Nonlinear distortion analysis of multi-band carrier aggregated OFDM signals

This paper presents the theoretical characterization of nonlinear distortion effects on a concurrent multi-band orthogonal frequency division multiplexed (OFDM) signal when passed through a nonlinear high power amplifier (HPA). The behavioural model of HPA considered for theoretical analysis is a 2-D memory polynomial model (MPM), which is a truncated form of the Volterra series. We show that the inband and cross modulation distortion introduced due to nonlinear amplification of aggregated OFDM signals can be modelled as a complex attenuation factor and Gaussian nonlinear noise that distorted the received data symbol. Generalised expressions for the complex attenuation factor and Gaussian nonlinear noise in Rayleigh multi-path fading channel have been derived. From the derived expressions, received signal to noise ratio and probability of symbol error for each subcarrier is evaluated and illustrated for N band carrier aggregated OFDM system. Simulation results demonstrate the validity of analytically derived expressions.