A space time code for DS-SS

As a joint design of coding, modulation and transmit diversity for flat Rayleigh fading channels, space-time code modulation can obtain both diversity gain and coding gain. This paper describes a new trellis code more fit for DS-SS (direct sequence spread spectra) communication systems, as well as the approach to construct it. We can find the optimal space-time code through systematic code search by computer; also we can construct them with optimal distance convolutional code. The space-time code proposed here can get maximal diversity gain and coding gain in a DS-SS system. The simulation results indicate that it outperforms other known codes in a DS-SS system.