Doc.: IEEE 802.11-02/214r0 Submission March 2002 Wentink, IntersilSlide 1 A simpler and better EDCF Menzo Wentink Ron Brockmann Maarten Hoeben Intersil.

doc.: IEEE 802.11-02/214r0 Submission March 2002 Wentink, IntersilSlide 1 A simpler and better EDCF Menzo Wentink Ron Brockmann Maarten Hoeben Intersil

doc.: IEEE 802.11-02/214r0 Submission March 2002 Wentink, IntersilSlide 2 Related letter ballot comments

doc.: IEEE 802.11-02/214r0 Submission March 2002 Wentink, IntersilSlide 3 Categories of LB comments EDCF justificationEDCF justification –Complexity –Performance – can it do the job EDCF requests for enhancementsEDCF requests for enhancements No solution for IBSS operationNo solution for IBSS operation No proven solution for overlapNo proven solution for overlap

doc.: IEEE 802.11-02/214r0 Submission March 2002 Wentink, IntersilSlide 4 Line of thinking

doc.: IEEE 802.11-02/214r0 Submission March 2002 Wentink, IntersilSlide 5 Line of thinking (1) In the current EDCF, IFS and CW are used for latency and bandwidth differentiationIn the current EDCF, IFS and CW are used for latency and bandwidth differentiation However: the CW space is limited as a differentiator for both latency and bandwidth, and AIFS is complexHowever: the CW space is limited as a differentiator for both latency and bandwidth, and AIFS is complex Instead, the CFB length per priority is a more effective bandwidth differentiatorInstead, the CFB length per priority is a more effective bandwidth differentiator Separate latency and bandwidth differentiationSeparate latency and bandwidth differentiation –CW for latency (CWmin/CWmax) –CFB size for bandwidth Fixed parameter values!Fixed parameter values!

doc.: IEEE 802.11-02/214r0 Submission March 2002 Wentink, IntersilSlide 6 Line of thinking (2) So for EDCF, we propose to differentiate three parameters:So for EDCF, we propose to differentiate three parameters: –CWmin, CWmax, CFB length

doc.: IEEE 802.11-02/214r0 Submission March 2002 Wentink, IntersilSlide 7 Applications - bandwidth vs latency Bandwidth Latency CFB length CWmin/CWmax excellent effort video best effort HDTV interactive voice 10 ms100 ms 0.5 ms 3 ms 0/115/10237/15 64 kbps 25 Mbps

doc.: IEEE 802.11-02/214r0 Submission March 2002 Wentink, IntersilSlide 8 RTSThreshold = 300 Bytes.RTSThreshold = 300 Bytes. Suggested EDCF default settings priorityCWminCWmax CFB limit 0 (be) 151023 1 frame exch. 1 (ee) 1510231.5ms 2 (it) 715 1 frame exch. 3 – spare --- 4 (vi) 7153.0ms 5 (vo) 010.5ms 6 – spare --- 7 – spare ---

doc.: IEEE 802.11-02/214r0 Submission March 2002 Wentink, IntersilSlide 9 Simulations

doc.: IEEE 802.11-02/214r0 Submission March 2002 Wentink, IntersilSlide 10 Simulations (1) 24 Mbps PHY rate, unless noted otherwise24 Mbps PHY rate, unless noted otherwise 802.11g slots (20 usec) are used, unless noted otherwise802.11g slots (20 usec) are used, unless noted otherwise RTSThreshold = 300 BytesRTSThreshold = 300 Bytes Simulations are performed with Network SimulatorSimulations are performed with Network Simulator

doc.: IEEE 802.11-02/214r0 Submission March 2002 Wentink, IntersilSlide 11 Simulations (2) Traffic types in each scenarioTraffic types in each scenario –Voice: UDP, 290 Byte packets, 30 pps (G.711) –Video: UDP, 2300 Byte packets, increasing load (+1 Mbps per second) –Data: TCP, 1500 Byte packets All flows are upstreamAll flows are upstream Note that the video latency and voice latency plots have a different scaleNote that the video latency and voice latency plots have a different scale

doc.: IEEE 802.11-02/214r0 Submission March 2002 Wentink, IntersilSlide 12 16 nodes 7 voice streams 1 video stream 7 data streams (16:7/1/7)

doc.: IEEE 802.11-02/214r0 Submission March 2002 Wentink, IntersilSlide 13 7 voice / 1 video (36) / 7 data / 16 nodes voice: CWmin=0, CWmax=1, CFB=0.5ms (24 Mbps) video: CWmin=7, CWmax=15, CFB=3.0ms (36 Mbps) data: CWmin=15, CWmax=1023 (24 Mbps) applied video load (Mbps) throughput per class data throughput video throughput - increases linearly with the offered load total throughout voice bandwidth – unaffected by other load video throughput capped when the applied video load exceeds a maximum level 25 Mbps

doc.: IEEE 802.11-02/214r0 Submission March 2002 Wentink, IntersilSlide 14 7 voice / 1 video (36) / 7 data / 16 nodes voice: CWmin=0, CWmax=1, CFB=0.5ms video: CWmin=7, CWmax=15, CFB=3.0ms data: CWmin=15, CWmax=1023 applied video load (Mbps) time fractions data fraction video fraction total useful time fraction voice fraction 100%

doc.: IEEE 802.11-02/214r0 Submission March 2002 Wentink, IntersilSlide 15 7 voice / 1 video (36) / 7 data / 16 nodes voice: CWmin=0, CWmax=1, CFB=0.5ms video: CWmin=7, CWmax=15, CFB=3.0ms data: CWmin=15, CWmax=1023 applied video load (Mbps) video throughput is capped when the applied video load exceeds a maximum level the video throughput rises linearly with the offered video load 25 Mbps

doc.: IEEE 802.11-02/214r0 Submission March 2002 Wentink, IntersilSlide 16 7 voice / 1 video (36) / 7 data / 16 nodes voice: CWmin=0, CWmax=1, CFB=0.5ms video: CWmin=7, CWmax=15, CFB=3.0ms data: CWmin=15, CWmax=1023 applied video load (Mbps) video latency the video latency stays low over a very wide range sharp increase when the offered load exceeds the maximum possible 50ms

doc.: IEEE 802.11-02/214r0 Submission March 2002 Wentink, IntersilSlide 17 7 voice / 1 video (36) / 7 data / 16 nodes voice: CWmin=0, CWmax=1, CFB=0.5ms video: CWmin=7, CWmax=15, CFB=3.0ms data: CWmin=15, CWmax=1023 applied video load (Mbps) voice latency the voice latency stays very low, even under heavy overload conditions 10ms

doc.: IEEE 802.11-02/214r0 Submission March 2002 Wentink, IntersilSlide 18 Explanation of the EDCF parameters

doc.: IEEE 802.11-02/214r0 Submission March 2002 Wentink, IntersilSlide 19 Why does CFB differentiation work EDCF assigns TXOPs independent of the TXOP lengthEDCF assigns TXOPs independent of the TXOP length Longer CFBs results in higher usage per TXOP, for same CW, thus higher bandwidthLonger CFBs results in higher usage per TXOP, for same CW, thus higher bandwidth CFBs reduce network contention and increase the efficiency!CFBs reduce network contention and increase the efficiency! Effect of CFBs increases when overall traffic load increases, because the CFBs are more fully usedEffect of CFBs increases when overall traffic load increases, because the CFBs are more fully used

doc.: IEEE 802.11-02/214r0 Submission March 2002 Wentink, IntersilSlide 20 CFBs decrease latency and jitter CFBs help to reduce network contention and collisionsCFBs help to reduce network contention and collisions –jitter is reduced CFBs allow to use relatively high CWmin values for high-bandwidth priority streamsCFBs allow to use relatively high CWmin values for high-bandwidth priority streams Lower CWmin values can be used for low- latency applications like voiceLower CWmin values can be used for low- latency applications like voice

doc.: IEEE 802.11-02/214r0 Submission March 2002 Wentink, IntersilSlide 21 Another advantage of CFBs Higher PHY rates result in increasingly inefficient EDCF operationHigher PHY rates result in increasingly inefficient EDCF operation –IFS and slot-time overhead becomes larger compared to the length of frames Time-limited CFBs easily scale up to higher bitrates by aggregating more frames into a single CFBTime-limited CFBs easily scale up to higher bitrates by aggregating more frames into a single CFB

doc.: IEEE 802.11-02/214r0 Submission March 2002 Wentink, IntersilSlide 22 CWmin = 0? Ideal for transmitters with low traffic intensityIdeal for transmitters with low traffic intensity Exponential backoff ensures CW increaseExponential backoff ensures CW increase Very often, the medium is free at DIFSVery often, the medium is free at DIFS –nodes with interrupted backoff never transmit at DIFS, because minimum remaining backoff after deferral is 1 slot --> DIFS+1 is the soonest!!. Fixed CWmin=0 automatically adapts to the traffic load (more interrupted backoff)Fixed CWmin=0 automatically adapts to the traffic load (more interrupted backoff)

doc.: IEEE 802.11-02/214r0 Submission March 2002 Wentink, IntersilSlide 23 CWmax Worst-case latency and jitter are determined by CWmaxWorst-case latency and jitter are determined by CWmax –after few collisions the current CW can become very large, even when started with a low CWmin –latency insensitive traffic should defer to latency sensitive traffic in case of collisions. –CWmax differentiation helps bounding jitter for low-latency streams The effect automatically adapts to traffic load, based on fixed CWmax settingsThe effect automatically adapts to traffic load, based on fixed CWmax settings

doc.: IEEE 802.11-02/214r0 Submission March 2002 Wentink, IntersilSlide 24 RTS/CTS Protects no-Ack burstsProtects no-Ack bursts Resolves hidden nodes situationsResolves hidden nodes situations Reduces the cost of collisionsReduces the cost of collisions The effect scales with the traffic load, based on a fixed RTS thresholdThe effect scales with the traffic load, based on a fixed RTS threshold

doc.: IEEE 802.11-02/214r0 Submission March 2002 Wentink, IntersilSlide 25 Implementation is extremely simple CWmin: existingCWmin: existing CWmax: existingCWmax: existing CFBs: similar to fragment burstingCFBs: similar to fragment bursting RTS/CTS: existingRTS/CTS: existing No IFS differentiationNo IFS differentiation No new frame formatsNo new frame formats No dynamic parameter updatesNo dynamic parameter updates Simple, but the functionality is great!Simple, but the functionality is great!

doc.: IEEE 802.11-02/214r0 Submission March 2002 Wentink, IntersilSlide 26 Conclusions

doc.: IEEE 802.11-02/214r0 Submission March 2002 Wentink, IntersilSlide 27 Conclusions (1) Excellent support for voice under any scenario (< 10 ms delay)Excellent support for voice under any scenario (< 10 ms delay) Excellent support for video (<< 50 ms delay)Excellent support for video (<< 50 ms delay) Excellent bandwidth and latency differentiationExcellent bandwidth and latency differentiation Very high channel efficiencyVery high channel efficiency Scales transparantly to higher rate PHYsScales transparantly to higher rate PHYs Works in overlap and non-overlap scenariosWorks in overlap and non-overlap scenarios Works for IBSS and infrastructureWorks for IBSS and infrastructure Supports unicast, multicast and no-ACK (FEC)Supports unicast, multicast and no-ACK (FEC) Works upstream, downstream and sidestreamWorks upstream, downstream and sidestream

doc.: IEEE 802.11-02/214r0 Submission March 2002 Wentink, IntersilSlide 28 Conclusions (2) Requires no changes to current 802.11 MAC framesRequires no changes to current 802.11 MAC frames Simple - Minimal set of mechanismsSimple - Minimal set of mechanisms Constant parameters - no parameter-tuning intelligence needed in APConstant parameters - no parameter-tuning intelligence needed in AP –No possible oscillations between different implementations in overlap situations Implicit accommodation of bursty trafficImplicit accommodation of bursty traffic Legacy STAs can participate in QoS network, and receive QoS flowsLegacy STAs can participate in QoS network, and receive QoS flows –No need for legacy upgrade Simple to Analyze/Simulate/ImplementSimple to Analyze/Simulate/Implement Predictable behaviorPredictable behavior Works with hidden nodesWorks with hidden nodes

doc.: IEEE 802.11-02/214r0 Submission March 2002 Wentink, IntersilSlide 29 Explanation of the classesExplanation of the classes –be: Best Effort –ee: Excellent Effort –it: Interactive TCP –vi: Video –vo: Voice Default settings (2)

doc.: IEEE 802.11-02/214r0 Submission March 2002 Wentink, IntersilSlide 30 Motions

doc.: IEEE 802.11-02/214r0 Submission March 2002 Wentink, IntersilSlide 31 Motion 1 Instruct the Editor to change the words MPDU or MMPDU into CFB in the first paragraph of 9.10.3.Instruct the Editor to change the words MPDU or MMPDU into CFB in the first paragraph of 9.10.3. –A TXOP obtained by winning EDCF contention may be used to send a CFB with total medium occupancy time not exceeding the TXOP limit from the QoS parameter set element in the beacon. […]

doc.: IEEE 802.11-02/214r0 Submission March 2002 Wentink, IntersilSlide 32 Motion 2 Instruct the Editor to create 8 TXOP limits (from 1), in the QoS Parameter Set.Instruct the Editor to create 8 TXOP limits (from 1), in the QoS Parameter Set.

doc.: IEEE 802.11-02/214r0 Submission March 2002 Wentink, IntersilSlide 33 Motion 3 Instruct the Editor to incorporate changes the the TGe draft, such that EDCF differentiation is limited to CWmin, CWmax and the TXOP limit per priority.Instruct the Editor to incorporate changes the the TGe draft, such that EDCF differentiation is limited to CWmin, CWmax and the TXOP limit per priority.

doc.: IEEE 802.11-02/214r0 Submission March 2002 Wentink, IntersilSlide 34 Instruct the Editor to specify the following mandatory default values for the QoS Parameter Set, for 802.11g and 802.11a PHYs:Instruct the Editor to specify the following mandatory default values for the QoS Parameter Set, for 802.11g and 802.11a PHYs: –RTSThreshold = 300 Bytes. Motion 4 priorityCWminCWmax CFB limit 0 (be) 151023 1 frame exch. 1 (ee) 1510231.5ms 2 (it) 715 1 frame exch. 3--- 4 (vi) 7153.0ms 5 (vo) 010.5ms 6--- 7---

doc.: IEEE 802.11-02/214r0 Submission March 2002 Wentink, IntersilSlide 35 Motion 5 Instruct the Editor to remove the QoS Parameter Set from the beacon.Instruct the Editor to remove the QoS Parameter Set from the beacon.

doc.: IEEE 802.11-02/214r0 Submission March 2002 Wentink, IntersilSlide 36 More simulations

doc.: IEEE 802.11-02/214r0 Submission March 2002 Wentink, IntersilSlide 37 Simulations All flows are upstream (sidestream)All flows are upstream (sidestream) Traffic typesTraffic types –voice: UDP, 290 Byte packets, 30 pps (G.711) –video: UDP, 2300 Byte packets, increasing load (+1 Mbps per second) –data: TCP, 1500 Byte packets Note that the video and voice latency plots have a different scaleNote that the video and voice latency plots have a different scale NotationNotation –4:1/1/1 for 4 active nodes, 1 voice, 1 video, 1 background –7-15-3.0 for CWmin=7, CWmax=15, CFB size=3.0ms

doc.: IEEE 802.11-02/214r0 Submission March 2002 Wentink, IntersilSlide 38 4:1/1/1 7-15-3.0

doc.: IEEE 802.11-02/214r0 Submission March 2002 Wentink, IntersilSlide 39 1 voice (24) / 1 video (36) / 1 data (24) / 4 voice: CWmin=0, CWmax=1, CFB=0.5ms video: CWmin=7, CWmax=15, CFB=3.0ms data: CWmin=15, CWmax=1023, CFB=0 video load (Mbps) throughput per class 25 Mbps

doc.: IEEE 802.11-02/214r0 Submission March 2002 Wentink, IntersilSlide 40 1 voice / 1 video (36) / 1 data / 4 voice: CWmin=0, CWmax=1, CFB=0.5ms video: CWmin=7, CWmax=15, CFB=3.0ms data: CWmin=15, CWmax=1023, CFB=0 video load (Mbps) time fractions 100%

doc.: IEEE 802.11-02/214r0 Submission March 2002 Wentink, IntersilSlide 41 1 voice / 1 video (36) / 1 data / 4 voice: CWmin=0, CWmax=1, CFB=0.5ms video: CWmin=7, CWmax=15, CFB=3.0ms data: CWmin=15, CWmax=1023, CFB=0 video load (Mbps) video throughput 25 Mbps

doc.: IEEE 802.11-02/214r0 Submission March 2002 Wentink, IntersilSlide 42 1 voice / 1 video (36) / 1 data / 4 voice: CWmin=0, CWmax=1, CFB=0.5ms video: CWmin=7, CWmax=15, CFB=3.0ms data: CWmin=15, CWmax=1023, CFB=0 video load (Mbps) video latency

doc.: IEEE 802.11-02/214r0 Submission March 2002 Wentink, IntersilSlide 43 1 voice / 1 video (36) / 1 data / 4 voice: CWmin=0, CWmax=1, CFB=0.5ms video: CWmin=7, CWmax=15, CFB=3.0ms data: CWmin=15, CWmax=1023, CFB=0 video load (Mbps) voice latency

doc.: IEEE 802.11-02/214r0 Submission March 2002 Wentink, IntersilSlide 45 7 voice / 3 video (36) / 7 data / 19 voice: CWmin=0, CWmax=1, CFB=0.5ms video: CWmin=7, CWmax=15, CFB=3.0ms data: CWmin=15, CWmax=1023, CFB=0 video load (Mbps) throughput per class 25 Mbps

doc.: IEEE 802.11-02/214r0 Submission March 2002 Wentink, IntersilSlide 46 7 voice / 3 video (36) / 7 data / 19 voice: CWmin=0, CWmax=1, CFB=0.5ms video: CWmin=7, CWmax=15, CFB=3.0ms data: CWmin=15, CWmax=1023, CFB=0 video load (Mbps) time fractions per class 100%

doc.: IEEE 802.11-02/214r0 Submission March 2002 Wentink, IntersilSlide 52 7 voice / 1 video (36) / 7 data / 16 voice: CWmin=0, CWmax=1, CFB=0.5ms video: CWmin=15, CWmax=15, CFB=4.5ms data: CWmin=15, CWmax=1023, CFB=0 video load (Mbps) time fraction per class 100%

doc.: IEEE 802.11-02/214r0 Submission March 2002 Wentink, IntersilSlide 58 7 voice / 3 video (36) / 7 data / 18 voice: CWmin=0, CWmax=1, CFB=0.5ms video: CWmin=15, CWmax=15, CFB=4.5ms data: CWmin=15, CWmax=1023, CFB=0 video load (Mbps) time fraction per class 100%

doc.: IEEE 802.11-02/214r0 Submission March 2002 Wentink, IntersilSlide 59 7 voice / 3 video (36) / 7 data / 18 voice: CWmin=0, CWmax=1, CFB=0.5ms video: CWmin=15, CWmax=15, CFB=4.5ms data: CWmin=15, CWmax=1023, CFB=0 video load (Mbps) video throughput

doc.: IEEE 802.11-02/214r0 Submission March 2002 Wentink, IntersilSlide 62 8:3/1/3 7-15-3.5 CCK RTS/CTS

doc.: IEEE 802.11-02/214r0 Submission March 2002 Wentink, IntersilSlide 63 3 voice / 1 video (36) / 3 data / 8 voice: CWmin=0, CWmax=1, CFB=0.5ms video: CWmin=7, CWmax=15, CFB=3.5ms data: CWmin=15, CWmax=1023 video load (Mbps) throughput per class 25 Mbps

doc.: IEEE 802.11-02/214r0 Submission March 2002 Wentink, IntersilSlide 64 3 voice / 1 video (36) / 3 data / 8 voice: CWmin=0, CWmax=1, CFB=0.5ms video: CWmin=7, CWmax=15, CFB=3.5ms data: CWmin=15, CWmax=1023 video load (Mbps) time fraction per class

doc.: IEEE 802.11-02/214r0 Submission March 2002 Wentink, IntersilSlide 65 3 voice / 1 video (36) / 3 data / 8 voice: CWmin=0, CWmax=1, CFB=0.5ms video: CWmin=7, CWmax=15, CFB=3.5ms data: CWmin=15, CWmax=1023 video load (Mbps) video throughput 25 Mbps

doc.: IEEE 802.11-02/214r0 Submission March 2002 Wentink, IntersilSlide 66 3 voice / 1 video (36) / 3 data / 8 voice: CWmin=0, CWmax=1, CFB=0.5ms video: CWmin=7, CWmax=15, CFB=3.5ms data: CWmin=15, CWmax=1023 video load (Mbps) video latency

doc.: IEEE 802.11-02/214r0 Submission March 2002 Wentink, IntersilSlide 67 3 voice / 1 video (36) / 3 data / 8 voice: CWmin=0, CWmax=1, CFB=0.5ms video: CWmin=7, CWmax=15, CFB=3.5ms data: CWmin=15, CWmax=1023 video load (Mbps) voice latency

doc.: IEEE 802.11-02/214r0 Submission March 2002 Wentink, IntersilSlide 68 10:3/3/3 7-15-3.0 802.11a PHY

doc.: IEEE 802.11-02/214r0 Submission March 2002 Wentink, IntersilSlide 74 10:5/1/5 7-15-3.0 0% PHY frame loss (+ collisions)

doc.: IEEE 802.11-02/214r0 Submission March 2002 Wentink, IntersilSlide 80 10:5/1/5 7-15-3.0 2% PHY frame loss (+ collisions)

doc.: IEEE 802.11-02/214r0 Submission March 2002 Wentink, IntersilSlide 86 10:5/1/5 7-15-3.0 hidden video node

doc.: IEEE 802.11-02/214r0 Submission March 2002 Wentink, IntersilSlide 92 8:3/1/3 7-15-3.0 Best effort at 12Mbps

doc.: IEEE 802.11-02/214r0 Submission March 2002 Wentink, IntersilSlide 93 3 voice / 3 video (36) / 3 data (12) / 10 voice: CWmin=0, CWmax=1, CFB=0.5ms video: CWmin=7, CWmax=15, CFB=3.0ms data: CWmin=15, CWmax=1023 video load (Mbps) throughput per class 25 Mbps

doc.: IEEE 802.11-02/214r0 Submission March 2002 Wentink, IntersilSlide 94 3 voice / 3 video (36) / 3 data (12) / 10 voice: CWmin=0, CWmax=1, CFB=0.5ms video: CWmin=7, CWmax=15, CFB=3.0ms data: CWmin=15, CWmax=1023 video load (Mbps) time fraction per class

doc.: IEEE 802.11-02/214r0 Submission March 2002 Wentink, IntersilSlide 95 3 voice / 3 video (36) / 3 data (12) / 10 voice: CWmin=0, CWmax=1, CFB=0.5ms video: CWmin=7, CWmax=15, CFB=3.0ms data: CWmin=15, CWmax=1023 video load (Mbps) video throughput 25 Mbps

doc.: IEEE 802.11-02/214r0 Submission March 2002 Wentink, IntersilSlide 96 3 voice / 3 video (36) / 3 data (12) / 10 voice: CWmin=0, CWmax=1, CFB=0.5ms video: CWmin=7, CWmax=15, CFB=3.0ms data: CWmin=15, CWmax=1023 video load (Mbps) video latency

doc.: IEEE 802.11-02/214r0 Submission March 2002 Wentink, IntersilSlide 97 3 voice / 3 video (36) / 3 data (12) / 10 voice: CWmin=0, CWmax=1, CFB=0.5ms video: CWmin=7, CWmax=15, CFB=3.0ms data: CWmin=15, CWmax=1023 video load (Mbps) voice latency

Doc.: IEEE 802.11-02/214r0 Submission March 2002 Wentink, IntersilSlide 1 A simpler and better EDCF Menzo Wentink Ron Brockmann Maarten Hoeben Intersil.

Similar presentations

Presentation on theme: "Doc.: IEEE 802.11-02/214r0 Submission March 2002 Wentink, IntersilSlide 1 A simpler and better EDCF Menzo Wentink Ron Brockmann Maarten Hoeben Intersil."— Presentation transcript:

Similar presentations

About project

Feedback

Log in

Auth with social network:

Doc.: IEEE 802.11-02/214r0 Submission March 2002 Wentink, IntersilSlide 1 A simpler and better EDCF Menzo Wentink Ron Brockmann Maarten Hoeben Intersil.

Similar presentations

Presentation on theme: "Doc.: IEEE 802.11-02/214r0 Submission March 2002 Wentink, IntersilSlide 1 A simpler and better EDCF Menzo Wentink Ron Brockmann Maarten Hoeben Intersil."— Presentation transcript:

Similar presentations

About project

Feedback