Acquisition of Fast Frequency Hopping at HF

In this paper we propose an acquisition scheme for a frequency-hopped spread-spectrum signal received over a nonspecular Rayleigh fading multipath channel. We consider relatively fast frequency hopping with hopping rate of 1 KHz, and 127 different hopping frequencies. We assume that any two hopping frequencies propagate via statistically independent channels, i.e. via channels with statistically independent time and frequency spreading and statistically independent delay times. Also according to the measurement results we assume that the maximum deviation of the delay time from the nominal delay time is 1 msec and is uniformly distributed around the nominal delay time. For such a case we propose an acquisition scheme whose characteristics are analyzed mathematically and by computer simulation.