Patent ID: 8755462

Claim:
A method of estimating the frequency offset of an RF or IF signal which has been downconverted to baseband comprising: beginning each transmission with a signal preamble consisting of a sequence of symbols known to both transmitter and receiver; utilizing the received version of this signal preamble in the receiver in order to calculate the frequency offset present in the transmission; wherein the calculation is performed by constructing a composite estimator which is an average of the output of a series of elementary estimators; wherein each of the elementary estimators makes use of only a subset of the total signal preamble; and wherein the preamble subsets have the following characteristics: all of the preamble subsets comprise a series of consecutive symbols; all of the preamble subsets used by the elementary estimators must contain the same number M+1 of symbols; no two preamble subsets may start or end on the same symbol; wherein each elementary estimator estimates the frequency offset by: using a 1 symbol wide differential detector and angle computation device in order to determine the angular difference between each pair of symbols in the preamble subset; and computing the average value of this angular difference.