Medium Congestion Control (MCC) Framework Month Year doc.: IEEE 802.11-yy/xxxxr0 November 2006 Medium Congestion Control (MCC) Framework Date: 2006-11-14 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>. DENSO LA Laboratories John Doe, Some Company

November 2006 Abstract A MAC Medium Congestion Control (MCC) framework is presented for locally 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. DENSO LA Laboratories

November 2006 Problem description Existing primitives such as MLME-MEASURE and MLME-MREQUEST are useful for remote (AP) channel measurement associated with channel switching or channel selection for spectrum sharing in an Infrastructure BSS. Additional primitives are needed to locally manage congestion for QoS in an IBSS and allow real-time manipulation of local MAC/PHY parameters effecting medium congestion control. DENSO LA Laboratories

Goals Define MAC/PHY components to efficiently: November 2006 Goals Define MAC/PHY components to efficiently: Enable local congestion control without OTA messaging. Minimize frame loss, Minimize latency, particularly for high priority frames, Maximize channel availability, Allow client to accurately measure congestion. Allow client to appropriately control congestion. DENSO LA Laboratories

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

Client/Server Model Client (e.g. SME) Server (e.g. MLME) November 2006 Client/Server Model Client (e.g. SME) Decision maker Request measurements Analyze measurements Request controls Server (e.g. MLME) Perform MAC/PHY measurements Calculate/derive MCC measurements Report MCC measurements Execute controls requested by client DENSO LA Laboratories

Congestion Monitoring November 2006 Congestion Monitoring Measurement values indicate a level of wireless medium congestion or an effect of wireless medium congestion on a specific channel. Client may request a one-time Measurement or periodic Measurements and Reports. Measure Requests may be cancelled or changed by the Client. Client requests a measurement on a specific channel. Server collects MAC/PHY measurements. Server derives MCC measurements from one or more MAC/PHY measures. Server reports requested measures to the Client. DENSO LA Laboratories

Example MAC/PHY Measures November 2006 Example MAC/PHY Measures Name Layer Type Focus Clear Channel Acquisition (CCA) PHY Fast Per channel Network Activity Vector (NAV) MAC Contention Window (CW) Index Slow Per channel, AC. Queue size (QS) MAC/UL Receive or Transmit a MAC Frame (RX/TX) Per channel, AC, frame. Retry count (RC), Frame drop count (DC) DENSO LA Laboratories

MCC Measurement Examples November 2006 MCC Measurement Examples Derived Measurement Dependencies Description of derivation Aggregate Frame Rate (Utilization) (AFR) RX/TX, PHY-CHAR Rate of frames received and transmitted (including received frames destined to other STAs). Aggregate Data Rate (Utilization) (ADR) Ratio of utilization to burst rate used (including received frames destined to other STAs). Queue Level (QL) QS Queue size relative to maximum size. Mean Retry Count (MRC) RC Average of retry count or frame drop rate 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) RX/TX Number of unique MAC addresses observed over total time period(s). DENSO LA Laboratories

November 2006 Controls Control involves potential actions to address over-utilization or underutilization on a particular channel, and potential reporting of action taken to an upper layer. Control requests may be cancelled or changed by the Client. Basic Controls Active Control by Client Allow the client to manually manipulate controls. Adaptive Controls Passive Control, once set up by Client Allow the client to configure automated congestion detection and control by the MAC. One or more controls can be applied based on the result of one or more measurements. DENSO LA Laboratories

Control Examples November 2006 Control Units CWmin See 802.11e CWmax AIFS SuspendAC 0 (normal), 1 (suspend) Delay [us] Throttle 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) DENSO LA Laboratories

Basic Control (Active Client Control) November 2006 Basic Control (Active Client Control) SME MLME Measurement Policy MCC Measurement Measurement Control Decision Control Parameter Management DCF Control DENSO LA Laboratories

Basic Congestion Control Sequence November 2006 Basic Congestion Control Sequence Client MAC/PHY Medium decision Request (Measure) validate Confirm Observe measure Indicate (Measure) report decision Request (Control) validate Confirm Impact execute DENSO LA Laboratories

November 2006 Adaptive Controls Adaptive controls are executed by the MAC without requiring further input from a client. A client may request an adaptation on a specific channel by specifying a Measure Control Pair including: The Measure to monitor, (e.g., Aggregate Frame Rate) The Condition and Threshold to compare against, (e.g., exceeds 100 Frames/second) The Adjustment, Control, and Value to adjust, (e.g., increase CWMin by 2x) How often to repeat the adaptation, (e.g., repeat every 50ms). DENSO LA Laboratories

Adaptive Control (Passive Client Control) November 2006 Adaptive Control (Passive Client Control) SME MLME Control Parameter Management Measurement Policy Adaptation Policy Adaptation Decision DCF Measure & Control Control Policy MCC Measurement DENSO LA Laboratories

Adaptive Congestion Control Sequence November 2006 Adaptive Congestion Control Sequence Client MAC/PHY Medium Request Control Confirm validate Observe measure execute Impact … Observe measure execute Impact Indicate Control report DENSO LA Laboratories

November 2006 Summary The MAC MCC Framework allows a client residing in an upper layer or a control plane to effect a congestion control policy. Normative text describing the MCC Framework has been drafted (see 802.11-06/1706r0). DENSO LA Laboratories

November 2006 Straw Poll Is the proposed MCC Framework appropriate and relevant to TGv? Yes: No: DENSO LA Laboratories

November 2006 Straw Poll Should TGv include appropriate normative text describing the MCC Framework in the TGv draft? Yes: No: DENSO LA Laboratories

November 2006 Straw Poll Should TGv include the text in 802.11-06/1706r0 be used as a baseline for text to be included in the TGv draft? Yes: No: DENSO LA Laboratories