Variable Active Antennas Design for Spatial Media-based Modulation

Media-based modulation (MBM) leverages channel path indices to enhance spectral efficiency (SE), yet existing MBM-based schemes struggle to balance spatial diversity and SE without sacrificing time slots. To address this, a new designing of Spatial MBM with Variable Active Antennas (SMBM-VA), which dynamically partitions the transmit antennas into two groups (each with ≥1 active antenna) to construct antenna index (AI) vector matrices, is investigated. In this design, transmission of two independent constellation symbols via pre-selected channel paths is enhanced for achieving the spatial diversity; Signal spaces through variable active antennas are expanded for improving SE. Furthermore, the spectral efficiency and bit error probability are analyzed. In simulation results, it is shown that the SMBM-VA outperforms conventional MBM (e.g., QCM-III) by 4 dB SNR gain at BER=10<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−3</sup> and 14 bits/s/Hz SE. This work provides a hardware-efficient solution for high-reliability MBM systems.