Power-save method for 802.11 multicast paging applications

• US 7,424,007 B2
• Filed: 05/12/2004
• Issued: 09/09/2008
• 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
• Primary Examiner(s): Orgad; Edan
• Assistant Examiner(s): HALIYUR, VENKATESH N
• Application Number:
  US10/844,303
• Publication Number:
  US 20050254444A1
• Time in Patent Office: 1,581 Days
• Field of Search: 370/318, 370/338, 370/432, 370/311, 370/328, 370/352, 370/449, 370/459, 370/473, 455/574, 455/502, 455/503, 455/343, 455/465, 455/525, 709/238, 709/242
• US Class Current: 370/352
• 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;

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

determining multicast group membership for each associated client station;

examining at least one Internet Group Management Protocol Membership Report;

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

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, 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.

13. 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.

25. The method of claim 1, 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.

26. The method of claim 25, wherein the multicast indication element includes information indicating frames are buffered for the power-save multicast group.

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

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

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

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

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

means 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;

means for determining multicast cigroup membership for each associated client station;

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

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

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

15. The power-save system of claim 14, 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.

16. The power-save system of claim 15, 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.

17. The power-save system of claim 16, 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.

18. The power-save system of claim 17, 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 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 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 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.

19. The power-save system of claim 14, further comprising:

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

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

20. 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;

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

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;

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.

21. The computer implemented power-save method of claim 20, 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.

22. The computer implemented power-save method of claim 21, 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.

23. The computer implemented power-save method of claim 22, 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.

24. The computer implemented power-save method of claim 23, 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.