1. Peer Power Save Mode Date: 2008-03-17 Authors: March 2008 March 2008
doc.: IEEE /0070r1
March 2008
Peer Power Save Mode
Date:
Authors:
Alexander Safonov, IITP RAS
Alexander Safonov, IITP RAS

2. PSM in 802.11z-D0.02 (1/2) TDLS Rx Path Switch Request/Response
March 2008
doc.: IEEE /0070r1
March 2008
PSM in z-D0.02 (1/2)
TDLS Rx Path Switch Request/Response 1
Encapsulated DATA frame (TDLS Rx Path Switch Request)
Path Element (AP Path Switch) AP AP AP
Encapsulated DATA frame (TDLS Rx Path Switch Response)
Path Element (AP Path Switch) 2
QSTA1 changes to Power Saving Mode 3
QSTA2
QSTA2
QSTA1
QSTA1
QSTA1
Alexander Safonov, IITP RAS
Alexander Safonov, IITP RAS

3. PSM in 802.11z-D0.02 (2/2) Legacy PSM March 2008
doc.: IEEE /0070r1
March 2008
PSM in z-D0.02 (2/2)
Legacy PSM
In PSM, AP path is used, but not direct path AP 3
TIM element
DATA frame 1
PS-poll 4
DATA frame 5
QSTA2
QSTA1
in PSM 2
QSTA1 awakes
Alexander Safonov, IITP RAS
Alexander Safonov, IITP RAS

4. Legacy PSM vs. Peer PSM Legacy PSM Proposed Peer PSM March 2008
doc.: IEEE /0070r1
March 2008
Legacy PSM vs. Peer PSM
Legacy PSM
In PSM, the AP path is still used
thus two successful transmissions of a long data packet are needed to deliver the packet from peer to peer
Data is buffered at the AP which becomes a bottleneck
No QoS differentiation because of the legacy AP
Proposed Peer PSM
Peers enter PSM remaining on the direct path
Data is buffered at the originator QSTA, but not at the legacy AP
QoS differentiation
Peers use the concept of Service Period to deliver data directly, but not over the AP
Using full potential of the direct path
A Service Period may be initiated at arbitrary time or after a beacon by using Peer Traffic Indication frame
Alexander Safonov, IITP RAS
Alexander Safonov, IITP RAS

5. Peer PSM (1/2) The case when QSTA2 is in Active mode March 2008
doc.: IEEE /0070r1
March 2008
Peer PSM (1/2)
The case when QSTA2 is in Active mode
Power Management bit controls the state in Peer PSM
Service Period is triggered to retrieve buffered data from peer
QSTA2 may inform QSTA1 about buffered data by sending Peer Traffic Indication over the AP AP
QSTA1 changes to Power Saving Mode
QSTA1 changes to Power Saving Mode 4
Null DATA frame (Power Management Field is set to 0) 6 2
QSTA2 in Active Mode
QSTA1 in Peer PSM 5
Buffered DATA frame (EOSP is set to 1)
QSTA1 wakes up 3
A frame with Power Management bit set to 1 1
Alexander Safonov, IITP RAS
Alexander Safonov, IITP RAS

6. Encapsulated DATA frame (Peer Traffic Indication)
March 2008
doc.: IEEE /0070r1
March 2008
Peer PSM (2/2)
The case when both QSTA1 and QSTA2 are in Peer PSM
Power Management bit controls the state in Peer PSM
Service Period is triggered to retrieve buffered data from peer
A QSTA may inform the peer QSTA about buffered data by sending Peer Traffic Indication over the AP
Encapsulated DATA frame (Peer Traffic Indication) 4 AP
A frame with Power Management bit set to 1 1 2
QSTA2 changes to Power Saving Mode
QSTA1 changes to Doze state 4
Null DATA frame (Power Management Field is set to 0) 6
QSTA2
QSTA1 in Peer PSM
QSTA2 wakes up 3 5
Buffered DATA frame (EOSP is set to 1)
Alexander Safonov, IITP RAS
Alexander Safonov, IITP RAS

7. March 2008
doc.: IEEE /0070r1
March 2008
Motion
Move to include the normative text in document z-normative-text-peer-power-save-mode.doc into the current TGz draft
Mover:
Seconder:
Result:
Alexander Safonov, IITP RAS
Alexander Safonov, IITP RAS