FEMTO CELL VISITATION HISTORY FOR AUTOMATIC LOCATION AREA CODE PLANNING

• US 20100136984A1
• Filed: 12/03/2008
• Published: 06/03/2010
• Est. Priority Date: 12/03/2008
• Status: Active Grant

• Current Assignee: AT&T Mobility II LLC (AT&T, Inc.)
• Original Assignee: AT&T Mobility II LLC (AT&T, Inc.)
• Inventors: Brisebois, Arthur Richard
• Granted Patent: US 8,630,258 B2
• Time in Patent Office: Days
• US Class Current: 455/446
• CPC Class Codes: H04W 16/00 Network planning, e.g. coverage or traffic planning tools; Network deployment, e.g. resource partitioning or cells structures
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 84/045 using private Base Stations, e.g. femto Base Stations, home Node B

Abstract

System(s) and method(s) are provided for automatic radio paging parameter planning. For location area update (LAC), reuse plan is based at least in part on actual subscriber mobility in a set of deployed femto access points (APs). Mobility data is incorporate in LAC planning through a visitation matrix spanned by the set of deployed femto APs. Visitation matrix elements are counts of failed attachment attempts, or unwelcomed visits, from a subscriber station authorized to attach to a first femto AP into a second femto AP in which the subscriber station is not authorized to attach. Automatic LAC planning is achieved iteratively through a search algorithm that minimizes a cost function related to unwelcome visits, and through a planning principle that assigns disparate LACs to pairs of femto APs with high reciprocal unwelcome visits and same LACs to pairs of femto APs with low reciprocal unwelcome visits.

Claims

1. A method for automatic location area code planning, the method comprising:

generating a current location area code (LAC) plan for a set of femto access points (APs);

receiving visitation data for each femto access point in the set of femto APs for the current LAC plan for the set of femto access APs;

formatting the received visitation data to facilitate, at least in part, evaluation of a cost function that measures performance of the current LAC plan for the set of femto APs; and

when the cost is below a tolerance, retaining the current LAC plan for the set of femto access points.

2. The method of claim 1, further comprising conveying the current LAC plan for the set of femto APs.

3. The method of claim 1, wherein formatting the received visitation data to facilitate, at least in part, evaluation of a cost function that measures performance of the current LAC plan for the set of femto APs includes arranging the data into a visitation matrix.

4. The method of claim 3, wherein the visitation matrix is spanned by the set of femto APs, and each matrix element equals a count of failed attempts to attach to a second femto AP of a subscriber station authorized to attach to a first femto AP, wherein the subscriber station is not authorized to attach to the second femto AP.

5. The method of claim 4, wherein generating the current LAC plan for the set of femto APs further comprises:

receiving a visitation matrix for the set of femto APs;

computing statistics associated with the matrix elements of the visitation matrix, and extracting a first threshold and a second threshold that determine, respectively, a reference level of most and least reciprocal unwelcome visits among pairs of femto APs in the set of femto APs;

assigning distinct LACs to one or more pairs of femto APs with unwelcome visit counts above the first threshold within the set of femto APs; and

assigning equal LACs to one or more pairs of femto APs with unwelcome visit counts below the second threshold within the set of femto APs.

6. The method of claim 5, further comprising collecting data on LAC planning algorithm performance for a set of algorithm heuristic parameters, and analyzing the collected data.

7. The method of claim 6, further comprising inferring at least one of a sampling time, a sampling set of femto APs, a cost function, or a set of LACs to modify or equalize.

8. The method of claim 7, further comprising retaining the at least one of the sampling time, the sampling set of femto APs, the cost function, or the set of LACs to modify or equalize.

9. A system, comprising:

a component that receives visitation data for a set of femto access points (APs); and

a location area code (LAC) engine that automatically generates a location area code (LAC) reuse plan for the set of femto APs based at least in part on the received visitation data.

10. The system of claim 9, further comprising a mobility component that generates the visitation data, and conveys the visitation data.

11. The system of claim 9, wherein the component that receives the visitation data for a set of femto APs further formats the received visitation data into a visitation matrix associated with a current LAC reuse plan, the visitation matrix is spanned by the set of femto APs and each matrix element equals a count of failed attempts to attach to a second femto AP of a subscriber station authorized to attach to a first femto AP, wherein the subscriber station is not authorized to attach to the second femto AP.

12. The system of claim 11, to automatically generate the location area code (LAC) reuse plan for the set of femto APs based at least in part on the received visitation data, the LAC engine includes a code planning component that receives a visitation matrix and generates an iteration of an updated LAC code plan based at least in part on the received visitation matrix.

13. The system of claim 12, wherein the code planning component conveys the updated LAC code plan and receives an updated visitation matrix to generate a new iteration of an updated LAC code.

14. The system of claim 13, wherein the code planning component stops to generate a new iteration of an update LAC code when a tolerance threshold is reached for a cost function value associated with a search algorithm that drives generation of the updated LAC code.

15. The system of claim 14, the search algorithm includes at least one of Monte Carlo method, simulated annealing method, genetic algorithm, or tabu search.

16. The system of claim 15, wherein the cost function depends at least in part on matrix elements of the updated visitation matrix.

17. The system of claim 12, wherein the code planning component exploits a code plan generator to generate a new iteration of an updated LAC code, the code plan generator assigns distinct LACs to one or more pairs of femto access points with the highest unwelcome visit counts and equal LACs to one or more pairs of femto APs with the lowest unwelcome visit counts.

18. A computer-readable program comprising code instructions stored thereon that, when executed by at least one processor, cause the at least one processor to carry out the following acts:

generating a current location area code (LAC) plan for a set of femto access points (APs);

conveying the current LAC plan for the set of femto APs;

receiving visitation data for each femto access point in the set of femto APs for the current LAC plan for the set of femto access APs;

formatting the received visitation data to facilitate, at least in part, evaluation of a cost function that measures performance of the current LAC plan for the set of femto APs; and

when the cost is below a tolerance, retaining the current LAC plan for the set of femto access points.

19. The computer-readable medium of claim 18, wherein formatting the received visitation data to facilitate, at least in part, evaluation of a cost function that measures performance of the current LAC plan for the set of femto APs includes arranging the data into a visitation matrix.

20. The computer-readable medium of claim 19, wherein the visitation matrix is spanned by the set of femto APs, and each matrix element equals a count of failed attempts to attach to a second femto AP of a subscriber station authorized to attach to a first femto AP, wherein the subscriber station is not authorized to attach to the second femto AP.

21. The computer-readable medium of claim 20, further comprising code instructions stored thereon that, when executed by the at least one processor, cause the at least one processor to carry out the following acts:

receiving a visitation matrix for the set of femto APs;

computing statistics associated with the matrix elements of the visitation matrix, and extracting a first threshold and a second threshold that determine, respectively, a reference level of most and least reciprocal unwelcome visits among pairs of femto APs in the set of femto APs;

assigning distinct LACs to one or more pairs of femto APs with unwelcome visit counts above the first threshold within the set of femto APs; and

assigning equal LACs to one or more pairs of femto APs with unwelcome visit counts below the second threshold within the set of femto APs.