Closed-Form BER Expression for (QAM or OQAM)-Based OFDM System With HPA Nonlinearity Over Rayleigh Fading Channel

Nonlinear distortions caused by high-power amplifiers are considered the key impairment in multicarrier techniques-based communication systems. However, there are few past investigations addressing their effect on the performance of filter bank multicarrier-based systems. In this letter, we derive a closed-form expression for the BER of Gray-coded $M$ -ary [quadrature amplitude modulation (QAM) or offset QAM] -based OFDM running under a frequency-flat-fading Rayleigh channel, which is valid for any memoryless nonlinearity model and can be evaluated without a numerical integration method.