Patent ID: 7916799

Claim:
A method for frequency offset compensation in a communication system, comprising: determining a first measure of frequency offset in a received signal for a first frequency; determining a first frequency offset correction factor for use in compensating for frequency offset in received signals at the first frequency using the first measure; determining a plurality of second frequency offset correction factors for use in compensating for frequency offset in the received signals at a plurality of second frequencies using the first measure; and compensating for frequency offsets by: applying the first frequency offset correction factor to the received signals at the first frequency, and applying the plurality of second frequency offset correction factors to the received signals at the plurality of second frequencies, wherein determining a first measure of frequency offset includes: receiving a packet of the packets; determining the packet synchronization sequence corresponding to the time-frequency code of the packet; cross-correlating the samples of the symbols of the packet with the packet synchronization sequence to obtain cross-correlation results for the symbols of the packet, the cross-correlation results including cross-correlation peaks; removing the cover sequence from the cross-correlation results to obtain cross-correlations; averaging the cross-correlations over a window of samples about the cross-correlation peaks to obtain averaged cross-correlations for each of the symbols; autocorrelating the averaged cross-correlations using a first delay of symbols to obtain autocorrelation results, the first delay equal to a delay number; summing the autocorrelation results for a first group of symbols to obtain an initial offset vector, a number of the symbols in the first group equal to the delay number, the symbols of the first group being in the preamble; and dividing the initial offset vector by the delay number and by a duration of each of the symbols and by an inverse of the center frequency to obtain the initial frequency offset factor.