Randomization of periodic channel scans

• US 8,275,373 B2
• Filed: 09/28/2007
• Issued: 09/25/2012
• Est. Priority Date: 09/28/2007
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Julian, David Jonathan, Jia, Zhanfeng
• Primary Examiner(s): LEE, JUSTIN YE
• Application Number:
  US11/864,728
• Publication Number:
  US 20090086702A1
• Time in Patent Office: 1,824 Days
• Field of Search: 455/434, 455/41.2, 455/41.3, 370/329
• US Class Current: 455/434
• CPC Class Codes: H04W 48/16 Discovering, processing access restriction or access information
• CPC Class Codes: H04W 8/005 Discovery of network devices, e.g. terminals

Abstract

An apparatus and method for wireless communications supports a periodic scan for wireless devices. The periodic scan includes a plurality of scans spaced apart in time. The phase of the periodic scan is changed in response to one of the wireless devices being detected in one of the scans.

Claims

1. An apparatus for wireless communications, comprising:

a processing system configured to support a periodic scan for wireless devices, the periodic scan comprising a plurality of scans spaced apart in time, the processing system being further configured to change a phase of the periodic scan in response to one of the wireless devices being detected in one of the scans, wherein the change in the phase of the periodic scan is based on a fixed time period of the periodic scan and a pseudorandom number;

wherein the processing system is further configured to change the phase of the periodic scan while maintaining the fixed time period between the scans; and

wherein the processing system is further configured to schedule each of the scans, and wherein the processing system is further configured to change the phase of the periodic scan by scheduling a next scan at a time following said one of the scans, the time being equal to the fixed time period multiplied by the pseudo-random number.

2. The apparatus of claim 1 wherein the processing system is further configured to attempt to associate with the detected wireless device, and wherein the processing system is further configured to change the phase of the periodic scan independent of whether the processing system is able to associate with the detected wireless device.

3. The apparatus of claim 1 wherein the processing system is further configured to support a plurality of paging scans spaced apart in time, the processing system being further configured to change the phase of the periodic scan by shifting the periodic scan such that a first boundary of said one of the scans is aligned with a second boundary of one of the paging scans.

4. The apparatus of claim 3 wherein said one of the paging scans is a last paging scan in time preceding said one of the scans.

5. The apparatus of claim 1 wherein the processing system is further configured to support a plurality of paging scans spaced apart in time, the paging scans each having a fixed duration, and wherein the fixed time period of the periodic scan is a multiple of the fixed duration, the processing system being further configured to change the phase of the periodic scan by shifting the periodic scan such that a first boundary of said one of the scans is aligned with a second boundary of one of the paging scans.

6. The apparatus of claim 1 wherein the processing system is further configured to support a plurality of paging scans spaced apart in time, the paging scans each having a fixed duration.

7. The apparatus of claim 1 wherein the processing system is further configured to attempt to associate with the detected wireless device by sending parameters to support a time-hopping channel with the detected wireless device.

8. The apparatus of claim 1 wherein the processing system is further configured to transmit a discovery signal between two of the scans for detection by any of the wireless devices.

9. The apparatus of claim 1, wherein the change in the phase of the periodic scan is greater than the period of the periodic scan.

10. A method for wireless communications, comprising:

periodically scanning for wireless devices, the periodic scan comprising a plurality of scans spaced apart in time; and

changing a phase of the periodic scan in response to one of the wireless devices being detected in one of the scans, wherein the change in the phase of the periodic scan is based on a fixed time period of the periodic scan and a pseudorandom number, wherein the phase of the periodic scan is changed while maintaining the fixed time period between the scans; and

scheduling each of the scans, and wherein the phase of the periodic scan is changed by scheduling a next scan following said one of the scans based on the pseudo-random number, wherein the phase of the periodic scan is changed by scheduling the next scan at a time following said one of the scans, the time being equal to the fixed time period multiplied by the pseudo-random number.

11. The method of claim 10 further comprising attempting to associate with the detected wireless device, and wherein the phase of the periodic scan is changed independent of whether the attempt to associate with the detected wireless device is successful.

12. The method of claim 10 further comprising support a plurality of paging scans spaced apart in time, and wherein the phase of the periodic scan is changed by shifting the periodic scan such that a first boundary of said one of the scans is aligned with a second boundary of one of the paging scans.

13. The method of claim 12 wherein said one of the paging scans is a last paging scan in time preceding said one of the scans.

14. The method of claim 10 further comprising supporting a plurality of paging scans spaced apart in time, the paging scans each having a fixed duration, the fixed time period of the periodic scan being a multiple of the fixed duration, and wherein the periodic scan is changed by shifting the periodic scan such that a first boundary of said one of the scans is aligned with a second boundary of one of the paging scans.

15. The method of claim 10 further comprising supporting a plurality of paging scans spaced apart in time, the paging scans each having a fixed duration.

16. The method of claim 10 further comprising attempting to associate with the detected wireless device by sending parameters to support a time-hopping channel with the detected wireless device.

17. The method of claim 10 further comprising transmitting a discovery signal between two of the scans for detection by any of the wireless devices.

18. The method of claim 10, wherein the change in the phase of the periodic scan is greater than the period of the periodic scan.

19. An apparatus for wireless communications, comprising:

means for periodically scanning for wireless devices, the periodic scan comprising a plurality of scans spaced apart in time; and

means for changing a phase of the periodic scan in response to one of the wireless devices being detected in one of the scans, wherein the change in the phase of the periodic scan is based on a fixed time period of the periodic scan and a pseudorandom number, wherein the means for changing a phase of the periodic scan is configured to change the phase while maintaining the fixed time period between the scans;

wherein the means for changing a phase of the periodic scan comprises means for each of the scans, and wherein the means for changing a phase of the periodic scan is configured to change the phase by scheduling a next scan following said one of the scans based on the pseudo-random number;

wherein the means for changing a phase of the periodic scan is configured to change the phase by scheduling the next scan at a time following said one of the scans, the time being equal to the fixed time period multiplied by the pseudo-random number.

20. The apparatus of claim 19 further comprising means for attempting to associate with the detected wireless device, and wherein the means for changing a phase of the periodic scan is configured to change the phase independent of whether the attempt to associate with the detected wireless device is successful.

21. The apparatus of claim 19 further comprising means for support a plurality of paging scans spaced apart in time, and wherein the means for changing a phase of the periodic scan is configured to change the phase by shifting the periodic scan such that a first boundary of said one of the scans is aligned with a second boundary of one of the paging scans.

22. The apparatus of claim 21 wherein said one of the paging scans is the last paging scan in time preceding said one of the scans.

23. The apparatus of claim 19 further comprising means for supporting a plurality of paging scans spaced apart in time, the paging scans each having a fixed duration, the fixed time period of the periodic scan being a multiple of the fixed duration, and wherein the means for changing a phase of the periodic scan is configured to change the phase by shifting the periodic scan such that a first boundary of said one of the scans is aligned with a second boundary of one of the paging scans.

24. The apparatus of claim 19 further comprising means for supporting a plurality of paging scans spaced apart in time, the paging scans each having a fixed duration.

25. The apparatus of claim 19 further comprising means for attempting to associate with the detected wireless device by sending parameters to support a time-hopping channel with the detected wireless device.

26. The apparatus of claim 19 further comprising means for transmitting a discovery signal between two of the scans for detection by any of the wireless devices.

27. The apparatus of claim 19, wherein the change in the phase of the periodic scan is greater than the period of the periodic scan.

28. A computer-program product for wireless communications, comprising:

a non-transitory computer-readable storage medium comprising codes executable by at least one processor to;

periodically scan for wireless devices, the periodic scan comprising a plurality of scans spaced apart in time;

change a phase of the periodic scan in response to one of the wireless devices being detected in one of the scans, wherein the change in the phase of the periodic scan is based on a fixed time period of the periodic scan and a pseudorandom number, wherein the phase of the periodic scan is changed while maintaining the fixed time period between the scans; and

schedule each of the scans, and wherein the phase of the periodic scan is changed by scheduling a next scan following said one of the scans based on the pseudo-random number, wherein the phase of the periodic scan is changed by scheduling the next scan at a time following said one of the scans, the time being equal to the fixed time period multiplied by the pseudo-random number.

29. A headset, comprising:

a processing system configured to support a periodic scan for wireless devices, the periodic scan comprising a plurality of scans spaced apart in time, the processing system being further configured to change a phase of the periodic scan in response to one of the wireless devices being detected in one of the scans, wherein the change in the phase of the periodic scan is based on a fixed time period of the periodic scan and a pseudorandom number wherein the processing system is further configured to change the phase of the periodic scan while maintaining the fixed time period between the scans and wherein the processing system is further configured to schedule each of the scans, and wherein the processing system is further configured to change the phase of the periodic scan by scheduling a next scan at a time following said one of the scans, the time being equal to the fixed time period multiplied by the pseudo-random number;

a wireless interface configured to support a wireless connection with the detected wireless device; and

a transducer configured to provide an audio output based on data received over the wireless connection.

30. A watch comprising:

a processing system configured to support a periodic scan for wireless devices, the periodic scan comprising a plurality of scans spaced apart in time, the processing system being further configured to change a phase of the periodic scan in response to one of the wireless devices being detected in one of the scans, wherein the change in the phase of the periodic scan is based on a fixed time period of the periodic scan and a pseudorandom number wherein the processing system is further configured to change the phase of the periodic scan while maintaining the fixed time period between the scans and wherein the processing system is further configured to schedule each of the scans, and wherein the processing system is further configured to change the phase of the periodic scan by scheduling a next scan at a time following said one of the scans, the time being equal to the fixed time period multiplied by the pseudo-random number;

a wireless interface configured to support a wireless connection with the detected wireless device; and

a user interface configured to provide an indication based on data received over the wireless link.

31. A sensing device for wireless communications, comprising:

a processing system configured to support a periodic scan for wireless devices, the periodic scan comprising a plurality of scans spaced apart in time, the processing system being further configured to change a phase of the periodic scan in response to one of the wireless devices being detected in one of the scans, wherein the change in the phase of the periodic scan is based on a fixed time period of the periodic scan and a pseudorandom number wherein the processing system is further configured to change the phase of the periodic scan while maintaining the fixed time period between the scans and wherein the processing system is further configured to schedule each of the scans, and wherein the processing system is further configured to change the phase of the periodic scan by scheduling a next scan at a time following said one of the scans, the time being equal to the fixed time period multiplied by the pseudo-random number;

a wireless interface configured to support a wireless connection with the detected wireless device; and

a sensor configured to provide data to the wireless interface for transmission over the wireless link.