Iterative channel estimation and decoding in turbo coded space time systems

A non-coherent multiple antenna coded communication system over both a block fading and a time-selective flat fading Rayleigh channel is considered. Several iterative decoding strategies consisting of pilot symbol assisted demodulation and turbo decoding are proposed. It is shown that, at a system rate of 0.9 bits per channel, the SNR required to achieve a BER of 10^-4 is only about 2 dB away from the imperfect CSI capacity lower bound. The channel estimation error variance is demonstrated to be close to the theoretical limit set by the modified Cramer-Rao bound. The simulation results coincide with the trends dictated by recent information-theoretic analysis and demonstrate the effect that the inaccuracy of the channel estimation has on the performance of the iterative decoding scheme.