  Signal clipping is a classic technique for reducing peak-to-average power
ratio (PAPR) in orthogonal frequency division multiplexing (OFDM) systems. It
has been widely applied in consumer electronic devices owing to its low
complexity and high efficiency. Although clipping reduces the nonlinear
distortion caused by power amplifiers (PAs), it induces additional clipping
distortion. Optimizing the joint system performance with consideration of both
PA nonlinearity and clipping distortion remains an open problem due to the
complex PA modeling. In this paper, we analyze the PA nonlinearity through the
Bessel-Fourier PA (BFPA) model and simplify its power expression using
inter-modulation product (IMP) analysis. We derive expressions of the receiver
signal-to-noise ratio (SNR) and system symbol error rate (SER) for the
nonlinear clipped OFDM system. With the derivations, we investigate the optimal
system setting to achieve the SER lower bound in a practical OFDM system that
considers both PA nonlinearity and clipping distortion. The methods and results
presented in this paper can serve as a useful reference for the system-level
optimization of clipped OFDM systems with nonlinear PA.
