individual data symbols in the code to be sequentially decoded. Simulation results show that the new codes outperform some existing codes, and that the low-complexity receivers approach the performance of maximum-likelihood decoding in the high-rate, large-array regime.