Analysis of joint effect of phase noise, IQ imbalance and amplifier nonlinearity in OFDM system

The Orthogonal Frequency Division Multiplexing (OFDM) based system is highly sensitive to Radio Frequency (RF) impairments including phase noise and IQ imbalance at the receiver and High Power Amplifier (HPA) nonlinearity at the transmitter. In this paper, the theoretical characterization of the joint effects of these RF impairments on the performance of the OFDM system with QPSK and 16QAM modulations are presented. The theoretical models for the three RF impairments are derived individually and jointly. Furthermore, the Bit Error Rate (BER) as a function of the RF impairments parameters is formulated for the OFDM system over AWGN channels. The results indicate that phase noise, IQ imbalance and HPA nonlinearity strengthen each other when they are jointly evaluated. The average BER performance is inversely proportional to the RF impairments, and there exists a BER error floor when RF impairments are high. The close matching of the work presented in this paper with previous works confirm the validity of the proposed theoretical approach.