International Journal of Engineering Trends and Technology (IJETT) – Volume 20 Number 1 – Feb 2015
A Review on General Issues and Challenges on Vehicular Adhoc Network
1
Mr. V. Rajasekaran 1 Dr. T. Karthikeyan 2
Assistant Professor, Dept of Computer Science, PSG College of Arts & Science, Cbe - 14
2
Associate Professor, PG Dept of Research, PSG College of Arts & Science, Cbe - 14
Abstract
Vehicular Adhoc network is a special kind of Adhoc network
which has high node mobility and fast changing topology as its
characteristics. The VANET can give different types of services
that ranges from safety related warning systems to more
advanced navigation mechanisms that will give more
information to the users about the condition of the road. In this
Adhoc network more challenging vulnerability of data is
available. The problems include VANET protocol, and various
security issues. In this paper, we present a study which is related
to vehicular Adhoc network and also proposed solutions for
related challenges and issues.
INTRODUCTION
Vehicular networks represent a particularly new class of wireless
ad hoc networks that enable vehicles to communicate with each
other and/or with roadside infrastructure. VANET is a new
standard that integrates Wi-Fi, Bluetooth, IRA, ZIGBEE and
other mobile connectivity protocols. In recent years, with the
sharp growth of vehicles on roads, driving becomes more
challenging and dangerous .In a Record 1.2 million People
worldwide are estimated to be killed each year on the roads . For
this reason, nowadays the invest are heavily done in automobile
industry to increase road safety and traffic efficiency, as well
as to reduce the impact of transportation on the environment.
VANETs have turned into an important research area over the
last few years. VANETs are distinguished from MANET by their
hybrid network architectures, node movement characteristics,
and new application scenarios.
Characteristics
Drive behaviour, conditions on mobility, and Data transfer are
much faster in VANET provides individuality. These
characteristics are as follows:
High m obil ity a n d Rapi d c hangi ng topology: Vehicles
move very fast and quick especially on highways. Thus, they
stay in the communication range of each other just for several
seconds, and links are recognized and wrecked fast. Before
formulating fresh routes, it has mass possibility that the route
may be avoided. So the previous routing protocols in MANET
are not suitable for VANETs.
Geographic position available: Vehicles can be operational with
accurate positioning systems integrated by graphical output such
as maps. For example, GPS users are more while driving the
car to access the specific location they need.
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Mobility modelling and prediction: Vehicular nodes are usually
embarrassed by prebuilt highways, roads and streets, so given
the speed and provides side by side view or next location in the
map for the future position and the destination can be predicted
quickly. Vehicles move along pre-defined paths, this provides
an opportunity to predict t h e d e s t i n a t i o n l on g w i t h
th e r espect i ve di stan ces.
Hard delay constraints: In VANETs applications, such as the
collision warning or Pre-Crash Sensing, the network does
not require high data rates but has hard delay
constraints, and the maximum delay will be critical
No power constraint: Since nodes are cars instead of small
handheld devices, power constraint can be neglected thanks to
always recharging batteries.
VANET ROUTING PROTOCOLS
In VANET, the routing protocols are divided into five
categories: Position based routing protocol, Topology based
routing protocol, Geo cast routing protocol and Cluster based
routing protocol,
and Broadcast routing protocol. On the
basis of application/area these protocols are characterized .
Topology Based Routing Protocols:
For packet forwarding these routing protocols use links
information that exists in the network. They are further divided
into Proactive, Reactive & Hybrid Protocols.
i)
Proactive routing protocols(PRP):
This Routing Protocol means that the routing information, like
next forwarding hop is maintained int the background process.
Its merit has that, there is no route discovery since the
destination route is stored in the background, but its demerit is
that, provides low latency for real time application. A table is
constructed and maintained within a n ode. So that, each entry
in the table indicates the next hop node towards a particular
target. It also c a r r i e s t h e c on t r ol o f vacant data paths
and too minimize the utilization of bandwidth. The various
types of proactive routing protocols are: LSR, FSR.
ii) Reactive/Ad hoc based routing This Protocol will perform
only when it is necessary for a node to communicate with
each other reactive routing opens the route. It maintains only
the routes that are alive, as the outcome it decr ea ses the
weight in the network.
Reactive routing consists of route
discovery phase in which the query packets are flooded into the
network for the path search and this phase completes when the
original path is identified. The o t h e r types of Re-Active
protocols are AODV, PGB, DSR and TORA
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International Journal of Engineering Trends and Technology (IJETT) – Volume 20 Number 1 – Feb 2015
Hybrid Protocols: To minimize the process of manage overhead
of proactive routing protocols and it reduce the time to identify
the first route holdup in reactive routing protocols. The hybrid
protocols are introduced.
b) Position Based Routing Protocols This Routing protocol
are classified into number of algorithm. In order to select the
next forwarding hops they use to access the functionality
of GPS. The packet is send without any gr a ph i ca l out put
suppor t to the one hop neighbour, which is n e a r to end
node. PBR is beneficial since no global route from source
node to destination node need to be created and
maintained.
c)Cluster Based Routing
Cluster based routing is favoured in clusters. A group of nodes
identifies themselves to be a part of cluster and a node is
designated as cluster head will broadcast the packet to
cluster. Good scalability can be provided for large networks
but
network
delays
and overhead are incurred when
forming clusters in highly mobile VANET. In this Protocol
virtual network infrastructure must be created through the
clustering of nodes in order to provide scalability. The various
Clusters based routing protocols are COIN and LORA_CBF
d) Broadcast Routing
This
routing protocol is frequently used in VANET for
sharing, traffic, weather and emergency, road conditions
among
vehicles and delivering advertisements and
announcements. The various Broadcast routing protocols are
BROADCOMM, UMB, V- TRADE, and DV-CAST.
e)
Geo Cast Routing
Geocast routing is fundamentally a location based multicast
routing. Its goal is to transfer the packet from the initial node to
all other nodes within a particular geographical region (ZOR).
To avoid unnecessary hasty reaction, these routing vehicles
outside the ZOR are not alerted. A zone of forwarding (ZOF) is
explained as the geographic area which vehicles in this area
must deliver the packets to other ZOR vehicles
VULNERABILITIES AND PROBABLE SOLUTIONS TO
ISSUES AND CHALLENGES IN VEHICULAR ADHOC
NETWORKS (VANETS)
sparse as well as dense network scenarios, while optimally
leveraging the available bandwidth. Therefore, methods for
defining and evaluating the benefit of certain information
become important to determine the optimal network usage [9].
Solution: The Relevance-based approach provides a
complete concept that operates adeptly both in dense and
sparse networks and manages to deliver information to
where it is needed, independent of the current scenario. U s i n g
m e s s a g e i n p u t , both a n in-vehicle and inter-vehicle
message prioritization is realized, which is predictable in the
context of limited network resources. The relevance value of
one specific message is determined by estimating the benefit that
the receiving node will be provided on the basis of several
parameters about current vehicle context, message content, and
network situation.
By implementing these methods which is used to manage
injustice in scheduling the broadcast of data packets, bandwidth
can be used optimally and the benefit provided to all the vehicles
participating in a VANET is optimized at the same time.
Privacy:
Vehicular ad hoc networks (VANETs) can be probable to
improve traffic safety and transportation management in the near
future. This is realized by letting vehicles exchange their
sensed traffic environment changes with other vehicles. Such
exchanges also create privacy concerns since the vehiclegenerated reports contain much private information on the
vehicle and its driver.
Solution: Vehicles in pseudonym based approaches can
anonymously authenticate their own vehicular reports. This is
conceptually simple approach and it is supported by the
DSRC standard [9]. A Huge shortcoming is that each vehicle
needs to pre-load a large pool of anonymous certificates to
achieve privacy, and a trusted authority also needs to maintain
and manage them, which implies a serious burden of pseudonym
management. To avoid the intricate pseudonym management,
some of the proposals suggest using group signatures to
namelessly authenticate traffic reports. In this approach [10],
every vehicle registers to the transportation administration
office and obtains a secret token. With this token, the vehicle
can authenticate any message and the authenticated message
can be verified by any vehicle getting it.
Scalability:
Bandwidth limitation:
Inter-vehicle communication (IVC) and its assorted
application potential are experiencing increasing interest both in
research and industry. The main challenges inherent to the
deployment of VANETs is operability, both in
highly
overloaded and very sparse networks. This scalability problem
is not exhaustively addressed by vacant approaches, as they only
focus on parts of the problem. We consider a VANET to
be scalable if information is circulated through the network in
Unlike the wired counterparts the networking scenario is far
more distributed in nature in vehicular ad hoc wireless network,
which adds a considerable responsibility upon the nodes. In such
environment the optimal utilization of the bandwidth among
nodes is not f u l l y f u l f i l l e d supported. Thus the minimum
frequency signal transfer through radio band w h i c h offer data
rates becomes a challenge in mobile ad hoc networks.
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International Journal of Engineering Trends and Technology (IJETT) – Volume 20 Number 1 – Feb 2015
Solution: Adaptive protocols. To countermeasure the effects
caused by the bandwidth constrained ad hoc network, an
adaptive scheme must be deployed. Forwarded data packet is
entrenched with some information regarding the bandwidth it
requires
for
its
relaying
and
processing.
The
intermediate/destination nodes check this requirement and then
take an action accordingly.
Traffic congestion:
Traffic congestion has been plaguing motorists for years, and
it increasingly continues to get worse as the population is highly
increases, output may be number f vehicles are more in the
specific lane[11]. Congestion can occur either naturally due to
external factors such as road maintenance, rush hours etc., or
indirectly created due to bad driving behaviour and not
following the rules of the road.
Solution: Integrate Vehicular Ad-hoc Network (VANET) with
artificial intelligence to create a driver aid that helps in
combating traffic congestion as well as embedding safety
consciousness by dynamically rerouting traffic depending on
road conditions. Vibrant Ambient Intelligence with Agents based
Service Oriented Approach focuses on the ambient intelligence
environment of managing the traffic congestion control in
Coimbatore city through VAISTC4 proposal without crippling
the mobility of users using Mobile Internet Protocol Version
6(IPV6)[14].
Network Congestion and Overhead:
Unlike VANETs and MANETs nodes are transferring data at
high bandwidth, i t becomes difficult to manage for maintaining
stable path for broadcasting, Emergency and Warning (E/W)
messages from a risk zone. So routing takes an vital role in
VANETs. Reducing traffic congestion, network overhead,
avoiding network congestion and increasing packet delivery ratio
are the major issues of routing in VANETs.
Solution: Broadcast the risk announcement (RN) messages such
as disaster and injury guard information, dense control message,
lane situation and other emergency/ warning messages in time to
the rear vehicles. The node which receives the emergency
message will intimate to all the other members of its node. By
p a r t i t i o n i n g t h e c l u s t e r m e t h o d s i t can
change its current path before reaching the risk zone. Due to
this, the network congestion and traffic congestion will be
highly reduced.
Safety
Accidents currently account for 42 000 fatalities annually [12],
and an estimated 18% of the health care expenditure in the U.S.
technologies are spend more money against vehicular safety.
The automation of driving tasks is highly emerged and ready to
prove the importance of driver assistance systems that have
come to the market over the last decade Collision evasion
technologies are currently largely vehicle-based systems that are
offered by original equipment manufacturers as autonomous
packages that broadly serve the following two functions: 1)
collision warning and 2) driver assistance. . It is necessary to
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improve road traffic safety to reduce the number of daily
accidents so that human lives can be saved.
Solution: The automation of driving tasks is of growing
interest for highway traffic management [13].The rising
technologies of global positioning and inter-vehicular
wireless communications combined with in-vehicle computation
and sensing capabilities, can potentially give remarkable
improvements in safety and efficiency. Intelligent intersections
that are representative of class of complex hybrid systems also
provide improved efficiency.
CONCLUSION
This paper represents an overview and class of various issues
and challenges in vehicular adhoc network. Various types of
challenges in vehicular network have been identified and point
out with respective solutions. The above number of proposed
solutions for certain vulnerabilities has to handle with a
challenging environment including high mobility and hard delay
constraints in thin and dense connected network. These solutions
only cover a subset of all the vulnerabilities and are far from
providing a comprehensive answer to the routing and security
problems in VANETs.
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