1. doc.: IEEE 802.11-07/0182r1 Submission Sept 2006 Menzo WentinkSlide 1 TIM Request 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, 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 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.http:// ieee802.org/guides/bylaws/sb-bylaws.pdfstuart.kerry@philips.compatcom@ieee.org Date: 2007-01-18 Author(s): NameCompanyAddressPhoneemail Menzo WentinkConexantOudegracht 3a, Utrecht, Netherlands +31 65 183 6231 menzo.wentink@conexant.co m Jari JokelaNokiaVisiokatu 1, 33720 Tampere, Finland +35850486 0445 jari.jokela@nokia.com Marc de CourvilleMotorolaParc les Algorithmes, 91193 Gif-sur- Yvette, France +33169352 518 marc.de.courville@motorola.c om Yongho SeokLG Electronics16 Woomyeon-Dong, Seocho-Gu, Seoul 137-724, Korea +82252642 25 yhseok@tge.com

2. doc.: IEEE 802.11-07/0182r1 Submission Sept 2006 Menzo WentinkSlide 2 Introduction TIM request is a mechanism to obtain the TIM field with as little overhead as possible The frame exchange consists of two new control frames: –TIM Request – SIFS – TIM Response TIM request has a significant time advantage over other methods: –1,620 usreceiving a Beacon (all Rx) –1,024 usProbe Request/Response (152 us Tx) –185 usTIM Request/Response (52 us Tx)

3. doc.: IEEE 802.11-07/0182r1 Submission Sept 2006 Menzo WentinkSlide 3 TIM Request/Response Frame ControlDuration/IDBSSIDTAFCS Octets:226 64 Frame ControlDuration/IDRATIMFCS Octets:226 6 - 2574 TIM Request frame TIM Response frame

4. doc.: IEEE 802.11-07/0182r1 Submission Sept 2006 Menzo WentinkSlide 4 Frame Exchanges The frame exchanges compare as follows: –backoff – TIM Request – SIFS – TIM Response –backoff – Probe Request – SIFS – ACK – AP turnaround – backoff – Probe Response – SIFS – ACK An essential part of this proposal is that it´s a SIFS response. This removes the AP turnaround time. –A SIFS response is possible because the TIM field can be readily cached inside the APs lower MAC, so that a station specific lookup is not required during the SIFS. Another advantage is that no synchronization with the beacon is required.

5. doc.: IEEE 802.11-07/0182r1 Submission Sept 2006 Menzo WentinkSlide 5 Time Usage Assume a BSS with 40 stations which send a TIM request every 2 seconds –TIM Request is sent every 50 ms, or 2 per beacon period (assuming 100 ms beacon period) –The overhead is 0.37%