January 2006 doc IEEE 802 11 051263 r

January 2006 doc. : IEEE 802. 11 -05/1263 r 3 A Novel Idle Mode Operation in IEEE 802. 11 WLANs Date: 2006 -01 -17 Authors: Sunggeun Jin, Sunghyun Choi, Youngsoo Kim, Kyunghun Jang Notice: This document has been prepared to assist IEEE 802. 11. It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein. Release: The contributor grants a free, irrevocable license to the IEEE to incorporate material contained in this contribution, and any modifications thereof, in the creation of an IEEE Standards publication; to copyright in the IEEE’s name any IEEE Standards publication even though it may include portions of this contribution; and at the IEEE’s sole discretion to permit others to reproduce in whole or in part the resulting IEEE Standards publication. The contributor also acknowledges and accepts that this contribution may be made public by IEEE 802. 11. Patent Policy and Procedures: The contributor is familiar with the IEEE 802 Patent Policy and Procedures <http: // ieee 802. org/guides/bylaws/sb-bylaws. pdf>, including the statement "IEEE standards may include the known use of patent(s), including patent applications, provided the IEEE receives assurance from the patent holder or applicant with respect to patents essential for compliance with both mandatory and optional portions of the standard. " Early disclosure to the Working Group of patent information that might be relevant to the standard is essential to reduce the possibility for delays in the development process and increase the likelihood that the draft publication will be approved for publication. Please notify the Chair <stuart. kerry@philips. com> as early as possible, in written or electronic form, if patented technology (or technology under patent application) might be incorporated into a draft standard being developed within the IEEE 802. 11 Working Group. If you have questions, contact the IEEE Patent Committee Administrator at <patcom@ieee. org>. Submission S. Jin, S. Choi (Seoul National U. ), Y. Kim, K. Jang (Samsung)

January 2006 doc. : IEEE 802. 11 -05/1263 r 3 A Novel Idle Mode Operation in IEEE 802. 11 WLANs January 2006 Sunggeun Jin, Sunghyun Choi (Seoul National University) Youngsoo Kim, Kyunghun Jang (Samsung Advanced Institute of Technology) Submission S. Jin, S. Choi (Seoul National U. ), Y. Kim, K. Jang (Samsung)

January 2006 doc. : IEEE 802. 11 -05/1263 r 3 Outline • Need for idle mode operation • Limitations of the current alternative • “Idle Mode (IM)” in IEEE 802. 11 WLANs • Introduction of new concepts for the “Idle Mode” • Performance evaluation • Summary Submission S. Jin, S. Choi (Seoul National U. ), Y. Kim, K. Jang (Samsung)

January 2006 doc. : IEEE 802. 11 -05/1263 r 3 Recent Enhancement of Mobility and Power Saving Support • Mobility support of current/emerging standards – Focused on reducing handoff delay for fast roaming • 802. 11 k, 802. 11 r – No consideration for the mobile hosts without active traffic • Even without traffic, mobiles hosts must perform handoff operation • Power saving schemes in current/emerging standards – Focused on reducing power consumption without Qo. S compromise • 802. 11 PSM, 802. 11 e APSD, 802. 11 n Multi-Phase PSMP – Need further consideration for the mobile hosts without active traffic • Current PSM is not efficient enough as will see later! Submission S. Jin, S. Choi (Seoul National U. ), Y. Kim, K. Jang (Samsung)

January 2006 doc. : IEEE 802. 11 -05/1263 r 3 Needs for Idle Mode (IM) • What is Idle Mode operation? – Operation to efficiently support idle mobile hosts without active traffic – No association while no active traffic, and then the station is paged (i. e. , broadcast/multicast across multiple BSSs within a given paging area) once a frame arrives – In addition to active mode (AM) and power save mode (PSM) • What is it for? – Reducing power consumption of idle mobile hosts, thus increasing the “standby” time – Reducing signaling cost for networks when supporting idle mobile hosts Submission S. Jin, S. Choi (Seoul National U. ), Y. Kim, K. Jang (Samsung)

January 2006 doc. : IEEE 802. 11 -05/1263 r 3 Available Alternative to Idle Mode • PSM + IP Paging [4, 5, 6] – Utilization of PSM and IP paging is widely accepted scheme for the alternative to Idle Mode – Mobile hosts in PSM can be paged via IP paging protocol – IP paging is a functional extension of IP mobility protocol such as MIP and HAWAII [2, 3] Submission S. Jin, S. Choi (Seoul National U. ), Y. Kim, K. Jang (Samsung)

January 2006 doc. : IEEE 802. 11 -05/1263 r 3 IP Paging • Paging scheme to support IP mobility when no active IP session. • Two or more routers are grouped into a paging area. • There is no handoff within a paging area. • Page an idle mobile host using multicast when a packet destined to the mobile host exists. Submission S. Jin, S. Choi (Seoul National U. ), Y. Kim, K. Jang (Samsung)

January 2006 doc. : IEEE 802. 11 -05/1263 r 3 Limitations of Current Alternative (1) • Limitations of PSM – Always associated • “Association” should keep maintained • Handoff failures would cause waste of power consumption – Long handoff duration • L 3 handoff takes several seconds – Inefficient power consumption • Frequent handoffs need more power consumption Submission S. Jin, S. Choi (Seoul National U. ), Y. Kim, K. Jang (Samsung)

January 2006 doc. : IEEE 802. 11 -05/1263 r 3 Limitations of Current Alternative (2) • Limitations of IP paging – Redundant operation if MAC level paging is supported – Naturally weak in IEEE 802. 11 WLANs • IP paging relies on multicast frames • Broadcast/multicast frames make mobile hosts in IM wake up frequently • Since mobile cannot differentiate between IP-paging and other broadcast/multicast frames until it receive them 0~10 ms 10~100 ms~1 s ≥ 1 s 67% 27% 6% 0% < Multicast and broadcast packet inter-arrival time in NESPOT, a commercial WLAN service in Korea> Submission S. Jin, S. Choi (Seoul National U. ), Y. Kim, K. Jang (Samsung)

January 2006 doc. : IEEE 802. 11 -05/1263 r 3 Proposed Idle Mode (IM) Operation [1] Submission S. Jin, S. Choi (Seoul National U. ), Y. Kim, K. Jang (Samsung)

January 2006 doc. : IEEE 802. 11 -05/1263 r 3 Idle Mode Operation in IEEE 802. 11 WLANs • Requirements – – Backward compatibility Efficient power consumption Location tracking Paging We developed new protocol to meet the requirements Submission S. Jin, S. Choi (Seoul National U. ), Y. Kim, K. Jang (Samsung)

January 2006 doc. : IEEE 802. 11 -05/1263 r 3 Idle Mode Operation in IEEE 802. 11 WLANs • Major components – Paging – Idle handoff – Delayed handoff • New concepts and terms – Delayed handoff • layer-3 handoff should be deferred until a successful paging – AP reselection • in order to receive beacon including paging information, new AP should be selected while a mobile host moves around – Home-Node • A node which a mobile host signals to in order to enter the idle mode – Most Recently Associated Node (MRA-Node) • A node (in a different paging area), which a mobile host in the idle mode has most recently associated with Submission S. Jin, S. Choi (Seoul National U. ), Y. Kim, K. Jang (Samsung)

January 2006 doc. : IEEE 802. 11 -05/1263 r 3 New Concepts & New Terms Submission S. Jin, S. Choi (Seoul National U. ), Y. Kim, K. Jang (Samsung)

January 2006 doc. : IEEE 802. 11 -05/1263 r 3 Procedures for Idle Mode Operation in IEEE 802. 11 WLANs (from the previous figure) • Beginning of idle mode operation – A mobile host enters idle mode when it is associated with “AP 2” • AP reselection – The mobile host in idle mode moves from “AP 2” to “AP 4” • Mobile host changes AP without handoff • Mobile host continues to listen to the beacons for paging • Idle handoff – The mobile host performs idle handoff from “AP 4” to “AP 5” • Idle handoff operation is newly defined • The node, which is firstly associated by the mobile host, becomes “MRA -Node” • “AP 5” becomes MRA-Node • Paging – The mobile host is paged when it is in the coverage of “AP 7” Submission S. Jin, S. Choi (Seoul National U. ), Y. Kim, K. Jang (Samsung)

January 2006 doc. : IEEE 802. 11 -05/1263 r 3 Procedure for Beginning of IM and Paging * PM: Power Mngt bit in Frame Control field of the MAC header Submission S. Jin, S. Choi (Seoul National U. ), Y. Kim, K. Jang (Samsung)

January 2006 doc. : IEEE 802. 11 -05/1263 r 3 Procedure for Idle Handoff Submission S. Jin, S. Choi (Seoul National U. ), Y. Kim, K. Jang (Samsung)

January 2006 doc. : IEEE 802. 11 -05/1263 r 3 Delayed Handoff • New concept – IP related operations are deferred as late as possible • Why is “delayed handoff” needed? – Location tracking in layer 2 comes true • WLAN MAC and network can support the location tracking without IP mobility management schemes when there is no active IP session. • It is possible to replace IP level mobility management with Idle Mode operation. – IP level handoff should be supported • However, IP related operations still remain to support active IP session, and hence, IP level handoff operation is performed at the end of the Idle Mode. • Goals – MH does not perform IP related operations while in IM. – Physical separation between WNIC and MH is possible. • Enhance power saving efficiency Submission S. Jin, S. Choi (Seoul National U. ), Y. Kim, K. Jang (Samsung)

January 2006 doc. : IEEE 802. 11 -05/1263 r 3 Information Conveyed over Beacon • Paging Area Identification (PAID) – to indicate the paging area which the corresponding AP belongs to – allows the station in idle mode to learn which paging area it currently resides in • Paging information – to indicate the paging to a particular station in idle mode – the MAC address of the station being paged is included Submission S. Jin, S. Choi (Seoul National U. ), Y. Kim, K. Jang (Samsung)

January 2006 doc. : IEEE 802. 11 -05/1263 r 3 Performance Evaluation (numerical analysis [1]) Actual values and gaps will vary depending on devices and environments (a) Power consumption of WNIC (b) Remaining energy In (b), we assume that cell sojourn time is 20 seconds. The standby time is estimated under the consideration of power consumption by both PDA and WNIC Submission S. Jin, S. Choi (Seoul National U. ), Y. Kim, K. Jang (Samsung)

January 2006 doc. : IEEE 802. 11 -05/1263 r 3 Prototype Implementation of Idle Mode • Implementation Environment – Mobile Host : LG-IBM X 40 – WNIC : MW-500 CB, MMC Tech. – WNIC chipset : Atheros Communications, Inc. AR 5212 • Experiments – Capture IEEE 802. 11 frames for idle mode operation – Measure remaining energy while idle mode operation performing Submission S. Jin, S. Choi (Seoul National U. ), Y. Kim, K. Jang (Samsung)

January 2006 doc. : IEEE 802. 11 -05/1263 r 3 Captured IEEE 802. 11 Frames for the IM Submission S. Jin, S. Choi (Seoul National U. ), Y. Kim, K. Jang (Samsung)

January 2006 doc. : IEEE 802. 11 -05/1263 r 3 Captured IEEE 802. 11 Frames for the IM • (1) – (6) : initial association with AP • (7) : beginning of Idle Mode operation – WNIC transmits ‘disassociation’ frame with PM bit set to ‘ 1’ • (8) : paging via beacon • (9)-(10) : re-association – Paging is successfully performed and MH wakes up to begin active IP session. Submission S. Jin, S. Choi (Seoul National U. ), Y. Kim, K. Jang (Samsung)

January 2006 doc. : IEEE 802. 11 -05/1263 r 3 Performance Evaluation (measurement result) In this figure, if paging is successfully performed, mobile host changes operation mode into “active mode. ” In this period, it consumes more power. Note: the power consumption difference between active mode and idle mode is not much due to high power consumption at the laptop Submission S. Jin, S. Choi (Seoul National U. ), Y. Kim, K. Jang (Samsung)

January 2006 doc. : IEEE 802. 11 -05/1263 r 3 Summary • New concepts – Idle mode operation – Paging, Home-Node, and MRA-Node – Delayed handoff and AP reselection • Performance – IM operation outperforms both PSM and IP paging – IM operation extends standby time of a Mobile Host Submission S. Jin, S. Choi (Seoul National U. ), Y. Kim, K. Jang (Samsung)

January 2006 doc. : IEEE 802. 11 -05/1263 r 3 Straw Poll (1) • Do support defining an Idle Mode operation (not particularly the presented one) as part of 11 v in support of Power Saving objective in accordance with REQ 2010? • Yes 23 • No 1 • Need more time to think over Submission S. Jin, S. Choi (Seoul National U. ), Y. Kim, K. Jang (Samsung)

January 2006 doc. : IEEE 802. 11 -05/1263 r 3 Straw Poll (2) • Do you support defining an Idle Mode operation based on this presentation as part of 11 v? • Yes 10 • No 6 • Need more time to think over Submission S. Jin, S. Choi (Seoul National U. ), Y. Kim, K. Jang (Samsung)

January 2006 doc. : IEEE 802. 11 -05/1263 r 3 References [1] S. Jin, K. Han, and S. Choi, “A Novel Idle Mode Operation in IEEE 802. 11 WLANs, ” to appear in Proc. IEEE ICC’ 06, June 2006. [2] R. Ramjee, L. Li, T. L. Porta, and S. Kasera, “IP Paging Service for Mobile Hosts, ” in Proc. ACM Mobi. Com’ 01, 2001. [3] X. Zhang, J. Gomez, G. Castellanos, and A. T. Campbell, “P-MIP: Paging Extensions for Mobile IP, ” ACM Mobile Networks and Applications, July 2002. [4] S. Pack and Y. Choi, "An Adaptive Power Saving Mechanism in IEEE 802. 11 Wireless IP Networks, " KICS/IEEE Journal of Communications and Networks (JCN), June 2005. [5] M. Liebsch, X. Perez-Costa, “Utilization of the IEEE 802. 11 Power Save Mode with IP Paging, ” in Proc. IEEE ICC’ 05, 2005. [6] B. Sarikaya and T. Ozugur, “Tracking Agent Based Paging for Wireless LANs, ” in Proc. IEEE CCNC’ 04, 2004. Submission S. Jin, S. Choi (Seoul National U. ), Y. Kim, K. Jang (Samsung)