Space-time bit-interleaved coded modulation for OFDM systems in wireless LAN applications

Space-time coding techniques are methods to improve transmission efficiency in radio channels by using multiple transmit and/or receive antennas. Bit-interleaved coded modulation gives good diversity gains with higher order modulation schemes using well known binary convolutional codes. By using orthogonal frequency division multiplexing (OFDM), wideband transmission can be achieved over frequency selective fading radio channels. In this paper, we combine these three ideas into a family of flexible space-time coding methods where modulation order and coding rates as well as the number of transmit and receive antennas can be changed without drastic redesign of the space-time codes. Near optimum iterative decoders are evaluated in terms of simulation for slowly varying wireless LAN type channels. Significant performance gains over the 802.11a standard system are reported.