Space code design in delay diversity transmission for PSK modulation

Delay diversity transmission is well-known as a simple and efficient transmission scheme to exploit transmit diversity in wireless communications. The interpretation of a spatial repetition code transmitted by multiple antennas in a delayed fashion opens up the possibility of. better code design to enhance the performance. This paper considers the design criteria for different channel models. It Is shown that all flat Rayleigh fading models, regardless of the time selectivity, share a common design criterion, which is to maximize the minimum effective product distance. This result further verities the flexibility and robustness of delay diversity transmission. Nonbinary spatial block code construction is then proposed over a ring of integers for PSK modulation. Some optimal systematic linear block codes are provided through exhaustive search for up to 64PSK modulation and with up to 5 transmit antennas. Comparing with the repetition codes employed in original delay diversity transmission, the newly designed codes can achieve significant coding improvement without any increase of decoding complexity.