METHOD AND SYSTEM FOR REDUCING POWER CONSUMPTION OF A WIRELESS TRANSMIT/RECEIVE UNIT

• US 20070037548A1
• Filed: 07/18/2006
• Published: 02/15/2007
• Est. Priority Date: 07/20/2005
• Status: Active Grant

• Current Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Original Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Inventors: Sammour, Mohammed, Grandhi, Sudheer
• Granted Patent: US 7,733,835 B2
• Time in Patent Office: Days
• US Class Current: 455/343.200
• CPC Class Codes: H04W 52/0235 where the received signal is a power saving command
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A method and system for reducing power consumption of a wireless transmit/receive unit (WTRU), (i.e., mobile station), are disclosed. A first WTRU measures a predetermined parameter and determines whether the measured predetermined parameter exceeds a threshold. If so, the first WTRU sends a sleep frame to a second WTRU. The sleep frame indicates sleep duration. The second WTRU receives the sleep frame and enters a sleep state for the sleep duration. The predetermined parameter may be an inactivity time of wireless medium. The second WTRU may or may not be allowed to send transmission to the first WTRU during the sleep duration. The sleep frame may be a control frame, a management frame, a data frame or an action frame. One of a multiple receiver aggregate (MRA) multi-poll frame, a power saving aggregation descriptor frame, or a power save multi-poll frame may be used as the sleep frame.

Claims

1. In a wireless communication system including a plurality of wireless transmit/receive units (WTRUs), a method of reducing power consumption of the WTRU, the method comprising:

a first WTRU measuring a predetermined parameter;

the first WTRU determining whether the measured predetermined parameter exceeds a threshold;

if the measured predetermined parameter exceeds the threshold, the first WTRU sending a sleep frame to at least one second WTRU, the sleep frame indicating a sleep duration; and

the second WTRU receiving the sleep frame and entering a sleep state for the sleep duration.

2. The method of claim 1 wherein the predetermined parameter is an inactivity time of a wireless medium.

3. The method of claim 2 wherein the inactivity time is defined as the time which has elapsed since a last relevant frame was sent over wireless medium, the relevant frame being a frame transmitted by either the first WTRU or the second WTRU.

4. The method of claim 1 wherein the predetermined parameter is at least one of an amount of data stored in a buffer of the first WTRU and an amount of data stored in a buffer of the second WTRU.

5. The method of claim 1 wherein the predetermined parameter includes at least one of an idle time, a traffic load, wireless medium utilization, quality of service (QoS) requirements, a number of the second WTRUs associated to the first WTRU, a traffic profile of the second WTRU, access class (AC) of data, error rate and delay and jitter.

6. The method of claim 1 further comprising:

the first WTRU waiting for a minimum wait time before measuring the predetermined parameter.

7. The method of claim 1 further comprising:

the second WTRU verifying a sender of the sleep frame, whereby the second WTRU enters a sleep state only if the sender of the sleep frame is a WTRU with which the second WTRU is associated.

8. The method of claim 1 wherein the second WTRU is not allowed to send a transmission to the first WTRU during the sleep duration.

9. The method of claim 1 wherein the second WTRU is allowed to send a transmission to the first WTRU during the sleep duration.

10. The method of claim 1 wherein the first WTRU includes an indication in the sleep frame that the second WTRU may send a transmission to the first WTRU during the sleep duration.

11. The method of claim 9 wherein the second WTRU is allowed to send a reverse direction grant (RDG) to the first WTRU.

12. The method of claim 11 wherein the first WTRU responds to the RDG by transmitting data to the second WTRU.

13. The method of claim 11 wherein the first WTRU ignores the RDG during the sleep duration.

14. The method of claim 13 wherein the first WTRU sends a frame indicating that the first WTRU does not intend to send a transmission to the second WTRU during the sleep duration.

15. The method of claim 1 wherein the sleep duration is on the order of a transmit opportunity (TXOP) limit.

16. The method of claim 1 wherein the sleep duration is dynamically adjusted depending on other conditions.

17. The method of claim 16 wherein the other conditions include at least one of traffic load measurements and quality of service (QoS) requirements.

18. The method of claim 1 wherein the threshold is dynamically adjusted depending on other factors.

19. The method of claim 1 wherein the sleep duration starts as soon as the sleep frame ends.

20. The method of claim 1 wherein the sleep frame specifies a start point and an end point of the sleep duration.

21. The method of claim 1 wherein the sleep frame includes an identification of the second WTRU that should go into a sleep state.

22. The method of claim 21 wherein the identification is at least one of a broadcast address, a multicast address and a list of unicast addresses.

23. The method of claim 21 wherein the identification is given in a complementary manner, whereby the sleep frame identifies second WTRUs that should not go into a sleep state.

24. The method of claim 1 wherein the sleep frame includes an indication of whether or not the second WTRU shall update a network allocation vector (NAV) duration in accordance with the sleep duration.

25. The method of claim 1 wherein the sleep frame is one of a control frame, a management frame, a data frame and an action frame.

26. The method of claim 1 wherein the sleep frame is one of a quality of service (QoS) poll frame, a contention free (CF) poll frame, a power save (PS) poll frame, a clear-to-send (CTS) frame, and a request-to-send (RTS) frame.

27. The method of claim 1 wherein the sleep frame is a multiple receiver aggregate (MRA) multi-poll (MMP) frame.

28. The method of claim 27 wherein an N STA field of the MMP frame is set to ‘

0’

to indicate that no upcoming frame sequences for the second WTRU are present.

29. The method of claim 27 wherein an N STA field of the MMP frame is omitted to indicate that no upcoming frame sequences for the second WTRU are present.

30. The method of claim 27 wherein the first WTRU sends the MMP frame which schedules at least one transmission from the second WTRU in a manner that allows unnecessary idle time between the sleep frame and the first scheduled uplink frame or the scheduled uplink frames.

31. The method of claim 27 wherein the MMP frame includes a schedule for a dummy frame.

32. The method of claim 1 wherein the sleep frame is a power saving aggregation descriptor (PSAD) frame.

33. The method of claim 32 wherein a PSAD parameter field of the PSAD frame is set to ‘

0’

to indicate that no upcoming frame sequences for the second WTRU are present.

34. The method of claim 32 wherein a PSAD parameter field of the PSAD frame is omitted to indicate that no upcoming frame sequences for the second WTRU are present.

35. The method of claim 32 wherein the first WTRU sends the PSAD frame which schedules at least one transmission from the second WTRU in a manner that allows unnecessary idle time between the sleep frame and the first scheduled uplink frame or the scheduled uplink frames.

36. The method of claim 32 wherein the PSAD frame includes a schedule for a dummy frame.

37. The method of claim 1 wherein the sleep duration indicates a first period during which the first WTRU will not initiate transmissions to the second WTRU.

38. The method of claim 37 wherein the sleep duration further indicates a second period during which transmissions shall not be initiated by the second WTRU.

39. The method of claim 38 wherein the second period is set by setting a network allocation vector (NAV) of the second WTRU.

40. The method of claim 1 wherein the sleep frame is a power save multi-poll (PSMP) frame.

41. The method of claim 40 wherein an N STA field of the PSMP frame is set to ‘

0’

to indicate that no upcoming frame sequences for the second WTRU are present.

42. The method of claim 40 wherein an N STA field of the PSMP frame is omitted to indicate that no upcoming frame sequences for the second WTRU are present.

43. The method of claim 40 wherein the first WTRU sends the PSMP frame which schedules at least one transmission from the second WTRU in a manner that allows unnecessary idle time between the sleep frame and the first scheduled uplink frame or the scheduled uplink frames.

44. The method of claim 40 wherein the PSMP frame includes a schedule for a dummy frame.

45. The method of claim 40 wherein a PSMP sequence duration field of the PSMP frame is used for specifying the sleep duration.

46. The method of claim 45 wherein the sleep duration is equal to the value specified in the PSMP sequence duration field.

47. The method of claim 45 wherein additional bits are used for the PSMP sequence duration field to allow a higher maximum value for the sleep duration.

48. The method of claim 45 wherein a minimum resolution of the PSMP sequence duration field is increased to achieve a larger value for a maximum sleep duration.

49. The method of claim 1 wherein a resolution of the sleep duration is dynamically adjusted.

50. The method of claim 49 wherein the dynamic adjustment of the resolution of the sleep duration is indicated implicitly.

51. The method of claim 49 wherein the sleep frame includes a scaling field to indicate the resolution of the sleep duration.

52. The method of claim 51 wherein the scaling field indicates more than two duration granularities.

53. The method of claim 51 wherein the scale field indicates different levels of granularity for at least one of a duration/ID field, a spoofed duration field, uplink transmission start offset, downlink transmission start offset, uplink transmission duration and downlink transmission duration.

54. The method of claim 1 further comprising:

the first WTRU sending capability information to indicate its capability to support for the sleep frame for power management.

55. The method of claim 54 wherein the capability information is included in at least one of a beacon frame, a probe response frame, an association request frame and a re-association request frame.

56. The method of claim 1 wherein the wireless communication system is at least one of an infrastructure-mode wireless local area network (WLAN), an ad-hoc mode WLAN, a WLAN mesh network, a WIMAX network, an IEEE 802-based network, a wideband code division multiple access (WCDMA) network, a CDMA2000 network, an universal mobile telecommunication system (UMTS) long term evolution (LTE) network, a high speed downlink packet access (HSDPA) network, an HSDPA evolution network, a high speed uplink packet access (HSUPA) network, and an HSUPA evolution network.

57. In a wireless communication system including a plurality of wireless transmit/receive units (WTRUs), an apparatus for reducing power consumption of the WTRU, the apparatus comprising:

a measurement unit for measuring a predetermined parameter;

a comparator for comparing the measured predetermined parameter with a threshold; and

a power saving controller electrically coupled to the measurement unit and the comparator and configured to send a sleep frame to at least one WTRU if the measured predetermined parameter exceeds the threshold, the sleep frame indicating a sleep duration, whereby the WTRU enters a sleep state for the sleep duration.

58. The apparatus of claim 57 wherein the predetermined parameter is an inactivity time of wireless medium.

59. The apparatus of claim 58 wherein the inactivity time is defined as the time which has elapsed since a last relevant frame was sent over wireless medium, the relevant frame being a frame transmitted by either the first WTRU or the second WTRU.

60. The apparatus of claim 57 wherein the predetermined parameter is at least one of an amount of data stored in a buffer of the first WTRU and an amount of data stored in a buffer of the second WTRU.

61. The apparatus of claim 57 wherein the predetermined parameter includes at least one of an idle time, a traffic load, wireless medium utilization, quality of service (QoS) requirements, a number of the second WTRUs associated to the first WTRU, a traffic profile of the second WTRU, access class (AC) of data, error rate and delay and jitter.

62. The apparatus of claim 57 wherein the power saving controller is configured to control the measurement unit to wait for a minimum wait time before measuring the predetermined parameter.

63. The apparatus of claim 57 wherein the sleep frame includes an indication that the WTRU may send data during the sleep duration.

64. The apparatus of claim 57 wherein the sleep duration is in the order of a transmit opportunity (TXOP) limit.

65. The apparatus of claim 57 wherein the power saving controller dynamically adjusts the sleep duration depending on other conditions.

66. The apparatus of claim 65 wherein the conditions include at least one of traffic load measurements and quality of service (QoS) requirements.

67. The apparatus of claim 57 wherein the power saving controller dynamically adjusts the threshold depending on other factors.

68. The apparatus of claim 57 wherein the sleep duration starts as soon as the sleep frame ends.

69. The apparatus of claim 57 wherein the sleep frame specifies a start point and an end point of the sleep duration.

70. The apparatus of claim 57 wherein the sleep frame includes an identification of the WTRU that should go into a sleep state.

71. The apparatus of claim 70 wherein the identification is at least one of a broadcast address, a multicast address and a list of unicast addresses.

72. The apparatus of claim 70 wherein the identification is given in a complementary manner, whereby the sleep frame identifies the WTRUs that should not go into a sleep state.

73. The apparatus of claim 57 wherein the sleep frame includes an indication of whether or not the WTRU shall update a network allocation vector (NAV) duration in accordance with the sleep duration.

74. The apparatus of claim 57 wherein the sleep frame is one of a control frame, a management frame, a data frame and an action frame.

75. The apparatus of claim 57 wherein the sleep frame is one of a quality of service (QoS) poll frame, a contention free (CF) poll frame, a power save (PS) poll frame, a clear-to-send (CTS) frame, and a request-to-send (RTS) frame.

76. The apparatus of claim 57 wherein the sleep frame is a multiple receiver aggregate (MRA) multi-poll (MMP) frame.

77. The apparatus of claim 76 wherein an N STA field of the MMP frame is set to ‘

0’

to indicate that no upcoming frame sequences for the WTRU are present.

78. The apparatus of claim 76 wherein an N STA field of the MMP frame is omitted to indicate that no upcoming frame sequences for the WTRU are present.

79. The apparatus of claim 76 wherein the power saving controller sends the MMP frame which schedules at least one transmission from the WTRU in a manner that allows unnecessary idle time between the sleep frame and the first scheduled frame.

80. The apparatus of claim 76 wherein the MMP frame includes a schedule for a dummy frame.

81. The apparatus of claim 57 wherein the sleep frame is a power saving aggregation descriptor (PSAD) frame.

82. The apparatus of claim 81 wherein a PSAD parameter field of the PSAD frame is set to ‘

0’

to indicate that no upcoming frame sequences for the WTRU are present.

83. The apparatus of claim 81 wherein a PSAD field of the PSAD frame is omitted to indicate that no upcoming frame sequences for the WTRU are present.

84. The apparatus of claim 81 wherein the power saving controller sends the PSAD frame which schedules at least one transmission from the WTRU in a manner that allows unnecessary idle time between the sleep frame and the first scheduled frame.

85. The apparatus of claim 81 wherein the PSAD frame includes a schedule for a dummy frame.

86. The apparatus of claim 57 wherein the sleep duration indicates a first period during which transmissions will not be initiated to the WTRU.

87. The apparatus of claim 86 wherein the sleep duration further indicates a second period during which transmissions shall not be initiated by the WTRU.

88. The apparatus of claim 87 wherein the second period is set by setting a network allocation vector (NAV) of the WTRU.

89. The apparatus of claim 57 wherein the sleep frame is a power save multi-poll (PSMP) frame.

90. The apparatus of claim 89 wherein an N STA field of the PSMP frame is set to ‘

0’

to indicate that no upcoming frame sequences for the second WTRU are present.

91. The apparatus of claim 89 wherein an N STA field of the PSMP frame is omitted to indicate that no upcoming frame sequences for the second WTRU are present.

92. The apparatus of claim 89 wherein the first WTRU sends the PSMP frame which schedules one or more transmissions from the second WTRU in a manner that allows unnecessary idle time between the sleep frame and the first scheduled uplink frame or the scheduled uplink frames.

93. The apparatus of claim 89 wherein the PSMP frame includes a schedule for a dummy frame.

94. The apparatus of claim 89 wherein a PSMP sequence duration field of the PSMP frame is used for specifying the sleep duration.

95. The apparatus of claim 94 wherein the sleep duration is equal to the value specified in the PSMP sequence duration field.

96. The apparatus of claim 94 wherein additional bits are used for the PSMP sequence duration field to allow a higher maximum value for the sleep duration.

97. The apparatus of claim 94 wherein a minimum resolution of the PSMP sequence duration field is increased to achieve a larger value for a maximum sleep duration.

98. The apparatus of claim 57 wherein a resolution of the sleep duration is dynamically adjusted.

99. The apparatus of claim 98 wherein the dynamic adjustment of the resolution of the sleep duration is indicated implicitly.

100. The apparatus of claim 98 wherein the sleep frame includes a scaling field to indicate the resolution of the sleep duration.

101. The apparatus of claim 100 wherein the scaling field indicates more than two duration granularities.

102. The apparatus of claim 100 wherein the scale field indicates different levels of granularity for at least one of a duration/ID field, a spoofed duration field, uplink transmission start offset, downlink transmission start offset, uplink transmission duration and downlink transmission duration.

103. The apparatus of claim 57 wherein the power saving controller is configured to send capability information to indicate its capability to support for the sleep frame for power management.

104. The apparatus of claim 103 wherein the capability information is included in at least one of a beacon frame, a probe response frame, an association request frame and a re-association request frame.

105. The system of claim 57 wherein the wireless communication system is at least one of an infrastructure-mode wireless local area network (WLAN), an ad-hoc mode WLAN, a WLAN mesh network, a WIMAX network, an IEEE 802-based network, a wideband code division multiple access (WCDMA) network, a CDMA2000 network, an universal mobile telecommunication system (UMTS) long term evolution (LTE) network, a high speed downlink packet access (HSDPA) network, an HSDPA evolution network, a high speed uplink packet access (HSUPA) network, and an HSUPA evolution network.

106. A wireless communication system for reducing power consumption of a wireless transmit/receive unit (WTRU), the system comprising:

an access point (AP) comprising;

a measurement unit for measuring a predetermined parameter;

a comparator for comparing the measured predetermined parameter with a threshold; and

a first power saving controller electrically coupled to the measurement unit and the comparator and configured to send a sleep frame to at least one WTRU if the measured predetermined parameter exceeds the threshold, the sleep frame indicating a sleep duration; and

the WTRU comprising a second power saving controller configured to receive the sleep frame and trigger the WTRU to enter a sleep state for the sleep duration.

107. The system of claim 106 wherein the second power saving controller is configured to verify a sender of the sleep frame, whereby the second power saving controller triggers to enter a sleep state only if the sender of the sleep frame is an AP with which the WTRU is associated.

108. The system of claim 106 wherein the WTRU is not allowed to send a transmission to the AP during the sleep duration.

109. The system of claim 106 wherein the WTRU is allowed to send a transmission to the AP during the sleep duration.

110. The system of claim 106 wherein the wireless communication system is at least one of an infrastructure-mode wireless local area network (WLAN), an ad-hoc mode WLAN, a WLAN mesh network, a WIMAX network, an IEEE 802-based network, a wideband code division multiple access (WCDMA) network, a CDMA2000 network, an universal mobile telecommunication system (UMTS) long term evolution (LTE) network, a high speed downlink packet access (HSDPA) network, an HSDPA evolution network, a high speed uplink packet access (HSUPA) network, and an HSUPA evolution network.