IMPLICIT DRX CYCLE LENGTH ADJUSTMENT CONTROL IN LTE_ACTIVE MODE

• US 20080181127A1
• Filed: 01/30/2008
• Published: 07/31/2008
• Est. Priority Date: 01/30/2007
• Status: Active Grant

• Current Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Original Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Inventors: Terry, Stephen E., Wang, Peter S., Wang, Jin
• Granted Patent: US 8,238,260 B2
• Time in Patent Office: Days
• US Class Current: 370/252
• CPC Class Codes: H04W 52/0212 managed by the network, e.g. network or access point is master and terminal is slave
• CPC Class Codes: H04W 52/0216 using a pre-established activity schedule, e.g. traffic indication frame
• CPC Class Codes: H04W 52/0229 where the received signal is a wanted signal
• CPC Class Codes: H04W 52/0235 where the received signal is a power saving command
• CPC Class Codes: H04W 76/28 Discontinuous transmission [DTX]; Discontinuous reception [DRX]
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A method for controlling discontinuous reception in a wireless transmit/receive unit includes defining a plurality of DRX levels, wherein each DRX level includes a respective DRX cycle length and transitioning between DRX levels based on a set of criteria. The transitioning may be triggered by implicit rules.

Claims

1. A method for controlling discontinuous reception (DRX) in a wireless transmit/receive unit (WTRU), the method comprising:

defining a plurality of DRX levels, wherein each DRX level includes a respective DRX cycle length; and

transitioning between DRX levels based on a set of criteria.

2. The method as in claim 1 wherein the set of criteria is predefined.

3. The method as in claim 1 wherein the set of criteria is based on events detected by the WTRU.

4. The method as in claim 1 wherein the set of criteria is based on explicit signals received by the WTRU.

5. The method as in claim 1 wherein the set of criteria is defined dynamically.

6. The method as in claim 1 wherein transitioning between the plurality of DRX levels is based upon learned traffic patterns.

7. The method of claim as in claim 1 wherein transitioning between the plurality of DRX levels is based upon measured events.

8. The method as in claim 1 further comprising defining three DRX levels.

9. The method as in claim 1 further comprising defining two DRX levels.

10. The method as in claim 1 wherein each respective DRX cycle length is a function of a shortest DRX cycle length.

11. The method as in claim 10 wherein each respective DRX cycle length is below a maximum DRX cycle length.

12. The method as in claim 1 wherein each respective cycle length is a multiple of a base cycle length

13. The method as in claim 1 further comprising the WTRU synchronizing DRX cycle length with an E Node B (eNB).

14. The method as in claim 13 further comprising the WTRU increasing the DRX cycle length upon loss of synchronization.

15. The method as in claim 14 further comprising the WTRU increasing the DRX cycle length until the WTRU is synchronized with the eNB.

16. The method as in claim 13 further comprising the WTRU decreasing the DRX cycle length upon loss of synchronization.

17. The method as in claim 16 further comprising the WTRU decreasing the DRX cycle length until the WTRU is synchronized with the eNB.

18. The method as in claim 1 further comprising:

defining a DRX life span; and

redefining the DRX cycle lengths of the plurality of DRX levels once per DRX life span.

19. The method as in claim 1 further comprising:

periodically changing the DRX level of a WTRU to a DRX level having a shorter DRX cycle length.

20. The method as in claim 1 further comprising changing DRX levels based on a trigger.

21. The method as in claim 11 wherein the trigger is the expiry of a timer.

22. The method as in claim 21 further comprising resetting the timer upon transmission activity.

23. The method as in claim 20 wherein the trigger is a traffic event.

24. The method as in claim 23 wherein the traffic event is a transmission.

25. The method as in claim 20 wherein the trigger is a radio bearer reconfiguration request.

26. The method as in claim 19 further comprising changing DRX levels periodically based on learned traffic patterns.

27. The method as in claim 1 further comprising:

measuring traffic volume at a WTRU;

adjusting the DRX cycle length of the plurality of DRX levels based on the measured traffic volume.

28. The method as in claim 27 further comprising:

shortening the DRX cycle length when traffic volume is above a predetermined threshold; and

lengthening the DRX cycle length when traffic volume is below a predetermined threshold.

29. The method as in claim 26 further comprising:

adding a radio bearer when the measured traffic volume exceeds a predetermined threshold.

30. The method as in claim 1 further comprising:

setting a resume period timer upon adjusting a DRX cycle length; and

returning the DRX cycle length to an original value upon expiration of the resume period timer.

31. The method as in claim 1 further comprising changing the DRX level of a WTRU based on handover measurements.

32. The method as in claim 31 further comprising changing the DRX level of a WTRU when a serving cell measurement is below a predetermined threshold.

33. The method as in claim 32 further comprising changing the DRX level of a WTRU when an intra-frequency neighbor cell measurement is above a threshold.

34. The method as in claim 32 further comprising changing the DRX level of a WTRU when an inter-frequency neighbor cell measurement is above a threshold.

35. The method as in claim 32 further comprising changing the DRX level of a WTRU when an inter-radio access technology (RAT) neighbor measurement is above a threshold.

36. The method as in claim 1 further comprising:

receiving downlink commands at the WTRU; and

changing the DRX level based on the type of downlink command.

37. A wireless transmit receive unit (WTRU) comprising a processor, the processor configured to:

define a plurality of DRX levels, wherein each DRX level includes a respective DRX cycle length; and

transition the WTRU between DRX levels based on a set of criteria.

38. The WTRU as in claim 37 wherein the processor is further configured to periodically change the DRX level of the WTRU to a shorter DRX cycle length.

39. The WTRU as in claim 37 wherein the processor is further configured to transition the WTRU between DRX levels based on a trigger.

40. The WTRU as in claim 39 wherein the trigger comprises a measurement event.

41. The WTRU as in claim 39 wherein the trigger comprises a timer.

42. The WTRU as in claim 39 wherein the trigger comprises a counter.

43. The WTRU as in claim 39 wherein the trigger comprises a downlink command.