Patent ID: 7027429

Claim:
An orthogonal frequency division multiplexing (OFDM) communication device, comprising: an OFDM receiver for receiving an OFDM signal containing a multitone synchronization signal; a synchronization interval sampler coupled to said receiver; an initial time and frequency offset estimator connected to said sampler and said receiver; and a frequency offset estimate refinement unit connected to said receiver, said sampler and said receiver, wherein a reference multitone synchronization signal is used by said estimator and said refinement device in calculating a time offset and a frequency offset of said multitone synchronization signal, said receiver utilizing said time offset and said frequency offset to synchronize with said received QFDM signal, and wherein said initial time and frequency offset estimator comprises: a plurality of smoothed time-domain correlation estimators for outputting a series of time offset estimate and correlation estimate pairs, each pair related to a frequency offset estimate; and a selector for selecting a selected time offset estimate and a selected initial frequency offset based in part upon the selection of the frequency offset estimate and time offset estimate that corresponds with the largest value of correlation estimate.