Improvements to Power Management Month Year doc.: IEEE 802.11-yy/xxxxr0 January 2008 Improvements to Power Management Date: 2008-01-14 Authors: Michelle Gong, Intel John Doe, Some Company

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

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

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

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

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

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