Performance of MIMO space-time coded discrete modulations .1. Introduction and flat-fading channels

We consider the maximum-likelihood (ML) decoding performance of concatenated space-time (ST) random coded communication utilizing multiple input and multiple output (MIMO) antennas on quasi-static fading channels. The ensemble-averaged codeword error rates of such systems can be upper bounded by the outage probabilities of the corresponding conditional cutoff rates. We refer to these as the information cutoff probabilities and evaluate them numerically for a wide range of ST coding schemes. The slope behaviors of these cutoff probabilities are found to be consistent with the maximum achievable diversity orders given by a new unified bound. With simulations of a class of ST coding schemes based on bit-interleaved coded modulations and iterative spatial/temporal decoders, we further show these cutoff probabilities can provide accurate predictions for total performance gains.