Timed fingerprint locating for idle-state user equipment in wireless networks

• US 8,254,959 B2
• Filed: 07/14/2010
• Issued: 08/28/2012
• Est. Priority Date: 02/25/2010
• Status: Expired due to Fees

• 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
• Primary Examiner(s): Chang, Joseph
• Application Number:
  US12/836,471
• Publication Number:
  US 20110205964A1
• Time in Patent Office: 776 Days
• Field of Search: 455/456.1, 370/328
• US Class Current: 455/456.1
• 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, by a system including at least one processor, a set of geographical frame locations for a bin grid framework, the bin grid framework having a predetermined granularity;

determining, by the system, a set of NodeB site pairs (NBSPs) comprising a first NodeB site and a second NodeB site, wherein locations of the first NodeB site and the second NodeB site are known;

determining, by the system, a set of reference frames, wherein the set of NodeB site pairs respectively have at least one reference frame having a known location;

determining, by the system, a frame data value set comprising computed differential values for the set of NodeB site pairs and sets of frames within a predetermined distance from NodeB site pairs, wherein the computed differential values are related, at least in part, to respective differences between respective locations of respective frames of the sets of frames and locations of a relevant NodeB site pair, wherein the relevant NodeB site pair is a NodeB site pair within the predetermined distance;

accessing, by the system, a first time value (OV(1)) for an idle-state UE;

determining, by the system, a first differential value (DV(1)) for a first frame of the sets of frames, related, at least in part, to a difference between location information of the first frame and location information of a first NodeB site pair of the set of NodeB site pairs;

accessing, by the system, a second time value (OV(2)) for the first frame;

determining a lookup value based at least in part on OV(1), DV(1), and OV(2); and

accessing, by the system, a first subset of frames for a search through the frame data value set, the accessing including searching for frames correlated to the lookup value and a NodeB site pair of the set of NodeB site pairs.

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

Lookup Value=OV(2)−

OV(1)+DV(1).

3. The method of claim 1, wherein the 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.

4. The method of claim 1, further comprising:

determining, by the system, a second lookup value related to a second of NodeB site pair of the set of NodeB site pairs;

accessing, by the system, a second subset of frames for a search through the frame data value set, the search including searching for frames correlated to the second lookup value and the second NodeB site pair; and

indicating, by the system, intersecting frames between the first subset of frames and second subset of frames.

5. The method of claim 4 wherein the indicating the intersecting frames results in a single intersecting frame being indicated, and the geographic location of the single intersecting frame is determined to be a probable location of the idle-state UE.

6. The method of claim 4, wherein the indicating the intersecting frames further comprises determining additional intersecting frames from additional subsets of frames including searching the frame data value set for frames correlated to the lookup value and an additional NodeB site pair of the set of NodeB site pairs including converging on a single frame being a probable location for the idle-state UE.

7. The method of claim 1, wherein the accessing the first time value OV(1) includes OV(1) being a time difference between system frame numbers (SFN-SFN) observed time difference measurement.

8. The method of claim 1, wherein the accessing the first time value OV(1) includes deriving OV(1) from values reported out in response to a system information block type 11 (SIB11) message.

9. The method of claim 1, wherein the accessing the first time value OV(1) includes deriving OV(1) from values reported on a radio resource control protocol channel.

10. The method of claim 1, wherein the accessing the first time value OV(1) includes deriving OV(1) from values reported as part of measured results on a reverse access channel.

11. The method of claim 1, wherein the determining the set of geographical frame locations includes determining the predetermined granularity of the geographical frame locations to be 100 m×

100 m for each frame.

12. The method of claim 1, wherein the determining the set of geographical frame locations includes determining the predetermined granularity of the geographical frame locations to be 1×

1 chip for each frame.

13. A system to facilitate locating an idle-state user equipment (UE) in a wireless network, the system comprising:

at least one memory that stores computer-executable instructions;

at least one processor, communicatively coupled to the at least one memory, that facilitates execution of the computer-executable instructions to at least;

communicatively couple to a plurality of NodeBs;

store a data set relating to differential frame values for at least one NodeB site pair of the plurality of NodeBs;

access timing data relating to the idle-state UE;

compare the timing data to at least a subset of the data set relating to the at least one NodeB site pair to facilitate a determination of a location of the idle-state UE within the wireless network,

wherein at least one bin grid framework, with a predetermined level of granularity, is mapped to a geographic area of the wireless network to facilitate location of idle-state UEs within frames of the at least one bin grid framework based, at least in part, on idle-state UE timing data.

14. The system of claim 13, wherein the data set represents a differential distance of a target frame of the at least one bin grid framework from NodeBs of the at least one NodeB site pair calculated by:

DV(ij,X)=OV(ji,X)−

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

wherein i is one NodeB of the NodeB site pair, j is the other NodeB of the NodeB site pair, 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 across the set of NodeB site pairs.

15. The system of claim 13, wherein the at least one processor further facilitates the execution of the computer-executable instructions to compute a first set of frames that represent possible locations of the idle-state UE based, at least in part, on a first lookup that compares a first target value with stored values of a first subset of the data set, the first subset being determined by an index relating to a first NodeB site pair.

16. The system of claim 15, wherein the at least one processor further facilitates the execution of the computer-executable instructions to compute a second set of frames that represent possible locations of the idle-state UE based, at least in part, on a second lookup that compares a second target value with stored values of a second subset of the data set, the second subset being determined by an index relating to a second NodeB site pair.

17. The system of claim 16, wherein the at least one processor further facilitates the execution of the computer-executable instructions to determine an 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, and the location of the idle-state UE is determined to be within the geographic area of the wireless network mapped by the resulting single frame.

19. The system of claim 16, wherein the first target value is related to an observed time difference reported from the idle-state UE.

20. The system of claim 16, wherein the first target value is derived from a time difference between system frame numbers (SFN-SFN) observed time difference measurement for the idle-state UE.