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Preamble detection with unknown channel

  • US 8,031,784 B2
  • Filed: 12/29/2006
  • Issued: 10/04/2011
  • Est. Priority Date: 03/17/2006
  • Status: Active Grant
First Claim
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1. A system, comprising:

  • a differential demodulation module that differentially demodulates modulated signals to generate differentially demodulated signals,wherein the modulated signals include subcarriers,wherein every Pth one of the sub-carriers is modulated with a preamble bit, where P is an integer greater than or equal to 1, andwherein the differential demodulation module generates the differentially demodulated signals by multiplying a Qth one of the modulated signals by a complex conjugate of a (Q+P)th one of the modulated signals, where Q is an integer greater than or equal to 1;

    a correlation module that generates correlation values based on a correlation of the differentially demodulated signals with derived preamble sequences, wherein each one of the correlation values has a real part and an imaginary part; and

    a control module that selects one of the correlation values having a largest real part and that detects a preamble sequence in the modulated signals upon determining that the largest real part is greater than or equal to a predetermined threshold.

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