March 2007 doc IEEE 802 11 070467 r

March 2007 doc: IEEE 802. 11 -07/0467 r 0 Interference Diagnostics Authors: Name Company Address Phone email Joe Kwak Inter. Digital Bolingbrook, IL 630 -739 -4159 joekwak@sbcglobal. net Jari Jokela Nokia Visiokatu 1, 33720 Tampere, Finland +358 50 486 0445 Jari. jokela@nokia. com Roger Durand RIM rdurand@rim. com 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 1 Joe Kwak( Inter. Digital), Jokela, Durand

March 2007 doc: IEEE 802. 11 -07/0467 r 0 OUTLINE n n n n Introduction Interference definitions New Interference Measurands Measurement details Normative text framework Usefulness of Diagnostic Alert Conclusions Submission 2 Joe Kwak( Inter. Digital), Jokela, Durand

March 2007 doc: IEEE 802. 11 -07/0467 r 0 Introduction n n The detection and measurement of RF Interference (RFI) is important for managing radio and network resources. Hi RFI levels degrade link performance, causing errors and retransmissions, reduced data rates and decreased radio range. TGv has incorporated features to detect and report on internal interference: Co-located Interference Request/Report. This proposal considers a new Management Diagnostic for external interference reporting. Submission 3 Joe Kwak( Inter. Digital), Jokela, Durand

March 2007 doc: IEEE 802. 11 -07/0467 r 0 What is RF Interference n n Not thermal noise Not the intended receive signal But everything else: Local RFI from nearby electronics (electric motors, microwaves), remote in-band users of other technologies (bluetooth, radars) , remote in-band users of 802. 11 in nearby BSSs, space radiation, etc. Characterized as: n n n Transient or steady state (SS) Wide area (affecting all STAs iin BSS) Local (affecting some STAs in BSS) Submission 4 Joe Kwak( Inter. Digital), Jokela, Durand

March 2007 doc: IEEE 802. 11 -07/0467 r 0 Interference Measurement n n n No easy direct measurement for RFI Lab/field installation measurements usually conducted by “controlling” RFI sources and measuring received power with/without interference. Not practical for operating networks. RFI presence may be indirectly inferred from other directly measurable parameters: ANPI, Channel. Load, FER n n RFl is summed with noise in ANPI (only when RFI < EDT). RFI may limit channel access (RFI >EDT) and increase Channel. Load. RFI decreases RSNI and may increase frame errors and retransmissions. This proposal uses existing measurements to detect RFI. Submission 5 Joe Kwak( Inter. Digital), Jokela, Durand

March 2007 doc: IEEE 802. 11 -07/0467 r 0 New RFI Measurands ID Measurand Use Description Pros/Cons 1 Quiet_ANPI Null_Ant_ANPI AP & STA Quiet_ANPI= No activity ANPI (3 AM? ) Null_Ant_ANPI= Dummy load or config Detects SS RFI as background level. Some STAs can’t switch to null ant. Disruptive to quiet all BSSs for measurement. 2 ANPI. Quiet_ANPI AP & STA Detects changes from background level, both SS and transient interference. Disruptive to quiet all BSSs for measure. Quiet_ANPI varies for mobile STAs. Fails for RFI > EDT. 3 d/dt[ANPI] AP & STA Detects onset of interference. Requires continuing measures. 4 d/dt[FER] AP & STA Detects onset of interference using Fcs. Error. Cnt and Rcd. Frag. Cnt Requires continuing measures. Fails for very low FERs. 5 STA_ANPI AP_ANPI STA Detects local interference at a STA compared to AP baseline. Requires updates of AP baseline at STA. Fails for RFI > EDT. 6 STA_Chan. Load AP_Chan. Load STA Detects local interference at a STA compared to AP baseline. Requires updates of AP baseline at STA. Fails for RFI < EDT. 7 d [AP Chan. Load] dt [ BSS_Thruput] AP Detects SS and transient RFI. Requires continuing measures. Submission Fails for RFI > EDT. Need BSS_Thruput measure. Fails for RFI < EDT. 6 Joe Kwak( Inter. Digital), Jokela, Durand

March 2007 doc: IEEE 802. 11 -07/0467 r 0 Simplified d/dt Processing n Rate of change measurand computed as ratio of A/B where: n n n FER is computed using existing MAC counters, FER is ratio of A/B where: n n n A is most recent measurand value B is moving average value of same measurand with specified decay constant A is (FCSError. Countn-1) or (Qos. Retries. Received. Count n-1) B is (Received. Fragment. Count n-1) or (Qos. Received. Fragment. Count n-1) BSSThruput needs new definition using received MPDU size and received data rate. Submission 7 Joe Kwak( Inter. Digital), Jokela, Durand

March 2007 doc: IEEE 802. 11 -07/0467 r 0 Framework for RFI Reporting n n Create new Diagnostic Management Alert for RFI detection, similar to Multicast Diagnostic Request/Report. Triggered Interference Request/Report would permit requestor to: n Select RFI Measurand n Select measurement duration and interval n Select trigger thresholds n Select reporting period Once requested, RFI detection runs continuously until cancelled. One Request for each measurand may run concurrently. Submission 8 Joe Kwak( Inter. Digital), Jokela, Durand

March 2007 doc: IEEE 802. 11 -07/0467 r 0 Element Format Outline n Triggered Interference Request element contains: n n n n n Measurand ID UP (optional, for QOS APs) Measurement Duration Measurement Interval (time between measurements) Aging Window (optional, for d/dt measurands) Trigger threshold AP baseline measurement (optional, for baseline measurands) Reporting period Triggered Interference Report element contains only the Measurand value. Dialog tokens match report to request. Submission 9 Joe Kwak( Inter. Digital), Jokela, Durand

March 2007 doc: IEEE 802. 11 -07/0467 r 0 What Happens Upon RFI Alert? n n Like other Measurement and Management tools, out of scope for specification. Possible AP actions upon receipt: n n n n Determine scope of interference (more measurements) Decrease data rates Increase Tx powers Limit BSS rate sets Limit new admissions Consider channel switch Consider load shedding Submission 10 Joe Kwak( Inter. Digital), Jokela, Durand

March 2007 doc: IEEE 802. 11 -07/0467 r 0 Conclusions n n n Interference detection using multiple simple measurands is practical and easy to implement. External interference measurement complements the TGv internal interference diagnostic. Table of measurands designed to allow growth as new detection techniques emerge. As WIFI uptake continues, and as unlicensed applications proliferate, RFI detection becomes increasingly important for WLAN performance. If supported, draft normative text will be presented at next meeting. Triggered Interference Request/Report satisfies real need and complements existing TGv/TGk measurements. Submission 11 Joe Kwak( Inter. Digital), Jokela, Durand

March 2007 doc: IEEE 802. 11 -07/0467 r 0 STRAW POLL n n Do you support use of Triggered Interference Request/Report? YES NO ABSTAIN Submission _______ 12 Joe Kwak( Inter. Digital), Jokela, Durand

March 2007 Submission doc: IEEE 802. 11 -07/0467 r 0 13 Joe Kwak( Inter. Digital), Jokela, Durand