Clipping-Induced Impulse Noise and Its Effect on Performance in OFDM Systems

摘要

A new theoretical analysis and performance evaluation of OFDM Systems in nonlinear fading channels are presented. Rather than widely used nonlinear additive Gaussian noise models or the approach of employing conditional probability of bit error, the new theoretical model is based on the asymptotic clipping and shot noise theories, which offer important insights into true nature of clipping process. The received continuous-time noise model of Poisson arriving delta functions with random power Rayleigh distributed area can be further simplified as equivalent Bernoulli-Gaussian impulse noise model in the discrete time domain. The probability density of combined Gaussian and clipping-induced impulse noise is then easily obtained by performing inverse Fourier transform on the closed-form characteristic function, and analytical average symbol-error rate (SER) results in Rayleigh fading channels are derived. The methodology can be extended to the downlink performance analysis of large capacity DS-CDMA systems.