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Dedicated Short Range Communications:Connecting vehicles
John KenneyToyota InfoTechnology Center, USA
June 11, [email protected]
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33,561 2012Traffic Fatalities in
What if …
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we could use wireless communicationto make driving safer?
DSRCDedicated Short
Range Communication
80%US DOT estimates DSRC can
address 80% of crashes involvingnon-impaired drivers
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DSRC Outline
• What is it?• What is it good for?• How does it work?• What’s hard about this?• What happens next?
What is DSRC?
• Ad hoc networking to and from vehicles– V2X where X = {vehicle, roadside infrastructure,
phone, bicycle, train, pedestrian …}
• Part of the Intelligent TransportationSystem (ITS)
• Key for US DOTConnectedVehicleprogram
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What is DSRC Good For?
• Saving Lives• Preventing or reducing:
– Injuries– Property destruction– Time lost in traffic– Fuel consumption/Greenhouse gas emissions
• Enabling mobile commerce• Informing drivers• Creating sandbox for innovation …
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DSRC V2V Safety Concept• Concept: each vehicle
sends Basic SafetyMessages frequently.
• Receiving vehiclesassess collision threats
• Threat: Warn driver ortake control of car
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Example collision scenarios
• All enabledby exchangeof BSMs
• Receiverapps notstandard
• Innovativeuses of BSMencouraged
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Emergency Electronic Brake Lights (EEBL)
Forward Collision Warning (FCW)
Blind Spot / Lane Change Warning (BSW / LCW)
Do Not Pass Warning (DNPW)
Intersection Movement Assist (IMA)
Left Turn Assist (LTA)
Roadside use case:Work Zone Warning
Grass Divider
up to 1100 ftrange
Work Zone Warning Com. Zone
Work Zone
Traffic Cones
RSU
In-Vehicle Displayand AnnunciationZONE
AHEAD
WORK
9RSU = Roadside Unit
V2I Safety Use Case:Emergency Signal Preemption
EmergencyVehicle
RSU
up to 1000 m(3281 ft)
Preempt Transaction1. DSRC OBE-to-RSE: Vehicle Host Preemption Request2. DSRC RSE-to-OBE: ACK3. Emergency Vehicle Host Displays Preempt-ACK within vehicle
DSRC Transaction occurs on Ch. 184 at high power.
OBU
10OBU = On Board Unit, RSU = Roadside Unit
How does DSRC Work?• Necessary for interoperability
DSRC PHY+MAC (IEEE 802.11p)
DSRC Upper-MAC (IEEE 1609.4)
IPv6
TCP/UDP
Safety Message (SAE J2735)Min. Perf. Req. (SAE J2945)
Non-safety applications
DSRC Security (IE
EE
1609.2)
DSRC WSMPwith safety sublayer
(IEEE 1609.3)
See: J. Kenney, “DSRC Standards in the United States”, Proc. IEEE, July 2011, Vol. 99, No. 7, pp. 1162-118211
• Most standards mature
DSRC System
InternalSensors
Computer
DSRCRadio
GPS
DriverInterface
Example of DSRC Prototype SystemMany suppliers are in this space
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DSRC Spectrum
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Frequency(GHz)
Ch 172BSMs
Ch 174 Ch 176 Ch 180 Ch 184PublicSafety
Ch 182Ch 178ControlChannel
Long Range
Intersections
Control
Channel
Designated Public SafetyShort Range
Service
Shared Public Safety /Private Service
40 dBm
33 dBm
23 dBm
40.0
33.0
23.0
44.8 dBm
Public limit
Private limit
Medium Range
Service
V2V and
Safety of Life
44.8
5.85
0
5.85
5
5.86
5
5.87
5
5.88
5
5.89
5
5.90
5
5.91
5
5.92
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PowerLimits(dBm EIRP)
Recent move to allow unlicensed sharing discussed below
What is hard about DSRC?
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Mobility:• Testing shows
802.11p capableof dependablecommunicationover ~300 meters@ 20 dBm
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Scalability
Basic question: will all this still work here?
Distributed Adaptive Control
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Each vehicle computesits message rate ri(t)adaptively based onchannel load
Vehicle KMessage Rate Control System
Vehicle 1Message Rate Control System
DSRC Channel
r1(t)
rK(t)
CBR(t)
Algorithm Goals: controlled load, convergence, fairness
Σ+
_
CBR TargetCBR Target isassociated with highchannel throughput
CBR = Channel Busy RatioA channel loading metric
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Adaptive Algorithm: LIMERIC• LInear MEssage Rate Integrated Controller• Toyota ITC idea• Currently under evaluation in US and Europe
See: G. Bansal, J. Kenney, and C. Rohrs, “LIMERIC: A Linear Message Rate Control Algorithm for DSRCCongestion Control”, IEEE Transactions on Vehicular Technology, to appear fall 2013.
Convergence:• Provable conditions• Fair• Exact
• Mathematicallyprovable behavior
• Demonstrated viasimulation
• Verified by radioimplementation
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Security and Privacy
• Goals:– Receiver needs to trust information it gets– We need to preserve privacy of drivers– Costs need to be controlled
• Two principal areas:– Per-message security– Security Infrastructure
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Per-Message Security
• IEEE 1609.2 standard defines how toauthenticate and how to encrypt
• Authentication proves– Sender was authorized– Content was not changed
• No permanent identifiers are included
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Get/Renew credentials?Detect misbehavior?Remove bad actors?
Security Infrastructure
CertificateAuthority (CA)
New CertificatesCertificateRevocation Lists
MisbehaviorReports
What medium?
Status of DSRC Deployment
• 10+ years of research (US DOT, industry)• Standards are mature• Aug. 2012-Aug. 2013 Model deployment
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• Testing collisionavoidance
• ~3000 DSRCequippedvehicles
• Includes cars,trucks, buses,motorcycles
• > 20infrastructurelocations
• 100s GB datacollected
• > 10 TB videocollected
What happens next for DSRC?
• Feb. 3, 2014: NHTSA planto require DSRC
– http://www.nhtsa.gov/About+NHTSA/Press+Releases/USDOT+to+Move+Forward+with+Vehicle-to-Vehicle+Communication+Technology+for+Light+Vehicles
– Regulatory process is starting
• US DOT expanding test beds and field trials:– Michigan, Florida, New York, California– http://www.its.dot.gov/testbed.htm
• Engagement from suppliers• OEMs ramping development• Technical challenges remaining:
– Spectrum Sharing– Global harmonization– Protocol evolution– Automated control
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Conclusions
• DSRC has great potential to make drivingsafer: 33,561
• DSRC can enable many other services,including automated driving
• Technology is relatively mature• US DOT planning to require DSRC• Remaining challenges include:
– Congestion Control (Scalability)– Security– Spectrum Sharing 23
