Differential unitary space-time modulation for a large number of receive antennas

For high signal to noise ratios, the design criteria for differential unitary space-time (DUST) codes follow the rank-and-determinant criterion. In this paper, we show that when the number of receiver antennas is large, the Euclidean distance among codewords dominates the performance of DUST codes. Therefore, in the presence of a large number of receive antennas; DUST codes can be optimized by using the Euclidean-distance criterion. Simulation results are given to corroborate the theoretical analysis.