System Optimization for Serial Concatenated OFDM with Extended Constellation STBC

We propose a serial concatenated convolutional and extended constellation space-time block coded (SC-EC-STBC) OFDM scheme that achieves high diversity gain through frequency-selective multipath fading channels. The new scheme combines an inner accumulated linear constellation coded space-time block code (LCC-STBC) with an outer convolutional code (CC) that provides additional coding and diversity gain. The iterative decoder performance of proposed system is optimized via extrinsic information transfer (EXIT) diagrams, and the bit error rate (BER) performance improvement provided by the proposed system with iterative decoding is confirmed by computer simulations.