Enhanced dual‐mode subcarrier‐index‐modulated orthogonal frequency‐division multiplexing: A low‐ complexity spectrally efficient multicarrier modulation technique

Orthogonal frequency‐division multiplexing with index modulation (OFDM‐IM) is a promising multicarrier transmission technology for future wireless communication systems. Existing OFDM‐IM‐based schemes mainly employ either lookup tables or certain algorithms to map information bits onto indexed entities. However, both of these methods encounter limitations in the form of large storage requirements for either massive tables or complex algorithms as data dimensionality and design parameters increase. This paper presents an enhanced dual‐mode subcarrier‐index‐modulated OFDM scheme that employs a simple on–off keying technique for information mapping and offers reduced implementation complexity with reliable error performance. We present the design criteria utilized to achieve improved spectral efficiency compared with relevant existing schemes at lower modulation orders, as well as computational complexity analysis. An upper bound on the error performance of the proposed scheme is derived and validated through simulations. The proposed scheme is a promising candidate for future 5G communication systems and beyond.