Determination of mobile station location
First Claim
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1. A method for mobile station location determination, the method comprising, at a processing unit, the steps of:
- retrieving received signal strength measurements of signals sent from a plurality of base stations to the mobile station;
retrieving the transmitted signal strength value and the electromagnetic field distribution model function corresponding to each of the plurality of base stations;
setting up an estimation error function with, for each of the plurality of base stations, the transmitted signal strength, received signal strength, and electromagnetic field distribution model function, the estimation error function being given by;
where x and y are coordinates of the mobile station, m is the number of base stations that the mobile station measured signals from, M is a metric of optimisation, PRj is received signal strength, PTj is transmitted signal strength, γ
is an attenuation factor and Gj(x,y) is the electromagnetic field distribution model function;
calculating a global minimum of the estimation error function; and
communicating the solution to the global minimum.
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Abstract
A system, method and processing unit for mobile station location determination. Mobile Assisted Handoff (MAHO) measurements are sent to the processing unit that also retrieves the corresponding transmitted signal strengths and electromagnetic field distribution functions for the relevant base stations. The location of the mobile station is then determined by minimising the following formula:
- where m is the number of relevant base stations, M is an optimisation metric (such as (εj)2 or |εj|)PRj is received signal strength, PTj transmitted signal strength, γ attenuation (e.g. in the mobile station), and Gj(x,y) the electromagnetic field distribution function.
20 Citations
11 Claims
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1. A method for mobile station location determination, the method comprising, at a processing unit, the steps of:
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retrieving received signal strength measurements of signals sent from a plurality of base stations to the mobile station;
retrieving the transmitted signal strength value and the electromagnetic field distribution model function corresponding to each of the plurality of base stations;
setting up an estimation error function with, for each of the plurality of base stations, the transmitted signal strength, received signal strength, and electromagnetic field distribution model function, the estimation error function being given by;
where x and y are coordinates of the mobile station, m is the number of base stations that the mobile station measured signals from, M is a metric of optimisation, PRj is received signal strength, PTj is transmitted signal strength, γ
is an attenuation factor and Gj(x,y) is the electromagnetic field distribution model function;
calculating a global minimum of the estimation error function; and
communicating the solution to the global minimum. - View Dependent Claims (2, 3, 4)
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5. A system for mobile station location determination, the system comprising:
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a plurality of base stations that;
transmit signals to the mobile station; and
a processing unit that;
retrieves received signal strength measurements of signals sent from the plurality of base stations to the mobile station;
retrieves the transmitted signal strength value and the electromagnetic field distribution model function corresponding to each of the plurality of base stations;
sets up an estimation error function with, for each of the plurality of base stations, the transmitted signal strength, received signal strength, and propagation model function, wherein the estimation error function is given by;
where x and y are coordinates of the mobile station with respect to the base station, m is the number of base stations that the mobile station measured signals from, M is a metric, PRj is received signal strength, PTj is transmitted signal strength, γ
is an attenuation factor and Gj(x,y) is the electromagnetic field distribution model function;
calculates a global minimum of the estimation error function; and
communicates the solution to the global minimum. - View Dependent Claims (6, 7)
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8. A processing unit for determining mobile station location, comprising:
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a communication unit that;
receives received signal strength measurements of signals sent from a plurality of base stations to the mobile station;
forwards the measurements to a processor; and
communicates a global minimum; and
a processor that, upon reception of the received signal strength measurements and the transmitted signal strength values;
retrieves the transmitted signal strength value and the electromagnetic field distribution model function corresponding to each of the plurality of base stations;
sets up an estimation error function with, for each of the plurality of base stations, the transmitted signal strength, received signal strength, and the electromagnetic field distribution model function, wherein the estimation error function is given by;
where x and y are coordinates of the mobile station with respect to the base station, m is the number of base stations that the mobile station measured signals from, M is a metric, PRj is received signal strength, PTj is transmitted signal strength, γ
is an attenuation factor and Gj(x,y) is the electromagnetic field distribution model function;
calculates a global minimum of the estimation error function; and
sends the solution to the global minimum to the communication unit. - View Dependent Claims (9, 10, 11)
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Specification