Enhanced-Diversity Index Modulation-Based Orthogonal Frequency Division Multiple Access Scheme

The recently proposed Index Modulation based Orthogonal Frequency Division Multiple Access (IM-OFDMA) scheme has shown a promising performance in terms of the spectral efficiency, the error rate and the number of served users. This letter proposes an enhanced IM-OFDMA aiming at further enhancing the performance of IM-OFDMA scheme by improving the transmit frequency diversity. The basic idea of the proposed scheme is to divide the subcarriers of each chunk into pairs, where each user should activate a single subcarrier from each pair based on its transmitted data. The proposed scheme is able to attain better performance as compared to IM-OFDMA and other counterpart multiple access schemes. For example, at a spectral efficiency of 4 bps/Hz per user, a chunk of 4 subcarriers and 4 users, the proposed scheme can achieve 36 dB and 10 dB SNR gain as compared to OFDMA and IM-OFDMA, respectively.