1. V2V Communication for Safety, Information and Entertainment
J. Parikh
General Motors R&D
Nov. 14, 2006

2. Content Introduction and Background DSRC Wireless Communication
Safety, Information and Entertainment Applications
Technical Challenges
Current and Future Research Work

3. Introduction

4. 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).

5. Communication on Road…

6. Today’s Vehicles - Wireless Data Interfaces
Terrestrial
Broadcast
Digital
Radio
Satellite
A/V
GPS
DSRC
PCS/
Cellular
802.11
WLAN
Ad Hoc
Networks
WPAN
Bluetooth
802.11
Existing and proposed vehicle connectivity

7. Integrated Traffic Management Systems
Central Control Center
Transit
Dynamic Signal Control
En-Route Traffic Advisory and Assistance
DSRC and Other Communications
911 and Other Call Center
Trip Planning
This slide shows but a few of the elements that may make up a complete traffic management systems. Key to all of these is a central control center with communications capabilities to all of the sensors, displays, and other control centers (such as police and fire) with which it must interact.
Commercial Vehicle Operation
Traveler Assistance
VARIABLE MESSAGE SIGNS

8. DSRC – Wireless Communication

9. 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.”

10. 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 peer
Based on IEEE a
High speed impacts physical layer
Very latency (<50ms) – MAC impact
Random MAC addresses for privacy
IPv6 for network layer
Support for in-car networks

11. Standards Program

12. 5.9 GHz Channel Plan Shared Public Safety/Private
Dedicated Public Safety
Control
Med Rng Service
Short Rng Service
Hi Av-Low Lat
Intersections
Power Limit
43 dBm
40 dBm
Power Limit
33 dBm
Power Limit
23 dBm
Uplink
Downlink
Public
Safety
Veh-Veh
Public
Safety/
Private
Public
Safety/
Private
Public
Safety/
Private
Public
Safety/
Private
Public Safety
Intersections
Control Channel
Ch 172
Ch 174
Ch 176
Ch 178
Ch 180
Ch 182
Ch 184
5.925
5.825
5.830
5.835
5.840
5.845
5.850
5.855
5.860
5.865
5.870
5.875
5.880
5.885
5.890
5.895
5.900
5.905
5.910
5.915
5.920
Frequency (GHz)
Canadian Special License Zones*

13. – DSRC Applications – Safety, Information & Entertainment

14. 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.

15. Safety Application Areas

16. Example Traffic Scenario – Safety Application
Incidence notification to OnStar
Information relay to other vehicles for dynamic route guidance
Exit
Immediate spread of knowledge to surrounding vehicles within broadcast range

17. V2V/V2I Safety Application

18. Traffic Probe - Information
Report
GPS Time
Speed
Lon, Lat
Heading
GPS
Vehicles report speed, position and heading
Form small clusters of vehicles
Aggregate data within cluster
Transmit aggregated values

19. 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 to learn more…

20. Application Categories
Applications
Network Configurations
V2V
V2V + Ad-Hoc
Ad-Hoc + Other wireless (Pervasive)
Active Safety 
Security X
Productivity
Convenience
Entertainment

21. Technical Challenges

22. “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 OLSR
CGSR STAR
Hybrid
ABR DSR
TORA AODV
RDMAR CBRP
ZRP/GRID/LAR

23. 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
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

24. 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

25. 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)

26. Research Work

27. 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

28. 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

29. Vehicle Networks: Unique Degrees of Freedom
Protocol Operation Modes
Time of Day: “Rush Hour – Set cluster size to 3-hops”
Traffic Characteristic: “Highway Driving – Switch to Cluster-based Routing Mode”
Traffic Database Update: “Traffic Probe: Congestion ahead – Routing Table Burst Update”
Routing Metrics
(a) Hop count (b) SNR (c) Signal Stability
(d) Connectivity (e) Link load (f) Multiple Paths

30. Experimental Multi-hop Vehicular Network Test-bed
5.9 GHz DSRC Dedicated Short Range Communications Between vehicles
GPS
1xRTT Cellular Data
Network
Differential GPS reference station beacons
Mobile Nodes
Internet
Remote Monitoring of Experiment
Vehicle-to-Vehicle Multi-hop
Vehicle-to-Mobile Gateway
Vehicle-to-Infrastructure

31. Vehicular Networking Application Categories
Safety Alerts
Sudden Braking
Airbag deployment
Skidding
Traffic Congestion Probing
Travel Time
Dynamic Route Planning
Road Condition Notification
Interactive Applications
Social Networking
Multimedia Content Exchange
Advertising

32. GeoRoute: Broadcast Scenarios
Highway Driving City Driving Rural Driving
Path with Intermediate points
Static Source Routing
Radial Broadcast
Bounding Box
Controlled Flooding

33. Conclusion
Communicating vehicles and infrastructure will bring cost effective, large scale gains in safety, traffic management and convenience.
DSRC (IEEE p) 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.

34. Questions ???