Location estimation of wireless terminals using indoor radio frequency models
First Claim
1. A method for estimating a location of a wireless terminal, said method comprising:
- defining a rasterized footprint of a building, wherein said rasterized footprint comprises a plurality of rasters, and wherein said rasterized footprint has a boundary and an interior; and
estimating signal attenuation due to said building, wherein the estimate of signal attenuation is based on signal losses at a first group of said rasters, wherein said rasters in said first group define said boundary of said rasterized footprint.
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Abstract
A method of estimating the location of a wireless terminal that is within a structure is disclosed. In some embodiments, the method can be practiced without the addition of hardware to either the wireless terminal or to base stations of the telecommunications system. In the illustrative embodiment, an indoor radio frequency-signal propagation model is used to correct signal-strength predictions that are obtained from an outdoor radio frequency-signal propagation model. The indoor radio frequency model accounts for a “boundary” loss, which occurs as a radio signal first penetrates a structure (e.g., building, etc.), and/or, optionally, “interior” losses, which are experienced as the radio signal propagates further into the structure. Furthermore, in some embodiments, the model accounts for the effect of building orientation (e.g., the surface of the building, etc.) relative to outdoor transmitters (e.g., base stations, etc.).
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Citations
30 Claims
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1. A method for estimating a location of a wireless terminal, said method comprising:
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defining a rasterized footprint of a building, wherein said rasterized footprint comprises a plurality of rasters, and wherein said rasterized footprint has a boundary and an interior; and
estimating signal attenuation due to said building, wherein the estimate of signal attenuation is based on signal losses at a first group of said rasters, wherein said rasters in said first group define said boundary of said rasterized footprint. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method for estimating a location of a wireless terminal, said method comprising:
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defining a rasterized footprint of a building, wherein said rasterized footprint comprises a plurality of rasters, and wherein said rasterized footprint has a boundary and an interior, and further wherein rasters at said boundary of said rasterized footprint define a first group of rasters; and
estimating signal attenuation due to said building, wherein the estimate of signal attenuation is based on signal losses in a second group of said rasters, wherein said rasters in said second group are in said interior of said rasterized footprint. - View Dependent Claims (12, 13, 14)
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11. The method of 10 further comprising determining a depth of said raster within said interior of said rasterized footprint,
wherein said depth of said raster is defined by a layer number, L; -
wherein rasters defining said boundary have a layer number, L=1;
wherein rasters within said interior have a layer number L=2 to n, wherein n is a positive integer; and
wherein signal attenuation experienced at layer L=m, wherein m≧
2, is based on the signal losses at layers L=1 through m−
1.
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15. A method for estimating a location of a wireless terminal, said method comprising:
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defining a rasterized footprint of a building, wherein said rasterized footprint comprises a plurality of rasters, and wherein said rasterized footprint has a boundary, an interior, and an exterior; and
estimating signal attenuation due to said building, wherein the estimated signal attenuation is a function of an angle of incidence of a signal with respect to one or more physical features of said building, wherein said signal is transmitted from a transmitter. - View Dependent Claims (16, 17, 18, 19, 20)
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21. A method for estimating a location of a wireless terminal, said method comprising:
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defining a rasterized footprint of a building, wherein said rasterized footprint comprises a plurality of rasters, and wherein said rasterized footprint has a boundary, an interior, and an exterior; and
estimating signal attenuation due to said building, wherein the estimated signal attenuation is a function of signal losses that occur within said building, which losses are a function an angle of incidence of a signal with respect to said building, wherein said signal is transmitted from a transmitter. - View Dependent Claims (22, 23, 24, 25, 26)
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27. A method for estimating a location of a wireless terminal, said method comprising:
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accessing an outdoor radio frequency database, wherein said outdoor radio frequency database provides signal strength as a function of location; and
modifying said signal strength, as provided by said outdoor radio frequency database, with signal-attenuation values from an indoor radio frequency database, wherein said indoor radio frequency database provides signal attenuation as a function of location within a structure. - View Dependent Claims (28, 29, 30)
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Specification