Patent ID: 7995680

Claim:
An apparatus for preamble detection and integer carrier frequency offset estimation, comprising: a subcarrier windowing device for determining a window of useful subcarriers in a preamble transformed to the frequency domain based on a pre-determined possible integer carrier frequency offset and the length of the preamble, so as to select the useful subcarriers; a subcarrier shift extractor for extracting a plurality of subcarrier sequences from the useful subcarriers; a conjugative multiplier for calculating conjugative multiplications of each subcarrier and its neighboring subcarriers in the plurality of subcarrier sequences extracted; a real part acquirer for acquiring a real part of the conjugative multiplications; a cross correlator for calculating cross correlations between the real part of the conjugative multiplications and known preambles modulated by a differential phase shift keying modulation scheme, and outputting the calculated correlation values; and a cell and integer carrier frequency offset selector for detecting a preamble index of a target base station with the calculated correlation values, and selecting a target cell, and estimating integer carrier frequency offset with respect to the target base station.