TIMED FINGERPRINT LOCATING FOR IDLE-STATE USER EQUIPMENT IN WIRELESS NETWORKS

• US 20110205964A1
• Filed: 07/14/2010
• Published: 08/25/2011
• Est. Priority Date: 02/25/2010
• Status: Active Grant

• Current Assignee: AT&T Mobility II LLC (AT&T, Inc.)
• Original Assignee: AT&T Mobility II LLC (AT&T, Inc.)
• Inventors: Fix, Jeremy, Austin, Mark, Meredith, Sheldon
• Granted Patent: US 8,254,959 B2
• Time in Patent Office: Days
• US Class Current: 370/328
• CPC Class Codes: G01S 5/0252 Radio frequency fingerprinting
• CPC Class Codes: G01S 5/12 by co-ordinating position lines of different shape, e.g. hyperbolic, circular, elliptical or radial
• 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 88/08 Access point devices

Abstract

Systems and techniques for determining the location of user equipment (UE) in a wireless network are disclosed. These techniques leverage geometric calculations for an overlaid bin grid framework mapping the wireless network area to store differential values for each frame of the bin grid framework for each pair of relevant NodeBs. A timing offset can be determined, such that when a time value from a target UE is accessed, the location can be quickly determined with minimal real time computation. In an aspect, the time value from an idle-state target UE can be accessed. The target UE time value can be searched among pre-computed differential value data sets indexed by relevant NodeB site pairs to return sets of frames that can facilitate converging on a location for the target UE. Intersecting frames can represent the geographic location of the UE in the wireless network. Further, the data can be leveraged to correct timing in the network.

Claims

1. A method facilitating locating a User Equipment (UE) in a wireless network, the method comprising:

determining a set of geographical bin grid framework frame locations, the bin grid framework having a predetermined granularity;

determining a set of NodeB Site Pairs (NBSPs), the set of NBSPs comprising a first NodeB site and a second NodeB site, wherein the location of each NodeB site is known relative to the set of geographical bin grid framework frame locations;

determining a frame data value set of values corresponding to the set of geographical bin grid framework frame locations, the frame data value set, at least in part, comprising computed differential values for each NB SP of the set of NBSPs and the frames within a predetermined distance from each NBSP of the set of NBSPs, wherein each computed differential value is related, at least in part, to a difference between a location of a frame and the location of a NBSP;

accessing a time value for an idle-state UE in the network as OV(1);

determining a subset of NBSPs relative to the idle-state UE;

determining a lookup value based at least in part on OV(1),

returning a first subset of frames for a search through the frame data value set, searching for frames correlated to the lookup value and a NBSP of the subset of NBSPs.

2. The method of claim 1, wherein determining the lookup value employs the formula:

Lookup Value=OV(2)−

OV(1)+DV(1).

3. The method of claim 1, wherein determining the frame data value set employs the formula:

DV(NBSP_PQ,X_F)=OV(NBSP_QP, X_F)−

OV(NBSP_QP,X_R)+DV(NBSP_PQ,X_R) for a set of P, set of Q, and set of F, and where R is correlated to P, and wherein P, Q, F and R are index values that can be incremented.

4. The method of claim 1, further comprising:

determining a second subset of NBSPs relative to the idle-state UE;

returning a second subset of frames for a search through the frame data value set, searching for frames correlated to the lookup value and the second subset of NBSPs; and

indicating intersecting frames between the first returned subset of frames and second returned subset of frames.

5. The method of claim 4 wherein a single intersecting frame is indicated, such that the geographic location of the intersecting frame is the most probable location of the idle-state UE.

6. The method of claim 4, wherein a plurality of intersecting frames is indicated, determining additional intersecting frames from additional subsets of returned frames by searching the frame data value set for frames correlated to the lookup value and additional subsets of NBSPs, so as to converge on a single frame being the most probable location for the UE.

7. The method of claim 1, wherein OV(1) is a SFN-SFN observed time difference measurement.

8. The method of claim 1, wherein OV(1) is derived from values reported out in response to a SIB11 message.

9. The method of claim 1, wherein OV(1) is derived from values reported on URA_PCH, CELL_PCH, CELL_FACH or CELL_DCH.

10. The method of claim 1, wherein OV(1) is derived from values reported as part of the Measured Results on RACH.

11. The method of claim 1, wherein the predetermined granularity of the geographical frame locations is 100 m×

100 m for each frame.

12. The method of claim 1, wherein the predetermined granularity of the geographical frame locations is 1×

1 UMTS chip for each frame.

13. A system for determining the location of a UE in a wireless network, the system comprising:

a plurality of NodeBs comprising a set of NodeB Site Pairs (NBSPs) including at least one NBSP;

at least one bin grid framework, with a predetermined level of granularity, mapped to a geographic area of the wireless network to facilitate locating UEs within particular frames based at least in part on UE time data; and

a time fingerprint locating (TFL) platform that is communicatively coupled to a processor and memory storing at least a data set relating to differential frame values for at least one NBSP of the set of NBSPs, the TFL platform capable of accessing timing data related to an idle-state UE and capable of comparing the timing data to the stored data set correlated to a NBSP to facilitate determining the location of the idle-state UE within the wireless network.

14. The system of claim 13, wherein the stored data represents the differential distance of each frame of the bin grid framework from each NBSP of the set of NBSPs calculated by:

DV(ij,X)=OV(ji,X)−

OV(ji,R)+DV(ij,R),

wherein i is one NodeB of the NBSP, j is the other NodeB of a NBSP of the set of NBSPs, X indicates the target frame, R indicates a reference frame, DV indicates a differential value and OV indicates an observed value, and

the data set is indexed by NBSP across the set of NBSPs.

15. The system of claim 13, the TFL platform is further capable of computing a first set of frames that represent possible locations of the idle-state UE based, at least in part, on a first lookup target value compared with stored values, the comparison performed by the processor on a subset of the stored data, the subset being determined by an index relating to a first NBSP of the set of NBSPs.

16. The system of claim 15, the TFL platform is further capable of computing a second set of frames that represent possible locations of the idle-state UE based, at least in part, on a second lookup target value compared with stored values, the comparison performed by the processor on a subset of the stored data, the subset being determined by an index relating to a second NBSP of the set of NBSPs.

17. The system of claim 16, wherein the processor determines the intersection of the first and second set of frames that represent possible locations of the idle-state UE.

18. The system of claim 17, wherein a single frame results from the determined intersection, the TFL platform designates the location of the idle-state UE to be within the granular area of the geographic area or the wireless network mapped by the resulting single frame.

19. The system of claim 16, wherein at least one of the lookup target values is related to a observed time difference reported from an idle-state UE.

20. The system of claim 16, wherein at least one of the lookup target values is derived from a SFN-SFN observed time difference measurement for an idle-state UE.