Spectrally Efficient Frequency Division Multiplexing with QRM-MLD for Rician Fading Channel

Spectrally efficient frequency division multiplexing (SEFDM) is attracting attention as one solution to the problem of frequency resource scarcity. This transmission scheme improves spectral efficiency by overlapping subcarriers compared to OFDM. However, SEFDM suffers from inter-carrier interference, which leads to severe performance degradation. To eliminate this interference, linear detection methods such as zero-forcing (ZF) and minimum mean square error (MMSE) are superior in complexity but weak in decoding performance. On the other hand, using maximum likelihood detection (MLD) can achieve the best performance, but that is unrealistic in terms of computational complexity. To address this trade-off, we propose SEFDM with QR decomposition with M-algorithm maximum likelihood detection (QRM-MLD). Our results show that, even in a Rician fading environment, the proposed scheme can reduce computational complexity compared to conventional MLD and maintain BER performance.