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Method of locating a mobile station

  • US 5,293,642 A
  • Filed: 12/19/1990
  • Issued: 03/08/1994
  • Est. Priority Date: 12/19/1990
  • Status: Expired due to Term
First Claim
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1. In a cellular communication system having a plurality of base station radios and mobile stations, a method of estimating the location of a mobile station being served by a first base station radio with respect to other base station radios, the method comprising the steps of:

  • a) transmitting a radio signal from said mobile station operating in said cellular communication system;

    b) receiving said transmitted radio signal from said mobile station at said first base station radio and at a second base station radio and at any other base station radios operating in said cellular communications system within the propagation range of said mobile station;

    c) measuring, for each received radio signal, radio propagation parameters associated with each of said base station radios;

    d) operating on at least one of the measured propagation parameters of each base station radio, to form a location probability density function (pdf) expressed as ##EQU8## wherein k is a scaling constant, e is an error probability function, fi (r,θ

    ) is the signal propagation parameter function and fi0 is a measured propagation parameter of base station i and r is the distance from the base station to the mobile;

    e) constructing a joint pdf by combining each individual pdf formed in step d;

    f) estimating, with respect to said base station radios, the location of the mobile station in said cellular communication system using the resulting joint probability density function.

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