A system employs space-time coding characterized at the transmitter by
bit-interleaved coded modulation (BICM) combined with multi-carrier
Orthogonal Frequency Division Multiplexing (OFDM) modulation. 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. OFDM modulation allows for wideband
transmission over frequency selective radio channels. A receiver
demodulates the OFDM signal 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. The
MIMO demapping and MAP decoding processes exchange likelihood information
to improve the bit error rate performance over several iterations of
demapping/decoding. By applying well-known turbo-decoding principles to
iteratively demap and decode, the overall receiver performance is
significantly improved.