Faster Than Canonical Nyquist: A Novel Faster-Than-Nyquist Technique

In this paper, we propose a novel signaling transmission method, denoted as faster-than-canonical-Nyquist (FTCN), which combines the linear canonical transform (LCT) and the faster-than-Nyquist techniques. By adopting an adjustable overlapping chirp waveform, FTCN achieves high robustness in high-mobility communications while realizing a high data rate. In the time-varying channel model of high mobility communications, the Doppler frequency changes linearly with time and the input-output relationship is modeled as a canonical convolution. This inspires the design of shaping and matching filters for FTCN, which can be fast implemented using the fast Fourier transform. Additionally, to mitigate intersymbol interference and enhance detection performance, strategies for precoding, pre-decoding, and power allocation are devised. Finally, several simulations are designed to validate the superiority of the FTCN.