Performance of DSTTD-IDMA system using polarization diversity over correlated frequency-selective channel

In this letter, we evaluate the performance of double space-time transmit diversity (DSTTD)-interleave division multiple access (IDMA) system over correlated frequency-selective channels under perfect channel state information. DSTTD system requires four transmit antennas to implement two STBC block units at the base station for down link (DL) communication. In our considered work, we replace four uni-Polarized transmit antennas by two dual polarized antennas in order to achieve polarization diversity by employing orthogonal polarization. Further we consider non linear multi-user detection based on Space-Time Block Nulling technique at each mobile station by realizing one dual polarized receive antenna to obtain higher throughput with reduced size of mobile unit. Furthermore, we consider iterative style of turbo decoding algorithm at the receiver to mitigate the effects of multi-user interferences. In particular, we investigate the performance of turbo coded dual polarized DSTTD-IDMA system based on Stanford University Interim (SUI) specifications. Our simulation results demonstrate that our considered Dual-Polarized DSTTD-IDMA system provides better BER performance with reduced size of mobile units in the context of DL communication.