Wireless access point methods and apparatus for reduced power consumption and cost

• US 7,436,790 B2
• Filed: 03/24/2005
• Issued: 10/14/2008
• Est. Priority Date: 03/25/2004
• Status: Active Grant

• Current Assignee: Blackberry Limited, Mcmaster University
• Original Assignee: Blackberry Limited
• Inventors: Kezys, Vytautas Robertas, Zhao, Dongmei, Todd, Terence D.
• Primary Examiner(s): Beamer; Temica M
• Application Number:
  US11/088,433
• Publication Number:
  US 20050249137A1
• Time in Patent Office: 1,300 Days
• Field of Search: 370/311, 455/572, 455/574
• 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: H04W 74/00 Wireless channel access
• CPC Class Codes: H04W 74/02 Hybrid access
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

In one illustrative technique, a contention-free period indication is communicated by a wireless access point (AP) (e.g. a battery-powered AP) to a plurality of mobile communication devices within a beacon of a superframe. The contention-free period indication identifies a duration of a contention-free period within which the mobile devices must refrain from communicating through the AP. During each contention period subframe of each superframe, information is communicated to and/or from the mobile devices through a wireless transceiver of the AP. During each power conservation subframe of each superframe, the wireless transceiver is placed into a power conservation mode which is at least part of the contention-free period. Alternatively, or in combination with the wireless transceiver being placed in the power conservation mode, information for the mobile devices may be communicated to and/or from another AP within each relay subframe of each superframe which is at least part of the contention-free period. Advantageously, power consumption may be reduced in the AP and/or a single radio interface may be utilized in the AP for communications. The durations of the power conservation subframe and the other subframes may be variably adjusted to tradeoff power savings with a real-time capacity requirement of the AP.

Claims

1. A method in a wireless access point for use in reducing power consumption in the wireless access point, the method comprising the acts of:

causing a contention-free period indication to be communicated to a plurality of mobile communication devices, the contention-free period indication identifying a duration of a contention-free period within which the plurality of mobile communication devices must refrain from communicating through the wireless access point;

causing information to be communicated between the wireless access point and the mobile communication devices through a wireless transceiver of the wireless access point during a contention period subframe of a superframe; and

causing the wireless transceiver to be placed into a power conservation mode during a power conservation subframe of the superframe during which no information is communicated between the wireless access point and any of the mobile communication devices, the power conservation subframe being at least part of the duration of the contention-free period.

2. The method of claim 1, wherein the act of causing the contention-free period indication to be communicated comprises the further act of transmitting the contention-free period indication within a beacon of the superframe.

3. The method of claim 1, wherein the act of causing the contention-free period indication to be communicated comprises the further act of transmitting the contention-free period indication within a CFPMaxDuration field of a beacon of the superframe.

4. The method of claim 1, further comprising:

causing information for the mobile communication devices to be communicated between the wireless access point and another wireless access point within a relay subframe of the superframe during which no information is communicated between the wireless access point and any of the mobile communication devices, the relay subframe being part of the duration of the contention-free period.

5. The method of claim 1, further comprising:

selecting an offered capacity for facilitating communications for the mobile communication devices through the wireless access point; and

determining a power conservation mode duration of the power conservation subframe based on the selected capacity, the power conservation mode duration having a relationship with the selected capacity such that as the selected capacity increases, the power conservation mode decreases.

6. The method of claim 1, wherein the wireless access point operates in accordance with an IEEE 802.11-based standard.

7. The method of claim 1, wherein the power conservation subframe has a duration that is variable during operation of the wireless access point.

8. The method of claim 1, wherein the wireless access point comprises a battery-powered wireless access point.

41. The method of claim 1, wherein the act of causing the wireless transceiver to be placed into the power conservation mode comprises the further act of powering down the wireless transceiver.

42. The method of claim 1, wherein the power conservation subframe precedes the contention period subframe in the superframe.

43. The method of claim 1, wherein the duration of the contention-free period is the same as the duration of the power conservation subframe.

44. The method of claim 4, wherein the duration of the contention-free period is the same as the sum of the durations of the power conservation subframe and the relay subframe.

9. A wireless access point, comprising:

electrical components;

a battery or solar power interface adapted for coupling to a battery or solar power source for supplying electrical power to the electrical components;

the electrical components including;

at least one wireless transceiver;

an antenna coupled to the at least one wireless transceiver;

one or more processors coupled to the at least one wireless transceiver;

the one or more processors being operative to;

cause a contention-free period indication to be communicated to a plurality of mobile communication devices, the contention-free period indication identifying a duration of a contention-free period within which the plurality of mobile communication devices must refrain from communicating through the wireless access point;

cause information to be communicated between the wireless access point and the mobile communication devices through the wireless transceiver during a contention period subframe of a superframe; and

cause the wireless transceiver to be placed into a power conservation mode during a power conservation subframe of the superframe during which no information is communicated between the wireless access point and any of the mobile communication devices, the power conservation subframe being at least part of the duration of the contention-free period.

10. The wireless access point of claim 9, wherein the one or more processors are further operative to cause the contention-free period indication to be communicated by transmitting the contention-free period indication within a beacon of the superframe.

11. The wireless access point of claim 9, wherein the one or more processors are further operative to cause information for the mobile communication devices to be communicated between the wireless access point and at least one other access point during a relay subframe of the superframe during which no information is communicated between the wireless access point and any of the mobile communication devices, the relay subframe being part of the duration of the contention-free period.

12. The wireless access point of claim 9, being operative in accordance with an IEEE 802.11-based standard.

13. The wireless access point of claim 9, wherein the power conservation subframe has a duration that is variable during operation of the wireless access point.

14. The wireless access point of claim 9, wherein the one or more processors are further operative to:

select an offered capacity for facilitating communications for the mobile communication devices through the wireless access point; and

determine a power conservation mode duration of the power conservation subframe based on the selected capacity, the power conservation mode duration having a relationship with the selected capacity such that as the selected capacity increases, the power conservation mode duration decreases.

45. The wireless access point of claim 9, wherein the one or more processors are further operative to cause the contention-free period indication to be communicated by transmitting the contention-free period indication within a CFPMaxDuration field of a beacon of the superframe.

46. The wireless access point of claim 9, wherein the one or more processors cause the wireless transceiver to be placed into the power conservation mode by powering down the wireless transceiver.

47. The wireless access point of claim 9, wherein the duration of the contention-free period is the same as the duration of the power conservation subframe.

48. The wireless access point of claim 11, wherein the duration of the contention-free period is the same as the sum of the durations of the power conservation subframe and the relay subframe.

15. A method of operating a wireless access point comprising the acts of:

causing a contention-free period indication to be communicated to a plurality of mobile communication devices, the contention-free period indication identifying a duration of a contention-free period within which the plurality of mobile communication devices must refrain from communicating through the wireless access point;

causing information to be communicated between the wireless access point and the mobile communication devices through a wireless transceiver of the wireless access point during a contention period subframe of a superframe; and

causing information to be communicated between the wireless access point and at least one other access point through the wireless transceiver during a relay subframe of the superframe during which no information is communicated between the wireless access point and any of the mobile communication devices, the relay subframe being at least part of the duration of the contention-free period.

16. The method of claim 15, wherein the act of causing the contention-free period indication to be communicated comprises the further act of transmitting the contention-free period indication within a beacon of the superframe.

17. The method of claim 15, further comprising:

causing the wireless transceiver to be placed into a power conservation mode during a power conservation subframe of the superframe during which no information is communicated between the wireless access point and any of the mobile communication devices, the power conservation subframe being part of the duration of the contention-free period.

18. The method of claim 15, wherein the wireless access point operates in accordance with an IEEE 802.11-based standard.

19. The method of claim 15, wherein the relay subframe has a duration that is variable during operation of the battery-powered wireless access point.

20. The method of claim 15, further comprising:

selecting an offered capacity for facilitating communications for the mobile communication devices through the wireless access point; and

determining a duration of the relay subframe based on the selected capacity, the duration being inversely proportional to the selected capacity.

21. The method of claim 15, wherein the act of causing the information to be communicated between the wireless access point and the mobile communication devices is performed over a first set of frequencies and the act of causing the information to be communicated between the wireless access point and the at least one other access point is performed over a second set of frequencies.

49. The method of claim 15, wherein the act of causing the contention-free period indication to be communicated comprises the further act of transmitting the contention-free period indication within a CFPMaxDuration field of a beacon of the superframe.

50. The method of claim 15, wherein the duration of the contention-free period is the same as the duration of the relay subframe.

51. The method of claim 17, wherein the duration of the contention-free period is the same as the sum of the durations of the power conservation subframe and the relay subframe.

22. A wireless access point, comprising:

at least one wireless transceiver;

an antenna coupled to the at least one wireless transceiver;

one or more processors coupled to the at least one wireless transceiver;

the one or more processors being operative to;

cause a contention-free period indication to be communicated to a plurality of mobile communication devices, the contention-free period indication identifying a duration of a contention-free period within which the plurality of mobile communication devices must refrain from communicating through the wireless access point;

cause information to be communicated between the wireless access point and the mobile communication devices through a wireless transceiver of the wireless access point during a contention period subframe of a superframe; and

cause information to be communicated between the wireless access point and at least one other access point through the wireless transceiver during a relay subframe of the superframe during which no information is communicated between the wireless access point and any of the mobile communication devices, the relay subframe being at least part of the duration of the contention-free period.

23. The wireless access point of claim 22, wherein the one or more processors are further operative to cause the contention-free period indication to be communicated by transmitting the contention-free period indication within a beacon subframe of the superframe.

24. The wireless access point of claim 22, wherein the one or more processors are further operative to cause the wireless transceiver to be placed into a power conservation mode during a power conservation subframe of the superframe during which no information is communicated between the wireless access point and any of the mobile communication devices, the power conservation subframe being part of the duration of the contention-free period.

25. The wireless access point of claim 22, being operative in accordance with an IEEE 802.11-based standard.

26. The wireless access point of claim 22, wherein the relay subframe has a duration that is variable during operation of the wireless access point.

27. The wireless access point of claim 22, wherein the one or more processors are further operative to:

select an offered capacity for facilitating communications for the mobile communication devices through the wireless access point; and

determine a duration of the relay subframe based on the selected capacity, the duration being inversely proportional to the selected capacity.

28. The wireless access point of claim 22, wherein the one or more processors cause the information to be communicated between the wireless access point and the mobile communication devices over a first set of frequencies and cause the information to be communicated between the wireless access point and the at least one other access point over a second set of frequencies.

29. The wireless access point of claim 22, having a single radio interface comprising the wireless transceiver.

52. The wireless access point of claim 22, wherein the one or more processors are further operative to cause the contention-free period indication to be communicated by transmitting the contention-free period indication within a CFPMaxDuration field of a beacon of the superframe.

30. A method of operating a wireless access point comprising the acts of:

selecting an offered capacity for communications for a plurality of mobile communication devices through the wireless access point;

determining a communication duration and a power conservation duration of the wireless access point based on the selected capacity, the selected capacity having a relationship with the communication and power conservation durations such that, as the selected capacity increases, the communication duration increases and the power conservation duration decreases;

causing information to be communicated between the wireless access point and the mobile communication devices with use of a wireless transceiver of the wireless access point within each communication subframe of each superframe for a plurality of superframes, each communication subframe having the communication duration; and

causing the wireless transceiver to be placed into a power conservation mode within each power conservation subframe of each superframe of the plurality of superframes, each power conservation subframe having the power conservation duration during which no information is communicated between the wireless access point and any of the mobile communication devices.

31. The method of claim 30, wherein the wireless AP operates in accordance with IEEE 802.11-based standards.

32. The method of claim 30, wherein each communication subframe comprises a relay subframe for communicating with at least one other access point.

33. The method of claim 30, wherein each communication subframe comprises a contention period subframe for communicating with the mobile communication devices.

34. The method of claim 30, wherein at least one of the acts of selecting the offered capacity and determining the communication duration are performed prior to operation of the wireless access point.

35. The method of claim 30, wherein at least one of the acts of selecting the offered capacity and determining the communication duration are performed by one or more processors of the wireless access point during operation of the wireless access point.

36. A wireless access point, comprising:

electrical components;

a battery or solar power interface adapted for coupling to a battery or solar power source for supplying electrical power to the electrical components;

the electrical components including;

at least one wireless transceiver;

an antenna coupled to the at least one wireless transceiver;

one or more processors coupled to the at least one wireless transceiver;

the one or more processors being operative to;

cause information to be communicated for a plurality of mobile communication devices through the wireless transceiver within each communication subframe of each superframe for a plurality of superframes, each communication subframe having a communication duration determined based on an offered capacity for facilitating communications for the plurality of mobile communication devices, the communication duration having a relationship with the offered capacity such that as the offered capacity increases, the communication duration increases; and

cause the wireless transceiver to be placed into a power conservation mode within each power conservation subframe of each superframe of the plurality of superframes, each power conservation subframe having a power conservation duration over which no information is communicated between the wireless access point and any of the mobile communication devices, the power conservation duration being determined based on the offered capacity for facilitating communications for the mobile communication devices and having a relationship with the offered capacity such that as the offered capacity increases, the power conservation duration decreases.

37. The wireless access point of claim 36, wherein the one or more processors are further operative to:

select the offered capacity for facilitating communications for the mobile communication devices through the wireless access point; and

determine the communication duration of the wireless access point based on the selected capacity.

38. The wireless access point of claim 36, wherein the one or more processors are further operative to:

select the offered capacity for facilitating communications for the mobile communication devices through the wireless access point;

determine the communication duration and power conservation duration of the wireless access point based on the selected capacity; and

continue to repeat the selecting and determining during operation of the wireless access point.

39. The wireless access point of claim 36, wherein each communication subframe comprises a relay subframe for communicating with at least one other access point.

40. The wireless access point of claim 36, wherein each communication subframe comprises a contention period subframe for communicating with the mobile communication devices.