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VANET: Vehicular Ad-Hoc Network (VANET)

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VANET stands for Vehicular Ad-Hoc Network

It is a technology that uses moving cars asnodes in a network to create a mobile network.

VANETs are a subset of MANET

Turns every participating car into a wirelessrouter or node, allowing cars approximately

100 to 300 metres of each other to connect and,in turn, create a network with a wide range

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Ad-Hoc Network: is a wireless technology where all nodes are one

level topology and can communicate directly with each other

without the use of centralized nodes

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The high mobility of nodes

For a faster rate of deployment

To offer the service at no charge

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Mobile devices communicate in peer-to-peerfashion

Self-organizing network without the need offixed network infrastructure

Multi-hop communication

Decentralized,mobility-adaptive operation

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What are in a vehicular network Vehicles (on-board unit) Road side unit/equipment

Communication protocols

Vehicle to vehicleVehicle to road side

Vehicle to handheld device

Network infrastructure

GPS (optional)

Back-end system

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Personal area networking cell phone, laptop, ear phone, wrist watch

Military environments soldiers, tanks, planes

Civilian environmentsMesh networks taxi cab networkmeeting rooms sports stadiums

boats, small aircraftEmergency operations

search-and-rescuepolicing and fire fighting

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The distribution of nodes changes rapidly and

unexpectedly

The wireless links initialize and break down

frequently and unpredictably.

The OBUs are forced to organize the network

distributively

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Requirements:

Reliability

Minimum latency

Minimum collisions High dissemination speed

Problems:

No feedback

No prior control messaging Hidden node problem

Different traffic volumes

Different environments (Urban or rural)

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11

Co-operative Collision Warning Lane Change Warning Intersection Collision Warning

Approaching Emergency vehicle Rollover Warning Work Zone Warning

Coupling/Decoupling Inter-Vehicle Communications Electronic Toll Collection

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Public Safety Co-operative Collision warning [V-V]

Intersection CollisionWarning

Approaching Emergency Vehicle

Work ZoneWarning [R-V]

Non-Public Safety

Electronic Toll Collection

Data Transfer

Parking Lot Payment

Traffic Information

The main categorized applications of VANETs are

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Vehicles detect congestion when: # Vehicles > Threshold 1

Speed < Threshold 2

Relay congestion information Hop-by-hop message forwarding

Other vehicles can choose alternate routes

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Prevent pile-ups when a vehicle deceleratesrapidly

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Safety concerns

Traffic conditions

Driving comfort

Economical reasons

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DSRC: Dedicated Short Range Communications

In the USA (IEEE):WAVE, Wireless Access in Vehicular

Environments

In Europe (CEN): General Specifications for Medium-Range Pre-

Information Via Dedicated Short-Range Communication

In Japan (ARIB): Dedicated Short-Range Communication System

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restricted mobility (highways and roads)

fast topology changes (network nodes move athigh speeds)

no power and storage limitations

nodes are aware of their position (via GPS)

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Advantages:

restricted mobility (highways and roads)

no power and storage limitations

nodes are aware of their position (via GPS)

Disadvantages:

fast topology changes (network nodes move at

high speeds) less reliable and suboptimal

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Highly dynamic topology

Frequently disconnected network (Intermittentconnectivity)

Patterned Mobility

Propagation Model

Unlimited Battery Power and Storage

On-board Sensors

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Uses DSRC as a protocol

Range of 300m to 1km

10MHZ wide channel

Automotive sensors:

1. Autonomous sensors

2. Co-operative sensors

Roadside base station provides information todriver using the network

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Security

Electronic license plates

Vehicular public key infrastructure

Dealing with bogus messages with trafficinformation.

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Formed by wireless hosts which may be mobile

Without (necessarily) using a pre-existing

infrastructure

Routes between nodes may potentially containmultiple hops

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A European Information Society for growthand employment

The European Commission's strategic policy

framework laying out broad policy guidelinesforth information society and the media in theyears up to 2010

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Night vision

Advanced cruise control

Use radar to maintain safe

distance

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CyberCars

Driver-less

Run at low speed (30km/hr)

Can avoid obstaclesPark automatically

With a fee, users would have accessright

CyberCars2Follow-up project

Focus on V-to-V and V-toinfrastructure communication

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CarTalk project

Focus on vehicle-to vehiclecommunication

Information is transmitted fromone car to another car

Vehicles nearby form an ad-hoc

network

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Dedicated Short Range Communications (DSRC) Started in IEEE 1609, spun into 802.11p

Aka (WAVE) Wireless Access for Vehicular Environment

Goal Telematics (collision avoidance a big driver)

Roadside-to-vehicle

Vehicle-to-vehicle environments 54 Mbps,

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802.11p part of several standards which willjointly enable widescale telematics

Intelligent Transportation Systems

doc.: IEEE 802.11-07/2045r0

S. Biswas, R. Tatchikou, F. Dion,Vehicle-to-vehicle wirelesscommunication protocols forenhancing highway traffic safety,

IEEE Comm Mag, Jan 06, pp. 74-82.

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Applications Emergency warning system for vehicles Cooperative Adaptive Cruise Control Cooperative Forward CollisionWarning

Intersection collision avoidance Approaching emergency vehicle warning (BlueWaves) Vehicle safety inspection Transit or emergency vehicle signal priority Electronic parking payments Commercial vehicle clearance and safety inspections

In-vehicle signing Rollover warning Probe data collection Highway-rail intersection warning

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IMMINENTFRONT

COLLISION

Note 1: The OBU in the vehicle recognizing the threattransmits a WARNING andCOLLISION PREPARATIONMESSAGEwith the location address of the threat vehicle.

In-Vehicle

Displays and

Annunciations

Traffic Signal

Traffic Signal

OBUs on Control Ch

IMMINENTLEFT

COLLISION

Radar Threat Identification

Note 2: Only the OBU in the threatening vehicle processesthe message because only it matches the threat address.

Note 3: COLLISION PREPARATION includes seat belttightening, side air bag deployment, side bumperexpansion, etc.

Car NOT Stopping

From: IEEE 802.11- 04/ 0121r0Available: http://www.npstc.org/meetings/Cash%20WAVE%20Information%20for%205.9%20GHz%20061404.pdf

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akaWiMax

Wireless Metro Internet

Fast last mile access to network

Target Applications

Data

Voice

VideoReal time videoconferencing

Fast cable/fiber to end user is expensive

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The bandwidth and range ofWiMAX make itsuitable for the following potential applications:

Providing portable mobile broadband

connectivity across cities and countries through avariety of devices.

Providing a wireless alternative to cableand digital subscriber line(DSL) for "last mile"broadband access.

Providing data, telecommunications (VoIP)and IPTV services (triple play).

Providing a source of Internet connectivity aspart of a business continuity plan. Comparison

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Comparisons and confusion betweenWiMAX andWi-Fi are frequent because both are related to wirelessconnectivity and Internet access.

WiMAX is a long range system, covering many

kilometres, that uses licensed or unlicensed spectrumto deliver connection to a network, in most cases theInternet.

Wi-Fi uses unlicensed spectrum to provide access to alocal network.

Wi-Fi is more popular in end user devices.

Wi-Fi runs on the Media Access Control's CSMA/CAprotocol, which is connectionless and contention based,whereasWiMAX runs a connection-oriented MAC.

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Both 802.11(which includesWi-Fi)and 802.16 (which includesWiMAX)define Peer-to-Peer (P2P) and ad hoc networks,

where an end user communicates to users orservers on another Local Area Network(LAN) using its access point or base station.However, 802.11 supports also direct ad hoc orpeer to peer networking between end user

devices without an access point while 802.16end user devices must be in range of the basestation.

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Better spectral efficiency than 3G

Consider multiple antennas right from the start

Higher peak data rate

Higher average throughput

Support more symmetric links

Lower cost

IP architecture from bottom up

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