Space-time bit-interleaved coded modulation over frequency selective fading channels with iterative decoding

A space-time serial concatenated coding approach for spectrally efficient and reliable communications over fading channels is presented. The approach is based on bit-interleaved convolutionally coded modulation with multiple transmit antennas. The decoding problem of such a scheme is addressed in frequency selective fading channels, where an iterative procedure is proposed. At the first step a multiple-soft-in multiple-soft-out maximum a posteriori equalizer is deployed. Then, a soft-in soft-out maximum a posteriori convolutional decoder follows after deinterleaving. Soft information is exchanged between the decoder and the equalizer through multiple equalization and decoding iterations. A 2 bits/s/Hz system deploying two transmit antennas is presented. Simulation results show that, with just one receive antenna, few decoding iterations yield significant BER/FER gains in both frequency selective block fading and frequency selective fast fading over the uncoded system with dual receive diversity.