Efficient index modulation techniques for 5G and beyond

Abstract

Index modulation (IM) techniques are emerging as promising approaches to improve spectral efficiency and reliability for 5G/future wireless networks. This paper pro vides an overview of key IM schemes including spatial modula tion, orthogonal frequency division multiplexing with index modulation (OFDM-IM), and enhanced variants like SIM OFDM. The spectral efficiency gains of these techniques are quantified mathematically. Spatial modulation uses antenna indices to convey additional information bits, while OFDM-IM utilizes subcarrier indices. SIM-OFDM further activates sub carriers selectively based on incoming bits. Experiments demonstrate spectral efficiency improvements over classical OFDM.