| CPC H04L 27/2663 (2013.01) [H04L 27/2665 (2013.01); H04L 27/2666 (2013.01)] | 20 Claims |
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1. A method for detecting a preamble waveform of a received signal over a range of frequency offsets, the received signal comprising a preamble, the preamble having a preamble length corresponding to a plurality of complex samples in the preamble, the preamble comprising a plurality of waveforms in a sequence, each waveform having a plurality of samples, the method comprising:
dividing a correlation into a plurality of sub-correlations, the correlation being associated with the received signal and being for a plurality of frequency offset indices covering the range of frequency offsets, the correlation having a fixed correlation length and each sub-correlation of the plurality of sub-correlations having a fixed sub-correlation length;
approximating a complex oscillation for a template frequency offset associated with the plurality of frequency offset indices, the approximation to be constant over the fixed sub-correlation length, the approximation being a piece-wise approximation, the approximated complex oscillation having a length equal to the number of waveforms in the plurality of waveforms;
assembling a quantity of sub-correlations at each frequency offset index of the plurality of frequency offset indices using the approximated complex oscillation; and
determining that the received signal comprises the preamble based on the assembled sub-correlations and a correlation threshold.
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