Transmit diversity combining for fast fading vector channel

Transmit diversity and space-time coding have drawn lots of research activity. In this paper we propose a direction-time transmit scheme for fast block fading channel exploiting the parametric structure of the time-varying vector channel. Specular propagation and local scattering are assumed at the base-station and mobile station respectively. The partial channel knowledge needed for the transmit design includes: number of specular paths, path direction vectors, and length of coherent interval. Transmission matrix codewords are formed according to the partial channel information such that multiple channels are induced and symbols are spread over different transmission directions. Diversity gain and blind channel estimation are achieved simultaneously at the mobile station through equalization.