Performance of dual-polarized DSTTD-IDMA system in frequency-selective channel

Abstract

This paper evaluates the performance of dual-polarized double space time transmit diversity (DSTTD) aided multiple input multiple output (MIMO) interleave division multiple access (IDMA) scheme over correlated frequency-selective channels for downlink (DL) communication. DSSTD system employs two space-time block code (STBC) units at the transmitter side. In our considered work, we employ two dual-polarized antennas both at the transmitter side and receiver side. The unique feature of IDMA is that user specific interleaving patterns are used for user-separation as against orthogonal spreading sequence used in conventional code division multiple access (CDMA). In our considered work, non-linear multi-user detection (MUD) based on maximum likely-hood ratio (ML) algorithm is employed to detect the signals and to mitigate the effects of multiple access interference (MAI) and multi stream interference (MSI). In this paper, the benefits of dual-polarized antennas are exploited to achieve MIMO gain and iterative style of turbo decoding algorithm are employed to enhance the BER performance. We evaluate the performance of dual polarized DSTTD-IDMA system based on Standard University Interim (SUI) channel model specifications. Our simulation results show that DSTTD-IDMA system with dual polarized antennas provides better performance in terms of achievable bit error rate (BER) with lesser number of antennas elements spacing at the mobile stations (MSs).