Power-save method for 802.11 multicast paging applications

• US 20050254444A1
• Filed: 05/12/2004
• Published: 11/17/2005
• Est. Priority Date: 05/12/2004
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Meier, Robert C., Griswold, Victor
• Granted Patent: US 7,424,007 B2
• Time in Patent Office: Days
• US Class Current: 370/312
• CPC Class Codes: H04W 4/06 Selective distribution of broadcast services, e.g. multimedia broadcast multicast service [MBMS]; Services to user groups; One-way selective calling services
• CPC Class Codes: H04W 52/0216 using a pre-established activity schedule, e.g. traffic indication frame
• CPC Class Codes: H04W 72/30 Resource management for broadcast services
• CPC Class Codes: H04W 88/08 Access point devices
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A power-save method for a network with an access point and an associated power-save client. The access point buffers wireless data that includes a unicast frame and a multicast frame. A periodic scheduled beacon message is transmitted with a unicast indication element and a multicast indication element. The unicast element instructs a client to remain awake to receive a buffered unicast frame, which includes a destination MAC address. The multicast element instructs a client to remain awake following the beacon to receive a buffered multicast frame, which includes a destination multicast address designating a multicast group of which the client is a member. At least one beacon message is designated as a multicast delivery beacon. The buffered multicast frame is transmitted following the designated multicast beacon. The multicast element contains a list of entries, each entry corresponding to either a multicast MAC address, multicast IP address, or client identifier.

Claims

1. A power-save method for a network having at least one access point and at least one associated power-save client comprising the steps of:

buffering, at the access point, wireless data including at least one of a unicast frame and a multicast frame;

transmitting a periodic scheduled beacon message over at least one wireless link, the beacon message including a unicast indication element and a multicast indication element;

designating at least one beacon message as a multicast delivery beacon; and

transmitting the buffered multicast frame following the designated at least one multicast delivery beacon.

2. The method of claim 1, wherein the unicast indication element includes a unicast indicator, the unicast indicator instructing the client to remain awake to receive at least one unicast frame buffered in the access point;

and

the multicast indication element includes a multicast indicator, the multicast indicator instructing the client to remain awake, following a beacon transmission, to receive at least one multicast frame.

3. The method of claim 2, wherein the unicast frame includes a destination MAC address identifying the client, and wherein the multicast frame includes a destination multicast address designating a multicast group of which the client is a member.

4. The method of claim 3, wherein the multicast indication element further comprises a list having a plurality of entries.

5. The method of claim 4, wherein each entry in the list corresponds to a multicast MAC address.

6. The method of claim 4, wherein each entry in the list corresponds to a multicast IP address.

7. The method of claim 4, wherein each entry in the list corresponds to a client identifier, wherein the client identifier identifies the client to receive the multicast frame following the transmission beacon.

8. The method of claim 7, wherein the multicast indication element is structured as a standard 802.11 TIM element including an array of bit flags.

9. The method of claim 8, wherein each bit flag of the array of bit flags corresponds to an 802.11 16-bit association identifier.

10. The method of claim 9, further comprising the steps of:

setting one of the bit flags in the array of bit flags to 0, wherein the setting of 0 is indicative to a client having the corresponding 16-bit association identifier to return to a power-save mode; and

setting one of the bit flags in the array of bit flags to 1, wherein the setting of 1 is indicative to a client having the corresponding 16-bit association identifier to remain active to receive the multicast transmission.

11. The method in claim 9 further comprising the step of setting a special bit flag in the array of bit flags to 1, wherein the setting of 1 is indicative to all associated clients to remain active to receive a multicast transmission.

12. The method of claim 1, further comprising the step of operating a proxy Address Resolution Protocol service, wherein the power-save client does not need to remain awake following the multicast beacon transmission to receive a broadcast Address Resolution Protocol message.

13. The method of claim 1, wherein the multicast indication element includes a special entry, the special entry indicating all associated clients are to remain awake following delivery of the beacon message.

14. The method in claim 1 further comprising the step of omitting, from the beacon message, the multicast indication element, wherein the omission indicates to all clients to remain in an active mode.

15. The method of claim 1, further comprising the steps of:

determining multicast group membership for each associated client station; and

classifying each multicast group;

wherein a multicast group is disabled when no associated clients are members,

wherein a multicast group is active when all member stations are in active mode, and

wherein a multicast group is power-save when at least one associated member station is in power-save mode.

16. The method of claim 15, further comprising the steps of:

deleting multicast frames that are destined to the disabled multicast group;

immediately transmitting multicast frames that are destined to the active multicast group immediately; and

buffering multicast frames destined to the power-save multicast group for transmission following a beacon transmission.

17. The method of claim 16, wherein the multicast indication element includes information indicating frames are buffered for the power-save multicast group.

18. The method of claim 1, further comprising the steps of:

examining at least one Internet Group Management Protocol Membership Report; and

determining, from the at least one Internet Group Management Protocol Membership Report a multicast group membership for the associated client.

19. A power-save method for use by a power-save client comprising the steps of:

receiving a periodic scheduled beacon message over at least one wireless link, the beacon message including a unicast indication element and a multicast indication element;

waking to receive the periodic beacon message including the multicast indication element; and

sleeping, immediately, when the multicast indication element indicates the multicast group has no pending multicast messages buffered by the access point and when the unicast indication element indicates that the client has no pending unicast messages buffered by the access point.

20. The method of claim 19, wherein the client is a host computer including an intelligent wireless network communications adapter, the adapter is configured to wake and receive the periodic beacon message independently of the host computer.

21. The method of claim 20, wherein the network adapter is configured to determine membership in a multicast group via a programming interface, wherein the host computer enables a multicast address on the network adapter.

22. The method of claim 20, wherein the network adapter determines membership in a multicast group by examining at least one message transmitted by the host computer.

23. The method of claim 20, wherein the at least one message transmitted by the host computer is an Internet Group Management Protocol Membership Report.

24. The method of claim 19, wherein the unicast indication element includes a unicast indicator, the unicast indicator instructing the client to remain awake, following a beacon transmission, to receive at least one unicast frame buffered in an access point;

and

the multicast indication element includes a multicast indicator, the multicast indicator instructing the client to remain awake, following a beacon transmission, to receive at least one multicast frame.

25. The method of claim 24, wherein the unicast frame includes a destination MAC address identifying the client, and wherein the multicast frame includes a destination multicast address designating a multicast group of which the client is a member.

26. The method of claim 25, wherein at least one of the unicast indication element and the multicast indication element further comprises a list having a plurality of entries.

27. The method of claim 26, wherein each entry in the list corresponds to a MAC address.

28. The method of claim 26, wherein each entry in the list corresponds to an IP address.

29. A power-save system for wireless data streaming, comprising

an access point adapted to provide a wireless data link to at least one associated power-save client;

means adapted for buffering, at the access point, wireless data including at least one of a unicast frame and a multicast frame;

means adapted for transmitting a periodic scheduled beacon message over at least one wireless link, the beacon message including a unicast indication element and a multicast indication element;

means adapted for designating at least one beacon message as a multicast delivery beacon; and

means adapted for transmitting the buffered multicast frame following the designated at least one multicast delivery beacon.

30. The power-save system of claim 29, wherein the unicast indication element includes a unicast indicator, the unicast indicator instructing the client to remain awake to receive at least one unicast frame buffered in the access point;

and

the multicast indication element includes a multicast indicator, the multicast indicator instructing the client to remain awake, following a beacon transmission, to receive at least one multicast frame.

31. The power-save system of claim 30, wherein the unicast frame includes a destination MAC address identifying the client, and wherein the multicast frame includes a destination multicast address designating a multicast group of which the client is a member.

32. The power-save system of claim 31, wherein the multicast indication element further comprises a list having a plurality of entries, wherein each entry in the list corresponds to one of the group consisting of a multicast MAC address, a multicast IP address, and a client identifier.

33. The power-save system of claim 32, wherein each bit flag of an array of bit flags in a TIM element corresponds to an 802.11 16-bit association identifier, further comprising:

means adapted for setting one of the bit flags in the array of bit flags to 0, wherein the setting of 0 is indicative to a client having the corresponding 16-bit association identifier to return to a power-save mode;

means adapted for setting one of the bit flags in the array of bit flags to 1, wherein the setting of 1 is indicative to a client having the corresponding 16-bit association identifier to remain active to receive the multicast transmission; and

means adapted for setting a special bit flag in the array of bit flags to 1, wherein the setting of 1 is indicative to all associated clients to remain active to receive a multicast transmission.

34. The power-save system of claim 29, further comprising means adapted for operating a proxy Address Resolution Protocol service, wherein the power-save client does not need to remain awake following the multicast beacon transmission to receive a broadcast Address Resolution Protocol message.

35. The power-save system of claim 29, further comprising:

means adapted for determining multicast group membership for each associated client station;

means adapted for classifying each multicast group;

wherein a multicast group is disabled when no associated clients are members,

wherein a multicast group is active when all member stations are in active mode, and

wherein a multicast group is power-save when at least one associated member station is in power-save mode;

means adapted for deleting multicast frames that are destined to the disabled multicast group;

means adapted for immediately transmitting multicast frames that are destined to the active multicast group immediately; and

means adapted for buffering multicast frames destined to the power-save multicast group for transmission following a beacon transmission.

36. The power-save system of claim 29, further comprising:

means adapted for examining at least one Internet Group Management Protocol Membership Report; and

means adapted for determining, from the at least one Internet Group Management Protocol Membership Report a multicast group membership for the associated client.

37. A power-save client comprising:

means adapted for receiving a periodic scheduled beacon message over at least one wireless link, the beacon message including a unicast indication element and a multicast indication element;

means adapted for waking to receive the periodic beacon message including the multicast indication element; and

means adapted for sleeping, immediately, when the multicast indication element indicates the multicast group has no pending multicast messages buffered by the access point and when the unicast indication element indicates that the client has no pending unicast messages buffered by the access point,

wherein the client is configured as a host computer including an intelligent wireless network communications adapter, the adapter is configured to wake and receive the periodic beacon message independently of the host computer.

38. The power-save client of claim 37, wherein the network communications adapter is configured to determine membership in a multicast group via a programming interface, wherein the host computer enables a multicast address on the network adapter.

39. A computer implemented power-save method for a network having at least one access point and at least one associated power-save client comprising the steps of:

buffering, at the access point, wireless data including at least one of a unicast frame and a multicast frame;

transmitting a periodic scheduled beacon message over at least one wireless link, the beacon message including a unicast indication element and a multicast indication element;

designating at least one beacon message as a multicast delivery beacon; and

transmitting the buffered multicast frame following the designated at least one multicast delivery beacon.

40. The computer implemented power-save method of claim 39, wherein the unicast indication element includes a unicast indicator, the unicast indicator instructing the client to remain awake to receive at least one unicast frame buffered in the access point;

and

the multicast indication element includes a multicast indicator, the multicast indicator instructing the client to remain awake, following a beacon transmission, to receive at least one multicast frame.

41. The computer implemented power-save method of claim 40, wherein the unicast frame includes a destination MAC address identifying the client, and wherein the multicast frame includes a destination multicast address designating a multicast group of which the client is a member.

42. The computer implemented power-save method of claim 41, wherein the multicast indication element further comprises a list having a plurality of entries, wherein each entry in the list corresponds to one of the group consisting of a multicast MAC address, a multicast IP address, and a client identifier.

43. The computer implemented power-save method of claim 42, wherein each bit flag of an array of bit flags in a TIM element corresponds to an 802.11 16-bit association identifier, further comprising the steps of:

setting one of the bit flags in the array of bit flags to 0, wherein the setting of 0 is indicative to a client having the corresponding 16-bit association identifier to return to a power-save mode;

setting one of the bit flags in the array of bit flags to 1, wherein the setting of 1 is indicative to a client having the corresponding 16-bit association identifier to remain active to receive the multicast transmission; and

setting a special bit flag in the array of bit flags to 1, wherein the setting of 1 is indicative to all associated clients to remain active to receive a multicast transmission.

44. The computer implemented power-save method of claim 39, further comprising the step of operating a proxy Address Resolution Protocol service, wherein the power-save client does not need to remain awake following the multicast beacon transmission to receive a broadcast Address Resolution Protocol message.

45. The computer implemented power-save method of claim 39, further comprising:

determining multicast group membership for each associated client station;

classifying each multicast group;

wherein a multicast group is disabled when no associated clients are members,

wherein a multicast group is active when all member stations are in active mode, and

wherein a multicast group is power-save when at least one associated member station is in power-save mode;

deleting multicast frames that are destined to the disabled multicast group;

immediately transmitting multicast frames that are destined to the active multicast group immediately; and

buffering multicast frames destined to the power-save multicast group for transmission following a beacon transmission.