Impact of phase noise on the performance of the QPSK modulated signal

This paper presents the impact of phase noise on the performance of a communication link with QPSK digital modulation. For example, how phase noise affects bit error rate is demonstrated with detailed simulations. Also, this paper illustrates how phase noise affects the receiver signal constellation diagram and employs a model for simulating the phase noise. More importantly, this paper shows clearly both by simulation and analysis that a band limiting filter such as a root raised cosine (RRC) filter, which is commonly used in digital communication systems, has little effect on the receiver phase noise probability density function, the phase noise variance, and the probability of bit error. Furthermore, this paper emphasizes certain intuitive aspects of phase noise, such as its impact on the signal constellation diagram showing that phase noise can result in crossover of the decision boundaries in the signal space and thus cause symbol errors even in the absence of the receiver additive noise. Significantly, this intuitive result is also verified by bit error results obtained by both simulations and analysis.