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Method for rapid carrier frequency estimation in a communication system

  • US 6,731,710 B1
  • Filed: 09/30/1998
  • Issued: 05/04/2004
  • Est. Priority Date: 09/30/1998
  • Status: Expired due to Fees
First Claim
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1. A method for estimating a frequency offset of at least one frame, containing at least one synchronization field being divided into at least two subsections, the at least two subsections being composed of substantially equivalent pseudorandom symbols, the frame being received by a receiver from a transmitter, the receiver including at least an analog-to-digital processing unit, the steps of the method being performed by a data processor, the steps of the method comprising:

  • (a) determining an initial frequency offset, finitial;

    (b) calculating a first phase in radians for at least a portion of a first subsection according to an equation;

    ϕ

    1
    =angle

    (

    i=imin






    ai**exp

    (-j*i*finitial*2





    π

    *Ts
    )


    Yi
    )
    embedded imagewherein i denotes time in symbols;

    Ts is a symbol period;

    n and m are integers, in

    im;

    a length of said at least portion of said first subsection is in

    im+1;

    Yi is an output of the analog-to-digital processing unit;

    ai* is the complex conjugate of the ith training symbol ai;

    (c) calculating a second phase in radians for at least a portion of a second subsection according to an equation;

    ϕ

    2
    =angle

    (

    i=ipiq






    ai**exp

    (-j*i*finitial*2





    π

    *Ts
    )


    Yi
    )
    embedded imagewherein q and p are integers, iq

    ip;

    a length of said at least a portion of said second subsection is iq

    ip+1;

    (d) calculating a phase difference of said first phase and said second phase angle according to an equation;

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