1. Improvements to Power Management
Month Year
doc.: IEEE yy/xxxxr0
January 2008
Improvements to Power Management
Date:
Authors:
Michelle Gong, Intel
John Doe, Some Company

2. January 2008
Several improvements have been made to the power management schemes in 11s
An MP utilizes unicast frames to change its power mode to a lower activity level
An MP may convert important broadcast frames to unicast frames and send them to MPs in power save mode
Periodic APSD operation will be removed
We’re currently defining sleep modes for peer-to-peer mesh operation
We suggest two improvements to power management to facilitate faster peer link set up
Michelle Gong, Intel

3. January 2008
Background: a candidate peer MP becomes a peer MP after a peer link is set up
A peer link is established when
1) both MPs have correctly sent and received a Peer Link Open frame regarding this link;
2) both MPs have correctly sent and received a corresponding Peer Link Confirm frame regarding this link
Mesh Point A
Mesh Point B
Peer Link Open
Peer Link Confirm
Michelle Gong, Intel

4. January 2008
Power management (PM) and peer link management (PLM) are not completely uncorrelated
If PM and PLM are independent of each other, an MP can go into doze mode during any step of the peer link set up procedure
This does not affect the correctness of either PM or PLM but can significantly slow down the peer link set up
Mesh Point A (PS MP)
Mesh Point B
Peer Link Open
Peer Link Confirm
Peer Link Open
Peer Link Confirm
Michelle Gong, Intel

5. January 2008
The proposed power management functions can be achieved via PLM primitives
To facilitate faster peer link setup, a PS MP shall remain awake during the peer link setup procedure
An MP’s SME shall delay entering doze state for the MLME-SignalPeerLinkStatus.indication primitive for all unestablished PLM instances. An unestablished PLM instance is a PLM instance not in the ESTABLISHED state
An MP may close some established peer links prior to entering into power save mode
An MP’s SME may use the MLME-CancelPeerLink.request primitive to terminate any established peer link prior to entering power save mode
An MP in power save mode may not want to set up new peer links
Before an MP enters into power save mode, it may elect not to set up new peer links. In this case, it terminates its link instance in “listen” state using the MLME-CancelPeerLink.request primitive. This means it will no longer respond to new PLM instances initiated by others
Michelle Gong, Intel

6. January 2008
A PS MP shall remain awake after transmitting a beacon with the Awake Window IE
An Awake Window IE may be carried in the beacon and the probe response frame but shall be carried in the DTIM beacon
This IE indicates how long a PS MP shall remain awake after successfully transmitting a beacon
If the PS MP enters into peer link setup procedure before the expiration of advertised Awake Window, it shall remain awake until the completion (i.e. success or failure) of peer link setup
Octets: 1 1 2 ID
Length
Awake Window
Michelle Gong, Intel

7. January 2008
In summary, two new improvements are made to facilitate faster peer link set up
An Awake Window IE may be carried in the beacon
This IE indicates how long a PS MP shall remain awake after transmitting a beacon
A PS MP shall remain awake during the peer link set up procedure
The PS MP can resume its power save mode after the peer link set up procedure completes
Michelle Gong, Intel