OFDM System under the Combined Effect Analysis of the Phase Noise, Carrier Frequency Offset, Doppler Spread, and Amplifier Nonlinearity of the SEL

In this paper, we provide an exact closed-form expression of the effective signal-to-noise ratio (SNR) for orthogonal frequency division multiplexing (OFDM) performance under the combined effect of the phase noise, frequency offset, and amplifier nonlinearities of the soft envelope limiter (SEL). A simplified approximate expression is also obtained for the effective SNR under certain conditions. This formula describes explicitly the various parameters with the system performance. After deriving the effective SNR, we evaluate the bit-error-rate (BER) for slowly fading Rayleigh channel for QPSK and 16-QAM modulation formats. We also obtain the minimum total degradation (TD) versus phase noise rate for different values of frequency offset rate as a criterion of performance evaluation. We show that the degradation is increased as the phase noise levels and frequency offset levels are increased. For 16-QAM modulation format, we have obtained even worse results compared with QPSK modulation format. Key-Words: OFDM, Phase Noise, CFO, Doppler Spread, and Nonlinear Amplifier.