Influence of input power backoff of nonlinear power amplifier on ber performance of optimal SEFDM signals

Abstract

In this article we present the approach to increase data rate for multifrequency signals. It can be done by location more frequency subcarriers in same occupied frequency bandwidth. Our approach is increasing duration of signals for fixed data rate in contrast to “classic” SEFDM signals. Fixed data rate results in significant interference in time domain - ISI. But ISI can be controlled by cross-correlation coefficient. Mutual interference of neighboring subcarriers (ICI) is compensated by application of frequency spacing as minimal value of zeros of energy spectrum. Envelopes for these signals can be obtained by optimization task. Disadvantage of optimal SEFDM signals is high peak-to-average power ratio (PAPR). So we must determine influence of input power backoff on BER performance. We use “Total degradation” (TD) as metric for energy efficiency examination. It is shown that minimum value of TD corresponds to IBO from the interval [0; 1] dB for optimal SEFDM signals.