Self learning roaming optimization

• US 8,155,081 B1
• Filed: 05/21/2008
• Issued: 04/10/2012
• Est. Priority Date: 05/21/2007
• Status: Active Grant

• Current Assignee: Marvell Asia Pte Limited (Marvell Technology Group Limited)
• Original Assignee: Marvell International Limited (Marvell Technology Group Limited)
• Inventors: Mater, Olaf, Schmalz, Joachim
• Primary Examiner(s): Ngo, Ricky
• Assistant Examiner(s): Masur, Paul
• Application Number:
  US12/124,682
• Time in Patent Office: 1,420 Days
• Field of Search: 370/254, 370/331, 370/338, 455/436, 455/440, 455/441, 455/446, 455/437, 455/456.6
• US Class Current: 370/331
• CPC Class Codes: H04W 16/18 Network planning tools
• CPC Class Codes: H04W 24/10 Scheduling measurement reports ; Arrangements for measurement reports
• CPC Class Codes: H04W 4/024 Guidance services
• CPC Class Codes: H04W 48/20 Selecting an access point
• 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 84/12 WLAN [Wireless Local Area Networks]

Abstract

A self learning roaming optimization approach allows a wireless client device to build signal strength maps that store wireless network access point signal strengths at locations along paths traveled by the wireless client device within an operational environment. The signal strengths collected at locations along a path may be analyzed to determine a recommended wireless network access point at the respective locations to achieve a reliable wireless network connection along the mapped path. The stored recommendations may take into account changes in wireless network access point signal strengths, e.g. due to obstructions and/or electromagnetic shields that may block portions of a wireless network access point signal at subsequent locations along the mapped path. A wireless client device may recognize the wireless client device'"'"'s location along a previously mapped path based on the unique combination, or signature, of wireless network access point signal strengths measured at the wireless client device'"'"'s location.

Claims

1. A client device that maintains a network connection between the client device and a wireless computer network, the client device comprising:

a path direction unit that identifies a path in a map by comparing signal strengths of a location associated with the path against previously stored signal strengths of the location;

a link quality monitor that assesses a link quality of the network connection; and

a map mode unit that selects a next wireless network access point for use by the client device for connecting to the wireless computer network based on the assessed link quality at a determined location of the client device in the path and an access point assignment for a next location in the path contained in the map of an operational environment of the wireless computer network.

2. The client device of claim 1, wherein an access point assignment for each of selected locations in the path in the operational environment is a function of the determined location of the client device in the path.

3. The client device of claim 1, further comprising:

an access point scanning unit that obtains measures of link quality between the client device and a plurality of wireless network access points for each of locations in the path,

wherein a map storage unit stores the measures of link quality for each location in the path in the map of the operational environment.

4. The client device of claim 3, further comprising:

a path analysis unit configured to generate an access point assignment for each of a plurality of locations in the path in the map of the operational environment.

5. The client device of claim 3, wherein the access point assignment is based, in part, on the determined location of the client device in the path, a determined direction of the client device along the path, and the stored measures of link quality for locations in the path in the direction of the client device along the path.

6. The client device of claim 3, wherein the access point scanning unit, in obtaining the measures of link quality between the client device and the plurality of wireless network access points for the location in the path, scans only wireless network access points identified in the map of the operational environment.

7. The client device of claim 3, further comprising:

a path analysis unit analyzes the measured signal strengths for a plurality of locations in the path in a selected direction along the path to determine the access point assignment for the location and updates the map to include the access point assignment for the location in the path.

8. The client device of claim 1, wherein the access point assignment for each location in the path corresponds to a wireless network access point that has the best reception over selected next locations along the path.

9. The client device of claim 1, wherein the access point assignment for each location in the path corresponds to a wireless network access point with a best continuity of reception as compared with other wireless network access points in the map at subsequent locations in the path in a direction traveled by the client device along the path.

10. The client device of claim 1, further comprising:

a map storage unit that stores an access point assignment for selected locations in the path in the map; and

the path direction unit that determines a direction in which the client device is traveling along the path,

wherein the access point assignment for each of locations in the path in the operational environment is a function of the determined location of the client device in the path and the determined direction in which the client device is traveling along the path.

11. The client device of claim 1, wherein the link quality monitor monitors a link quality of a wireless connection between the client device and a wireless network access point and generates an alert upon determining that the link quality has fallen below a predetermined minimum threshold.

12. The client device of claim 1, further comprising:

a network physical layer unit that supports wireless communication with a wireless network access point in accordance with a predetermined standard.

13. The client device of claim 12, wherein the predetermined standard is compatible with IEEE standard 802.11.

14. The client device of claim 1, further comprising:

a map storage unit that stores an access point assignment for each location in the path in a memory of the client device.

15. The client device of claim 1, further comprising:

a map storage unit that stores an access point assignment for each location in the path in a non-volatile memory of the client device.

16. A method of maintaining a network connection between a client device and a wireless computer network, comprising:

generating an access point assignment for each of a plurality of locations in a path in a map of an operational environment;

identifying the path in the map by comparing signal strengths of a location associated with the path against previously stored signal strengths of the location; and

selecting a next wireless network access point for use by the client device for connecting to the wireless computer network based on a determined location of the client device in the path and the access point assignment for a next location in the path contained in the map.

17. The method of claim 16, further comprising:

assessing a link quality of the network connection.

18. The method of claim 16, wherein the access point assignment for each of the plurality of locations in the path in the operational environment is a function of the determined location of the client device in the path.

19. The method of claim 16, further comprising:

obtaining measures of link quality between the client device and a plurality of wireless network access points for each of the plurality of locations in the path; and

storing the measures of link quality for each location in the path in the map of the operational environment.

20. The method of claim 19, wherein, in obtaining measures of link quality between the client device and the plurality of wireless network access points for the location in the path, scanning only wireless network access points identified in the map of the operational environment.

21. The method of claim 19, further comprising:

analyzing the measures of link quality for a plurality of locations in the path to determine the access point assignment for the location and update the stored operational environment map to include the access point assignment for the location in the path.

22. The method of claim 16, wherein the access point assignment for each location in the path corresponds to a wireless network access point with a best overall reception for a plurality of locations along the path.

23. The method of claim 16, wherein the access point assignment for each location in the path corresponds to a wireless network access point with a best overall reception for a plurality of next locations along the path.

24. The method of claim 16, wherein the access point assignment for each location in the path corresponds to a wireless network access point with a stronger reception than other wireless network access points in the map at subsequent locations in the path in a direction traveled by the client device along the path.

25. The method of claim 16, wherein the access point assignment for each location in the path corresponds to a wireless network access point with a most continuous reception along next locations in the path in a direction traveled by the client device along the path.

26. The method of claim 16, further comprising:

storing the access point assignment for the locations in the path in the map of the operational environment; and

determining a direction in which the client device is traveling along the path,

wherein the access point assignment for each of the plurality of locations in the path in the operational environment is a function of the determined location of the client device in the path and the determined direction in which the client device is traveling along the path.

27. The method of claim 16, further comprising:

monitoring a link quality of a wireless connection between the client device and a wireless network access point; and

generating an alert upon determining that the link quality has fallen below a predetermined minimum threshold.

28. The method of claim 16, wherein wireless communication with a wireless network access point is in accordance with a predetermined standard.

29. The method of claim 28, wherein the predetermined standard is compatible with IEEE standard 802.11.

30. The method of claim 16, further comprising:

storing the access point assignment for each location in a path in a memory of the client device.

31. The method of claim 16, further comprising:

storing the access point assignment for each location in a path in a non-volatile memory of the client device.

32. A method of maintaining a network connection between a client device and a wireless computer network, comprising:

identifying a path in a map by comparing signal strengths of a location associated with the path against previously stored signal strengths of the location;

monitoring a link quality of the network connection between the client device and the wireless computer network; and

selecting a wireless network access point defined in the map of an operational environment for a next connection based on the link quality of the network connection at a plurality of locations in the path.

33. The method of claim 32, wherein determining the location of the client device in the path in the operational environment, further comprises:

scanning wireless network access points identified by the map of the operational environment, thereby obtaining a measure of a link quality between the client device at the location and the wireless network access points; and

matching the obtained measures of link quality with measures of link quality stored in the map of the operational environment.

34. The method of claim 32, further comprising:

determining a path direction that the client device is traversing along the path through the operational environment; and

determining a next location in the path based in the path direction.

35. The method of claim 34, wherein determining a path direction, further comprises:

monitoring a link quality of the network connection;

scanning wireless network access points identified by the map of the operational environment, thereby obtaining a measure of a link quality between the client device at a second location and the wireless network access points; and

matching the obtained measures of link quality with measures of link quality stored in the map of the operational environment.

36. The method of claim 32, wherein the map of the operational environment defines a wireless network access point for each of a plurality of locations in each of a plurality of paths through the operational environment.

37. The method of claim 32, wherein the wireless network access point defined in the map of the operational environment for a next location in the path corresponds to a wireless network access point with a better link quality for a plurality of locations along the path than other wireless network access points in the map.

38. The method of claim 32, wherein the wireless network access point defined in the map of the operational environment for a next connection corresponds to a wireless network access point with a weaker link quality at a next location than other wireless network access points in the map.

39. The method of claim 32, wherein the wireless network access point defined in the map of the operational environment for a next connection corresponds to a wireless network access point with an improved connection quality at a plurality of next locations as compared with other wireless network access points in the map.

40. The method of claim 32, wherein the map of the operational environment is stored in a memory of the client device.

41. The method of claim 32, wherein the map of the operational environment is stored in a non-volatile memory of the client device.