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

2026-09-06

AI Summary

本文研究了在频率选择性衰落信道中，通过DFT预编码的FTN信号传输有限字母输入的受限容量问题，并提出了一种分解方法来解决ISI问题。

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.

Problem

• Constrained Capacity
• Faster-than-Nyquist Signaling
• Frequency-Selective Fading Channels

Innovation

• Faster-than-Nyquist (FTN)
• Discrete Fourier Transform (DFT) precoding
• Frequency-selective fading channels
• Constrained capacity
• Mismatched decoding