Method and apparatus for managing power during a discontinuous reception mode

• US 20070064662A1
• Filed: 12/30/2005
• Published: 03/22/2007
• Est. Priority Date: 09/16/2005
• Status: Active Grant

• Current Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Original Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Inventors: Bultan, Aykut, Grieco, Donald, DiFazio, Robert, Kearney, Kenneth, Haim, John
• Granted Patent: US 7,680,071 B2
• Time in Patent Office: Days
• US Class Current: 370/338
• CPC Class Codes: H04W 52/0225 using monitoring of external events, e.g. the presence of a signal
• CPC Class Codes: H04W 52/287 when the channel is in stand-by
• CPC Class Codes: H04W 52/44 in connection with interruption of transmission
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A method and apparatus for managing power during discontinuous reception (DRX) mode are disclosed. A DRX mode is defined for a wireless transmit/receive unit (WTRU) for reducing power consumption of the WTRU. During the DRX mode, the WTRU enters into a sleep state and periodically wakes up for processing paging blocks for detecting a paging indication for the WTRU and a corresponding paging message. If the WTRU is paged the WTRU terminates the DRX mode. If the WTRU is not paged, the WTRU reenters the sleep state. For power management during the DRX mode, a synchronization update period is defined. The synchronization update period is a period for performing automatic frequency correction and/or frame time correction.

Claims

1. In a time-slotted wireless communication system wherein a plurality of time slots comprise a frame and a discontinuous reception (DRX) mode is defined for a wireless transmit/receive unit (WTRU) for reducing power consumption of the WTRU, during the DRX mode, the WTRU enters into a sleep state and periodically wakes up at each paging occasion in each paging block which is provided for every DRX cycle for detecting a paging indication for the WTRU and a corresponding paging message whereby the WTRU reenters into the sleep state until next paging occasion if the WTRU is not paged and terminates the DRX mode if the WTRU is paged, a method for the WTRU to implement power management during the DRX mode, the method comprising:

defining a synchronization update block for the WTRU during DRX, the synchronization update block comprising a time period for performing at least one of automatic frequency correction (AFC) and frame time correction (FTC); and

performing at least one of AFC and FTC during the synchronization update block.

2. The method of claim 1 wherein the synchronization update block comprises 21 frames, whereby the AFC and the FTC are performed once in each synchronization update block by processing every fifth frame.

3. The method of claim 1 wherein if AFC convergence is not declared at beginning of a paging block following the synchronization update block, the AFC is performed during the paging block following the synchronization update block.

4. The method of claim 3 wherein the AFC is performed in every frame during the paging block until the AFC convergence is declared.

5. The method of claim 3 wherein if the AFC convergence is not declared at an end of the paging block, the AFC is performed during a following sleep state.

6. The method of claim 5 wherein the AFC is performed in every frame during the sleep state until the AFC convergence is declared.

7. The method of claim 1 wherein if a most significant path (MSP) valid is not declared at beginning of the paging block following the synchronization update block, the FTC is performed during the paging block following the synchronization update block.

8. The method of claim 7 wherein the FTC is performed in every frame during the paging block until the MSP valid is declared.

9. The method of claim 7 wherein if the MSP valid is not declared at the end of the paging block, the FTC is performed during the following sleep state.

10. The method of claim 9 wherein the FTC is performed in every frame during the sleep state until the MSP valid is declared.

11. The method of claim 1 wherein a DRX cycle length which is a period between two consecutive paging blocks is one of 8, 16, 32, 64, 128, 256 and 526 frames.

12. The method of claim 1 wherein a period between two consecutive synchronization update blocks is 256 frames for DRX cycle lengths up to 256 frames and 512 frames for the DRX cycle length of 512 frames.

13. The method of claim 1 wherein before entering into the DRX mode, the last value of a voltage controlled oscillator (VCO) digital-to-analog converter (DAC) register is saved in memory and used during the DRX mode.

14. The method of claim 1 wherein a radio power-up time is defined such that a temperature controlled crystal oscillator (TCXO) wakes up the radio power-up time before start of a frame that the WTRU needs to process.

15. The method of claim 14 wherein the radio power-up time is 5 ms.

16. The method of claim 14 wherein the radio power-up time is defined as one frame length.

17. The method of claim 1 wherein the AFC and the FTC are performed using beacon signals.

18. The method of claim 17 wherein the beacon signals are signals transmitted via a primary common control physical channel (P-CCPCH).

19. The method of claim 1 wherein the AFC and the FTC are performed in the same time frame.

20. In a time-slotted wireless communication system wherein a plurality of time slots comprise a frame and a discontinuous reception (DRX) mode is defined for a wireless transmit/receive unit (WTRU) for reducing power consumption of the WTRU, during the DRX mode, the WTRU enters into a sleep state and periodically wakes up at each paging occasion in each paging block which is provided for every DRX cycle for detecting a paging indication for the WTRU and a corresponding paging message whereby the WTRU reenters into the sleep state until next paging occasion if the WTRU is not paged and terminates the DRX mode if the WTRU is paged, a WTRU for power management during the DRX mode, the WTRU comprising:

at least one of an automatic frequency correction (AFC) unit for performing AFC during a synchronization update block and a frame time correction (FTC) unit for performing FTC during the synchronization update block, the synchronization update block being a time period for performing at least one of AFC and FTC.

21. The WTRU of claim 20 wherein the synchronization update block comprises 21 frames, whereby the AFC and the FTC are performed once in each synchronization update block by processing every fifth frame.

22. The WTRU of claim 20 wherein if AFC convergence is not declared at beginning of a paging block following the synchronization update block, the AFC unit runs AFC during the paging block following the synchronization update block.

23. The WTRU of claim 22 wherein the AFC is performed in every frame during the paging block until the AFC convergence is declared.

24. The WTRU of claim 22 wherein if the AFC convergence is not declared at an end of the paging block, the AFC unit runs AFC during a following sleep state.

25. The WTRU of claim 24 wherein the AFC is performed in every frame during the sleep state until the AFC convergence is declared.

26. The WTRU of claim 20 wherein if a most significant path (MSP) valid is not declared by the FTC unit at beginning of the paging block following the synchronization update block, the FTC unit runs FTC during the paging block following the synchronization update block.

27. The WTRU of claim 26 wherein the FTC is performed in every frame during the paging block until the MSP valid is declared by the FTC unit.

28. The WTRU of claim 26 wherein if the MSP valid is not declared by the FTC unit at the end of the paging block, the FTC unit runs FTC during the following sleep state.

29. The WTRU of claim 28 wherein the FTC is performed in every frame during the sleep state until the MSP valid is declared by the FTC unit.

30. The WTRU of claim 20 wherein a DRX cycle length which is a period between two consecutive paging blocks is one of 8, 16, 32, 64, 128, 256 and 526 frames.

31. The WTRU of claim 20 wherein a period between two consecutive synchronization update blocks is 256 frames for DRX cycle lengths up to 256 frames and 512 frames for the DRX cycle length of 512 frames.

32. The WTRU of claim 20 wherein the AFC unit comprises a memory for storing a last value of a voltage controlled oscillator (VCO) digital-to-analog converter (DAC) register before entering into the DRX mode, whereby the stored value is used during the DRX mode.

33. The WTRU of claim 20 wherein a radio power-up time is defined such that a temperature controlled crystal oscillator (TCXO) wakes up the radio power-up time before start of a frame that the AFC unit and the FTC unit need to process.

34. The WTRU of claim 33 wherein the radio power-up time is 5 ms.

35. The WTRU of claim 33 wherein the radio power-up time is defined as one frame length.

36. The WTRU of claim 20 wherein the AFC unit and the FTC unit process beacon signals for AFC and FTC, respectively.

37. The WTRU of claim 36 wherein the beacon signals are signals transmitted via a primary common control physical channel (P-CCPCH).

38. The WTRU of claim 20 wherein the AFC unit and the FTC unit process a same frame.