Error performance analysis of turbo space-time coded modulation over fading channels

In this paper, we derive performance bounds for a turbo space-time coded modulation (turbo-STCM) scheme over Rayleigh block-fading channels with multiple transmit and multiple receive antennas. The performance bounds are based on the union bound. It is shown that a subset of dominant error paths provide a good approximation of the bound thereby alleviating the computational effort involved in computing the full union bound. The bound is expressed in terms of parameters of the individual space-time codes that make up the turbo-STCM code, interleaver length, number of transmit/receive antennas, the squared Euclidean distance spectra, and the statistical properties of the channel. The theoretical expressions are demonstrated by a close match with simulation results. This bound provides researchers with a useful analytical tool for the design and analysis of turbo space-time codes.