On The Performance of IM-OFDMA: Higher Spectral Efficiency and Reduced Computational Complexity

Index Modulation based Orthogonal Frequency Multiple Access (IM-OFDMA) is a novel multiple access scheme that has been recently proposed. IM-OFDMA has been shown to outperform current multiple access, such as OFDMA, in terms of the error performance and spectral efficiency, which nominates it to be a good candidate for beyond 5G networks. In this paper, a new variant of IM-OFDMA is proposed, termed as Full IM-OFDMA (FIM-OFDMA), that is able to further improve the spectral efficiency and the error performance. Moreover, the computational complexity at the detection stage in IM-OFDMA is investigated, and consequently, a new reduced-complexity detector, termed as Signal Power (SP) detector, is proposed that is valid for both IM-OFDMA and FIM-OFDMA schemes. Both the average bit error rate and computational complexity are mathematically analyzed. Analytical and simulation results show that the proposed FIM-IMOFDA can attain better error performance as compared to the conventional IM-OFDMA. Also, explored results reveal that the propose SP detector can achieve a significant reduction in the computational complexity as compared to the optimal maximum likelihood detector, without scarifying the error performance.