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Synchronization method for a mobile radiotelephone

DC CAFC
  • US 5,390,216 A
  • Filed: 04/16/1993
  • Issued: 02/14/1995
  • Est. Priority Date: 11/02/1991
  • Status: Expired due to Term
First Claim
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1. A method of synchronizing a mobile radiotelephone in a cellular digital mobile radiotelephone network comprising a plurality of fixed radiotelephone stations and a plurality of mobile radio stations operating in accordance with a GSM standard or its equivalent, in which each communication frequency assignment is subdivided into interleaved time slots, a plurality of said time slots together comprising a frame, comprising the following steps which are carried out in the mobile radiotelephone:

  • (1) conducting an initial synchronization by means of a frequency correction burst substantially fully occupying a time slot with an unmodulated wave corresponding to repetition of bits of the same binary logic value;

    (2) maintaining normal synchronization during communication by means of interspersed normal synchronization bursts, each normal synchronization burst containing a training sequence occupying less than a third of a time slot, and(3) performing extended synchronization during communication as a background procedure by means of interspersed frequency synchronization bursts, each frequency synchronization burst containing an extended training sequence occupying less than an entire time slot and more than a third of a time slot, and wherein;

    said step of conducting said initial synchronization comprises the substeps of;

    (1.1) conducting a coarse frequency synchronization,(1.2) conducting a coarse frame synchronization over a plurality of said time slots which comprise a frame,(1.3) conducting a fine frequency synchronization, and(1.4) conducting a fine frame synchronization over said plurality of time slots which comprise a frame;

    said step of maintaining said normal synchronization comprises the substeps of;

    (2.1) conducting a frame synchronization with fine frequency synchronization, and(2.2) carrying out preliminary data signal processing; and

    said step of performing said extended synchronization comprises the substeps of;

    (3.1) conducting a coarse frame synchronization, and(3.2) conducting a fine frame synchronization with fine frequency synchronization.

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