Performance analysis of fast frequency-hopped DBPSK spread spectrum communications in AWGN

The performance of a fast frequency-hopped (FFH) spread-spectrum communication system using differential binary phase-shifted-keying (DBPSK) modulation and differentially coherent demodulation is studied. The hop timing error causes phase imperfection, and therefore degrades system performance. The receiver utilizes a hop-timing tracking loop to lock the hop clock. Through this tracking loop, the differentially coherent demodulation of an FFH signal is made possible. The hop-timing error is modeled as a finite Markov chain, and error performance of this system in a phase-distorted channel is presented. The numerical results show that with proper parameters, the degradation due to phase imperfection caused by timing error is only about a fraction of one decibel additive white Gaussian noise in an (AWGN) environment. The grouping number should be increased when the phase distortion becomes more serious