Space-Time Coded Generalized Spatial Modulation for Sparse Code Division Multiple Access

Space-time coded generalized spatial modulation-aided sparse code division multiple access (STC/GSM-SCDMA) is proposed, which exploits the two-dimensional transmit diversity potential of both and frequency domain. Hence, it constitutes a promising solution for pervasive connectivity devices in next-generation nonorthogonal (NOMA) systems. More explicitly, our STC/GSM scheme achieves spatial-domain, while signal-spreading action SCDMA results frequency-domain (FD) diversity. A single-user bit error rate (BER) bound derived as benchmark BER performance STC/GSM-SCDMA system. Furthermore, pair novel detectors, namely bespoke message passing aided (MPA) detector tailor-made approximate (AMP) are conceived by designing new factor graphs proposed The these detectors characterized terms their vs. complexity. Our simulation show that AMP capable operating within 2 dB MPA detector's signal-to-noise ratio (SNR) requirement, supporting normalized user load 150%, despite its appealing low complexity, about 1000 times lower than detector.