Analysis of carrier aggregated OFDM signals in presence of dual band power amplifiers

We investigate the effects of nonlinear distortion on a carrier aggregated orthogonal frequency division multiplexed (OFDM) signal when it is transmitted through the concurrent dual band nonlinear high power amplifier. Theoretical analysis shows that the signal at the receiver comprises of the original transmitted signal multiplied by the complex phase shift, Gaussian nonlinear noise term and inherent additive white Gaussian noise (AWGN). The mathematical expressions for the Gaussian nonlinear noise due to inter channel interference and the complex phase shift due to channel impairments are derived. The output signal to noise ratio is evaluated from the derived expressions and hence symbol error rate (SER) for M-QAM is calculated theoretically. The simulations for SER using different power amplifier models are also presented to corroborate the theoretical analysis.