Method and apparatus for estimating the location of a mobile terminal
First Claim
1. A method comprising the steps of:
- estimating the location of a mobile terminal using at least one forward-link geo-location technique without using any reverse-link geo-location techniques, this step being performed when there are enough base stations visible to the mobile terminal to be able to use the forward-link geo-location technique without using any reverse-link geo-location techniques to estimate the location; and
estimating the location of the mobile terminal using at least one reverse-link geo-location technique when there are not enough base stations visible to the mobile terminal to be able to use the forward-link geo-location technique without using any reverse-link geo-location techniques to estimate the location;
a forward-link geo-location technique being a geo-location technique that uses only information obtained from one or more forward-link signals to estimate the location of the mobile terminal; and
a reverse-link geo-location technique being a geo-location technique that uses information obtained from at least one reverse-link signal to estimate the location of the mobile terminal.
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Accused Products
Abstract
A method and apparatus for estimating the location of a mobile terminal. The method estimates the locations by: a) using at least one forward-link geo-location technique without using any reverse-link geo-location techniques, this being performed when there are enough base stations visible to the mobile terminal to be able to use the forward-link geo-location technique without using any reverse-link geo-location techniques to estimate the location, and b) using at least one reverse-link geo-location technique when there are not enough base stations visible to the mobile terminal to be able to use the forward-link geo-location technique without also concurrently using any reverse-link geo-location techniques to estimate the location. The forward-link geo-location techniques can be used either alone or in combination with each other, and include such known geo-location techniques as a time-difference-of-arrival technique and angle-difference-of-arrival technique. Illustratively, when the predetermined number, for example three, base stations are visible to the mobile terminal, the location of the mobile terminal is estimated using time-difference-of-arrival. When fewer than three base stations are visible to the mobile terminal, the location of the mobile terminal is estimated using round trip delay. Estimating the location of a mobile terminal by using only forward-link geo-location techniques when there are enough base stations visible to the mobile terminals to be able to use forward-link geo-location techniques, produces a more accurate estimation of the mobile terminal'"'"'s location. It also allows wireless assisted GPS (AGPS) systems to more quickly estimate a more precise location of the mobile terminal.
145 Citations
22 Claims
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1. A method comprising the steps of:
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estimating the location of a mobile terminal using at least one forward-link geo-location technique without using any reverse-link geo-location techniques, this step being performed when there are enough base stations visible to the mobile terminal to be able to use the forward-link geo-location technique without using any reverse-link geo-location techniques to estimate the location; and
estimating the location of the mobile terminal using at least one reverse-link geo-location technique when there are not enough base stations visible to the mobile terminal to be able to use the forward-link geo-location technique without using any reverse-link geo-location techniques to estimate the location;
a forward-link geo-location technique being a geo-location technique that uses only information obtained from one or more forward-link signals to estimate the location of the mobile terminal; and
a reverse-link geo-location technique being a geo-location technique that uses information obtained from at least one reverse-link signal to estimate the location of the mobile terminal.- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method comprising the steps of:
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estimating the location of a mobile terminal using at least one forward-link geo-location technique without using any reverse-link geo-location techniques when there are at least a predetermined number of base stations visible to the mobile terminal; and
estimating the location of the mobile terminal using at least one reverse-link geo-location technique when there are fewer than the predetermined number of base stations visible to the mobile terminal;
a forward-link geo-location technique being a geo-location technique that uses only information obtained from one or more forward-link signals to estimate the location of the mobile terminal; and
the reverse-link geo-location technique being a geo-location technique that uses information obtained from at least one reverse-link signal to estimate the location of the mobile terminal.- View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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Specification