Quadrature amplitude modulation-based filter-bank multicarrier system (FBMC-QAM) is a promising new radio access technology for the upcoming 5G standalone standard (5G-NR SA). By way of highly localized prototype filters, FBMC-QAM system is able to achieve low out-of-band (OOB) radiation and high spectral efficiency without the cyclic prefix (CP), at the price of non-orthogonality between adjacent subcarriers, intrinsic interferences, and bit error rate (BER) degradation. As an attempt to mitigate these impairments, a precoding scheme is proposed in this paper, which aims to maximize signal-to-leakage-and-noise ratio (SLNR) while allowing pulse-shaping filters with superb spectral characteristics to be leveraged. To justify the efficacy, performance analysis is conducted for prototype filters such as square-root raised cosine (SRRC), isotropic orthogonal transform algorithm (IOTA), and Mirrabasi-Martin (same as suggested in the PHY-DYAS project) for both additive white Gaussian noise (AWGN) and time-dispersive channels. The computer simulation shows that SLNR-based FBMC-QAM system incurs low complexity overhead and is able to enhance BER performance effectively.
