Medium Congestion Control (MCC) Framework Month Year doc.: IEEE 802.11-yy/xxxxr0 July 2006 Medium Congestion Control (MCC) Framework Date: 2006-07-17 Authors: 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:// ieee802.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>. B. Wells, DENSO LA Laboratories John Doe, Some Company

July 2006 Abstract Contribution submitted to address comments against 802.11 LB #81, P802.11p D1.0. A MAC Medium Congestion Control (MCC) framework is presented for detecting and controlling medium congestion. The framework and primitives allow an upper layer or control plane entity to manage a collection of measurements and controls via the MAC. The primary features of this framework include MAC components to measure congestion conditions and report these measurements to a client, and to influence congestion conditions based on client requests. B. Wells, DENSO LA Laboratories

Problem description Addresses the following LB81 comments: July 2006 Problem description Addresses the following LB81 comments: 101, 928, 956, 1009, 1029, 1131, 1201, 1207, 1217, 1278. As traffic on a communication medium increases, so does congestion and message latency. High priority management frames and safety messages must not be dropped or restricted from access to the medium. Congestion Control methods are needed to ensure high priority frames are not dropped and are delivered with minimal latency, even under heavy load conditions. B. Wells, DENSO LA Laboratories

Goals Define MAC/PHY components to efficiently: Minimize frame loss, July 2006 Goals Define MAC/PHY components to efficiently: Minimize frame loss, Minimize latency, particularly for high priority frames, Maximize channel availability, Allow client to accurately measure congestion. Allow client to control congestion. B. Wells, DENSO LA Laboratories

Requirements Local congestion monitoring. Congestion control methods. July 2006 Requirements Local congestion monitoring. Measure channel utilization. Measure station’s contribution to congestion. Provide measurements to client. Congestion control methods. Do not limit MAC/PHY performance. Provide manual control services. Promptly execute controls for stable feedback loop. Allow automated control. B. Wells, DENSO LA Laboratories

Client/Server Model Client (e.g. SME) Server (e.g. MLME) July 2006 Client/Server Model Client (e.g. SME) Decision maker Request measurements Analyze measurements Request controls Server (e.g. MLME) Collect direct measurements Calculate/derive indirect measurements Report indirect measurements Execute controls requested by client B. Wells, DENSO LA Laboratories

July 2006 Measures Measures indicate a level of wireless medium congestion or an effect of wireless medium congestion. Client requests measure. Server takes direct measurements within the MAC/PHY. Server derives indirect measurements from one or more direct measures. Server reports derivative (indirect) measures to the Client . B. Wells, DENSO LA Laboratories

Description of derivation July 2006 Measurement Examples Derived Measurement Dependencies Description of derivation Receive Frame Rate (RX/FR) MFP, PHY-CHAR Rate of frames received (destined to the measuring STA) (see 11A.7). Transmit Frame Rate (TX/FR) Rate of frames transmitted (by the measuring STA) (see 11A.7). Aggregate Frame Rate (Utilization) (AFR) Rate of frames received and transmitted (including received frames destined to other STAs) (see 11A.7). Receive Data Rate (RX/DR) Ratio of payload received to burst rate used (destined to the measuring STA) (see 11A.7). Transmit Data Rate (TX/DR) Ratio of payload transmitted to burst rate used (by the measuring STA) (see 11A.7). Aggregate Data Rate (Utilization) (ADR) Ratio of utilization to burst rate used (including received frames destined to other STAs) (see 11A.7). Queue Level (QL) QS Queue size relative to maximum size (see 11A.7). Mean Retry Count (MRC) RC Average of retry count or frame drop rate over a predetermined or given time. Mean Frame Drop Rate (MDR) FDE Fraction of frames dropped over a predetermined or given time. Mean Contention Window Index (MCW) CW Average of contention window index value over a predetermined or given time. Network Activity Rate Level (NARL) NAV, CCA Ratio of busy time to total time period(s) considered. Source Diversity (SD) MFP Number of unique MAC addresses observed over total time period(s). B. Wells, DENSO LA Laboratories

July 2006 Controls Control involves potential actions to address over-utilization or underutilization and potential reporting of action taken to an upper layer. Basic Controls Provide the client with manual controls. Can also be operated by an adaptation requested by the client. Adaptive Controls Allow automated congestion control. One or more controls can be applied based on the result of one or more measurements. B. Wells, DENSO LA Laboratories

Control Examples July 2006 B. Wells, DENSO LA Laboratories Control Units CWmin See 802.11e CWmax TXOP AIFS SuspendAC 0 (normal), 1 (suspend) Delay [us] Throttle AccessTimeConstraint Numerator in fraction N/255 (percentage) ShortRetryLimit Maximum number of attempts. LongRetryLimit RTSThreshold [bytes] AlwaysBackoff 0 (normal), 1 (force backoff) CWReversion Number of successful transmissions before reversion. CWIncrement CW Index Step SuspendChannel (mask, 1 = enabled) B. Wells, DENSO LA Laboratories

Basic Congestion Control Sequence July 2006 Basic Congestion Control Sequence Client MAC/PHY Medium decision Measure.Request validate Measure.Confirm Observe measure Measure.Indicate report decision Control.Request validate Control.Confirm Impact execute B. Wells, DENSO LA Laboratories

July 2006 Adaptive Controls Adaptive controls are executed by the MAC without requiring further input from a client. A client may request an adaptation by specifying: a derivative measure, a control, an adaptation (how to change the control), a threshold (how to trigger the adaptation to the control). B. Wells, DENSO LA Laboratories

Adaptive Congestion Control Sequence July 2006 Adaptive Congestion Control Sequence Client MAC/PHY Medium AdaptConfig.Request AdaptConfig.Confirm validate Adapt.Request Adapt.Confirm validate Observe measure execute Impact … Observe measure execute Impact Adapt.Indicate report B. Wells, DENSO LA Laboratories

July 2006 Summary The MAC MCC Framework allows a client residing in an upper layer or a control plane to manage medium congestion by providing derived MAC/PHY measures and providing both manual and automated controls of relevant 802.11 and 802.11e MAC/PHY parameters. This MAC MCC Framework overview and accompanying standards text is being submitted to TGp to address the following LB81 comments: 101, 928, 956, 1009, 1029, 1131, 1201, 1207, 1217, 1278. B. Wells, DENSO LA Laboratories

July 2006 Motion Move to accept the proposed MAC MCC Framework and request corresponding standards text to be drafted and submitted as TGp resolution to comments 101, 928, 956, 1009, 1029, 1131, 1201, 1207, 1217, and 1278, submitted against P802.11p D1.0 (LB81). Moved: Second: Approve: Against: Abstain: B. Wells, DENSO LA Laboratories

References FCC 03-324, US FCC Report & Order, February 2004. July 2006 References FCC 03-324, US FCC Report & Order, February 2004. IEEE P802.11p/D1.0, March 2006. IEEE P802.11s/D0.01, March 2006. IEEE P802.11-REVma/D6.0, May 2006. IEEE DCN 11-06-0553, LB81 D1.0 Comment Resolutions. B. Wells, DENSO LA Laboratories