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Item Low Complexity Lookup Table Aided Soft Output Semidefinite Relaxation based Faster-than-Nyquist Signaling Detector(Institute of Electrical and Electronic Engineers, 2024) Çiçek, Adem; Marsland, Ian; ÇAVUS, ENVER; Bedeer, Ebrahim; Yanikomeroglu, HalimSpectrum scarcity necessitates innovative, spectral- efficient strategies to meet the ever-growing demand for high data rates. Faster-than-Nyquist (FTN) signaling emerges as a compelling spectral-efficient transmission method that pushes transmit data symbols beyond the Nyquist limit, offering en- hanced spectral efficiency (SE). While FTN signaling maintains SE with the same energy and bandwidth as the Nyquist sig- naling, it introduces increased complexity, particularly at higher modulation levels. This complexity predominantly arises from the detection process, which seeks to mitigate the intentional intersymbol interference generated by FTN signaling. Another challenge involves the generation of reliable log-likelihood ratios (LLRs) vital for soft channel decoders. In this study, we introduce a lookup table (LUT) aided soft output semidefinite relaxation (soSDR) based sub-optimal FTN detector, which can be extended to higher modulation levels. This detector possesses polyno- mial computational complexity, given the negligible complexity associated with soft value generation. Our study assesses the performance of this soft output detector against that of the optimal FTN detector, Bahl, Cocke, Jelinek and Raviv (BCJR) algorithm as the benchmark. The likelihood values produced by our LUT aided semidefinite relaxation (SDR) based FTN signaling detector show promising viability in coded scenario.Item RIS-Assisted Receive Generalized Space Shift Keying and Receive Generalized Spatial Modulation(IEEE, 2024) Marin, Porfirio; Hanif, Muhammad; Bedeer, EbrahimIn this paper, we enhance the performance of wireless communication systems by utilizing reconfigurable intelligent surface (RIS) and index modulation (IM). In particular, we introduce two schemes: RIS-assisted receive generalized space-shift keying (RIS-RGSSK) and RIS-assisted receive generalized spatial modulation (RIS-RGSM). In the RIS-RGSSK scheme, information bits are conveyed through selection of multiple receive antennas. The RIS-RGSM scheme takes RIS-RGSSK a step further by conveying information bits not only through the selection of multiple receive antennas, but also through embedding information bits in the phase of the received signals using M - ary phase shift keying (PSK) modulation. We also present simple yet efficient greedy detectors (GDs) for non-coherent detection of both schemes. Simulation results demonstrate the advantages of our proposed methods over existing schemes such as the RIS-assisted receive quadrature space-shift keying (RIS-RQSSK).