Implicit DRX cycle length adjustment control in LTE — active mode

• US 8,238,260 B2
• Filed: 01/30/2008
• Issued: 08/07/2012
• 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
• Primary Examiner(s): Mesfin, Yemane
• Assistant Examiner(s): DAVENPORT, MON CHERI S
• Application Number:
  US12/022,233
• Publication Number:
  US 20080181127A1
• Time in Patent Office: 1,651 Days
• Field of Search: 370/252, 370/311, 370/329, 370/338, 455/343.2, 455/420, 455/436, 455/445, 455/450, 455/502, 455/574
• 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:

the WTRU receiving a DRX configuration comprising a plurality of DRX levels, each of the plurality of DRX levels comprising at least one DRX cycle length;

the WTRU operating at a first DRX level of the plurality of DRX levels;

the WTRU determining that a WTRU timer has expired; and

responsive to determining that the WTRU timer has expired, the WTRU transitioning from the first DRX level to a second DRX level of the plurality of DRX levels without receiving explicit signaling from a base station to transition from the first DRX level to the second DRX level, the second DRX level comprising a second DRX cycle length that is a multiple of a first DRX cycle length of the first DRX level.

2. The method as in claim 1, wherein the WTRU timer is synchronized with a base station timer.

3. The method as in claim 1, further comprising the WTRU transitioning from the second DRX level to the first DRX level.

4. The method as in claim 1, wherein the at least one DRX cycle length is a function of a shortest DRX cycle length.

5. The method as in claim 1, wherein the second DRX level is synchronized with the base station.

6. The method as in claim 1, further comprising the WTRU transitioning from the second DRX level to the first DRX level based on uplink traffic patterns.

7. The method as in claim 1, further comprising the WTRU transitioning from the second DRX level to the first DRX level based on measured events.

8. The method as in claim 1, wherein the DRX configuration comprises three DRX levels.

9. The method as in claim 1, wherein the first DRX cycle length of the first DRX level comprises a shortest DRX cycle length.

10. The method as in claim 9 wherein the shortest DRX cycle length is a DRX cycle length of at least one of the plurality of DRX levels.

11. The method as in claim 1, wherein the second DRX cycle length of the second DRX level is below a maximum DRX cycle length.

12. The method as in claim 1, wherein the second DRX cycle length of the second DRX level is a multiple of a base DRX cycle length.

13. The method as in claim 1, wherein the first DRX level is synchronized with the base station.

14. The method as in claim 1, further comprising the WTRU transitioning from the second DRX level to the first DRX level based on loss of synchronization.

15. The method as in claim 1, further comprising:

the WTRU measuring traffic volume; and

the WTRU transitioning from the second DRX level to the first DRX level in response to the measured traffic volume.

16. The method as in claim 15, wherein the traffic volume is uplink traffic volume.

17. The method as in claim 15, further comprising the WTRU determining that the measured traffic volume exceeds a predetermined threshold.

18. The method as in claim 1 further comprising:

the WTRU defining a DRX life span; and

the WTRU transitioning between the plurality of DRX levels once per DRX life span.

19. The method as in claim 1, further comprising the WTRU periodically transitioning between the first DRX level and the second DRX level.

20. The method as in claim 3, wherein the WTRU transitions from the second DRX level to the first DRX level in response to a trigger.

21. The method as in claim 20, wherein the trigger is an expiration of a timer.

22. The method as in claim 1, further comprising resetting the WTRU 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 15, further comprising the WTRU determining that the measured traffic volume is below a predetermined threshold.

27. The method as in claim 12, wherein the base DRX cycle length is a DRX cycle length of at least one of the plurality of DRX levels.

28. The method as in claim 1, further comprising the WTRU receiving a control message, and, in response to receiving the control message, the WTRU transitioning from the second DRX level to the first DRX level.

29. The method as in claim 17, further comprising the WTRU adding a radio bearer responsive to determining that the traffic volume exceeds the predetermined threshold.

30. The method as in claim 1, further comprising:

the WTRU setting a resume period timer upon transitioning to the second DRX level; and

the WTRU transitioning to the first DRX level responsive to expiration of the resume period timer.

31. The method as in claim 1, further comprising the WTRU transitioning from the second DRX level to the first DRX level responsive to a handover measurement.

32. The method as in claim 31, wherein the handover measurement comprises a determination that a serving cell measurement is below a threshold.

33. The method as in claim 31, wherein the handover measurement comprises a determination that an intra-frequency neighbor cell measurement is above a threshold.

34. The method as in claim 31, wherein the handover measurement comprises a determination that an inter-frequency neighbor cell measurement is above a threshold.

35. The method as in claim 31, wherein the handover measurement comprises a determination that an inter-radio access technology (RAT) neighbor measurement is above a threshold.

36. The method as in claim 1 further comprising:

the WTRU receiving a downlink command; and

the WTRU transitioning from one of the first DRX level and the second DRX level to the other of the first DRX level and the second DRX level in response to a type of the downlink command.

49. The method as in claim 1, wherein the WTRU timer is a timer for a transition from a shorter DRX cycle length to a longer DRX cycle length.

51. The method as in claim 1, wherein the DRX configuration is received from a base station via higher layer signaling.

53. The method as in claim 1, wherein the WTRU timer is a timer for implicit DRX cycle length transition.

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

receive a DRX configuration comprising a plurality of DRX levels, each of the plurality of DRX levels comprising at least one DRX cycle length;

operate the WTRU at a first DRX level of the plurality of DRX levels;

determine that a WTRU timer has expired; and

responsive to determining that the WTRU timer has expired, transition the WTRU from the first DRX level to a second DRX level of the plurality of DRX levels without receiving explicit signaling from a base station to transition from the first DRX level to the second DRX level, the second DRX level comprising a second DRX cycle length that is a multiple of a first DRX cycle length of the first DRX level.

38. The WTRU as in claim 37, wherein the at least one DRX cycle length is a function of a shortest DRX cycle length.

39. The WTRU as in claim 37, wherein the processor is further configured to transition the WTRU from the second DRX level to the first DRX level.

40. The WTRU as in claim 37, wherein the WTRU timer is synchronized with a base station timer.

41. The WTRU as in claim 37, wherein the processor is further configured to receive a control message, and, responsive to receiving the control message, transition the WTRU from the second DRX level to the first DRX level.

42. The WTRU as in claim 37, wherein the processor is further configured to transition the WTRU from the second DRX level to the first DRX level responsive to a trigger, and wherein the trigger comprises at least one of a counter, a downlink command, an expiration of a timer, a traffic event, a transmission, and a radio bearer reconfiguration request.

43. The WTRU as in claim 37, wherein the processor is further configured to:

measure traffic volume; and

transition the WTRU from the second DRX level to the first DRX level responsive to the measured traffic volume.

44. The WTRU as in claim 37, wherein the first DRX cycle length of the first DRX level comprises a shortest DRX cycle length.

45. The WTRU as in claim 44, wherein the shortest DRX cycle length is a DRX cycle length of at least one of the plurality of DRX levels.

46. The WTRU as in claim 37, wherein the second DRX cycle length of the second DRX level is below a maximum DRX cycle length.

47. The WTRU as in claim 37, wherein the second DRX cycle length of the second DRX level is a multiple of a base DRX cycle length.

48. The WTRU as in claim 47, wherein the base DRX cycle length is a DRX cycle length of at least one of the plurality of DRX levels.

50. The WTRU as in claim 37, wherein the WTRU timer is a timer for a transition from a shorter DRX cycle length to a longer DRX cycle length.

52. The WTRU as in claim 37, wherein the DRX configuration is received from a base station via higher layer signaling.

54. The WTRU as in claim 37, wherein the WTRU timer is a timer for implicit DRX cycle length transition.