Mobile location method for WLAN-type systems

1. A method comprising:

providing an estimate of a mobile location of a wireless node, point or terminal in a wireless local area network or other suitable network, the estimate being based at least partly on a correlation of a radio frequency signal strength measurement and a grid point in a signal strength database or radio map;

the signal strength database or radio map being built using a signal strength fingerprint algorithm that includes recording grid positions and signal strength measurements;

a data structure entry for each grid point being based at least partly on an identification number for each grid point, an estimated received information at a respective grid point, a physical location of the respective grid point, and received signal strength information from a respective transmission of an access point at the respective grid point; and

the signal strength fingerprint algorithm including:

placing access points in the wireless local area network or other suitable network and recording their coordinates;

taking signal strengths measurements in areas of interest in the wireless local area network or other suitable network;

applying a linear regression method to estimate propagation channels;

estimating propagation channels at each grid point; and

processing the results to form the signal strength database or radio map.

2. A method according to claim 1 , wherein the signal strength fingerprint algorithm includes selecting and measuring a set of grid points in the wireless local area network or other suitable network.

3. A method according to claim 1 , wherein the signal fingerprint algorithm includes using linear regression parameters to estimate mobile received signal strengths at each assigned grid point.

4. A method according to claim 1 , wherein the data structure entry for each grid point is defined as

R

i

=

{

P

⁡

(

x

i

,

y

i

,

z

i

)

SS

i

,

j

}

,

where i represents the identification number for each grid point, R i is the estimated received information at an i-th grid point, P(x i , y i , z i ) is the physical location of i-th grid point, and SS i,j is average received signal strengths from a j-th transmission of the access point at the i-th grid point.

5. A method according to claim 1 , wherein, in response to a request from the wireless node, point or terminal, a gradient search is used to determine the estimate.

6. A method according to claim 1 , wherein the grid point includes an access point in the wireless local area network or other suitable network.

7. A method according to claim 1 , wherein the wireless node, point or terminal may include a station, as well as user equipment, including a mobile terminal, phone, laptop computer or personal digital assistant.

8. A method according to claim 1 , wherein the method further comprises implementing the method via a computer program running in a processor, controller or other suitable module in one or more network nodes, points, terminals or elements in the wireless local area network or other suitable network.

9. A wireless local area network or other suitable network comprising:

a network node, point or element having one or more modules configured for providing an estimate of a mobile location of a wireless node, point or terminal therein, the estimate being based at least partly on a correlation of a radio frequency signal strength measurement and a grid point in a signal strength database or radio map;

the signal strength database or radio map being built using a signal strength fingerprint algorithm that includes recording grid positions and signal strength measurements;

a data structure entry for each grid point being based at least partly on an identification number for each grid point, an estimated received information at a respective grid point, a physical location of the respective grid point, and received signal strength information from a respective transmission of an access point at the respective grid point; and

the signal strength fingerprint algorithm including:

placing access points in the wireless local area network or other suitable network and recording their coordinates;

taking signal strengths measurements in areas of interest in the wireless local area network or other suitable network;

applying a linear regression method to estimate propagation channels;

estimating propagation channels at each grid point; and

processing the results to form the signal strength database or radio map.

10. A wireless local area network or other suitable network according to claim 9 , wherein the signal strength fingerprint algorithm includes selecting and measuring a set of grid points in the wireless local area network or other suitable network.

11. A wireless local area network or other suitable network according to claim 9 , wherein the signal fingerprint algorithm includes using linear regression parameters to estimate mobile received signal strengths at each assigned grid point.

12. A wireless local area network or other suitable network according to claim 9 , wherein the data structure entry for each grid point is defined as

R

i

=

{

P

⁡

(

x

i

,

y

i

,

z

i

)

SS

i

,

j

}

,

where i represents an identification number for each grid point, R i is the estimated received information at an i-th grid point, P(x i , y i , z i ) is the physical location of the i-th grid point, and SS i,j is average received signal strengths from a j-th transmission of the access point at the i-th grid point.

13. A wireless local area network or other suitable network according to claim 9 , wherein, in response to a request from the wireless node, point or terminal, a gradient search is used to determine the estimate.

14. A wireless local area network or other suitable network according to claim 9 , wherein the grid point includes an access point in the wireless local area network or other suitable network.

15. A wireless local area network or other suitable network according to claim 9 , wherein the wireless node, point or terminal includes a station, as well as user equipment, including a mobile terminal, phone, laptop computer or personal digital assistant.

16. A network node, point or element comprising:

a module configured for providing an estimate of a mobile location of a wireless node, point or terminal operating in a wireless local area network or other suitable network, the estimate being based at least partly on a correlation of a radio frequency signal strength measurement and a grid point in a signal strength database or radio map;

the signal strength database or radio map being built using a signal strength fingerprint algorithm that includes recording grid positions and signal strength measurements; and

a data structure entry for each grid point being based at least partly on an identification number for each grid point, an estimated received information at a respective grid point, a physical location of the respective grid point, and received signal strength information from a respective transmission of an access point at the respective grid point; and

the signal strength fingerprint algorithm including:

placing access points in the wireless local area network or other suitable network and recording their coordinates;

taking signal strengths measurements in areas of interest in the wireless local area network or other suitable network:

applying a linear regression method to estimate propagation channels;

estimating propagation channels at each grid point; and

processing the results to form the signal strength database or radio map.

17. A network node, point or element according to claim 16 , wherein the signal strength fingerprint algorithm includes selecting and measuring a set of grid points in the wireless local area network or other suitable network.

18. A network node, point or element according to claim 16 , wherein the signal fingerprint algorithm includes using linear regression parameters to estimate mobile received signal strengths at each assigned grid point.

19. A network node, point or element according to claim 16 , wherein the data structure entry for each grid point is defined as

R

i

=

{

P

⁡

(

x

i

,

y

i

,

z

i

)

SS

i

,

j

}

,

where i represents an identification number for each grid point, R i is the estimated received information at an i-th grid point, P(x i , y i , z i ) is the physical location of the i-th grid point, and SS i,j is average received signal strengths from a j-th transmission of the access point at the i-th grid point.

20. A network node, point or element according to claim 16 , wherein, in response to a request from the node, point or terminal, a gradient search is used to determine the estimate.

21. A network node, point or element according to claim 16 , wherein the network node, point or element is an access point or other suitable grid point in the wireless local area network or other suitable network.

22. A network node, point or element according to claim 16 , wherein the wireless node, point or terminal is a station or other suitable user equipment, including a mobile terminal, a mobile phone, a laptop computer or a personal digital assistant.

23. A computer program product with a program code, which program code is stored on a machine readable carrier, for carrying out the steps of a method comprising providing an estimate of a mobile location of a wireless node, point or terminal in a wireless local area network or other suitable network, the estimate being based on a correlation of a radio frequency signal strength measurement and a grid point in a signal strength database or radio map, the signal strength database or radio map being built using a signal strength fingerprint algorithm that includes recording grid positions and signal strength measurements; and a data structure entry for each grid point being based at least partly on an identification number for each grid point, an estimated received information at a respective grid point, a physical location of the respective grid point, and received signal strength information from a respective transmission of an access point at the respective grid point,; and the signal strength fingerprint algorithm including: placing access points in the wireless local area network or other suitable network and recording their coordinates; taking signal strengths measurements in areas of interest in the wireless local area network or other suitable network; applying a linear regression method to estimate propagation channels; estimating propagation channels at each grid point; and processing the results to form the signal strength database or radio map when the computer program is run in a module of either a node, point or terminal, including an Access Point or other suitable grid point, in the wireless local area network or other suitable network.

24. A method comprising:

building a database using a signal strength fingerprint algorithm for use in providing an estimate of a mobile location of a wireless node, point or terminal in a wireless local area network or other suitable network arranged in a geographic location;

placing access points or other suitable grid points in the wireless local area network or other suitable network and recording their coordinates in the geographic location;

taking signal strengths measurements in areas of interest in the wireless local area network or other suitable network;

applying a linear regression method to estimate propagation channels;

estimating propagation channels at each access or other suitable grid point;

processing the results to form the signal strength database or radio map;

the signal strength database or radio map being built using the signal strength fingerprint algorithm that includes recording grid positions and signal strength measurements;

a data structure entry for each grid point being based at least partly on an identification number for each grid point, an estimated received information at a respective grid point, a physical location of the respective grid point, and received signal strength information from a respective transmission of an access point at the respective grid point; and

the signal strength fingerprint algorithm including:

placing access points in the wireless local area network or other suitable network and recording their coordinates;

taking signal strengths measurements in areas of interest in the wireless local area network or other suitable network;

applying a linear regression method to estimate propagation channels;

estimating propagation channels at each grid point; and

processing the results to form the signal strength database or radio map.

25. A method according to claim 24 , wherein the data structure entry for each grid point is defined as

R

i

=

{

P

⁡

(

x

i

,

y

i

,

z

i

)

SS

i

,

j

}

,

where i represents the identification number for each grid point, R i is the estimated received information at an i-th grid point, P(x i , y i , z i ) is the physical location of the i-th grid point, and SS i,j is average received signal strengths from a j-th transmission of the access point at the i-th grid point.

26. A method according to claim 24 , wherein the estimate is based on a correlation of a radio frequency signal strength measurement and a grid point in a signal strength database or radio map.