DistributedEmbeddedSystems
UniversityofPaderborn
FromConnectedCarstoSmartCi9es:
OnWirelessCommunica9onLatency
andReliability
FalkoDressler
dressler@ccs-labs.org
IEEEWiMob2015
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Outline
²
Mo9va9on
ª
²
Greenandsafedrivinginsmartci9es
ª
²
Trendstowardsautonomousdrivingandintegratedinter-vehicle
communica9on
Interac9onswithtrafficlightsornotrafficlightsatall
Platooningasoneofthekillerapplica9ons
ª
ª
Inherentlyinterdisciplinary
Reliabilityandreal-9merequirements
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TowardsAutonomousDriving
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Inter-VehicleNetworkingforSitua9onAwareness
Illustrations: C2C-CC
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Standardiza9onandOpenResearch
²
Dedicatedspectrumforinter-vehiclecommunica9on
inEurope(ECC),theUS(FCC),andJapan
²
IEEEDSRC/WAVEandETSIITSG5
ª
²
Situa9onawarenessasmajoryear-one-applica9on
ª
²
ETSIDCC(DecentralizedConges9onControl)
Butmanyfundamentalresearchques9onss9llunanswered
ª
²
BothbuilduponIEEE802.11p
Scalability,real-9mecapabili9es,useofheterogeneousnetworks
Dagstuhlseminarseriesiden9fiedkeychallenges
ª
FalkoDressler,HannesHartenstein,OnurAl9ntasandOzanK.
Tonguz,"Inter-VehicleCommunica9on-QuoVadis,"IEEE
Communica,onsMagazine,vol.52(6),pp.170-177,June2014.
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GREENANDSAFEDRIVINGIN
SMARTCITIES
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Intersec9onManagement
²
Efficiency
No Traffic Lights
Regular Traffic Lights
[1]NoTrafficLightsVsTrafficLights©studiotdesCCBY-NC-SA2.5–hjp://www.youtube.com/watch?v=hFOo3e0nxSI
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Intersec9onManagement
²
Safety
No Traffic Lights
[1]Авария!Проигнорировалзнакстоп©SmexaMnogo,CCBY–hjp://www.youtube.com/watch?v=TO-eRnw1hTo
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SafeandEfficientTrafficinSmartCi9es
²
STEP1:Communica9onbetweentrafficlightsand
vehicles
²
Firstideasdatebacktothe1970ies
ª
ª
²
RealitytodayespeciallyinAsiancountries
ª
²
Analogcommunica9on
Transmissionofswitching9mestoapproachingvehicles
Largedisplaysindica9ngtheendofthecurrentlightphase
Vehicularnetworkingenablesthesolu9onsfortomorrow
ª
ª
WiFiorDSRCbased
Inves9gated,forexample,inTravolu9onproject
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SafeandEfficientTrafficinSmartCi9es
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STEP2:EnablingVirtualTrafficLights
²
Statusasoftoday
Only1-20%ofallintersec9onsareequippedwithtrafficlights
ª  Manyofthesearenotappropriatelyconnectedàmaycause
ar9ficialtrafficjams
ª  Newinstalla9onsareveryexpensive
ª
²
VTL–VirtualTrafficLights
ª
Firstinves9gatedbyCMU/UPorto
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VirtualTrafficLights
1.
2.
3.
²
Waitforintersec9on
Performleaderelec9on
Send/receiveTLprogram
Researchavenues:
ª
ª
ª
Leaderelec9on
TLprogramcomputa9on
Scalabilityandload?
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VirtualTrafficLights
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VirtualTrafficLights
²
Travel9mecomparedto(sta9c)trafficlights
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SafeandEfficientTrafficinSmartCi9es
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STEP3:UsingHeterogeneousNetworks
²
Today
ª
ª
ª
²
Bluetooth
WiFi(IEEE802.11a/b/g/n/ac)
3G/4G(UMTS/LTE)
Tomorrow
ª
ª
ª
ª
ª
DSRC/WAVE(IEEE802.11p)
60GHz(IEEE802.11ad)
4G+(LTEAdvanced/LTEDirect)
Millimeterwave(Radar)
Visiblelightcommunica9on
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SafeandEfficientTrafficinSmartCi9es
²
STEP3:UsingHeterogeneousNetworks
²
Causesnewchallengesbutprovidesmanynew
opportuni9es
Clustering
ª  Selec9ngthe
communica9on
channel
ª  Coopera9onand
self-organiza9on
ª
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VEHICULARNETWORKING
PROTOCOLS
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Communica9onParadigms
Infrastructure-assisted Data Exchange
Ad Hoc Multihop Broadcasting
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Taxonomy
²
Wealthofapplica9ons[T.L.Willke2009]
3G+
Cellular
?
Cost
Short-Range
Radio Broadcast
Range
Non-Safety
Comfort
Entertainment
Contextual
Information
Traffic Information
Systems
Optimal Speed
Advisory
Congestion,
Accident
Information
Safety
Situation
Awareness
Blind Spot
Warning
Adaptive
Cruise Control
Warning
Messages
Traffic Light
Violation
Electronic
Brake Light
[1] G. T. L. Willke, P. Tientrakool, and N. F. Maxemchuk, "A Survey of Inter-Vehicle Communication Protocols and Their Applications,"
IEEE Communications Surveys and Tutorials, vol. 11 (2), pp. 3-20, 2009
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TowardsHeterogeneousVehicularNetworks
²
Manycommunica9onchannelsavailable
ª
Whichtopickwhen?
mmWAVE
cellular
“Technology2020”
So…wareDefinedRadio
?
DSRC
VLC
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Wi-Fi
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FutureProofingShortRangeCommunica9on
²
Old:Classicradiohardware
ª
ª
ª
SendbitstreamtoNetworkInterfaceCard(NIC)
NICtransformsbitsfrom/toelectromagne9cwaves
Newradiotechnology newNIC
²
PC
Whichtechnologytopick?
ª
ª
ª
header,payload
NIC
802.11p,WAVE,ITSG5,futurework,…
Noclearwinner
Hardtocommittoday
“Technology 2020”
?
²
So…wareDefinedRadio(SDR)
ª
Newradiotechnology
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3G/4G–ak9vCoCar
²
ak9vCoCar
ª
Goals
§  Inves9gatefeasibilityofCar-to-X
over3G/3.5Gnetworks
§  Establishbusinesscase
ª
Coopera9onof
§  Telcos,OEMs
§  Carmanufacturers
§  Government,automobileassocia9on
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3G/3.5G–ak9vCoCar
²
Hierarchyof(logical)func9onblocks
ª
Reflector
§  blindre-broadcastofreceiveddata,copysentupstreamtoCoCarAggregator
§  envisionedtobedeployedclosetoroads,e.g.inbasesta9ons
ª
GeocastManager
§  autonomouswide-areadissemina9onofmessagesreceivedfromupstream
ª
CoCarAggregator
§  central
informa9on
broker
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3G/3.5G–ak9vCoCar
²
Selectedperformancemeasures
ª
UsingMBMS(mul9castservice),emergencymessagescanbehandled
wellusingtheFTAP(~120msend-to-enddelay)
[1] C. Sommer, A. Schmidt, R. German, W. Koch, and F. Dressler, "Simulative Evaluation of a UMTS-based Car-to-Infrastructure Traffic Information System," Proceedings of IEEE
Global Telecommunications Conference (GLOBECOM 2008), 3rd IEEE Workshop on Automotive Networking and Applications (AutoNet 2008), New Orleans, LA, December 2008
[2] C. Sommer, A. Schmidt, Y. Chen, R. German, W. Koch, and F. Dressler, "On the Feasibility of UMTS-based Traffic Information Systems," Elsevier Ad Hoc Networks, Special Issue
on Vehicular Networks, vol. 8 (5), pp. 506-517, July 2010
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IEEE802.11pDSRC
²
Defini9onofPHYandlowerlayerMAC
ª
²
Networkprotocolstack
ª
ª
²
RoughlyWiFi+IEEE802.11eEDCA+dedicatedspectrum
IEEE1609WAVE–Focusonfunc9onality
ETSIITS-G5–Focusonconges9oncontrol
Firstapplica9on:Coopera9veAwareness(CAM/BSM)
ª
Periodicbeaconscontaining
§
§
§
§
§
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Time
Speed
Posi9on
Heading
…
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ChannelCapacityMaaers
Adap%veTrafficBeacon
²  Beaconinterval:measureofchannelqualityandmessagepriori9es
²  Infrastructureelements:RSUsofdifferentcapabili9escanbeincluded
ª
ª
LightweightSSUs(servicesupportunit)
InterconnectedRSUs
Challenging questions
•  How frequently can the beacons be sent?
•  How frequently should the beacons be sent?
•  Which information should be included into the beacon?
[1] Christoph Sommer, Ozan K. Tonguz and Falko Dressler, "Traffic Information Systems: Efficient Message Dissemination via Adaptive Beaconing," IEEE Communications Magazine, vol.
49 (5), pp. 173-179, May 2011
[2] Christoph Sommer, Ozan K. Tonguz and Falko Dressler, "Adaptive Beaconing for Delay-Sensitive and Congestion-Aware Traffic Information Systems," Proceedings of 2nd IEEE
Vehicular Networking Conference (VNC 2010), Jersey City, NJ, December 2010, pp. 1-8
[3] C. Sommer, R. German, and F. Dressler, "Decentralized Traffic Information Systems and Adaptive Rerouting in Urban Scenarios," Proceedings of 29th IEEE Conference on Computer
Communications (INFOCOM 2010), Demo Session, San Diego, CA, March 2010
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BeaconInterval
²
IntervalparameterI
I=(1–wI)xP2+(wIxC2)
C…channelquality
P…messagepriority
wI …intervalweigh9ng
²
BeaconintervalΔI
ΔI=Imin+(Imax–Imin)xI
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50
40
30
20
10
Emergency msg delay in s
60
ProtocolPerformance
10s
3s
1s
300ms
100ms
30ms
ATB
Beacon interval
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IntermediateConclusion
²
Theseconceptsalsowentintostandardiza9on
ª
ª
ª
ETSIITS-G5developedDCC(DecentralizedConges9onControl)withTRC
(TransmitRateControl)
btisthe“busyra9o”ofthechannel
Coarsegrainedmeasurementintervals
[1] Werner, Marc and Lupoaie, Radu and Subramanian, Sundar and Jose, Jubin, "MAC Layer Performance of ITS G5 - Optimized DCC and Advanced Transmitter
Coordination," Proceedings of 4th ETSI TC ITS Workshop, Doha, Qatar, February 2012
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ProblemSolved?
²
Maybewealloverlookedsomeissues!
²
Antennacharacteris9cs
Radiosignalshadowing
²
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ExperimentalValida9on
[1] Christoph Sommer, David Eckhoff, Reinhard German and Falko Dressler, "A Computationally Inexpensive Empirical Model of IEEE 802.11p Radio Shadowing in Urban Environments,"
Proceedings of 8th IEEE/IFIP Conference on Wireless On demand Network Systems and Services (WONS 2011), Bardonecchia, Italy, January 2011, pp. 84-90
[2] David Eckhoff, Christoph Sommer, Reinhard German and Falko Dressler, "Cooperative Awareness At Low Vehicle Densities: How Parked Cars Can Help See Through Buildings,"
Proceedings of IEEE Global Telecommunications Conference (GLOBECOM 2011), Houston, TX, December 2011
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EstablishmentofNewModels
²
²
Modelsallowtakingintoconsidera9on
(a)sta9cand
(b)movingobstacles
Researchques9on:Whatistheirimpactonbeaconing?
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HowBusyCan/ShouldtheChannelBe?
²
Assumingapayloadofl=512bit(at18Mbit/s),
weobtain
tbusy = Tpreamble + Tsignal + Tsym [(16 + l + 6) / NDBPS] = 104 µs
UsingaminimumAIFSandanaverageini9albackoffcounter,
wegetamaximumbt
bt = tbusy / (tbusy + taifs + tidle) = 0.64
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DynB–DynamicBeaconing
²
²
Mainidea:con9nuouslyobservetheloadofthewireless
channeltocalculatethecurrentbeaconinterval
Assumingtwolargerclustersofvehiclesmee9ng
spontaneously(e.g.,atintersec9onsinsuburbanorwhen
somebigtrucksleavethefreeway)
[1] Christoph Sommer, Stefan Joerer, Michele Segata, Ozan K. Tonguz, Renato Lo Cigno and Falko Dressler, "How Shadowing Hurts Vehicular Communications and
How Dynamic Beaconing Can Help," IEEE Transactions on Mobile Computing, vol. 14 (7), pp. 1411-1421, July 2015.
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Conclusions
Today,westudied
²
Challengesandopportuni9esofusingconnectedcarsconcepts
ª
ª
ª
²
Capabilitytoconnecteveryoneandeverything
Canbeseenasabigdatastorage
Helpimprovingourdailyroadtrafficexperienceandsafety
Notdiscussed
ª
Securityissues:Strongdebateaboutprivacyvs.security
…ascanbeseen,therearemanyopenchallengesandques9onsfor
anotherdecadeofinteres9ngresearchJ
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MoreInforma9on?
VehicularNetworking
(CambridgeUniversityPress)
20%
off
IEEEWiMob2015
IEEEVehicularNetworking
Conference(VNC)
²  Tokyo,NewJersey,
Amsterdam,Seoul,
Boston,Paderborn
²
Next:KyotoinDec2015
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