METHOD AND APPARATUS FOR SEARCHING FOR SIGNALS IN A WIRELESS COMMUNICATION SYSTEM

• US 20090298437A1
• Filed: 05/30/2008
• Published: 12/03/2009
• Est. Priority Date: 05/30/2008
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Kanade, Parag Mohan, Hoefel, Guilherme Luiz Karnas
• Granted Patent: US 8,175,567 B2
• Time in Patent Office: Days
• US Class Current: 455/67.11
• CPC Class Codes: H04W 48/16 Discovering, processing access restriction or access information

Abstract

Techniques to search for signals while in an out-of-service state are described. In an aspect, a network entity may collect information for wireless devices within a designated area, determine at least one search parameter (e.g., a scan rate) based on the collected information, and provide the search parameter(s) to wireless devices within the designated area. The wireless devices may perform searches for signals in accordance with the search parameter(s) when they are out of service. In another aspect, a wireless device may collect information related to out-of-service events encountered by the wireless device, send the collected information to the network entity, receive the search parameter(s) from the network entity, and perform searches in accordance with the search parameter(s) when out of service. In yet another aspect, the wireless device may determine the search parameter(s) based on the collected information.

Claims

1. A method of supporting searches for signals in a wireless communication system, comprising:

collecting information for a plurality of wireless devices;

determining at least one search parameter based on the collected information; and

providing the at least one search parameter to wireless devices for use in performing searches for signals when the wireless devices are out of service.

2. The method of claim 1, wherein the collecting information comprises collecting information on out-of-service durations, locations of wireless devices, frequency of out-of-service events, network loading, dropped calls, weather conditions, or a combination thereof.

3. The method of claim 1, further comprising:

receiving the information for the plurality of wireless devices from the plurality of wireless devices, or from at least one network entity, or both.

4. The method of claim 1, wherein the at least one search parameter comprises a scan rate corresponding to a rate for performing searches.

5. The method of claim 1, wherein the at least one search parameter comprises a first scan rate to use in performing searches when longer battery life is desired, and a second scan rate to use in performing searches when faster signal re-acquisition is desired, the second scan rate being faster than the first scan rate.

6. The method of claim 1, wherein the determining the at least one search parameter comprises

estimating an average out-of-service time for the plurality of wireless devices based on the collected information, and

determining a scan rate based on the estimated average out-of-service time.

7. The method of claim 6, wherein the determining the at least one search parameter further comprises

adjusting the scan rate,

determining an updated average out-of-service time with the adjusted scan rate, and

using the adjusted scan rate if the updated average out-of-service time is improved over the estimated average out-of-service time.

8. The method of claim 7, wherein the determining the at least one search parameter further comprises

iteratively performing the adjusting the scan rate and the determining the updated average out-of-service time until a termination condition is encountered, and

using a final adjusted scan rate obtained when the termination condition is encountered.

9. The method of claim 1, wherein the determining the at least one search parameter comprises

determining a coverage map based on the collected information for the plurality of wireless devices, and

determining at least one scan rate for at least one area based on the coverage map.

10. The method of claim 9, wherein the determining the coverage map comprises

obtaining out-of-service durations and locations of the plurality of wireless devices from the collected information, and

identifying areas of poor coverage with long out-of-service time and areas of good coverage with short out-of-service time based on the out-of-service durations and the locations of the plurality of wireless devices.

11. The method of claim 10, wherein the areas of poor coverage are associated with scan rates slower than scan rates for areas of good coverage.

12. The method of claim 1, wherein the collecting information comprises collecting information for the plurality of wireless devices located within a designated area, and wherein the providing the at least one search parameter comprises providing the at least one search parameter to wireless devices located within the designated area.

13. An apparatus supporting searches for signals, comprising:

at least one processor configured to collect information for a plurality of wireless devices, to determine at least one search parameter based on the collected information, and to provide the at least one search parameter to wireless devices for use in performing searches for signals when the wireless devices are out of service.

14. The apparatus of claim 13, wherein the at least one processor is configured to collect information on out-of-service durations, locations of wireless devices, frequency of out-of-service events, network loading, dropped calls, weather conditions, or a combination thereof.

15. The apparatus of claim 13, wherein the at least one processor is configured to estimate an average out-of-service time for the plurality of wireless devices based on the collected information, and to determine a scan rate based on the estimated average out-of-service time.

16. The apparatus of claim 15, wherein the at least one processor is configured to adjust the scan rate, to determine an updated average out-of-service time with the adjusted scan rate, and to use the adjusted scan rate if the updated average out-of-service time is improved over the estimated average out-of-service time.

17. The apparatus of claim 13, wherein the at least one processor is configured to determine a coverage map based on the collected information for the plurality of wireless devices, and to determine at least one scan rate for at least one area based on the coverage map.

18. An apparatus supporting searches for signals, comprising:

means for collecting information for a plurality of wireless devices;

means for determining at least one search parameter based on the collected information; and

means for providing the at least one search parameter to wireless devices for use in performing searches for signals when the wireless devices are out of service.

19. The apparatus of claim 18, wherein the means for collecting information comprises means for collecting information on out-of-service durations, locations of wireless devices, frequency of out-of-service events, network loading, dropped calls, weather conditions, or a combination thereof.

20. The apparatus of claim 18, wherein the means for determining the at least one search parameter comprises

means for estimating an average out-of-service time for the plurality of wireless devices based on the collected information, and

means for determining a scan rate based on the estimated average out-of-service time.

21. The apparatus of claim 18, wherein the means for determining the at least one search parameter comprises

means for determining a coverage map based on the collected information for the plurality of wireless devices, and

means for determining at least one scan rate for at least one area based on the coverage map.

22. A computer program product, comprising:

a computer-readable medium comprising;

code for causing at least one computer to collect information for a plurality of wireless devices;

code for causing the at least one computer to determine at least one search parameter based on the collected information; and

code for causing the at least one computer to provide the at least one search parameter to wireless devices for use in performing searches for signals when the wireless devices are out of service.

23. The computer program product of claim 22, wherein the computer-readable medium further comprises:

code for causing the at least one computer to estimate an average out-of-service time for the plurality of wireless devices based on the collected information; and

code for causing the at least one computer to determine a scan rate based on the estimated average out-of-service time.

24. The computer program product of claim 22, wherein the computer-readable medium further comprises:

code for causing the at least one computer to determine a coverage map based on the collected information for the plurality of wireless devices; and

code for causing the at least one computer to determine at least one scan rate for at least one area based on the coverage map.

25. A method of operating a wireless device, comprising:

receiving at least one search parameter determined by a network entity based on information collected by the network entity for a plurality of wireless devices; and

performing searches for signals in accordance with the at least one search parameter when the wireless device is out of service.

26. The method of claim 25, further comprising:

collecting information related to out-of-service events encountered by the wireless device; and

sending the collected information to the network entity for use in determining the at least one search parameter.

27. The method of claim 25, wherein the at least one search parameter comprises a scan rate, the method further comprising:

determining current operating conditions of the wireless device; and

adjusting the scan rate based on the current operating conditions, and wherein searches are performed in accordance with the adjusted scan rate

28. The method of claim 25, wherein the at least one search parameter comprises a scan rate to use for entire duration in which the wireless device is covered by the network entity, and wherein searches are performed at the scan rate.

29. The method of claim 25, wherein the at least one search parameter comprises a scan rate changeable by the network entity during duration in which the wireless device is covered by the network entity, and wherein searches are performed at the scan rate.

30. An apparatus for wireless communication, comprising:

at least one processor configured to receive at least one search parameter determined by a network entity based on information collected by the network entity for a plurality of wireless devices, and to perform searches for signals in accordance with the at least one search parameter when a wireless device is out of service.

31. The apparatus of claim 30, wherein the at least one processor is configured to collect information related to out-of-service events encountered by the wireless device, and to send the collected information to the network entity for use in determining the at least one search parameter.

32. The apparatus of claim 30, wherein the at least one processor is configured to receive a scan rate from the network entity, to determine current operating conditions of the wireless device, to adjust the scan rate based on the current operating conditions, and to perform searches in accordance with the adjusted scan rate.

33. A method of operating a wireless device, comprising:

collecting information related to out-of-service events encountered by the wireless device;

determining at least one search parameter based on the collected information; and

performing searches for signals in accordance with the at least one search parameter when the wireless device is out of service.

34. The method of claim 33, wherein the collecting information comprises collecting information on out-of-service durations, locations of the wireless device, frequency of out-of-service events, signal strength, or a combination thereof.

35. The method of claim 33, wherein the determining the at least one search parameter comprises

determining current operating conditions of the wireless device, and

determining the at least one search parameter based further on the current operating conditions.

36. The method of claim 33, wherein the determining the at least one search parameter comprises

estimating an average out-of-service time for the wireless device based on the collected information, and

determining a scan rate based on the estimated average out-of-service time.

37. The method of claim 33, wherein the at least one search parameter comprises a first scan rate determined based on the collected information, the method further comprising:

receiving a second scan rate determined by a network entity based on information collected by the network entity for a plurality of wireless devices; and

determining a third scan rate based on the first and second scan rates, and

wherein searches are performed in accordance with the third scan rate when the wireless device is out of service.

38. An apparatus for wireless communication, comprising:

at least one processor configured to collect information related to out-of-service events encountered by a wireless device, to determine at least one search parameter based on the collected information, and to perform searches for signals in accordance with the at least one search parameter when the wireless device is out of service.

39. The apparatus of claim 38, wherein the at least one processor is configured to collect information on out-of-service durations, locations of the wireless device, frequency of out-of-service events, signal strength, or a combination thereof.

40. The apparatus of claim 38, wherein the at least one processor is configured to determine current operating conditions of the wireless device, and to determine the at least one search parameter based further on the current operating conditions.

41. The apparatus of claim 38, wherein the at least one processor is configured to estimate an average out-of-service time for the wireless device based on the collected information, and to determine a scan rate based on the estimated average out-of-service time.

42. The apparatus of claim 38, wherein the at least one processor is configured to determine a first scan rate based on the collected information, to receive a second scan rate determined by a network entity based on information collected by the network entity for a plurality of wireless devices, to determine a third scan rate based on the first and second scan rates, and to perform searches in accordance with the third scan rate when the wireless device is out of service.