Performance comparison of linearly-decodable RAR-QOSTBC & conventional QO-STBC for M-PSK modulation

Quasi-Orthogonal Space time block codes (QOSTBC) containing complex symbol terms in their code structure are widely famous for achieving full rate but they are having the disadvantages of less diversity gain and more decoding complexity. In conventional QOSTBC, decoding occurs with pairs of symbols instead of individual symbol. Due to the presence of interference from the neighboring symbols decoding complexity increases. In mathematical terms, the reason for more decoding complexity is because of the presence of non-diagonal terms in the detection matrix. In this work, a new method is proposed to create a non-diagonal detection matrix and further orthogonal channel matrix & Quasi-orthogonal symbol transmission matrix are generated. Proposed scheme have been designed to overcome the disadvantages of conventional QOSTBC and that can achieve improved diversity gain and less computational load while decoding. Evaluation has been done for different orders of PSK scheme over different channels. Experimental results show that the proposed scheme is responsible for an improvement in the performance of the system in terms of BER.