IEEE Access (Jan 2024)
Transmit Diversity-Achieving Quadrature Index Modulation Aided Media-Based Modulation
Abstract
In this paper, a new schematic of quadrature index modulation (QIM) with generalized spatial constellations is proposed and amalgamated with the media-based modulation (MBM) system for not only achieving the transmit diversity gains but also increasing the spectral efficiency (SE). Based on this, this new scheme may be named as Transmit Diversity-achieving QIM-MBM (TD-QIM-MBM). Specifically, all available transmit antennas (TAs), whose each TA is equipped with $n_{\mathrm {rf}}$ radio frequency (RF) mirrors, are firstly grouped into G groups of TAs, each group of which is assigned to one corresponding Bits-Modulator. Then, one mapped three dimension (3D) signal constellation point (CP) is copied into G versions and then are respectively fed into G groups of Bits-Modulators. In each group of Bits-Modulator, with the aid of the antenna index (AI) bits of three spatial domains, one version of 3D signal CP is modulated into one QIM vector symbol. Furthermore, the in-phase and quadrature vectors of the QIM vector symbol are respectively modulated on the specified channel states with the in-phase and quadrature channel index (CI) bits and then formed into one MBM vector symbol. On the design of G groups of Bits-Modulators, G MBM vector symbols are obtained and concatenated into one transmitted MBM vector (TMV) symbol. Finally, in order to outstand the advantage of the proposed TD-QIM-MBM, the SEs and the squared minimum Euclidean distances (MEDs) of the TD-QIM-MBM are provided in comparisons with other schemes, and the average bit error probability is also provided. In simulation results with the Monte Carlo method, it demonstrates that the TD-QIM-MBM outperforms the classic design schemes (e.g., GSM-MBM and QSM-MBM) in terms of the bit error rate (BER) performance for enhancing the reliability of MBM-based wireless communications.
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