Assessment and Comparison of Multicarrier Waveforms Under Nonlinear Conditions

Power Amplifiers (PAs) are inherently nonlinear devices for which power efficiency and amplifier linearity are a trade-off recourse. On the one hand, poor power efficiency reduces the battery life of a mobile device, or is accompanied by a significant financial burden in the case of a base station. On the other hand, driving the amplifier above the linear regime to increase power efficiency distorts the amplified signal in a nonlinear fashion. This distortion not only deteriorates the transmission quality, but also introduces interference in adjacent frequency channels. Multicarrier systems, in which the signal bandwidth is shared among multiple pulses, are particularly vulnerable to Out-Of-Band (OOB) interference. Robustness against such interferences caused by nonlinear amplification is to be considered when choosing the right modulation scheme. In this paper, the following modulation waveforms are compared: OFDM, FOFDM, WOLA, UFMC, FBMC-OQAM and Pruned DFT-Spread FBMC, and their sensitivity towards nonlinear distortions is assessed. For this purpose, the Vienna 5G Link Level Simulator is used, which allows for a fair comparison of the waveforms on a unified platform.