Fast reacquisition after long sleep

• US 20040002333A1
• Filed: 11/11/2002
• Published: 01/01/2004
• Est. Priority Date: 06/26/2002
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Neufeld, Arthur J.
• Granted Patent: US 6,973,310 B2
• Time in Patent Office: Days
• US Class Current: 455/436
• CPC Class Codes: H04W 36/30 by measured or perceived connection quality data
• CPC Class Codes: H04W 52/0216 using a pre-established activity schedule, e.g. traffic indication frame
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

The mobile station is in the sleep mode until just prior to a designated slot. Upon wakeup, the mobile station ensures a link is maintained with the network by measuring the strength of several pilots. If a neighbor pilot is stronger than the current pilot, a handoff is performed. After handoff, the Control Channel Capsule (CCC) may be demodulated by the mobile station to obtain new overhead information, such as neighbor pilots. If no handoff is performed, the reacquisition slew for the current pilot is measured and fed back to the sleep controller to determine the next wake-up time. The mobile station then returns to sleep mode.

Claims

1. A mobile station comprising:

a receiver for receiving a plurality of signals; and

a processor which controls the receiver and analyzes the plurality of signals, the processor configured to activate the receiver prior to a paging slot and determine if a handoff is desired based on the plurality of signals, wherein the processor deactivates the receiver prior to the paging slot if no handoff is desired.

2. The mobile station of claim 1, wherein the processor stores the plurality of signals in memory.

3. The mobile station of claim 1, wherein the plurality of signals includes pilot signals.

4. The mobile station of claim 3, wherein the processor determines if a handoff is desired by comparing the relative strengths of the pilot signals.

5. The mobile station of claim 1, wherein the processor demodulates one or more of the plurality of signals when a handoff is desired.

6. The mobile station of claim 5, wherein the processor stores the demodulated signal information in memory.

7. The mobile station of claim 6, wherein the processor retrieves the demodulated signal information in memory for repeated handoffs between the signal areas.

8. The mobile station of claim 1, wherein the processor determines when to activate the receiver based on a predetermined amount of time.

9. A method of fast reacquisition comprising:

receiving a plurality of signals prior to a designated time;

analyzing the plurality of signals to determine the presence of a triggering event; and

deactivating a receiver prior to the designated time if the triggering event is not present.

10. The method of claim 9, further comprising demodulating one or more of the plurality of signals if the triggering event is present.

11. The method of claim 9, further comprising determining if a handoff is desired to be the triggering event.

12. The method of claim 10, further comprising storing demodulated signal information.

13. The method of claim 12, further comprising retrieving the demodulated signal information from memory for repeated handoffs between signal areas.

14. The method of claim 11, further comprising comparing the relative strengths of the plurality of signals to determine if a handoff is desired.

15. A wireless communication system comprising:

a plurality of base stations, each of the plurality of base stations transmitting a pilot signal; and

a mobile station which activates prior to a paging slot to receive and analyze the pilot signals to determine if a handoff is desired, wherein the mobile station deactivates prior to the paging slot if no handoff is desired.

16. The wireless communication system of claim 15, wherein the mobile station demodulates the pilot signals to obtain overhead information if a handoff is desired.

17. The wireless communication system of claim 16, wherein the mobile station stores the overhead information in memory.

18. The wireless communication system of claim 15, wherein the mobile station performs a handoff based on the overhead information.

19. The wireless communication system of claim 17, wherein the mobile station uses the overhead information in memory for repeated handoff between two or more of the plurality of base stations.

20. The wireless communication system of claim 15, wherein the mobile station determines if a handoff is desired by comparing relative strengths of the plurality of pilot signals.

21. A mobile station comprising:

means for receiving a plurality of signals prior to a designated time;

means for analyzing the plurality of signals to determine the presence of a triggering event; and

means for deactivating a receiver prior to the designated time if the triggering event is not present.

22. The mobile station of claim 21, further comprising means for demodulating one or more of the plurality of signal if the triggering event is present.

23. The mobile station of claim 21, further comprising means for determining if a handoff is desired to be the triggering event.

24. The mobile station of claim 22, further comprising means for storing demodulated signal information.

25. The mobile station of claim 24, further comprising means for retrieving the demodulated signal information from memory for repeated handoffs between signal areas.

26. The mobile station of claim 23, further comprising means for comparing the relative strengths of the plurality of signals to determine if a handoff is desired.