Index and mode modulated orthogonal frequency division multiplexing with enhanced spectral efficiency

Index modulation aided orthogonal frequency division multiplexing (OFDM‐IM) is a potential multicarrier transmission technique for wireless data transmission systems due to its attractive error performance and energy efficiency. However, it fails to cope with increasing demand of high data rate in upcoming mobile data services, mainly, due to the lower spectral efficiency. In this communication, an efficient transmission technique, called index and mode modulation OFDM, is proposed that delivers additional information through permutations of multiple modes and indexed bits patterns resulting in higher spectral efficiency. For the proposed technique, a low complexity log‐likelihood ratio detector with suitable algorithm is designed and its computational complexity has been analysed. The simulation results indicate improved performance of this newly proposed scheme in terms of spectral efficiency, bit error rate, as well as energy efficiency over other existing index modulated and multiple mode based OFDM schemes, while maintaining considerably low computational complexity in detection. That proclaims the scheme as a potential transmission technique to meet the data transmission challenges in 5G and beyond. A newly designed transmission technique, named as index and mode modulation OFDM is proposed, which is aimed to overcome the loss in spectral efficiency suffered by traditional index modulated OFDM. Besides, this proposed scheme offers improved energy efficiency and error performance along with acceptable computational complexity in detection.