Joint VBLAST/STBC assisted MIMO MC-IDMA system in frequency selective channels: Performance results

In this paper, we evaluate the performance of multi carrier interleave division multiple access (MC-IDMA) system supported by joint transmit scheme employing Vertical Bell Laboratories Layered space-time architecture (VBLAST) and Space-Time Block Code (STBC) over correlated frequency selective channels. Spatial multiplexing and spatial diversity can be achieved by combing VBLAST and STBC processing. In IDMA, user specific interleaving pattern is used to distinguish different users as against signature sequence in the conventional code division multiple access (CDMA) system. In MC-IDMA system, the multi carrier is realized by orthogonal frequency division multiplexing (OFDM), which can eliminate the effects of time dispersion. At the mobile station (MS), non-linear multi-user detection (MUD) based on zero forcing (ZF) rule is employed to mitigate the effects of multiple access interference (MAI) and multi stream interference (MSI) in the context of downlink multi input multi output (MIMO) MC-IDMA system. In particular, we investigate the effects of three types of delay-spread distributions pertaining to Stanford university interim (SUI) channel models in MIMO MC-IDMA system. We also compare the performance of the considered system with double space-time transmit diversity (DSTTD) aided MC-IDMA system. It is demonstrated through computer simulations that coded MC-IDMA system with joint VBLAST/STBC processing is capable of achieving better bit error rate (BER) as compared to DSTTD system.