Analysis of Nonlinear Distortion Using Orthogonal Polynomials HPA Model

The OFDM systems are highly sensitive to the nonlinear distortion, introduced by the high power amplifier (HPA). The nonlinear HPA has two effects on the transmission system: the first is the spectral regrowth of the signal which leads to adjacent channel interference (ACI). The second effect is the distortion of the signal in the nominal frequency band which causes inter-symbol interference (ISI). This paper deals with the second phenomenon. In this paper, we propose a new theoretical approach for computing the bit error rate (BER) of the M-QAM-OFDM systems in presence of nonlinear HPA in AWGN channels. This analytical approach is based on HPA modeling using orthogonal polynomials. Theoretical results show closely matching with those obtained by simulations.