Estimating the frequency of received signals is an attractive topic in communicationtheory. In this work, some of these estimators are introduced. Also, a generalization oftwo of these estimators are derived. Performance of the estimators are compared togetherfor several preamble lengths, signal-to-noise values and steps. Generalized estimatorsattain the Cramer-Rao lower bound for lower signal-to-noise ratio values if the rightstep value is used. The computation complexity of the estimators is calculated anddiscussed. Also it is shown that computation complexity depends on how an algorithmis implemented by calculating computation complexity for two separate implementationsof a single estimator.