Method and apparatus for scanning in wireless computing devices

• US 20040120278A1
• Filed: 12/18/2002
• Published: 06/24/2004
• Est. Priority Date: 12/18/2002
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Abhishek, Abhishek, Ruan, Jiandong, Krantz, Anton W., Ayyagari, Arun
• Granted Patent: US 7,263,078 B2
• Time in Patent Office: Days
• US Class Current: 370/328
• CPC Class Codes: H04W 40/246 Connectivity information discovery
• CPC Class Codes: H04W 48/16 Discovering, processing access restriction or access information
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A method and system for scanning in a wireless device having a wireless network interface card (NIC) is presented. The system has a scanning history table for storing scanning results and a scanning engine that adjusts the scanning period based upon a history of scanning results and commands the NIC to scan for available networks after the period has expired. The engine receives scan results from the NIC, stores the scan results in the scanning history table, determines a scanning period based upon a history of scan results, sets the scanning period, and commands the NIC to scan for available networks after the scanning period has expired. The engine is programmed to set the scanning period using an exponential function and to reset the scanning period to a default period if the scan results are different from a prior scan result or if a triggering event is received.

Claims

1. A method for managing the scanning in a wireless device having a network interface card, the method comprising the steps of:

a) receiving scan results from the network interface card;

b) storing the scan results in a scanning history table;

c) determining a scanning period based upon a history of scan results;

d) setting the scanning period;

e) commanding the network interface card to scan for available networks after the scanning period has expired; and

f) repeating steps a-e.

2. The method of claim 1 further comprising the step of commanding the network interface card to scan for available networks.

3. The method of claim 1 wherein the step of determining the scanning period includes:

comparing the scan results to at least one prior scan result; and

increasing the scanning period if the scan results have not changed from the at least one prior scan result.

4. The method of claim 3 wherein the step of increasing the scanning period comprises increasing the scanning period exponentially.

5. The method of claim 3 wherein the step of increasing the scanning period comprises increasing the scanning period in accordance with a user preference.

6. The method of claim 3 further comprising the step of resetting the scanning period to a default period if the scan results are different from the at least one prior scan result.

7. The method of claim 1 further comprising the step of setting an initial scanning period to a default period.

8. The method of claim 7 wherein the step of setting the initial scanning period to a default period comprises setting the initial scanning period to 60 seconds.

9. The method of claim 1 wherein the steps of determining the scanning period and setting the scanning period comprises setting the scanning period to a default scanning period if the wireless device is in one of a continually awake mode and a power saving mode.

10. The method of claim 1 wherein the steps of determining the scanning period and setting the scanning period comprises setting the scanning period to a default scanning period if the wireless device is not operating on battery power.

11. The method of claim 1 further comprising the step of disabling the scanning in the network interface card if another network interface card is providing network access.

12. The method of claim 1 further comprising the step of initializing a timer to time-out the scanning period and wherein the step of commanding the network interface card to scan for available networks after the scanning period has expired comprises commanding the network interface card to scan for available networks after the timer has expired.

13. The method of claim 1 further comprising the step of setting the scanning period to a default period in response to receiving an indication of a triggering event.

14. A scanning system for use in a wireless device having a network interface card comprising:

a scanning history table for storing scanning results; and

a scanning engine for adjusting a scanning period based upon a history of scanning results and commanding the network interface card to scan for available networks after the scanning period has expired.

15. The scanning system of claim 14 wherein the scanning engine is programmed to perform the steps of:

a) receiving scan results from the network interface card;

b) storing the scan results in the scanning history table;

c) determining a scanning period based upon a history of scan results;

d) setting the scanning period;

e) commanding the network interface card to scan for available networks after the scanning period has expired; and

f) repeating steps a-e.

16. The scanning system of claim 15 wherein the scanning engine is programmed to set the scanning period using an exponential function.

17. The scanning system of claim 14 wherein the scanning engine is further programmed to reset the scanning period to a default period if the scan results are different from a prior scan result.

18. The scanning system of claim 14 wherein the scanning engine is further programmed to reset the scanning period to a default period if a triggering event is received.

19. A computer-readable medium having computer-executable instruction for performing the steps for managing the scanning in a wireless device having a network interface card, the steps comprising:

a) receiving scan results from the network interface card;

b) storing the scan results in a scanning history table;

c) setting a scanning period based upon a history of scan results;

d) commanding the network interface card to scan for available networks after the scanning period has expired; and

e) repeating steps a-d.

20. The computer readable medium of claim 19 further comprising the step of commanding the network interface card to scan for available networks.

21. The computer readable medium of claim 19 wherein the step of determining the scanning period includes:

comparing the scan results to at least one prior scan result; and

increasing the scanning period if the scan results have not changed from the at least one prior scan result.

22. The computer readable medium of claim 21 wherein the step of increasing the scanning period comprises increasing the scanning period exponentially.

23. The computer readable medium of claim 21 wherein the step of increasing the scanning period comprises increasing the scanning period in accordance with a user preference.

24. The computer readable medium of claim 21 further comprising the step of resetting the scanning period to a default period if the scan results are different from the at least one prior scan result.

25. The computer readable medium of claim 19 further comprising the step of setting an initial scanning period to a default period.

26. The computer readable medium of claim 25 wherein the step of setting the initial scanning period to a default period comprises setting the initial scanning period to 60 seconds.

27. The computer readable medium of claim 19 wherein the steps of determining the scanning period and setting the scanning period comprises setting the scanning period to a default scanning period if the wireless device is in one of a continually awake mode and a power saving mode.

28. The computer readable medium of claim 19 wherein the steps of determining the scanning period and setting the scanning period comprises setting the scanning period to a default scanning period if the wireless device is not operating on battery power.

29. The computer readable medium of claim 19 further comprising the step of disabling the scanning in the network interface card if another network interface card is providing network access.

30. The computer readable medium of claim 19 further comprising the step of initializing a timer to time-out the scanning period and wherein the step of commanding the network interface card to scan for available networks after the scanning period has expired comprises commanding the network interface card to scan for available networks after the timer has expired.

31. The computer readable medium of claim 19 further comprising the step of setting the scanning period to a default period in response to receiving an indication of a triggering event.

32. The computer readable medium of claim 19 wherein the step of commanding the network interface card to scan for available networks includes commanding the network interface card to delay scanning if traffic is being sent or received until the traffic is sent or received.

33. The computer readable medium of claim 19 wherein the step of commanding the network interface card to scan for available networks includes commanding the network interface card to delay scanning until at least a next scanning period if traffic is being sent or received when the scanning period expires.