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arXiv · 2609.06639

Constrained Capacity for Faster-than-Nyquist Signaling in Frequency-Selective Fading Channels

Zichao Zhang·Melda Yuksel·Gokhan M. Guvensen·Halim Yanikomeroglu
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Abstract

In this paper, we investigate the constrained capacity of discrete Fourier transform (DFT)-precoded faster-than-Nyquist (FTN) signaling over frequency-selective channels with finite-alphabet inputs. With a cyclic prefix (CP) and cyclic suffix (CS), the FTN and multipath induced intersymbol interference (ISI) is decomposed into parallel eigenchannels, whose gains are jointly determined by the folded FTN spectrum and the channel frequency response. Based on this decomposition, we derive the constrained capacity for finite-alphabet constellations and formulate a mismatched decoding achievable information rate for DFT-precoded FTN signaling without CP/CS, quantifying the finite-block rate loss caused by imperfect diagonalization. We find that even under mismatched decoding, FTN significantly improves upon Nyquist transmission.

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Zichao Zhang, Melda Yuksel, Gokhan M. Guvensen, Halim Yanikomeroglu. 2026-09-06. Constrained Capacity for Faster-than-Nyquist Signaling in Frequency-Selective Fading Channels. https://arxiv.org/abs/2609.06639

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