Coded beamforming for block fading vector channel

Most recent studies of transmit diversity and space-time coding have focused on random channels which feature rich scattering around both transmitters and receivers. In this paper, we consider a highly structured vector channel in a block fading scenario. Specular propagation and local scattering are assumed at the base-station and mobile station respectively. The channel knowledge required for the transmit design includes: a subspace formed by direction vectors of specular propagation and length of the fading coherent interval. The relatively stationary subspace information reflecting the spatial power spectral distribution is exploited to derive a code design criterion. The optimal design turns out to be a joint coding and beam-forming scheme and resistance to fading within the subspace is provided by such code.