Multi-mode selective OFDM index modulation transmission scheme

In order to solve the problem that index information was limited by the number of subcarrier activation patterns and single signal constellation mode in orthogonal frequency division multiplexing with index modulation (OFDM-IM), a multi-mode selective OFDM index modulation transmission scheme was proposed. The proposed scheme achieved better bit error rate performance by designing distinguishable signal constellations so that the Euclidean distances between adjacent constellation points within and between pattern groups were equal. In addition, the spectral efficiency of the system was improved by introducing full subcarrier activation patterns into the index information of multi-mode selective index modulation. Meanwhile, due to the subcarrier activation mode of the proposed scheme matching binary digits, the system could adopt a low complexity log likelihood ratio detection algorithm and maintained good bit error rate performance. Theoretical analysis and simulation results show that the proposed scheme effectively improves spectral efficiency and maintains good bit error rate performance compared with OFDM-IM, OFDM-SSIM and MMS-OFDM-IM transmission schemes in additive Gaussian white noise channel and Rayleigh fading channel.