Wireless communication network with distributed device location determination

Patent metadata

Field	Value
Publication number	US-10517060-B2
Application number	US-201715495417-A
Country	US
Kind code	B2
Filing date	Apr 24, 2017
Priority date	Jul 12, 2016
Publication date	Dec 24, 2019
Grant date	Dec 24, 2019

Abstract

There are disclosed methods and access points for estimating a location of a user device in a wireless communications network. A plurality of access points define respective received signal strength indicator (RSSI) values for transmissions received from the user device. Each of the plurality of access points sends the respective RSSI values to the other access points of the plurality of access points. One of the plurality of access points self-elects to estimate the location of the user device. The self-elected access point estimates a location of the user device based, at least in part, on the RSSI values.

First claim

It is claimed:

1. A method for estimating a location of a user device in a wireless communications network, comprising:
three or more access points defining a respective received signal strength indicator (RSSI) value for transmissions received from the user device;
all of the three or more access points sending the respective RSSI values to the other access points of the three or more access points;
all of the three or more access points comparing its own RSSI value associated with the user device to RSSI values associated with the user device received from the other access points of the three or more access points;
an access point having an own RSSI value associated with the user device higher than RSSI values associated with the user device received from the other access points determining it is responsible for estimating the location of the user device;
access points having own RSSI values associated with the user device less than at least one RSSI value associated with the user device received from the other access points determining they are not responsible for estimating the location of the user device; and
the responsible access point estimating a location of the user device based, at least in part, on the RSSI values associated with the user device.

2. The method of claim 1 , further comprising:
all of the three or more access points receiving location information indicating locations of all of the three or more access points; and
the responsible access point estimating the location of the user device based, at least in part, on the RSSI values associated with the user device and the location information.

3. The method of claim 2 , further comprising:
the responsible access point estimating the location of the user device in accordance with the formula:

d
=

∑

i
=
1

n

⁢

(

w
i

)

⁢

p
i

∑

i
=
1

n

⁢

(

w
i

)

where
d=(x, y, z)=location of the user device;
p i =(x i , y i , z i )=location of access point i;
wi=weight determined from the RSSI value reported by access point i;
n=number of access points.

4. The method of claim 3 , further comprising:
the responsible access point determining, for each access point i of the three or more access points, the respective weight wi by adding a respective bias value to the RSSI value associated with the user device reported by access point i.

5. The method of claim 4 , further comprising:
the responsible access point setting, for each access point i of the three or more access points, the respective bias value to a predetermined value.

6. The method of claim 4 , further comprising:
the responsible access point setting, for each access point i of the three or more access points, the respective bias value by:
determining a respective relative path loss between the responsible access point and each of the other access points of the three or more access points; and
setting the respective bias value associated with each of the other access points proportional to the respective relative path loss.

7. The method of claim 1 , further comprising:
the responsible access point sending an estimate of the location of the user device to a location server.

8. A method performed by every access point (AP) of a group of three or more access points that receive transmissions from a user device in a wireless communications network, comprising:
defining an own received signal strength indicator (RSSI) value for transmissions received from the user device;
transmitting the own RSSI value associated with the user device to the other access points of the group of access points;
receiving, from the other access points of the group of access points, respective other AP RSSI values for transmissions received from the user device at the other access points;
comparing the own RSSI value associated with the user device to the other AP RSSI values associated with the user device;
determining to estimate a location of the user device when the own RSSI value associated with the user device is greater than or equal to all of the other AP RSSI values associated with the user device; and
when a determination is made to estimate the location of the user device, estimating the location of the user device based, at least in part, on the own RSSI value associated with the user device and the other AP RSSI values associated with the user device.

9. The method of claim 8 , further comprising:
receiving location information indicating an own location and respective locations of all other access points of the group of access points; and
when a determination is made to estimate the location of the user device, estimating the location of the user device based, at least in part, on the own RSSI value associated with the user device, the other AP RSSI values associated with the user device and the location information.

10. The method of claim 9 , further comprising:
when a determination is made to estimate the location of the user device, estimating the location of the user device in accordance with the formula:

d
=

∑

i
=
1

n

⁢

(

w
i

)

⁢

p
i

∑

i
=
1

n

⁢

(

w
i

)

where
d=(x, y, z)=location of the user device;
p i =(x i , y i , z i )=location of access point I, where access point 0 is the access point performing the method and access points 1 to n are the other access points in the group of access poin

Assignees

• Riverbed Tech Inc
• Cambium Networks Ltd

Inventors

• Horner Jack
• Gates Dirk I

Classifications

• G01S5/0081

  Transmission between base stations · CPC title

• G01S5/0036

  of measured values, i.e. measurement on mobile and position calculation on base station · CPC title

• G01S5/0284

  Relative positioning · CPC title

• G01S5/0072

  Transmission between mobile stations, e.g. anti-collision systems · CPC title

• G01C21/206

  specially adapted for indoor navigation · CPC title