Nonorthogonal Multicarrier Signals Using Slepian Sequences

Controlled Spectra Using Set of Signals

Abstract

This article reviews the efficient usage of the set of multicarrier signals using nonorthogonal subcarriers. It is shown that in the orthogonalization process of the signals, this signal set "meets" the so-called Slepian sequences and changes itself into discrete prolate spheroidal wave functions that result in the highest spectral efficiency with a finite time duration. A simple method that alters the Slepian sequences is presented that reveals various interesting characteristics, for example, sharp notches can be embedded into the spectra of the signals, multiple frequency bands can be efficiently used, and the spectra of the signals can be controlled toward given target spectral masks.