Intelligent access point scanning with self-learning capability

• US 7,515,575 B1
• Filed: 08/26/2005
• Issued: 04/07/2009
• Est. Priority Date: 08/26/2005
• Status: Active Grant

• Current Assignee: Ribbon Communications Operating Company, Inc. (Ribbon Communications, Inc.)
• Original Assignee: Kineto Wireless Incorporated (Ribbon Communications, Inc.)
• Inventors: Baranowski, Joseph G., Shi, Jianxiong
• Primary Examiner(s): Appiah; Charles N
• Assistant Examiner(s): AJIBADE AKONAI, OLUMIDE
• Application Number:
  US11/212,353
• Time in Patent Office: 1,320 Days
• Field of Search: 455/41.2, 455/426.2, 455/550.1, 455/552.1, 455/553.1, 455/574, 455/434, 455/500, 455/435.1, 455/435.2, 455/435.3, 370/338, 370/328, 370/334, 370/310
• US Class Current: 370/338
• CPC Class Codes: H04W 48/10 using broadcasted information
• CPC Class Codes: H04W 48/16 Discovering, processing access restriction or access information
• CPC Class Codes: H04W 88/06 adapted for operation in multiple networks or having at least two operational modes, e.g. multi-mode terminals
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A method and apparatus for intelligent access point scanning with self-learning capability enables a wireless handset to conserve power while scanning for unlicensed mobile access.

Claims

1. A method, comprising:

detecting an identifier of a licensed mobile access cell (LMAC);

obtaining a probability measure for accessing an unlicensed wireless access point (UWAP) within the LMAC; and

scanning for the UWAP with a scan rate determined by the probability measure.

2. The method of claim 1, further comprising modifying the probability measure to reflect a result of scanning for the UWAP within the LMAC.

3. The method of claim 1, wherein obtaining the probability measure for accessing the UWAP within the LMAC comprises:

comparing the identifier of the LMAC to LMAC identifiers in a table, each LMAC identifier in the table having a corresponding probability measure; and

selecting the probability measure corresponding to an LMAC identifier in the table if the identifier of the LMAC matches the LMAC identifier in the table;

else

selecting a first default probability measure if the identifier of the LMAC partially matches an LMAC identifier in the table;

else

selecting a second default probability measure if the identifier of the LMAC does not match any LMAC identifier in the table.

4. The method of claim 3, wherein the first default probability measure corresponds to a minimum non-zero scan rate and the second default probability measure corresponds to a zero scan rate.

5. The method of claim 3, wherein the identifier of the LMAC matches an LMAC identifier in the table, each LMAC identifier in the table having a corresponding timestamp, the method further comprising:

locating the UWAP within the LMAC within a first period of time;

attempting to acquire a registration with an unlicensed mobile access network (UMAN);

setting the corresponding timestamp to a registration time; and

incrementing the corresponding probability measure if the registration is acquired and is a first registration with the UMAN within a second period of time.

6. The method of claim 3, wherein the identifier of the LMAC matches an LMAC identifier in the table, the method further comprising:

scanning for the UWAP within the LMAC at a scan rate associated with the matched LMAC identifier in the table; and

scanning for the UWAP at a first default scan rate when failing to locate the UWAP within a first period of time.

7. The method of claim 3, wherein the identifier of the LMAC partially matches an LMAC identifier in the table, the method further comprising:

locating the UWAP within the LMAC within a first period of time;

attempting to acquire a registration with an unlicensed mobile access network (UMAN); and

adding the identifier of the LMAC to the table of LMAC identifiers, setting a corresponding probability measure to an initial value and setting a corresponding timestamp to a registration time, if the registration is acquired.

8. The method of claim 7, wherein the table of LMAC identifiers is limited to a maximum number of entries, the method further comprising:

determining whether the table of LMAC identifiers comprises the maximum number of entries; and

deleting an LMAC identifier with a least probability measure if the LMAC identifier is the only LMAC identifier with the least probability measure; and

deleting the LMAC identifier with the least probability measure and an oldest timestamp if two or more LMAC identifiers have the least probability measure.

9. The method of claim 3, wherein the identifier of the LMAC partially matches an LMAC identifier in the table, the method further comprising:

scanning for the UWAP within the LMAC at a scan rate associated with the partially matched LMAC identifier in the table; and

scanning for the UWAP at a first default scan rate when failing to locate the UWAP within a first period of time.

10. The method of claim 5, further comprising auditing the table of LMAC identifiers every second period of time, wherein auditing comprises:

determining, for each LMAC identifier in the table of LMAC identifiers, whether the corresponding timestamp is older than the second period of time for each LMAC identifier in the table of LMAC identifiers; and

decrementing the corresponding probability measure if the corresponding timestamp is older than the second period of time; and

deleting the LMAC identifier from the table of LMAC identifiers if decrementing the corresponding probability measure reduces the corresponding probability measure to a minimum value.

11. The method of claim 7, further comprising auditing the table of LMAC identifiers every second period of time, wherein auditing comprises:

determining, for each LMAC identifier in the table of LMAC identifiers, whether the corresponding timestamp is older than the second period of time for each LMAC identifier in the table of LMAC identifiers; and

decrementing the corresponding probability measure if the corresponding timestamp is older than the second period of time; and

deleting the LMAC identifier from the table of LMAC identifiers if decrementing the corresponding probability measure reduces the corresponding probability measure to a minimum value.

12. The method of claim 1, wherein the scan rate is a function of the probability measure.

13. The method of claim 12, wherein the probability measure is limited to a range between a minimum value and a maximum value, and wherein the scan rate increases monotonically with increases in the probability measure and decreases monotonically with decreases in the probability measure.

14. The method of claim 13, wherein the scan rate is one of a linear function of the probability measure and a nonlinear function of the probability measure.

15. The method of claim 3, wherein the identifier of the LMAC comprises a global cell identifier (GCI), wherein the GCI comprises a location area identifier (LAI) and a cell identifier (CI).

16. The method of claim 15, wherein the identifier of the LMAC partially matches an LMAC identifier in the table when the LAI of the LMAC matches an LAI of the LMAC identifier in the table and the CI of the LMAC does not match the CI of the LMAC identifier in the table.

17. The method of claim 6, wherein the first default scan rate comprises a minimum non-zero scan rate corresponding to the first default probability measure.

18. An apparatus, comprising:

a wireless interface to communicate with a licensed mobile access service and with unlicensed wireless access points;

a memory to store licensed mobile access cell (LMAC) identifiers in a table; and

a processor coupled with the memory and the wireless interface, the processor to

detect an identifier of an LMAC;

obtain a probability measure from the table for accessing an unlicensed wireless access point (UWAP) within the LMAC; and

scan for the UWAP with a scan rate determined by the probability measure.

19. The apparatus of claim 18, the processor further to modify the probability measure to reflect a result of scanning for the UWAP within the LMAC.

20. The apparatus of claim 18, wherein to obtain the probability measure for accessing the UWAP within the LMAC, the processor to:

compare the identifier of the LMAC to the LMAC identifiers in the table, each LMAC identifier in the table having a corresponding probability measure; and

select the probability measure in the table corresponding to the LMAC identifier in the table if the identifier of the LMAC matches an LMAC identifier in the table;

else

select a first default probability measure if the identifier of the LMAC partially matches an LMAC identifier in the table;

else

select a second default probability measure if the identifier of the LMAC does not match an LMAC identifier in the table.

21. The apparatus of claim 20, wherein the first default probability measure corresponds to a minimum non-zero scan rate and the second default probability measure corresponds to a zero scan rate.

22. The apparatus of claim 20, wherein the identifier of the LMAC matches an LMAC identifier in the table, each LMAC identifier in the table having a corresponding timestamp, the processor further to:

locate the UWAP within the LMAC within a first period of time;

attempt to acquire a registration with an unlicensed mobile access network (UMAN);

set the corresponding timestamp to a registration time; and

increment the corresponding probability if the registration is acquired and is a first registration with the UMAN within a second period of time.

23. The apparatus of claim 20, wherein the identifier of the LMAC matches an LMAC identifier in the table, and wherein the processor fails to locate the UWAP within the LMAC within a first period of time, the processor further to scan for the UWAP at a first default scan rate.

24. The apparatus of claim 20, wherein the identifier of the LMAC partially matches an LMAC identifier in the table, the processor further to:

locate the UWAP within the LMAC within a first period of time;

attempt to acquire a registration with an unlicensed mobile access network (UMAN); and

add the identifier of the LMAC to the table of LMAC identifiers, set a corresponding probability measure to an initial value and set a corresponding timestamp to a registration time, if the registration is acquired.

25. The apparatus of claim 24, wherein the table of LMAC identifiers is limited to a maximum number of entries, the processor further to:

determine whether the table of LMAC identifiers comprises the maximum number of entries; and

delete an LMAC identifier with a least probability measure if the LMAC identifier is the only LMAC identifier with the least probability measure; and

delete the LMAC identifier with the least probability measure and an oldest timestamp if two or more LMAC identifiers have the least probability measure.

26. The apparatus of claim 20, wherein the identifier of the LMAC partially matches an LMAC identifier in the table, and wherein the processor fails to locate the UWAP within the LMAC within a first period of time, the processor further to scan for the UWAP at a first default scan rate.

27. The apparatus of claim 22, the processor further to audit the table of LMAC identifiers every second period of time, wherein for each LMAC identifier in the table of LMAC identifiers, the processor to

determine whether the corresponding timestamp is older than the second period of time;

and

decrement the corresponding probability measure if the corresponding timestamp is older than the second period of time; and

delete the LMAC identifier from the table of LMAC identifiers if a decrement to the corresponding probability measure reduces the corresponding probability measure to a minimum value.

28. The apparatus of claim 24, the processor further to audit the table of LMAC identifiers every second period of time, wherein for each LMAC identifier in the table of LMAC identifiers, the processor to

determine whether the corresponding timestamp is older than the second period of time;

and

decrement the corresponding probability measure if the corresponding timestamp is older than the second period of time; and

delete the LMAC identifier from the table of LMAC identifiers if a decrement to the corresponding probability measure reduces the corresponding probability measure to a minimum value.

29. The apparatus of claim 18, wherein the scan rate is a function of the probability measure.

30. The apparatus of claim 29, wherein the probability measure is limited to a range between a minimum value and a maximum value, and wherein the scan rate increase monotonically with the probability measure.

31. The apparatus of claim 30, wherein the scan rate is one of a linear function of the probability measure and a nonlinear function of the probability measure.

32. An article of manufacture including a computer-readable medium having instructions stored thereon, which when executed by a data-processing system, cause the data-processing system to perform a method, comprising:

detecting an identifier of a licensed mobile access cell (LMAC);

obtaining a probability measure for accessing an unlicensed mobile access point (UWAP) within the LMAC; and

scanning for the UWAP with a scan rate determined by the probability measure.

33. The article of manufacture of claim 32, the method further comprising modifying the probability measure to reflect a result of scanning for the UWAP within the LMAC.

34. The article of manufacture of claim 32, wherein obtaining the probability measure for accessing the UWAP within the LMAC comprises:

comparing the identifier of the LMAC to LMAC identifiers in a table, each LMAC identifier in the table having a corresponding probability measure; and

selecting the probability measure in the table corresponding to the LMAC identifier in the table if the identifier of the LMAC matches an LMAC identifier in the table;

else

selecting a first default probability measure if the identifier of the LMAC partially matches an LMAC identifier in the table;

else

selecting a second default probability measure if the identifier of the LMAC does not match an LMAC identifier in the table.

35. The article of manufacture of claim 34, wherein the first default probability measure corresponds to a minimum non-zero scan rate and the second default probability measure corresponds to a zero scan rate.

36. The article of manufacture of claim 34, wherein the identifier of the LMAC matches an-LMAC identifier in the table, each LMAC identifier in the table having a corresponding timestamp, the method further comprising:

locating the UWAP within the LMAC within a first period of time;

attempting to acquire a registration with an unlicensed mobile access network (UMAN);

setting the corresponding timestamp to a registration time; and

incrementing the corresponding probability measure if the registration is acquired and is a first registration with the UMAN within a second period of time.

37. The article of manufacture of claim 34, wherein the identifier of the LMAC matches an LMAC identifier in the table, the method further comprising:

scanning for the UWAP within the LMAC at a scan rate associated with the matched LMAC identifier in the table; and

scanning for the UWAP at a first default scan rate when failing to locate the UWAP within a first period of time.

38. The article of manufacture of claim 34, wherein the identifier of the LMAC partially matches an LMAC identifier in the table, the method further comprising:

locating the UWAP within the LMAC within a first period of time;

attempting to acquire a registration with an unlicensed mobile access network (UMAN); and

adding the identifier of the LMAC to the table of LMAC identifiers, setting the corresponding probability measure to an initial value and setting a corresponding timestamp to a registration time, if the registration is acquired.

39. The article of manufacture of claim 38, wherein the table of LMAC identifiers is limited to a maximum number of entries, the method further comprising:

determining whether the table of LMAC identifiers comprises the maximum number of entries; and

deleting an LMAC identifier with a least probability measure if the LMAC identifier is the only LMAC identifier with the least probability measure; and

deleting the LMAC identifier with the least probability measure and an oldest timestamp if two or more LMAC identifiers have the least probability measure.

40. The article of manufacture of claim 34, wherein the identifier of the LMAC partially matches an LMAC identifier in the table, the method further comprising:

scanning for the UWAP within the LMAC at a scan rate associated with the partially matched LMAC identifier in the table; and

scanning for the UWAP at a first default scan rate when failing to locate the UWAP within a first period of time.

41. The article of manufacture of claim 36, the method further comprising auditing the table of LMAC identifiers every second period of time, wherein auditing comprises:

determining, for each LMAC identifier in the table of LMAC identifiers, whether the corresponding timestamp is older than the second period of time; and

decrementing the corresponding probability measure, if the corresponding timestamp is older than the second period of time; and

deleting the LMAC identifier from the table of LMAC identifiers if decrementing the corresponding probability measure reduces the corresponding probability measure to a minimum value.

42. The article of manufacture of claim 38, the method further comprising auditing the table of LMAC identifiers every second period of time, wherein auditing comprises:

determining, for each LMAC identifier in the table of LMAC identifiers, whether the corresponding timestamp is older than the second period of time; and

decrementing the corresponding probability measure, if the corresponding timestamp is older than the second period of time; and

deleting the LMAC identifier from the table of LMAC identifiers if decrementing the corresponding probability measure reduces the corresponding probability measure to a minimum value.

43. The article of manufacture of claim 32, wherein the scan rate is a function of the probability measure.

44. The article of manufacture of claim 43, wherein the probability measure is limited to a range between a minimum value and a maximum value, and wherein the scan rate increase monotonically with the probability measure.

45. The article of manufacture of claim 44, wherein the scan rate is one of a linear function of the probability measure and a nonlinear function of the probability measure.

46. An apparatus comprising:

means for accessing a licensed wireless communication service;

means for accessing a wired communication service via unlicensed wireless access points; and

means for conserving power while scanning for unlicensed wireless access points within a service area of the licensed wireless communication service, wherein the means for conserving power comprises;

means for estimating a likelihood of accessing an unlicensed wireless access point within the service area of the licensed wireless communication service; and

means for adjusting a scan rate based on the likelihood of accessing the unlicensed wireless access point.