Timer-based sleep for terminals in wireless communication systems

• US 20040198302A1
• Filed: 01/24/2003
• Published: 10/07/2004
• Est. Priority Date: 06/26/2002
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Turner, Simon, Hutchison, James A.
• Granted Patent: US 7,689,196 B2
• Time in Patent Office: Days
• US Class Current: 455/343.1
• CPC Class Codes: H04W 52/0216 using a pre-established activity schedule, e.g. traffic indication frame
• CPC Class Codes: H04W 52/287 when the channel is in stand-by
• CPC Class Codes: H04W 52/288 taking into account the usage mode, e.g. hands-free, data transmission, telephone
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

Techniques for performing timer-based sleep to extend sleep time and thus battery life for a terminal in a wireless communication system. The likelihood of data traffic may be related to recent usage. If recent usage indicates that data traffic is unlikely, then the terminal can continue to maintain the link but monitor the signals from the system at a reduced rate. In one method, the probability of data traffic for the terminal is initially estimated (e.g., based on time since last activity and a particular usage model). A timer value is then determined based on the estimated probability of data traffic. The timer value may be modified based on an event, which may relate to link maintenance, hand-off, and so on. Sleep is then performed for the duration corresponding to the unmodified or modified timer value and may extend past one or more designated paging slots.

Claims

1. A method for performing sleep for a terminal in a wireless communication system, comprising:

estimating a probability of data traffic for the terminal;

determining a timer value based on the estimated probability of data traffic; and

performing a sleep for a duration of time corresponding to the timer value.

2. The method of claim 1, wherein the probability of data traffic is estimated based on time since last activity.

3. The method of claim 1, wherein the probability of data traffic is estimated based on a particular usage model.

4. The method of claim 1, wherein the determining includes

mapping the estimated probability of data traffic to one of a plurality of probability threshold values, wherein each of the plurality of probability threshold values is associated with a respective one of a plurality of timer values, and

identifying the timer value as the one associated with the probability threshold value to which the estimated probability of data traffic is mapped.

5. The method of claim 1, wherein the timer value is inversely related to the estimated probability of data traffic.

6. The method of claim 1, wherein the timer value is limited to a particular maximum value.

7. The method of claim 1, wherein the communication system supports an idle state, and wherein messages for the terminal are sent in designated slots at fixed intervals while the terminal is in the idle state.

8. The method of claim 7, wherein the duration of the sleep extends past at least one designated slot.

9. The method of claim 1, further comprising:

modifying the timer value based on an event, and wherein the sleep is performed for a duration of time corresponding to the modified timer value.

10. The method of claim 9, wherein the event relates to link maintenance.

11. The method of claim 9, wherein the event relates to monitoring for updated system information.

12. The method of claim 9, wherein the event relates to hand-off of the terminal from a first access point to a second access point.

13. The method of claim 9, wherein the event relates to a user input.

14. The method of claim 9, wherein the event relates to an alarm clock implemented by the terminal.

15. The method of claim 1, further comprising:

ascertaining whether or not slotted sleep is permitted; and

performing the estimating, determining, and performing the sleep if slotted sleep is permitted.

16. The method of claim 15, wherein whether or not slotted sleep is permitted is ascertained based on session information.

17. The method of claim 1, wherein the wireless communication system implements IS-856.

18. The method of claim 17, wherein the wireless communication system further implements IS-2000, or IS-95, or both IS-2000 and IS-95.

19. A method for performing sleep for a terminal in a CDMA communication system that supports an idle state, wherein messages for the terminal are sent in designated slots at fixed intervals while the terminal is in the idle state, the method comprising:

estimating a probability of data traffic for the terminal;

mapping the estimated probability of data traffic to one of a plurality of probability threshold values, wherein each of the plurality of probability threshold values is associated with a respective one of a plurality of timer values;

identifying a timer value associated with the probability threshold value to which the estimated probability of data traffic is mapped; and

performing a sleep for a duration of time corresponding to the timer value, wherein the duration of the sleep extends past at least one designated slot.

20. An apparatus in a wireless communication system, comprising:

means for estimating a probability of data traffic for a terminal;

means for determining a timer value based on the estimated probability of data traffic; and

means for performing a sleep for a duration of time corresponding to the timer value.

21. The apparatus of claim 20, comprising:

means for modifying the timer value based on an event, and wherein the sleep is performed for a duration of time corresponding to the modified timer value.

22. A terminal in a wireless communication system, comprising:

a controller operative to estimate a probability of data traffic for the terminal, determine a timer value based on the estimated probability of data traffic, and initiate a sleep for a duration of time corresponding to the timer value; and

a timer operative to receive the timer value and count the duration of time indicated by the timer value.

23. The terminal of claim 22, wherein a plurality of probability threshold values are associated with a plurality of timer values, and wherein the controller is further operative to map the estimated probability of data traffic to one of the plurality of probability threshold values and to identify the timer value as the one associated with the probability threshold value to which the estimated probability of data traffic is mapped.

24. The terminal of claim 22, wherein the wireless communication system implements IS-856.

25. The method of claim 24, wherein the wireless communication system further implements IS-2000, or IS-95, or both IS-2000 and IS-95.