Probing techniques and estimation processes for fine-time synchronization of FH systems

Five methods for estimating the time error in a frequency-hopped spread-spectrum (FHSS) system are analyzed and compared. These methods are based upon estimation of the second-order moments of the envelope-detected, match-filtered, received signal. The performance of these estimators is determined as a function of the Gaussian noise level and of the number of samples L used to form the estimate. The estimator mean and standard deviation are approximated by means of the central limit theorem. Solutions compare favorably with simulation results. Results for signal-to-noise ratios of 0, 5, and 10 dB and with L between 1 and 512 show that these estimators are superior to previously known methods.<
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