1. Idle Mode Operation for IEEE 802.11v
March 2006
Idle Mode Operation for IEEE v
Date:
Authors: Sunggeun Jin, Sunghyun Choi, Youngsoo Kim, Kyunghun Jang
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S. Jin, S. Choi (Seoul National U.), Y. Kim, K. Jang (Samsung)

2. March 2006
Abstract
In this presentation a new operation mode called Idle Mode (IM) is proposed for the power saving requirement in TGv. The original proposal (IEEE /1263r2) was presented in January meeting.
S. Jin, S. Choi (Seoul National U.), Y. Kim, K. Jang (Samsung)

3. Outline Brief Introduction to Idle Mode Operation
March 2006
Outline
Brief Introduction to Idle Mode Operation
Idle Mode Operation within Mobility Domain
Summary
S. Jin, S. Choi (Seoul National U.), Y. Kim, K. Jang (Samsung)

4. Brief Introduction to Idle Mode Operation
March 2006
Brief Introduction to Idle Mode Operation
A new mode for “deep” sleep
Major component
Paging
Concepts and terms
AP reselection
in order to receive beacons conveying paging information, new APs should be selected while a STA moves around
Home-AP
An AP which a mobile host signals to in order to enter the idle mode
S. Jin, S. Choi (Seoul National U.), Y. Kim, K. Jang (Samsung)

5. Benefits Provided by Idle Mode (IM)
March 2006
Benefits Provided by Idle Mode (IM)
Benefits provided to STA
Reduce the number of handoff operations
Reduce the operational load required for handoff
Save the power consumption required for handoff operation
Filter the unnecessary broadcast and multicast frames
save the power required for receiving broadcast and multicast frames
Benefits provided to network
Reduce the load required for handoff
Save the resources to maintain connectivity with associated STAs
S. Jin, S. Choi (Seoul National U.), Y. Kim, K. Jang (Samsung)

6. Idle Mode Operation Procedure
March 2006
Idle Mode Operation Procedure
S. Jin, S. Choi (Seoul National U.), Y. Kim, K. Jang (Samsung)

7. Idle Mode Operation within Mobility Domain
March 2006
Idle Mode Operation within Mobility Domain
Mobility Domain proposed in 11r
A set of BSSs within the same ESS, identified by a Mobility Domain
IEEE r Fast BSS transition is possible within Mobility Domain
Within the same Mobility Domain, a common key hierarchy is accessible at all BSSs
Access to common network service is available through all BSSs
Idle Mode (IM) operation within Mobility Domain
Mobility Domain can be used as Paging Area (PA)
In the same Mobility Domain ( i.e., PA), a STA in IM can be paged
Security related schemes proposed in IEEE r can be adopted as they are
S. Jin, S. Choi (Seoul National U.), Y. Kim, K. Jang (Samsung)

8. IM Operation of a STA within Mobility Domain
March 2006
IM Operation of a STA within Mobility Domain
IM within Mobility Domain
There are three major steps for IM procedure
IM entrance, AP reselection, Paging
IM entrance
The beginning of IM operation initiated by a STA
A STA transmits “Idle Mode Request” to Home-AP.
“Idle Mode Request” is a newly defined management action frame
All BSSs as well as Home-AP in the same Mobility Domain share PMK inherited by MSK or PSK to generate PTK.
PMK is created when a STA is associated with a BSS within a Mobility Domain. It can be still available when the STA enters IM.
Home-AP keeps the information for a STA in IM till the STA will be paged as if the STA is associated with the Home-AP.
S. Jin, S. Choi (Seoul National U.), Y. Kim, K. Jang (Samsung)

9. IM Operation of a STA within Mobility Domain (cont.)
March 2006
IM Operation of a STA within Mobility Domain (cont.)
AP reselection
The role of AP-reselection
During AP-reselection, a STA in IM receives and checks Paging Indication Message (PIM) conveyed in beacon periodically.
A STA does not need to receive every beacon.
There is no Fast transition between BSSs even when a STA moves to other BSSs from Home-AP due to AP-reselection.
PIM Management
The indication bit of the PIM is generated by a hash function using a MAC address of a paged STA.
Paging
The role of paging
The operation to page a STA in IM when a new frame destined to the STA is arrived.
The paging procedure
A STA re-associates with an AP immediately after receiving the PIM which indicates the STA is paged.
Fast BSS transition from Home-AP to the newly associated AP is performed using Over-the-Air method defined in IEEE r.
S. Jin, S. Choi (Seoul National U.), Y. Kim, K. Jang (Samsung)

10. Paging ID (PID) and Paging Indication Message (PIM)
March 2006
Paging ID (PID) and Paging Indication Message (PIM)
Paging ID (PID)
The identification number to wake up a STA in IM for paging.
two-octet.
AP generates a PID upon the reception of ‘Idle Mode request’ frame.
AP transmits ‘Idle Mode response’ frame with a PID to a STA.
PID is not unique value across STAs within a given PA.
Hash function generates a PID using MAC address.
Multiple STAs can be assigned the same PID because of the characteristic.
PIM
PIM contained in beacon frame is transmitted periodically.
Each bit in the PIM indicates which PID is activated for paging.
A part of PID can be used to determine the bit offset in PIM.
S. Jin, S. Choi (Seoul National U.), Y. Kim, K. Jang (Samsung)

11. Paging ID (PID) and Paging Indication Message (PIM) (cont.)
March 2006
Paging ID (PID) and Paging Indication Message (PIM) (cont.)
Bit generation in PIM
A bit corresponding to lower bits of a PID is assigned and set when paging a STA.
Considerations
Multiple STAs could be paged because of the characteristic of hash function.
Home-AP requests all APs in the Mobility Domain to page a STA with a particular MAC address.
Even though multiple STA could try to re-associate with an AP, other STAs except the valid STA will fail to re-associate with the AP.
The AP, which initiates paging, has the MAC address of the paged STA.
Error codes to notify the failure reasons are defined.
S. Jin, S. Choi (Seoul National U.), Y. Kim, K. Jang (Samsung)

12. March 2006
Summary
The proposed Idle Mode can reduce the number of handoff operations, which can save the power consumption required for handoff operation.
The proposed scheme can interoperable with emerging standard like TGv
Idle Mode operation outperforms PSM and can extend the standby time of a Mobile Host
S. Jin, S. Choi (Seoul National U.), Y. Kim, K. Jang (Samsung)