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Rake receiver for spread spectrum chaotic communications systems

  • US 8,363,700 B2
  • Filed: 07/01/2009
  • Issued: 01/29/2013
  • Est. Priority Date: 07/01/2009
  • Status: Active Grant
First Claim
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1. A method of recovering information encoded in a carrier modulated using a sequence of discrete-time chaotic samples and transmitted in a communications medium, the method comprising the steps of:

  • receiving a composite signal comprising a plurality of multi-path components, each of said plurality of multi-path components associated with a plurality of multi-path images of a transmitted signal;

    combining said sequence of discrete-time chaotic samples and a first dominate component of said plurality of multi-path components to obtain a first reference input signal;

    analyzing samples of said first reference input signal which are contained in a first correlation window to determine a first time-offset value;

    time synchronizing said sequence of discrete-time chaotic samples with said first dominant component using said first time-offset value;

    combining said sequence of discrete-time chaotic samples, which was time synchronized, with each of a plurality of second dominant components of said plurality of multi-path components to obtain a plurality of second reference input signals;

    analyzing samples of each said second reference input signal which are contained in a second correlation window to determine one of a plurality of different second time-offset values, said second correlation window smaller than said first correlation window;

    correlating the received composite signal with a spreading sequence using said plurality of different second time-offset values to generate a plurality of time-offset de-spread signals associated with said plurality of second dominate components, said spreading sequence based on said sequence of discrete-time chaotic samples;

    modifying at least a portion of said plurality of time-offset de-spread signals based at least on said second time-offset values to synchronize said plurality of time-offset de-spread signals; and

    combining said plurality of de-spread signals into a combined coherent de-spread signal after said modifying.

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