A
system employs space-time coding characterized at the
transmitter by bit-interleaved
coded modulation (BICM) combined with modulating several streams of the BICM encoded data for transmission over two or more antennas. Space-time coding techniques improve transmission efficiency in radio channels by using multiple transmit and / or receive antennas and coordination of the signaling over these antennas. Bit-interleaved
coded modulation provides good
diversity gain with higher-order modulation schemes that employ binary convolutional codes. A
receiver demodulates the received signals and applies multi-input, multi-output (
MIMO) demapping to estimate the BICM encoded
bitstream. After deinterleaving of the BICM encoded
bitstream, maximum a posteriori (MAP) decoding is applied to the resulting bit
stream to generate soft output values. By applying well-known turbo-decoding principles to iteratively demap and decode, the overall
receiver performance is significantly improved. The
MIMO demapping and
MAP decoding processes exchange likelihood information to improve the
bit error rate performance over several iterations of demapping / decoding. By generating tentative decisions for transmitted bits, the overall number of evaluations used for demapping may be reduced.