Abstract
A relay assisted system using Hybrid-STBC-VBLAST for Multiple Access Channel (MAC) is proposed in this paper. The proposed system encodes information at handsets of multiple users using Space Time Block Coding (STBC); decodes and re-encodes using Hybrid-STBC-VBLAST at relay; and decodes using Maximum-likelihood (ML) at destination. The results are evaluated for 4 to 8 transmit antennas of relay and 4 to 8 receive antennas of relay and destination, and it is shown in this paper that it is possible to increase number of transmit and receive antennas to get advantages of massive antennas with simple encoding techniques explained in this paper. Simulation results are presented to show the BER performance of the system. The BER performance of Hybrid-STBC-VBLAST is compared with relay assisted MAC using STBC and VBLAST. It is shown that the BER performance of Hybrid-STBC-VBLAST is very close to the performance of STBC but it outperforms VBLAST for relay assisted MAC. The performance of the proposed system is also evaluated with and without relay, and it is shown that proposed system provides 11-17 dB gain compared to a direct link system at 10(-6).