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Method and device for synchronizing mobile radio receivers in a mobile radio system

  • US 6,954,483 B2
  • Filed: 01/16/2002
  • Issued: 10/11/2005
  • Est. Priority Date: 07/16/1999
  • Status: Expired due to Fees
First Claim
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1. A method of synchronizing mobile CDMA radio receivers in a cellular CDMA mobile radio system, wherein a first synchronization channel with a first frequency is provided for transmitting a synchronization signal with a code that is known to the mobile radio receivers and to base stations of the mobile radio system, and wherein a transmission from a base station to a mobile radio receiver delays the synchronization signal by an unknown time period and the first frequency is shifted by the transmission to a second frequency, the method which comprises the following steps:

  • splitting the received synchronization signal into a real part signal and an imaginary part signal;

    sampling the real part signal and the imaginary part signal to form sampled signals;

    digitally filtering each sampled signal to correlate the sampled signal to the known code and to form filtered signals;

    squaring each filtered signal to form squared signals;

    determining a maximum signal level from the squared signals;

    estimating the unknown time period with the maximum signal level determined in the determining step;

    despreading the received synchronization signal with the known code and taking into account the time period estimated in the estimating step;

    determining a frequency deviation between the first frequency and the second frequency based on the despread received synchronization signal; and

    fine-tuning the second frequency to the first frequency based in part on the despread received synchronization signal.

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