Diversity performance of Ricean MIMO channels

In this paper, we assess the impact of real-world propagation conditions on the maximum achievable diversity performance of communication over MIMO channels. This is done by studying the outage behavior of the single-input single-output (SISO) channel induced by the use of orthogonal space-time block codes (OSTBCs). For Ricean fading MIMO channels we demonstrate the existence of an SNR-dependent critical rate, R_crit, below which signaling with zero outage is possible and hence the fading channel behaves like an AWGN channel. For SISO channels, R_crit is always zero. In the MIMO case, R_crit is a simple function of the angle between the vectorized Ricean component of the channel and the subspace spanned by the vectorized Rayleigh fading component