OFDM On-Off Keying Index Modulation (OFDM-OOK-IM) with Enhanced Spectral Efficiency

The proposed On-Off Keying-based OFDM-IM (OFDM-OOK-IM) technique indirectly conveys the significant number of data bits, as OOK-index bits, apart from the constellation data, resulting in improved Spectral Efficiency (SE) and Electrical Efficiency compared to its counterpart techniques with reduced end-user complexity in practice by avoiding the indexing using a lookup table. At the receiver, threshold detection is used, followed by a customised log-likelihood ratio (LLR) detection algorithm. SE comparison of contemporary IM schemes confirms the superiority of the proposed scheme.