V2V Communication for Safety, Information and Entertainment
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Transcript of V2V Communication for Safety, Information and Entertainment
J. Parikh
V2V Communication for Safety, Information and
Entertainment
J. Parikh
General Motors R&D
Nov. 14, 2006
2 J. Parikh
Content
•Introduction and Background
•DSRC Wireless Communication
•Safety, Information and Entertainment Applications
•Technical Challenges
•Current and Future Research Work
J. Parikh
Introduction
4 J. Parikh
What are wireless systems?
•Wireless systems encompass those technologies that enable communications of voice or data without a direct-wired connection.
•These currently employ much of the electromagnetic spectrum from very low radio frequencies (tens of kHz) through visible light (1012 kHz).
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Communication on Road…
6 J. Parikh
Today’s Vehicles - Wireless Data Interfaces
Bluetooth802.11802.15.3
GPSDigitalRadio
SatelliteA/V
DSRC
Ad HocNetworks
PCS/Cellular
802.11WLAN
802.15.3WPAN
TerrestrialBroadcast
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Integrated Traffic Management Systems
Transit
Dynamic Signal Control
911 and Other Call
Center
Traveler AssistanceVARIABL
E MESSAGE SIGNS
Trip Planning
En-Route Traffic Advisory and Assistance
Commercial Vehicle Operation
Central Control Center
DSRC and Other Communications
J. Parikh
DSRC – Wireless Communication
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Dedicated Short Range Communication
“… a short to medium range (1000 meters) communications service that supports both public safety and private operations in vehicle-to-vehicle and vehicle-to-roadside communication environments by providing very high data transfer rates where minimizing latency in the communication link and isolating relatively small communication zones is important.”
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Don’t Confuse With Existing DSRC
915 MHz
• Range < 30 meters• Data rate = 0.5 mbps• Designed for ETC, but can be
used for other applications• Single unlicensed channel• Requires special (custom)
chip set & software• Vehicle to Infrastructure• Command-response
5.9 GHz
• Range to 1000 meters• Data rate 6 to 27 mbps• Designed for general internet
access, can be used for ETC• 7 licensed channels• Uses open off-the-shelf chip set
& software• V2V and V2I• Command-response & peer to
peerBased on IEEE 802.11a
• High speed impacts physical layer
• Very latency (<50ms) – MAC impact
• Random MAC addresses for privacy
• IPv6 for network layer• Support for in-car networks
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Standards Program
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5.9 GHz Channel Plan
Frequency (GHz)
5.8
50
5.8
55
5.8
60
5.8
65
5.8
70
5.8
75
5.8
80
5.8
85
5.8
90
5.8
95
5.9
00
5.9
05
5.9
10
5.9
15
5.9
20 5.9
25
5.8
25
5.8
30
5.8
35
5.8
40
5.8
45
Canadian Special License Zones*
Uplink
Downlink
Ch 172 Ch 174 Ch 176 Ch 180 Ch 184Ch 182Ch 178
Public Safety/ Private
Public Safety IntersectionsControl
Channel
PublicSafety/Private
PublicSafety/Private
IntersectionsControl Hi Av-Low LatDedicated Public Safety
Short Rng ServiceMed Rng ServiceShared Public Safety/Private
Public Safety/ Private
Public SafetyVeh-Veh
40 dBm
33 dBm
23 dBm
Power Limit
Power Limit
Power Limit
43 dBm
J. Parikh
– DSRC Applications – Safety, Information &
Entertainment
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Classes of Application
• Active Safety – Actively monitors the environment around the vehicle in order to warn
• Driver Assistance – Assists drivers in the operation of the vehicle either by relieving them of certain driving tasks or by providing them with useful information about the surrounding environment.
• Traffic Efficiency – Provides information to the managers of the roadway infrastructure to enable more efficient control and maintenance of the roadways.
• Infotainment/Commercial – Provides drivers with various types of communication services in order to improve driver productivity, entertainment, and convenience.
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Safety Application Areas
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Example Traffic Scenario – Safety Application
• Immediate spread of knowledge to surrounding vehicles within broadcast range
Exit
• Incidence notification to OnStar• Information relay to other vehicles for
dynamic route guidance
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V2V/V2I Safety Application
V-V messages
Avoiding rear-end collision
Avoiding lane change collision
Vehicle brakes hard Collision mitigation
Traffic signal
Avoiding intersection collision
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Traffic Probe - Information
Report GPS Time SpeedLon, LatHeading
GPS
Report GPS Time SpeedLon, LatHeading
Report GPS Time SpeedLon, LatHeading
Report GPS Time SpeedLon, LatHeading
Report GPS Time SpeedLon, LatHeading
Report GPS Time SpeedLon, LatHeading
Report GPS Time SpeedLon, LatHeading
•Form small clusters of vehicles
•Aggregate data within cluster
•Transmit aggregated values
Vehicles report speed, position and heading
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Roadcasting - Entertainment
A prototype system that allows anyone to have their own radio station, broadcasted among wirelessly capable cars (devices) of an ad-hoc wireless network. The system can become aware of individual preferences and is able to choose songs and podcasts that people want to hear, on their own devices and car stereos.
Visit http:roadcasting.org to learn more…
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Application Categories
Applications
Network Configurations
V2V V2V + Ad-Hoc
Ad-Hoc + Other wireless
(Pervasive)
Active Safety Security X X Productivity X Convenience X Entertainment X
J. Parikh
Technical Challenges
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“Ad hoc” Routing Protocols
• Proactive, Reactive, Hybrid Goal: Find a node given a logical address based
on a flat addressing hierarchy Method of Operation: Flooding Mechanism: Handshaking - Route request, route
reply, route maintenance and route erasure
Ad hoc Routing Protocols
Proactive/Table Driven Reactive/On-Demand
DSDV OLSRCGSR STAR
Hybrid
ABR DSR TORA AODV RDMAR CBRP
ZRP/GRID/LAR
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Ad hoc Routing Protocols – Quick Overview• AODV Ad hoc On-demand Distance Vector
Reactive Forwarding addresses stored in routers Lightweight and flexible
• DSR Dynamic Source Routing Reactive Packet header contains route Independent of router state
• OLSR Optimized Link State Routing Proactive Similar to link state routing with clusters Bounded routing overhead
• GRID Geographic Routing Protocol Controlled flooding based on geographic coordinates Requires location service
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OLSR: Reduced Flooding Through Hierarchy
24 retransmissions to diffuse a message up to 3 hops
Retransmission node
11 retransmission to diffuse a message up to 3 hops
Retransmission node
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Key Issues with Ad hoc Protocols
• Scalability – Flooding generates LOT of traffic• Optimizations have limited impact:
Use Route Caching (beware of stale routes) Use Node Hierarchy (longer setup duration)
• Link Oscillation – Channel variations cause pathological rerouting• Damp rerouting requests – when a “better” path is
available• Use Signal Stability Routing Metric• Route repair with controlled flooding – hop-count based
on previous route length • End-to-end Route Repair – Causes lot of overhead
• Use local repair• Link Quality – Shortest path often performs poorly
• Use combined routing metric (hop count, stability, load)
J. Parikh
Research Work
27 J. Parikh
Vehicle Networks: Unique Applications
• Safety Messages – Critical Broadcasts
• Low latency
• Send Locally
• Non-critical Traffic Updates• Send to targeted groups (location, speed,
neighborhood, id)
• Maintain connectivity map
• Telematics Applications• Provide QoS Support
• “Suspend & Resume” applications and routes
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Vehicle Networks: Unique Challenges
• Network Density - Large Dynamic Range Same protocol must work in bumper-to-bumper downtown
traffic and on interstates
• Mobility Patterns and Varying Vehicle Speeds Cars entering or exiting highways need complete route
updates and can possibly pollute new neighbors during transitions
Traffic moves in parallel and at different speeds – difficult to form clusters or handshake
• Heterogeneous Nodes Connectivity: Support DSRC and Cellular Positioning Capability: GPS and no-GPS Application Support: Full-function and Reduced-function
devices
• Information is Geographic Route and Direction Specific Need to map geographic routes to logical routes Getting direction info is not too reliable
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Vehicle Networks: Unique Degrees of Freedom
1. Protocol Operation Modes
1.Time of Day: “Rush Hour – Set cluster size to 3-hops”
2.Traffic Characteristic: “Highway Driving – Switch to Cluster-based Routing Mode”
3.Traffic Database Update: “Traffic Probe: Congestion ahead – Routing Table Burst Update”
2. Routing Metrics
(a) Hop count (b) SNR (c) Signal Stability
(d) Connectivity (e) Link load (f) Multiple Paths
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Experimental Multi-hop Vehicular Network Test-bed
GPS
Differential GPS reference station beacons
1. Vehicle-to-Vehicle Multi-hop2. Vehicle-to-Mobile Gateway3. Vehicle-to-Infrastructure
5.9 GHz DSRC Dedicated Short Range Communications Between vehicles
1xRTT Cellular Data Network
Internet
Remote Monitoring of Experiment
Mobile Nodes
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Vehicular Networking Application Categories
1. Safety Alerts
• Sudden Braking
• Airbag deployment
• Skidding
2. Traffic Congestion Probing
• Travel Time
• Dynamic Route Planning
• Road Condition Notification
3. Interactive Applications
• Social Networking
• Multimedia Content Exchange
• Advertising
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GeoRoute: Broadcast Scenarios
Highway Driving City Driving Rural Driving
• Path with Intermediate points• Static Source Routing
• Radial Broadcast • Bounding Box• Controlled Flooding
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Conclusion• Communicating vehicles and infrastructure will
bring cost effective, large scale gains in safety, traffic management and convenience.
• DSRC (IEEE 802.11p) is the enabling technology for making this vision into reality.
• Number of technical challenges remain, but can and will be solved with government, industry and academic research partners.
• VII (Vehicle Infrastructure Integration) will provide the necessary business and deployment framework over the next few years.
• There are many exciting opportunities for other industry participants to make contributions and to benefit from a DSRC/WAVE and VII deployment.
J. Parikh
Questions ???