A Method for Increasing the Spectral and Energy Efficiency SEFDM Signals

Examination of a method of increasing the spectral and energy efficiency of the nonorthogonal multifrequency spectrally efficient frequency division multiplexing (SEFDM) signals is considered. This method consists in the application of optimal envelopes of signals increased duration on each subcarrier frequency under intersignal interference for fix data rate. Multistep optimization problem for the determination of the set of envelopes of these SEFDM signals was proposed and numerically solved. The proposed optimal SEFDM signals allow to increase spectral efficiency and to reduce the frequency bandwidth up to 32% with respect to orthogonal frequency division multiplexing (OFDM) signals.