Frequency-Domain-Equalization-Aided Iterative Detection of Faster-than-Nyquist Signaling

A reduced-complexity three-stage-concatenated faster-than-Nyquist signaling (FTNS)-based transceiver architecture is proposed, which operates with the aid of soft decision (SoD) frequency-domain equalization (FDE) at the receiver. More specifically, the decoding algorithm conceived allows us to attain near-capacity performance as an explicit benefit of iterative detection, which is capable of eliminating the intersymbol interference imposed by FTNS. The proposed SoD FDE-aided FTNS detector has low decoding complexity that linearly increases upon increasing the FTNS block length and, hence, is particularly beneficial for practical long-dispersion scenarios. Furthermore, extrinsic information transfer charts are utilized for designing a near-capacity three-stage-concatenated turbo FTNS system, which exhibits an explicit turbo cliff in the low-signal-to-noise-ratio region, hence outperforming its conventional two-stage-concatenated FTNS counterpart.