Impact of Spectrum Sharing on the Efficiency of Faster-Than-Nyquist Signaling

TL;DR

This paper analyzes how spectrum sharing affects the efficiency of Faster-Than-Nyquist signaling, revealing that sinc pulses optimize spectral efficiency and that roll-off factors impact capacity and efficiency.

Contribution

It provides capacity computations for FTN signaling with interference, highlighting the optimality of sinc pulses and the effects of roll-off factors on spectral efficiency.

Findings

Sinc pulses maximize spectral efficiency in multi-access FTN channels.

Spectral efficiency decreases with increasing roll-off factor.

High SNR capacity gap increases with roll-off factor.

Abstract

Capacity computations are presented for Faster-Than-Nyquist (FTN) signaling in the presence of interference from neighboring frequency bands. It is shown that Shannon's sinc pulses maximize the spectral efficiency for a multi-access channel, where spectral efficiency is defined as the sum rate in bits per second per Hertz. Comparisons using root raised cosine pulses show that the spectral efficiency decreases monotonically with the roll-off factor. At high signal-to-noise ratio, these pulses have an additive gap to capacity that increases monotonically with the roll-off factor.