Performance of STBC-OFDM-IDMA System incorporating a new GRP-based interleaver over frequency selective channel

Adopting the architecture combining Orthogonal Frequency Division Multiplexing (OFDM) scheme and Interleave Division Multiple Access (IDMA) technique, the so-called OFDM-IDMA is a promising scheme in uplink wireless communications channels. This architecture has shown potential in achieving high spectral efficiency and low decoding complexity. In this paper we propose to study the performance of a scheme resulting from the combination of the OFDM-IDMA architecture and the transmit diversity system designed by adopting space-time coded transmittion (STBC) and equipping the transmitter with multiple antennas. Furthermore, we propose a novel structure for the interleaver, the key block in the IDMA combined structure. The resulting architecture we have chosen to refer to as STBC-OFDM-IDMA is evaluated in terms of bit error rate (BER) performance. The architecture is designed to exploit the features of OFDM in increasing the robustness against inter-symbol interference (ISI), the IDMA in protecting against the multiple access interference (MAI), and the STBC in improving the reliability of the wireless link. It is shown in this paper that STBC-OFDM-IDMA outperforms its OFDM-IDMA counterpart in the quality of data reliability.