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Mid-call synchronization for U-TDOA and AoA location in UMTS

  • US 8,116,784 B2
  • Filed: 12/13/2007
  • Issued: 02/14/2012
  • Est. Priority Date: 12/13/2007
  • Status: Active Grant
First Claim
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1. In a wireless location system (WLS) for use in locating a mobile transmitter, a method for determining frame and slot timing information for use in receiving an uplink signal from a user equipment (UE) device assigned to an uplink Dedicated Physical Control Channel (DPCCH), comprising:

  • receiving uplink DPCCH signals in the uplink DPCCH at a location measurement unit (LMU) of the WLS, said uplink DPCCH signals being formatted into multiple frames and multiple slots per frame;

    detecting a predefined bit pattern known to be present in a plurality of predefined slots of the uplink DPCCH signals, wherein said predefined slots comprise slots 0, 5, 6, and 9 of a 10 millisecond (ms) frame, and said predefined bit pattern comprises the bit pattern “

    1-1-1”

    ;

    examining the DPCCH signals across multiple frames;

    determining the frame and slot timing information for the uplink DPCCH based on the detected bit pattern; and

    using the frame and slot timing information, collecting uplink signals from the UE for use in location processing, wherein the step of collecting uplink signals from the UE comprises collecting uplink signals at a plurality of LMUs and using said signals in time difference of arrival (TDOA) processing to determine the location of the UE.

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