Intelligent Transportation using VANET

by February 1, 2009 0 comments

–  Mainak Ghosh and Sumit Goswami 

Can vehicles be made intelligent enough to guide their drivers in situations
like traffic congestion and accidents? Providing intelligence to vehicles means
loading them with sensors which will be controlled by a telematics box inside
the car. The box in turn would communicate with the driver and will be its
guide. Vehicular Adhoc Network (VANET) is an important component of Intelligent
Transportation Systems, which has a future potential in terms of a rich set of
applications that it can provide to its customer.

VANET is a special class of Mobile Adhoc Networks (MANET), in which the nodes
are the vehicles which communicate with other vehicles or with the base station
which acts as a roadside infrastructure for using security and services
application. Though the nodes are mobile in VANETs as well as MANETs, the
mobility in VANET is constrained to the boundaries of the road unlike the nodes
in MANETs, where movement is more random in nature. Nodes in VANET are also
characterized by high node mobility and fast topology changes. Unlike MANET,
power is not of great concern in VANETs as the vehicle batteries have sufficient
and rechargeable power. The concept of network vehicle was first proposed by a
team of engineers from Delphi Delco Electronics Systems and IBM corporation in
the year 1998.

Applications of VANET
The three major classes of applications possible in VANET are safety oriented,
convenience oriented and commercial oriented. Safety applications will monitor
the surrounding road, approaching vehicles, surface of the road, road curves
etc. . They will exchange messages and co-operate to help other vehicles out
under such scenario. Though reliability and latency would be of major concern,
it may automate things like emergency braking to avoid potential accidents.
Convenience application will be mainly of traffic management type. Their goal
would be to enhance traffic efficiency by boosting the degree of convenience for
drivers. Commercial applications will provide the driver with the entertainment
and services as web access, streaming audio and video.

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Applies To: Developers
USP: Learn applications of VANET
Primary Link: None
Keywords: VANET, Intelligent
Transportation Systems

Safety Application: Safety applications would be Slow/Stop Vehicle
Advisor (SVA) in which a slow or stationary vehicle will broadcast warning
message to its neighbourhood. Another similar type of application is emergency
electronic brake-light (EEBL). In Post Crash Notification (PCN), a vehicle
involved in an accident would broadcast warning messages about its position to
trailing vehicles so that it can take decision with time in hand as well as to
the highway patrol for tow away support. Road Hazard Control Notification (RHCN)
deals with cars notifying other cars about road having landslide. Another
related application would be road feature notification which deals with
notification due to road curve, sudden downhill etc. Cooperative Collision
Warning (CCW) alerts two drivers potentially under crash route so that they can
mend their ways.

Convenience Application: Congested Road Notification (CRN) detects and
notifies about road congestions which can be used for route and trip planning.
TOLL is yet another application for vehicle toll collection at the toll booths
without stopping the vehicles. Parking Availability Notification (PAN) helps to
find the availability of slots in parking lots in a certain geographical area.

Schematic Representation of a
Vehicular Adhoc Network

Commercial Application: Remote Vehicle Personalisation / Diagnostics (RVP/D)
helps in downloading of personalized vehicle settings or uploading of vehicle
diagnostics from/to infrastructure. Service Announcements (SA) would be of
particular interest to roadside business like petrol pumps, highways restaurants
to announce their services to the drivers within communication range. Content
Map Database Download (CMDD) acts as a portal for getting valuable information
from mobile hotspots or home stations. Using Real Time Video Relay (RTVR),
on-demand movie experience will not be confined to the constraints of the home
and the driver can ask for real time video relay of his favourite movies. More
details of the applications is available at www.geocities.com /telbatt/Bai_Aut
onet06.pdf.

Components of VANET enabled vehicle
The components of a VANET enabled Vehicle include computer controlled devices
and radio transceivers for message exchange. The protocol that has been
standardized for communication in VANET is DSRC, which has a communication range
of 300 mts to 1 km. The roadside base station provides information to the driver
throughout his journey so that he can find a best route to his destination. The
information is periodically exchanged.

Automotive Sensors for Position Verification: Sensors in VANETS can be
classified into two types: autonomous sensors and co-operative sensors.
Autonomous sensors include Acceptance Range Threshold (ART), which is based on
the observation that all radio networks have a maximum communication range,
Mobility Grade Threshold (MGT) which is based on the assumption that the nodes
can move only at a maximum speed, Maximum Density Threshold based on the
assumption that only a restricted number of entities can reside in a certain
physical area. These aim at preventing so called Sybil attack in which a node
can create multiple copies of itself. Some other sensor includes map based
verification overhearing etc. Cooperative sensors include techniques like
proactive exchange of neighbour table to check if the positions received
correspond to their own data and reactive position request where sensors
co-operate on demand for position verification.

Schematic Representation of a
Vehicular Adhoc Network
Source: Leenand Hefferman, IEEE Computer, Jan 2002

Communication: The DSRC spectrum is divided into seven 10MHz wide
channel. Channel 178 is the control channel which is restricted to safety
communication. The extreme two channels on either side are reserved for accident
avoidance application and high power public safety communication usages. The
rest are used for both safety and non safety applications. The IEEE has proposed
the following standards for VANETs: IEEE P1609.1, P1609.2, P1609.3 and P1609.4.
IEEE P1609.1 is for Wireless Access for Vehicular Environments (WAVE) Resource
Manager. It defines services and interfaces as well as message formats. IEEE
P1609.2 is a standard for vehicular network security which includes message
formatting, processing and exchange. IEEE P1609.3 defines routing and transport
services and thus is an alternative to IPv6. IEEE P1609.4 provides
specifications of the multiple channels in the DSRC standard. The WAVE stack
uses a modified version of IEEE 802.11a known as IEEE 802.11p for its MAC layer
protocol. It uses CSMA/CA as the basic medium access scheme. By using the
orthogonal FDM system, it provides a communication range of 1 Km while taking
into account high absolute and relative velocities, fast multi-path fading and
different scenarios.

Threats : The prime concern that has plagued many VANET researchers is
the security of these networks. Take an example of two cars moving on a single
lane on a road. The car that is trailing behind can send a false message saying
that there is a chaos ahead due to a crashed car. The car in front on receiving
this message may believe this hoax to be true and take a detour leaving a
less-traffic road for the malicious driver behind. This is one possible misuse
of the several applications talked about here. Similar misuse can create havoc
in systems where safety is of primary concern. An obvious solutions that has
been looked into is asymmetric key based authentication. Few other possible
attacks that have been considered as a threat to these networks are bogus
information attack or disruption of network operation by jamming the wireless
channel which leads to denial of service (DoS). There can also be attacks like
cheating attack where identities, speed or position can be faked. Identity
disclosure attack can be performed by a global observer who has an access to all
the data gathered through these networks.

Ref ;
www.ieee802.org/802_tutorials/march02/IEEE_DSRC_Stds_Tutorial_03-10-02.ppt

Security: The main challenge in providing security in VANET depends on
privacy, trust, cost and gradual deployment. Some existing security tools in
some countries include electronic licence plates (ELP), which are
cryptographically verifiable numbers equivalent to traditional license plates
and help in identifying stolen cars and also keeping track of vehicles crossing
country border, vehicular public key infrastructure (VPKI) in which a
certification authority manages security issues of the network like key
distribution, certificate revocation etc., event data recording by which
important parameter can be registered during abnormal situation like accidents
etc. Tamper proof hardware is essential for storing the cryptographic material
like ELP and VPKI keys for decreasing the possibility of information leakage. To
keep a tap on bogus information attack, data correlation techniques are used. To
identify false position information, secure positioning techniques like
verifiable multilateration is commonly used.

Conclusion
VANET is definitely something to lookout for in the future. A lot of theoretical
work has been put into realizing these networks and few experiments has been
performed to validate this theory as cost of setting up this architecture is
high, but more such efforts can be expected in near future. A successful
vehicular network will open up a plethora of services to a huge number of
audience which will turn out to be life saving as well as fun.

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