Method and system for power saving scheduling in wireless local area networks

• US 20080232287A1
• Filed: 03/21/2007
• Published: 09/25/2008
• Est. Priority Date: 03/21/2007
• Status: Abandoned Application

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Shao, Huai-Rong, Ngo, Chiu
• Application Number:
  US11/726,260
• Publication Number:
  US 20080232287A1
• Time in Patent Office: Days
• US Class Current: 370/311
• 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

A power saving (PS) scheduling process is provided for scheduling uplink and downlink frame transmissions between a PS transmitter and at least one PS receiver using PSAD sequences in a wireless communication system. The power saving scheduling process involves determining a power saving schedule of transmission opportunities for communication between a PS transmitter and at least one PS receiver over a shared channel, wherein the schedule includes corresponding durations for uplink transmissions of frames from each PS receiver to the PS transmitter. A Power Saving Aggregation Descriptor (PSAD) frame containing said schedule is constructed. A PSAD sequence is initiated by transmitting the PSAD from the PS transmitter to each PS receiver.

Claims

1. A power saving (PS) scheduling method for communication in a wireless network, comprising the steps of:

determining a power saving schedule of transmission opportunities for communication between a PS transmitter and at least one PS receiver over a shared channel, wherein the schedule includes corresponding durations for uplink transmissions of frames from each PS receiver to the PS transmitter;

constructing a Power Saving Aggregation Descriptor (PSAD) frame containing said schedule; and

initiating a PSAD sequence by transmitting the PSAD from the PS transmitter to each PS receiver.

2. The method of claim 1 wherein the step of determining a power saving schedule further includes the steps of:

determining a downlink (DL) schedule for downlink transmissions (DLT) from the PS transmitter to each PS receiver; and

determining an uplink (UL) schedule for uplink transmissions (ULT) from each PS receiver to the PS transmitter, wherein the uplink schedule includes precise durations for uplink transmissions of variable size frames from each PS receiver to the PS transmitter.

3. The method of claim 1 wherein:

the network includes at least one non-PS receiver;

the step of determining a power saving schedule further includes the step of partitioning downlink transmissions from the PS transmitter to each PS receiver and each non-PS receiver into different PSAD sequences; and

the method further including the steps of, each PS receiver entering a power saving cycle during scheduled transmissions for non-PS receivers.

4. The method of claim 1 further comprising the steps of:

receiving a PSAD from the PS transmitter at a PS receiver;

analyzing the schedule in the PSAD; and

if the PSAD does not specify a schedule for this receiving PS receiver, then entering a power saving cycle, otherwise communicating with the PS transmitter according to a corresponding schedule in the PSAD.

5. The method of claim 1 further comprising the steps of:

receiving the PSAD from the PS transmitter at a PS receiver;

analyzing the schedule in the received PSAD; and

providing uplink transmission information to the PS transmitter based on signaling in the PSAD, by;

determining an indication of the length of an uplink frame for a next uplink transmission from the PS receiver to the PS transmitter; and

transmitting the indication of length of said uplink frame to the PS transmitter.

6. The method of claim 2 further comprising the steps of:

receiving the indication of the length of said uplink frame from the PS receiver; and

based on the indication of the length of said uplink frame, scheduling a precise duration for uplink transmission of said uplink frame from the PS receiver in a subsequent PSAD sequence.

7. The method of claim 5 wherein:

the step of constructing a PSAD further comprises the step of including a next frame notice in the PSAD for a PS receiver, to notify that PS receiver to provide an indication of the length of a subsequent uplink frame for uplink transmission from that PS receiver to the PS transmitter.

8. The method of claim 7 wherein:

the step of analyzing the schedule in the received PSAD further includes the step of checking for a next frame notice in the PSAD for this PS receiver; and

the step of providing uplink transmission information to the PS transmitter further includes the step of providing the uplink transmission information if the PSAD includes such a next frame notice for this PS receiver.

9. The method of claim 7 wherein the step of providing uplink transmission information to the PS transmitter further includes the step of transmitting the indication of length of said uplink frame to the PS transmitter in a control frame.

10. The method of claim 7 wherein the next frame notice indicates whether an ULT Start Offset and an ULT Duration in the PSAD for uplink transmission by the PS receiver describe the uplink transmission of said control frame.

11. The method of claim 5 wherein:

the step of constructing a PSAD further comprises the step of including a pre-specified uplink transmission duration in the PSAD for a PS receiver, to notify that PS receiver to provide an indication of the length of a subsequent uplink frame for uplink transmission from that PS receiver to the PS transmitter

12. The method of claim 11 wherein:

the step of analyzing the schedule in the received PSAD further includes the step of checking for a next frame notice in the PSAD for this PS receiver; and

the step of providing uplink transmission information further includes the step of providing the uplink transmission information if the PSAD includes such a next frame notice for this PS receiver.

13. The method of claim 12 wherein the step of providing uplink transmission information to the PS transmitter further includes the step of transmitting the indication of length of said uplink frame to the PS transmitter in a control frame to the PS transmitter.

14. The method of claim 13 wherein said pre-specified uplink transmission duration indicates a pre-specified length of said control frame length of 22 bytes.

15. The method of claim 14 wherein said pre-specified length is 22 bytes.

16. The method of claim 1 wherein the wireless network comprises a wireless local area network (WLAN).

17. The method of claim 16 wherein the transmitter comprises an access point and each receiver comprises a station.

18. A wireless communication system comprising:

a power saving (PS) transmitter and at least one PS receiver, configured to communicate a wireless channel; and

the PS transmitter comprising;

a scheduler that is configured to determine a power saving schedule of transmission opportunities for communication between a PS transmitter and at least one PS receiver over a shared channel, wherein the schedule includes corresponding durations for uplink transmissions of frames from each PS receiver to the PS transmitter;

a Power Saving Aggregation Descriptor (PSAD) constructor that is configured to construct a PSAD frame containing said schedule; and

a transmission module that is configured to transmit the PSAD frame, thereby initiating a PSAD sequence for communication between the PS transmitter and each PS receiver.

19. The system of claim 18 wherein the scheduler is further configured to:

determine a DL schedule for DLT from the PS transmitter to each PS receiver;

determine an UL schedule for ULT from each PS receiver to the PS transmitter, wherein the uplink schedule includes precise durations for uplink transmissions of variable size frames from each PS receiver to the PS transmitter.

20. The system of claim 18 further including at least one non-PS receiver, wherein the scheduler is further configured to determine a power saving schedule that partitions downlink transmissions from the PS transmitter to each PS receiver and each non-PS receiver into different PSAD sequences, such that each PS receiver is further configured to enter a power saving cycle during scheduled transmissions for non-PS receivers.

21. The system of claim 18 wherein each PS receiver comprises:

a receiving module that is configured to receive a PSAD from the PS transmitter; and

a PSAD analyzer that is configured to analyze the schedule in the PSAD, and if the received PSAD does not specify a schedule for this receiving PS receiver, then enter the PS receiver into a power saving cycle, otherwise communicate with the PS transmitter according to a corresponding schedule in the PSAD.

22. The system of claim 18 wherein the PS receiver comprises:

a receiving module that is configured to receive a PSAD from the PS transmitter; and

a PSAD analyzer that is configured to analyze the schedule in the PSAD and provide uplink transmission information to the PS transmitter by;

determining an indication of the length of an uplink frame for a next uplink transmission from the PS receiver to the PS transmitter; and

transmitting the indication of length of said uplink frame to the PS transmitter.

23. The system of claim 19 wherein the scheduler is further configured to schedule a precise duration for uplink transmission of said uplink frame from the PS receiver in a subsequent PSAD sequence, based on the indication of the length of said uplink frame from the PS receiver.

24. The system of claim 22 wherein the PSAD constructor is further configured to include a next frame notice in the PSAD for a PS receiver, to notify that PS receiver to provide an indication of the length of a subsequent uplink frame for uplink transmission from that PS receiver to the PS transmitter.

25. The system of claim 24 wherein:

the PSAD analyzer is further configured to check for a next frame notice in the received PSAD, for this PS receiver, and provide uplink transmission information to the PS transmitter if the PSAD includes such a next frame notice for this PS receiver.

26. The system of claim 24 wherein the PSAD analyzer is further configured to transmit the indication of length of said uplink frame to the PS transmitter during a scheduled uplink transmission period.

27. The system of claim 24 wherein the next frame notice indicates whether a ULT Start Offset and a ULT Duration in the PSAD for uplink transmission by the PS receiver describe the uplink transmission of said indication of length of said uplink frame.

28. The system of claim 22 wherein the PSAD constructor is further configured to include a pre-specified uplink transmission duration in the PSAD for a PS receiver, to notify that PS receiver to provide an indication of the length of a subsequent uplink frame for uplink transmission from that PS receiver to the PS transmitter.

29. The system of claim 28 wherein the PSAD analyzer is further configured to check for a pre-specified uplink transmission duration in the PSAD for this PS receiver and provide the uplink transmission information if the PSAD includes such a pre-specified uplink transmission duration for this PS receiver.

30. The system of claim 29 wherein the PSAD analyzer is further configured to provide said uplink transmission information in a control frame to the PS transmitter.

31. The system of claim 30 wherein said pre-specified uplink transmission duration indicates a pre-specified length of said control frame length of 22 bytes.

32. The system of claim 31 wherein said pre-specified length is 22 bytes.

33. The system of claim 18 wherein the wireless network comprises a WLAN.

34. The system of claim 18 wherein the transmitter comprises an access point and each receiver comprises a station.

35. The system of claim 18 wherein the communication system comprises a wireless personal area network.

36. The system of claim 29 wherein the communication system comprises a cellular network.

37. A power saving (PS) wireless transmitter for communication with at least one PS wireless receiver, comprising:

a scheduler that is configured to determine a power saving schedule of transmission opportunities for communication between a PS transmitter and at least one PS receiver over a shared channel, wherein the schedule includes corresponding durations for uplink transmissions of frames from each PS receiver to the PS transmitter;

a Power Saving Aggregation Descriptor (PSAD) constructor that is configured to construct a PSAD frame containing said schedule; and

a transmission module that is configured to transmit the PSAD frame, thereby initiating a PSAD sequence for communication between the PS transmitter and each PS receiver.

38. The transmitter of claim 37 wherein the scheduler is further configured to:

determine a DL schedule for DLT from the PS transmitter to each PS receiver;

determine an UL schedule for ULT from each PS receiver to the PS transmitter, wherein the uplink schedule includes precise durations for uplink transmissions of variable size frames from each PS receiver to the PS transmitter.

39. The transmitter of claim 37 wherein the scheduler is further configured to determine a power saving schedule that partitions downlink transmissions from the PS transmitter to each PS receiver and non-PS receivers into different PSAD sequences, thereby enabling each PS receiver to enter a power saving cycle during scheduled transmissions for non-PS receivers.

40. The transmitter of claim 37 wherein the schedule enables each PS receiver to enter a power saving cycle if no transmissions are scheduled for that PS receiver.

41. The transmitter of claim 38 wherein the scheduler is further configured to schedule a precise duration for uplink transmission of an uplink frame from the PS receiver in a subsequent PSAD sequence, based on indication of the length of said uplink frame from the PS receiver.

42. The transmitter of claim 41 wherein the PSAD constructor is further configured to include a next frame notice in the PSAD for a PS receiver, to notify that PS receiver to provide an indication of the length of a subsequent uplink frame for uplink transmission from that PS receiver to the PS transmitter.

43. The transmitter of claim 42 wherein the next frame notice indicates whether an ULT Start Offset and an ULT Duration in the PSAD for uplink transmission by the PS receiver describe the uplink transmission of said indication of length of said uplink frame.

44. The transmitter of claim 41 wherein the PSAD constructor is further configured to include a pre-specified uplink transmission duration in the PSAD for a PS receiver, to notify that PS receiver to provide an indication of the length of a subsequent uplink frame for uplink transmission from that PS receiver to the PS transmitter

45. The transmitter of claim 44 wherein said pre-specified uplink transmission duration indicates a pre-specified length of said control frame length of 22 bytes.

46. The transmitter of claim 45 wherein said pre-specified length is 22 bytes.

47. A power saving (PS) wireless receiver, comprising:

a receiving module that is configured to receive a Power Saving Aggregation Descriptor (PSAD) from a PS transmitter, the PSAD including a power saving schedule of transmission opportunities for communication between the PS transmitter and at least one PS receiver over a shared channel, wherein the schedule includes corresponding durations for uplink transmissions of frames from each PS receiver to the PS transmitter; and

a PSAD analyzer that is configured to analyze the schedule in the PSAD, and if the received PSAD does not specify a schedule for this receiving PS receiver, then enter the PS receiver into a power saving cycle, otherwise communicate with the PS transmitter according to a corresponding schedule in the PSAD.

48. The receiver of claim 47 wherein the schedule in the PSAD comprises:

a DL schedule for DLT from the PS transmitter to each PS receiver; and

an UL schedule for ULT from each PS receiver to the PS transmitter, wherein the uplink schedule includes precise durations for uplink transmissions of variable size frames from each PS receiver to the PS transmitter.

49. The receiver of claim 47 wherein:

the schedule partitions downlink transmissions from the PS transmitter to each PS receiver and each non-PS receiver into different PSAD sequences;

a PSAD analyzer is further configured to enter a power saving cycle during scheduled transmissions for non-PS receivers.

50. The receiver of claim 47 wherein the PSAD analyzer is further configured to analyze the schedule in the PSAD and provide uplink transmission information to the PS transmitter by:

determining an indication of the length of an uplink frame for a next uplink transmission from the PS receiver to the PS transmitter; and

transmitting the indication of length of said uplink frame to the PS transmitter.

51. The receiver of claim 50 wherein the PSAD analyzer is further configured to check for a next frame notice in the received PSAD, for this PS receiver, and provide uplink transmission information to the PS transmitter if the PSAD includes such a next frame notice for this PS receiver.

52. The receiver of claim 50 wherein the PSAD analyzer is further configured to transmit the indication of length of said uplink frame to the PS transmitter during a scheduled uplink transmission period.

53. The receiver of claim 51 wherein the next frame notice indicates whether an ULT Start Offset and an ULT Duration in the PSAD for uplink transmission by the PS receiver describe the uplink transmission of said indication of length of said uplink frame.

54. The receiver of claim 50 wherein the PSAD analyzer is further configured to provide said uplink transmission information in a control frame to the PS transmitter.

55. The receiver of claim 50 wherein the PSAD analyzer is further configured to check for a pre-specified uplink transmission duration in the PSAD for this PS receiver and provide the uplink transmission information if the PSAD includes such a pre-specified uplink transmission duration for this PS receiver.

56. The receiver of claim 55 wherein said pre-specified uplink transmission duration indicates a pre-specified length of said control frame length of 22 bytes.

57. The receiver of claim 56 wherein said pre-specified length is 22 bytes.