Patent ID: 6882694

Claim:
Apparatus for estimating in a communication system in which a data sequence, formed of initial data symbol values, is communicated upon a communication channel to a receiving station, said apparatus for estimating, responsive to received data symbol values, received at the receiving station, frequency offset of the received data symbols, said apparatus comprising: a multiplier coupled to receive values of the received symbols, said multiplier for multiplying the values of the received symbols by at least a first rotation term to form a first product value sequence and for multiplying the values of the received symbols by at least a second rotation term to form at least a second product value sequence; a first-stage data value determiner coupled to receive indications of the first and at least second product value sequences, respectively, formed by said multiplier, said first-stage data-value determiner for determining a first, first-stage estimate of the data sequence and at least a second, first-stage estimate of the data sequence; a noise indicia calculator coupled to said first-stage data-value determiner, said noise indicia calculator for calculating a noise indicia associated with each first-stage estimate formed by said data-value determiner; and a selector coupled to receive values of the noise indicia calculated by said noise indicia calculator, said selector for selecting a selected one of first and at least second, first-stage estimates, respectively, to be the frequency offset of the receiving data symbols.