Spectral Analysis of GFDM Modulated Signal under Nonlinear Behavior of Power Amplifier

TL;DR

This paper analyzes how nonlinear power amplifiers affect GFDM signals, deriving analytical expressions for spectral characteristics and validating them through simulations, comparing GFDM's performance with OFDM.

Contribution

It provides a closed-form PSD expression for GFDM signals affected by nonlinear PAs and evaluates key performance metrics, enhancing understanding of GFDM's robustness.

Findings

Analytical PSD expressions accurately predict spectral behavior.

GFDM shows comparable or improved spectral efficiency over OFDM under nonlinear conditions.

Performance metrics like ACP are effectively characterized by the derived formulas.

Abstract

General frequency division multiplexing (GFDM) is a flexible non-orthogonal waveform candidate for 5G which can offer some advantages such as low out-of-band (OOB) emission and high spectral efficiency. In this paper, the effects of nonlinear behavior of practical PAs on GFDM signal are studied. In the first step, a closed form expression for power spectral density (PSD) of GFDM signal is extracted. Then, the PSD at the output of PA as a function of input power and the coefficients of nonlinear polynomial PA model is derived. In addition, the adjacent channel power (ACP) and ACP ratio, as two important performance metrics, are evaluated. The simulation results confirm the accuracy of derived analytical expressions. Moreover, to validate the performance of GFDM modulation after nonlinear PA, it is compared with OFDM modulation.