MOBILE GEOLOCATION

• US 20140171102A1
• Filed: 12/18/2012
• Published: 06/19/2014
• Est. Priority Date: 12/18/2012
• Status: Active Grant

• Current Assignee: Viavi Solutions UK Limted (Lumentum Holdings Inc.)
• Original Assignee: Arieso Limited (Lumentum Holdings Inc.)
• Inventors: Kenington, Peter, Murphy, Christopher, Flnagan, Michael Joseph
• Granted Patent: US 9,439,162 B2
• Time in Patent Office: Days
• US Class Current: 455/456.1
• CPC Class Codes: G01S 5/02526 using non-dedicated equipment, e.g. user equipment or crowd-sourcing
• CPC Class Codes: H04W 56/001 Synchronization between nodes
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management
• CPC Class Codes: H04W 64/006 with additional information processing, e.g. for direction or speed determination

Abstract

A method and apparatus for generating reference signatures for use in geolocation in a cellular wireless communication system is provided. A first signature for a mobile communication unit comprises location information, a timestamp, and radio frequency measurement information obtained by a mobile communication unit at a location, but does not contain identification information for the mobile communication unit. The first signature is compared to signatures in a database, to identify a second signature that has a timestamp and radio frequency measurement information that correspond to those of the first signature. A reference signature is created by combining at least a part of the first signature with at least a part of the second signature. Repetition of the comparison and combination steps creates a database of reference signatures, for use in geolocating other received call signatures.

Claims

1. A method of generating reference signatures for use in geolocation in a cellular wireless communication system, comprising:

obtaining a first signature for a mobile communication unit, the first signature comprising location information, a timestamp, and radio frequency measurement information obtained by the mobile communication unit at the location, but not containing identification information for the mobile communication unit;

comparing the first signature to signatures in a database, to identify a second signature, the second signature having a timestamp and radio frequency measurement information that correspond to those of the first signature; and

creating a first reference signature, by combining at least a part of the first signature with at least a part of the second signature.

2. The method of claim 1, wherein creating the first reference signature further comprises:

combining the location information of the first signature with at least a part of the second signature.

3. The method of claim 2, wherein creating the first reference signature further comprises:

adding the location information of the first signature into the database holding the second signature.

4. The method of claim 1, wherein:

the second signature comprises a user identifier, and at least one of the following types of control information not included in the first signature;

timing advance;

burst throughput rate;

dynamic rate control, comprising at least channel quality indicators;

signal-to-noise ratio.

5. The method of claim 1, wherein the radio frequency measurement information of the first signature comprises at least one selected from:

signal quality; and

a cell identifier and corresponding observed power level.

6. The method of claim 1, wherein:

the first signature is from an anonymized call, the anonymized call being obtained in accordance with the Minimization of Drive Test 3GPP standard.

7. The method of claim 1, further comprising:

obtaining a third signature, the third signature comprising location information, a timestamp and radio frequency measurements obtained at a second location, but not containing identification information;

comparing the third signature to a second plurality of signatures in the database, to identify a fourth signature from the database having a timestamp and radio frequency measurement information that correspond to those of the third signature; and

when the second and fourth signatures from the database both have the identification information of the mobile communication unit;

creating a second reference signature, by combining at least a part of the third signature with at least a part of the fourth signature;

8. The method of claim 7, further comprising, when the second and fourth signatures from the database both have the identification information of the mobile communication unit:

creating at least a third reference signature, by interpolating or extrapolating location information from the first signature and the third signature to provide a location estimate for one or more additional signatures in the database, the one or more additional signatures having been obtained for the mobile communication unit at a time between the timestamp of the second signature and the timestamp of the fourth signature.

9. The method of claim 7, wherein creating the second reference signature further comprises:

combining the location information of the third signature with additional measurement data associated with the fourth signature.

10. The method of claim 9, wherein creating the second reference signature further comprises:

creating the second reference signature by adding the location information of the third signature into the database holding the fourth signature.

11. The method of claim 8, wherein the interpolation of location information to create the at least a third reference signature further comprises:

deriving a location estimate for each additional signature on the basis of;

a timestamp of each corresponding additional signature in the database;

the location information of the first signature; and

the location information of the third signature.

12. The method of claim 2, wherein:

additional measurement data associated with the second signature comprises;

a cell identifier and corresponding observed power level; and

at least one from;

signal quality;

timing advance;

burst throughput rate;

dynamic rate control, comprising at least channel quality indicators;

signal-to-noise ratio; and

creating the first reference signature comprises combining the location information of the first signature with the additional measurement data associated with the second signature.

13. The method of claim 1, wherein comparing the first signature to the plurality of signatures in the database to identify the second signature further comprises identifying a second signature that matches the first signature, a second signature being identified as matching the first signature based on:

determining that the timestamp of the second signature corresponds to the timestamp of the first signature, when the timestamp of the second signature matches the timestamp of the first signature within a predetermined timing accuracy; and

determining that the radio frequency measurement information of the second signature corresponds to the radio frequency measurement information of the first signature, when at least a part of the radio frequency measurement information of the second signature matches at least a part of the radio frequency measurement information of the first signature within a predetermined measurement accuracy.

20. A computer-readable storage device having executable program code stored therein for programming signal processing logic to perform the method of claim 1.

14. A cellular wireless communication system comprising a database of reference signatures for use in geolocation, the cellular wireless communication system, operable to:

obtain a first signature for a mobile communication unit, the first signature comprising location information, a timestamp and radio frequency measurement information obtained by the mobile communication unit at the location, but not containing identification information for the mobile communication unit;

compare the first signature to a plurality of signatures in a database, to identify a second signature of the plurality of signatures, the second signature having a timestamp and radio frequency measurement information that correspond to those of the first signature; and

create a first reference signature, by combining at least a part of the first signature with at least a part of the second signature.

15. The cellular wireless communication system of claim 14, further operable to:

create the first reference signature by combining the location information of the first signature with at least a part of the second signature.

16. The cellular wireless communication system of claim 15, further operable to:

create the first reference signature by adding the location information of the first signature into the database holding the second signature.

17. The cellular wireless communication system of claim 14, further operable to:

obtain a third signature, the third signature comprising location information, a timestamp and radio frequency measurements obtained at a second location, but not containing identification information;

compare the third signature to signatures in the database, to identify a fourth signature from the database having a timestamp and radio frequency measurement information that correspond to those of the third signature; and

when the second and fourth signatures from the database both have the identification information of the mobile communication unit;

create a second reference signature, by combining at least a part of the third signature with at least a part of the fourth signature.

18. The cellular wireless communication system of claim 17, further operable, when the second and fourth signatures from the database both have the identification information of the mobile communication unit, to:

create at least a third reference signature, by interpolating or extrapolating location information from the first signature and the third signature to provide a location estimate for one or more additional signatures in the database, the one or more additional signatures having been obtained for the mobile communication unit at a time between the timestamp of the second signature and the timestamp of the fourth signature.

19. The cellular wireless communication system of claim 14, further operable to identify a second signature that matches the first signature, a second signature being identified as matching the first signature based on:

the timestamp of the second signature corresponding to the timestamp of the first signature, when the timestamp of the second signature matches the timestamp of the first signature within a predetermined timing accuracy; and

the radio frequency measurement information of the second signature corresponding to the radio frequency measurement information of the first signature, when at least a part of the radio frequency measurement information of the second signature matches at least a part of the radio frequency measurement information of the first signature within a predetermined measurement accuracy.