Signal-Code Construction Based on Space-Time Block Coding with Dual-Mode Index Modulation Aided OFDM

In this paper, a Space-Time Block Coding (STBC) with Dual-Mode Index Modulation Aided OFDM (DM-OFDM-IM) scheme is proposed, which combines the techniques of orthogonal STBC with Alamouti's core and modulation of all OFDM subcarriers within each subblock by pairs of distinguishable constellation sets. The simulation results show that a new signal-code construction STBC-DM-OFDM-IM substantially enhances the Bit Error Rate performance and Spectral Efficiency of conventional STBC-OFDM and single-mode STBC-OFDM-IM schemes. The proposed STBC-DM-OFDM-IM method achieves the best possible results using lower order modulations and small size of subblocks, which allows the implementation of optimal Maximum Likelihood Detector.