Analysis of Error Rate and Capacity in the Presence of I/Q Imbalances Over an Impulsive Noise Channel

Abstract

Many state-of-the-art unmanned aerial vehicle-assisted communication systems adopt quadrature amplitude modulation (QAM) and zero intermediate frequency (IF) architecture. In zero-IF QAM devices, in-phase/quadrature (I/Q) amplitude and phase imbalances cause severe performance degradation. In addition, the performance of the devices in close proximity to the impulsive noise sources can also be significantly degraded. In this paper, we derive and analyze the symbol error rate (SER) of <italic>M</italic>-ary square QAM and the channel capacity of a system in the presence of I/Q imbalance over an impulsive noise channel. We first present an exact expression for the joint probability density function (PDF) of the demodulated I/Q signals affected by impulsive noise. By using the derived PDF, we then provide exact expressions for SER and SER floor of <italic>M</italic>-ary square QAM and average and asymptotic channel capacities of the system with I/Q amplitude and phase imbalances over an impulsive noise channel. We validate the theoretical results through computer simulations.