Performance of relay assisted turbo-VBLAST coded system for wireless communication

A Multiple Input Multiple Output (MIMO) relay assisted wireless communication system encoded with Turbo- VBLAST codes is studied in this paper. Source is equipped with multiple transmit antennas, relay is equipped with multiple transmit as well as receive antennas and destination is also equipped with multiple receive antennas. Turbo encoder encodes the input bits and then QPSK or 16 QAM or 64 QAM modulator modulates the turbo-encoded bits. Modulated symbols are further encoded using VBLAST and then split into n streams which are simultaneously transmitted through the n transmit antennas of source. It is observed that relay assisted Turbo- VBALST encoded system provides 3-7 dB coding gain for different combination of transmit and receive antennas at a BER of 10^-5 compared to Turbo-VBALST encoded direct link system. And there is around 3 to 7 dB gain for increasing number of receiving antennas from 2 to 6.