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An Overview of Inter-Vehicular Communication
Systems, Protocols and Middleware
Imad Jawhar, Nader Mohamed, and Hafsa Usmani
College of Information Technology, UAE University, Alain, UAE
Email:{ijawhar, nader.m}@uaeu.ac.ae, hafsa usmani@yahoo.com
Abstract— Inter-vehicular communication is an important
research area that is rapidly growing due to considerable
advances in mobile and wireless communication technologies, as
well as the growth of microprocessing capabilities inside today’s
cars, and other moving vehicles. A good amount of research has
been done to exploit the different services that can be provided
to enhance the safety and comfort of the driver. Additional
functions provide the car electronics and the passengers with
access to the Internet and other core network resources. This
paper provides a survey of the latest advances in the area of
inter-vehicular communication (IVC) including vehicle-to-vehicle
(V2V) and vehicle-to-infrastructure (V2I) functions and services.
In addition, the paper presents the most important projects
and protocols that are involved in IVC systems as well as the
different issues and challenges that exist at each layer of the
networking model.
Keywords: Wireless networks, mobile ad hoc networks
(MANETs), wireless sensor networks (WSNs), inter-vehicular
communication (IVC), middleware, routing.
I. INTRO DUC TIO N
One of the applications that can make good and efficient
use of wireless sensor networks is road-side networks that can
be used to monitor vehicular activities along roads such as
speeding cars, accidents, and more. Car and other vehicles
can have communication capabilities with other fixed wireless
access points and Internet gateways along the road sides which
can alert them to potential problems ahead, traffic conditions,
or provide useful and practical Internet access. In addition, this
type of communication can give quick life-saving warnings
to the vehicle control system to alert a sleepy or distracted
driver in case the car is about to be driven off the road. In
fact, vehicle controls can even take critical actions before the
driver can respond in time. Consequently, some researchers
have already proposed systems that are intended to make car
driving safer by using V2V and V2I communications which
allow moving vehicles to alert drivers of danger in crossing
an intersection or detecting an emergency situation that can
cause an imminent accident.
Traffic management is another serious problem in most
cities. The European Commission (EC) estimates that traffic
congestion currently costs 50 billion euros per year or 0.5
percent of the EC’s total Gross Domestic Product [1]. The
This work was supported in part by UAEU Research grant 04-03-9-11/09. A
primary version of some parts of this paper were published in The Fifth IEEE
International Conference on Networking, Architecture, and Storage (NAS
2010).
economic impact of motor vehicle crashes on U.S. roadways
is estimated by the National Highway Traffic Safety Admin-
istration (NHTSA) at $230.6 billion a year, nearly 2.3 percent
of the Nation’s gross domestic product, or an average of
$820 for every person living in the country. NHTSA has
reported that the average roadway fatality has economic costs
of $977,000, while the costs associated with a critically injured
crash survivor surpass $1 million [2]. Traffic congestion is
an $87.2 billions annual drain on the U.S economy, with
4.2 billion hours and 2.8 billion gallons of fuel spent on
sitting in traffic, the equivalent of one work week and three
weeks worth of gas every year [3]. The emission from the
vehicles is the single most man made source of carbon dioxide,
nitrous oxide and methane. The vehicle which are stationary,
or moving with stop and go pattern due to congestion emit
more than those travelling in free flow conditions [4]. Inter-
vehicular communication (IVC) is an important emerging field
of research that takes advantage of the latest advances in and
electronic circuitry that are installed inside moving vehicles
(MVs), as well as the increase in wireless communication
capabilities of such devices with their environment. This field
of research is expected to contribute considerably to driver and
passenger safety, as well as greatly enhance traffic manage-
ment. IVC systems offer important means of communication
that can provide a large number of services that maintain
connectivity of the individuals on the road to the Internet
as well as to passengers in other vehicles and businesses
in the same geographic area. A good amount of research is
being conducted in the IVC field in order to develop useful
applications and provide appropriate support at all layers of the
networking stack. Several research projects have been created
to design efficient networking protocols that are properly
adapted to the special nature of V2V and V2I communication.
The remainder of the paper is organized as follows. Sec-
tion 2 discusses IVC system architectures and characteristics.
Section 3 presents a list of existing IVC projects. Section
4 discusses the latest IVC systems research at the various
networking layers. Section 5 offers additional issues and chal-
lenges facing IVC systems. Finally, the last section concludes
the paper.
A good amount of research is being conducted in the
IVC field in order to develop useful applications and pro-
vide the appropriate support at all layers of the networking
stack. Several research projects have been created to design
efficient networking protocols that are properly adapted to
the special nature of V2V and V2I communication that is
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Fig. 1. Wireless networking technology in V2V and V2I communica-
tion. DSRC: Dedicated Short Range Communiation. WiFi: Wireless Fidelity.
WiMAX: Worldwide Interoperability for Microwave Access.
involved. Such projects include FleetNet [5], CarTalk 2000
[6], WILLWARN [7], Car2Car [8], ADASE [9], COMCAR
[10], DRiVE [11], and CHAUFFEUR [12]. In addition to these
projects, researchers proposed different frameworks, protocols,
and architectures that are tailored for the IVC environment.
One of the most important projects stated earlier is the FleeNet
project which is partly funded by the German ministry of
education and research BMB+F and led by Daimler Chrysler
AG. FleetNet is primarily based on the ad hoc networking
paradigm. However, it uses position information to alleviate
some of the overhead involved in route discovery and main-
tenance which can be very costly in the vehicular ad hoc
networking environment.
In [13], Franz et al. presents an overview of the FleetNet
applications, services, technical challenges, communication
protocols, routing, Internet integration, and standardization.
The paper in [14] presents a survey of IVC systems which
is focused on V2V communication. It discusses the proposed
techniques at the physical, MAC, and Network layers. The
paper also outlines some location awareness, security, and
mobility issues. The survey does not discuss the vehicle to
infrastructure applications, issues and challenges. In addition,
the paper includes a discussion of the possible use of IEEE
802.11b, 3G cellular, and Bluetooth as platforms for IVC
systems. A more detailed discussion of FleetNet and the other
IVC projects is presented in later sections in this paper.
In [15], the author presents a survey of the network layer
aspects for IVC communication. The survey briefly discusses
the different routing mobile ad hoc network (MANET) proto-
cols [16][17] including flat, hierarchical, location-based, geo-
graphical, and geographical multicast routing. In addition, an
overview of the mobility management aspects of IVC systems
is presented including location management, and handover
mechanisms using mobile IP, cellular, and vehicular strategies.
In [18], a survey of research in the area of information
dissemination and assurance in IVC networks is presented. The
paper discusses the different types of information exchanges
that are possible in vehicular communication along with the
different methods of information exchange. The paper also
briefly addresses the proposed solutions for ensuring authentic-
ity and integrity of information, location privacy, and eviction
of misbehaving vehicles from the network.
In [19], the authors present a survey of vehicular sensor
network (VSN) developments. The paper discusses the issues
of collection, storage and harvesting of sensor information
using IVC systems including mobility-assisted dissemination,
geographic storage, and using infrastructure. The authors con-
clude that system performance is impacted by wireless access
methods (e.g. cellular 2/3G, WIMAX/802.16, and WiFi IEEE
802.11), mobility, user location and popularity of information.
The survey presented in this paper has the following con-
tributions beyond the existing papers discussed earlier. It
presents an overview of the different IVC projects; it also
provides a discussion of the current research in IVC systems
at the various layers of the networking stack. In addition, the
paper includes a discussion of middleware support for IVC
systems as well as additional issues, challenges and research
opportunities in this area. Such research involves designing
architectures and protocols that take advantage of the linear
nature of most IVC mobile ad hoc networks in order to further
optimize the performance, scalability, congestion control and
response time of the network.
This paper presents a survey of the current state of the art in
this important field of research. The different IVC applications
and technologies are presented. The paper also discusses the
different protocols that have been designed for each layer of
the networking stack along with the related research issues,
challenges, and design considerations for each one of the
layers.
II. NET WORK ARCHITEC TUR E AND CHARACTERISTICS OF
IVC SYS TEMS
The architecture of Inter Vehicular communication can be
classified into three main categories [20]:
•Pure cellular or WLAN: Pure cellular and WLAN archi-
tecture uses cellular gateways and WLAN access points
at traffic intersections to connect to the Internet. These
structures can’t be widely deployed due to cost and
geographical limitations.
•Infrastructureless architecture is in pure ad hoc form in
which nodes perform V2V communication using ded-
icated short range communication (DRSC), and each
vehicle is equipped with wireless networking devices
•Hybrid: The hybrid architecture has both cellular/WLAN
and ad hoc network capabilities. Vehicles use the in-
frastructure unit to access dynamic and rich information
outside their range and also share information in V2V
communication through ad hoc infrastructureless commu-
nication as shown in Figure 1.
Additionally, vehicular ad hoc networks (VANETs), which
are used in IVC communication, constitute a specialized type
of MANETs with some unique characteristics that make them
more challenging and demanding. Some of those unique
characteristics are [21][22]:
•Highly dynamic topology: the vehicles are moving too
fast making it more difficult to maintain the topology, and
the number of nodes also is assumed to be very high.
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•Frequently disconnected network: due to topology
changes, the network frequently gets disconnected as
nodes constantly go out of each others’ coverage area.
The density of the traffic changes at different hours of the
day, ranging from dense to sparse and vice versa often
resulting in a disconnected network.
•Propagation Model: The propagation model is not in
free space, it has many obstacles like buildings, trees,
and other vehicles. In addition, there is considerable
interference from wireless transmissions emitted by other
vehicles and access points.
•Unlimited battery power and storage.
•On-board sensors: Most vehicles will be assumed to be
equipped with sensors and GPS units, which can help in
the communication and routing process.
III. IVC PROJECTS
As mentioned earlier, IVC systems involve two categories
of communication [23][24][5]:
•Vehicle-to-Vehicle (V2V) communication: In V2V com-
munication, vehicles communicate with each other in
order to support different applications and services such
as cooperative driver assistance and decentralized floating
car data (e.g. traffic state monitoring information).
•Vehicle-to-Infrastructure (V2I) communication: In this
type of communication, vehicles are able to communicate
with fixed infrastructure along side of the road in order
to provide user communication and information services
such as hot-spot Internet access, mobile advertising, Inter-
vehicle chat, and distributed games.
In this section, a list of the existing IVC projects and
systems is provided along with a brief description of each
one.
FleetNet: is an ”Internet on the Road” project, which was set
up by a consortium of six companies and three universities in
order to promote the development of inter-vehicle communi-
cation systems. FleetNet was started in September 2000.
CarTALK 2000: is a 3-year project started in August 2001.
The project focused on developing new driver assistance
systems which are based on inter-vehicle communications for
safe and comfortable driving. It has three application clusters:
Information and warning functions (IWF), communication-
based longitudinal control (CBC), and co-operative assistance
systems (CODA).
Wireless Local Danger Warning (WILLWARN): is one of
the sub-projects of the Integrated Project PReVENT which
contributes to road safety by developing and demonstrating
preventive safety application and technologies. WILLWARN is
a 3-year project aimed at developing, integrating and validating
a safety application that warns the driver whenever a safety-
related critical situation is occurring beyond the driver’s field
of view. This project explores both V2V and V2I communi-
cation.
Car2Car: is a communication consortium, which was founded
by six European car manufacturers. One of its main objectives
is to create and establish an open European industry standard
for Car2Car communication systems based on wireless LAN
components and to guarantee European-wide inter-vehicle
operability.
Network on Wheels (NOW): is a German research project
started in 2004. The main objectives of NOW are to solve tech-
nical key questions on the communication protocols and data
security for V2V communications and to submit the results
to the standardization activities of the V2V communication
consortium.
Dynamic Radio for IP-Services in Vehicular Environments
(DRiVE): One of the main objectives of this project is to
produce in-vehicle multimedia services that allow information
to be easily accessible anywhere as well as provide support
for education and entertainment.
Table I offers a summary of the IVC projects and sys-
tems that were discussed in this paper, along with additional
projects which include Cooperative Vehicle-Infrastructure Sys-
tems (CVIS), SAFESPOT, and COOPeratie systEms for intel-
ligent Road safety (COOPER).
In addition to the projects that are summarized in Table
I, the following projects mostly focus on coordination of
research and development efforts between various IVC-related
companies and organizations:
INVENT: is a research initiative, which consists of eight
component projects. These projects deal with different inves-
tigations into issues concerning driver assistance systems for
safer driving, traffic management systems to relieve traffic
jams and traffic management in transport and logistics, using
user-friendly technologies.
Advanced Driver Assistance Systems in Europe (ADASE):
is a project with a mission of increasing the road and traffic
safety in Europe by not only reducing accidents but also by
avoiding collisions before they occur. This is achieved by pro-
viding active safety systems in conjunction with infrastructure-
based roadside equipment and measures. The aim of the
project is to co-ordinate the ongoing research in Europe in
the inter-vehicular communication field and facilitate infor-
mation exchange between the different projects in the ADAS
(Advanced Driver Assistance System) group.
Communication and Mobility by Cellular Advanced Radio
(COMCAR): is a project is centered around the conception
and prototypical realization of an innovative mobile commu-
nication network. With its main focus on asymmetrical and
interactive mobile IP-based services, one of the key issues it
tackles is intra-vehicular and inter-vehicular communication.
CHAUFFEUR 2: is an extension of the CHAUFFEUR 1
project. This research project is based on platooning of ve-
hicles whereby a leading vehicle which is physically steered
by a driver electronically tows more than one vehicle behind
it.
The Main Features and Services Offered by a Typical IVC
System
In order to highlight the main features and services offered
by IVC systems, this section focuses on FleetNet which is
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TABLE I
IVC PRO JECT S AND SY STEM S SUMM ARY TABL E.
IVC Projects and Sys-
tems
Main Features Protocols V2V V2I
FleetNet Provides V2V Communication framework. Cooperative driving. Position-based for-
warding.
IEEE 802.11 √ √
CarTALK 2000 Ad hoc V2V communication. Traffic safety, and comfort. Three application clusters
(IWF, CBLC, and CODA).
IEEE 802.11. Uses infrared
sensors and GPS technology.
√ √
Wireless Local Dan-
ger Warning (WILL-
WARN)
Consortium of six European car manufacturers. Create an open industry standard
for wireless LAN Car2Car communication systems. Guarantee European-wide inter-
vehicle operability. Ad hoc network with position-based routing that is adaptable to
fast changing topology.
Uses sensor technology. IEEE
802.11
√ √
Car2Car Consortium of six European car manufacturers. Create an open industry standard
for wireless LAN Car2Car communication systems. Guarantee European-wide inter-
vehicle operability. Ad hoc network with position-based routing that is adaptable to
fast changing topology.
IEEE 802.11 √
Network on Wheels
(NOW)
Ad hoc networking. Provide traffic safety, efficiency, security, and infotainment. Vehicle
on-board unit (OBU) and application unit (AU) to provide interface to driver/passengers.
Road Side Units (RSUs) installed on roads.
IEEE 802.11, and GPS. √ √
Communication Radio
for IP-Services in Ve-
hicular Environments
(DRiVE)
Project addresses the convergence of cellular and broadcast networks to provide
cost-efficient provision of IP-based in-vehicular multimedia services for information,
education, training, and entertainment. Achieve an optimized inter-working of different
radio systems in a common dynamically allocated frequency range.
GSM, GPRS, UMTS, DAB,
DVB-T
√
Cooperative Vehicle-
Infrastructure Systems
(CVIS)
Allow seamless V2V and V2I communication between various protocols and standards.
Addresses issues of interoperability, security, and public policy needs. Cooperative V2I
systems. CVIS communication and networking (COMM). Uses CALM (Continuous Air
Interface for Long and Medium range), a set of automotive ISO standards supporting
universal interoperability. Provide seamless handover between media and applications.
IEEE 802.11, IPv6,
Infrared, Millimeter wave,
GSM/UMTS.CALM M5
radio communication.
√ √
SAFESPOT Ad hoc networking. Relative localization, integrate vehicles with intelligent systems
that warn drivers of road hazards. Real time representation of surrounding vehicles
and environment. Decentralized architecture. Information gathered by road side sensors
and mobile sensors. Road intersection safety, safe overtaking, head-on collision and
vulnerable road warning.
IEEE 802.11p, GPS. √ √
COOPerative systEms
for intelligent Road
safety (COOPER)
Improve traffic management and safety. Collects traffic information by using vehicles
as floating sensors. Project to test and analyze existing protocols and technologies to
see which one is best suited for use. Built on existing equipment and network on the
road infrastructure.
GSM/GPRS/UMTS,
Microwave and Infrared
√ √
one of the leading projects among the ones listed earlier.
This is a project that is funded by the German Ministry of
Education and Research (BMBF) and Daimler Chrysler AG.
It provides a V2V communication framework which uses
ad hoc networking principles. The framework is used for
different applications including cooperative driver assistance,
decentralized floating vehicle data (e.g. traffic jam monitoring
information, route weather forecast, etc), and user communi-
cations and information services (e.g. Internet access, mobile
advertising, distributed games, etc). Routing of data packets
is done using a position-based forwarding strategy. This latter
strategy is well suited for V2V communication. Nodes forward
packets from the source by performing a geocast which
consists of broadcasting a packet in a limited geographic
area around the source node. Forwarding of the packets is
done in a greedy fashion in the geographic direction of the
destination based on the position of the source, destination
and the intermediate node. Due to this forwarding strategy, no
route discovery is needed before sending data packets, and no
associated routing tables at intermediate nodes are necessary.
This routing approach requires location awareness of the nodes
through GPS or other positioning systems in addition to a
system for sharing and management of position information
in the corresponding ad hoc network.
The following are the main features of a typical IVC
systems such as FleetNet:
•Wireless multihop ad hoc networking with provisioning
for connectivity even in low traffic density situations.
•Use of unlicenced radio spectrum.
•Low data transmission delay which is necessary for
cooperative driving and safety applications.
•Position-based vehicle addressing which allows position-
based addressing and location-based services.
•V2V and V2I communication.
•Intended to be an open standard.
•Support for high bit rates and adaptability to relative high
speeds.
•IEEE 802.11 standard is used in the development and
testing phase.
IV. IVC S YST EMS RE SEA RCH AT EACH ONE OF THE
NETWORKING LAYER S
A. Physical layer and MAC Layers
Some research have been conducted to study the special
requirements of IVC communication at the physical and
medium access control layer level. We consider these two
layers together due to the following reasons: (1) In most
literature they are investigated and studied together. (2) They
are closely related since they are provided by the underlying
network protocol that is used (e.g. IEEE 802.11p, IEEE
802.14.5, etc.). (3) It is easier to classify and evaluate the
research work that addresses these two layers in IVC systems.
The paper in [25] presents a study of the effectiveness of using
steerable beam directional antennas with the IEEE 802.11b
protocol in V2V communication. The study shows that the
use of directional antennas improves the signal-to-noise ratio
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(SNR) with up to 14 dB, improves the transmission range
by 50% to 80% depending on the environment, and allows an
increase of 2 to 4 times in the data rate compared to the omni-
directional case. The protocol uses GPS coordinates in order
to determine beam direction in a continuous fashion without
the need for expensive scanning and probing methods.
In [26], a communication model for radio wave propagation
in IVC systems is presented. In the proposed model, the build-
ing density, defined as building existence to total area ratio,
and an angle between the road and the line-of-sight of two
vehicles are used instead of detailed information of buildings
and maps which are used in other models. This model can
be used to characterize radio wave propagation more easily
and accurately when simulating protocols designed for IVC
systems.
In [27] the authors provide a performance evaluation of
the IEEE 802.11p Wireless Access in Vehicular Environ-
ments (WAVE) standard. The standard provides multi-channel
Dedicated Short Range Communication (DSRC) for V2V
communication. At the physical layer, the WAVE standard
has seven channels with 10 MHz bandwidth for each. They
consist of one control channel (CCH), four service channels
(SCHs), one accident avoidance safety of life channel, and
one high power long range channel. The study found that with
an increase of the number of nodes, the collision probability
increases significantly, which result in many dead times where
the channel is blocked and no useful data is exchanged. In
dense scenarios the technology cannot ensure time critical
messages dissemination. The authors suggest the use of a re-
evaluation mechanism for messages to reduce the number of
high priority messages and prevent long message queues.
Another area of research is to study the characteristics and
efficiency of existing MAC protocols for use in IVC systems.
In [28], Khaled et al. provide a performance analysis of the
IEEE 802.11 protocol when it is used for IVC networks.
Through simulation using ns-2, the authors discovered that
UDP performs better than TCP for such networks. This is due
to the general instability of connections in the highly mobile
IVC networks which cause frequent dropping of transmitted
packets. On the other hand, TCP is designed to automatically
assume that all dropped packets are due to network conges-
tion because it was originally conceived for wired networks
with more stable connections. Consequently, TCP immediately
shrinks the transmitter’s congestion window thereby drastically
reducing the connection throughput. The IEEE 802.11b pro-
tocol was used with a communication range of 520 m. In the
related simulation, the following parameters are varied: the
number of vehicles (4 to 16 vehicles), inter-vehicular distance
(from 50 to 400 m), and inter-packet delay (from 11 to 50
ms). The authors measured the impact of these variables on
end-to-end delay, data loss, and the number of hops between
the source and the destination. Their results show that the
IEEE 802.11 protocol can be used for IVC networks with slow
data rates. They argue that with adding proper re-transmission
heuristics, better results could be obtained.
Medium access control (MAC) refers to the data link layer
that operates directly above the physical layer. It provides
mechanisms for physical addressing and access control for
the communication media. Designing or selecting the MAC
protocols is an important issue in the design of IVC networks.
This is mainly due to the characteristics and requirements of
IVC applications. For example, applications such as active
traffic safety require very low delay, reliable and real-time
communication with minimal transmission collisions [29].
There are some MAC protocols that are suitable for related
environments such as mobile ad hoc networks (MANETs).
Generally in MANETs, nodes use multiple transmission chan-
nels in which each one is considered as a shared medium
that two neighboring nodes cannot transmit simultaneously to
avoid transmission collisions. To efficiently utilize the trans-
mission channels a number of protocols were proposed. One of
the MAC protocols used for MANETs is the IEEE 802.11 [30].
IEEE 802.11 operates in two modes: communication through
access points mode and communication through ad hoc points
mode. In the second mode, mobile nodes are allowed to
communicate directly without using a centralized point. This
mode can be used for both MANETs and IVC. However, an
efficient transmission channel sharing is more difficult in IVC
due to the high node mobility and fast topology changes.
The IEEE 802.11 MAC layer is a Carrier Sense Multiple
Access with Collision Avoidance (CSMA/CA) protocol. There
are two mechanisms used in IEEE 802.11 to determine if the
communication medium is idle or not. The first is the physical
carrier sensing that depends on the availability of some hard-
ware in the physical layer. However, this mechanism cannot
overcome the hidden terminal problem [31]. The second is the
virtual carrier sensing based on a timer that indicates the period
for which the medium will be busy. Each node in the IEEE
802.11 ad hoc mode will first check the medium state before it
transmits. If the medium is idle for certain duration of time, the
node can transmit. Otherwise, it backs off and waits some time
before it tries again. IEEE 802.11 is based on RTS/CTS/ACK
to access the medium. This mechanism reduces the risk of
frame collisions [x4].
Khaled et al. [28] studied the characteristics and efficiency
of the IEEE 802.11 protocol and provided a performance anal-
ysis when it is used for IVC networks. Through simulations
using ns-2, the authors discovered that UDP performs better
than TCP for such networks. The IEEE 802.11b protocol was
used with a communication range of 520 m. In the related
simulation, the following parameters are varied: the number of
vehicles (4 to 16 vehicles), inter-vehicular distance (from 50 to
400 m), and inter-packet delay (from 11 to 50 ms). The authors
measured the impact of these variables on end-to-end delay,
data loss, and the number of hops between the source and the
destination. Their results show that the IEEE 802.11 protocol
can be used for IVC networks with only slow data rates. They
argue that with adding proper re-transmission heuristics, better
results could be obtained. It was clear that reliable and fast data
rates for IVC requires some enhancements in the IEEE 802.11
MAC layer.
An amendment version to the IEEE 802.11 standard is
the IEEE 802.11p which adds Wireless Access in Vehicular
Environments (WAVE). IEEE.11p specifies both the physi-
cal layer management and MAC layer management features
required for vehicular environments. It includes features for
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communication among high-speed vehicles as well as between
the vehicles and the roadside infrastructure. In addition, IEEE
802.11p was proposed to support QoS. The performance
of IEEE 802.11p was evaluated under different scenarios
[20][32]. The results show poor performance on the highways
with high node density scenarios where the collision prob-
ability increases. As a result, this increases packet loss and
average delay thus the critical message dissemination can not
be guaranteed for safety applications.
There are some proposals to use ALOHA, Frequency Divi-
sion Multiple Access (FDMA), Time Division Multiple Access
(TDMA), Code Division Multiple Access (CDMA), and Space
Division Multiple Access (SDMA) based MAC protocols
for IVC. These protocols can provide collision-free medium
access. However, these protocols also have drawbacks. Some
protocols such as CDMA and FDMA require additional com-
plex hardware while others like TDMA based MAC protocols
requires node synchronization which is difficult to achieve
as the network topology changes very dynamically. Some
research proposed the use of multiple directional antennas
for fast communication. One example is RPB-MAC protocol
[33] that guarantees minimum channel access delays by using
multiple antennas. The number of channel collisions is reduced
as vehicles in different directions communicate using different
antennas.
Cellular mobile networks such GSM, GPRS, 3G, and 4G
can be also used for IVC [34]. This solution is good for
communication as the infrastructure is already there and spe-
cialty when vehicles are on highways outside major cities. In
addition, cellular mobile networks support long-range commu-
nications, supports high-speed mobility as well as offer quality
of service guarantees. However, cellular networks can not
support a large number of users with high traffic volumes for
long periods as this network uses single hop communications
to centralized base stations which form major bottlenecks.
B. Network/routing layer
The network layer is the subject of a lot of research in IVC
systems since it is responsible for broadcasting, routing, and
managing the end-to-end communication of vehicles among
each other as well as between vehicles and the backbone
networking infrastructure. At the network layer we discuss
three types of research work: (1) Geographic routing. (2)
Broadcasting, and (3) Delay tolerant routing. In the geographic
routing category we mention two papers. In [24], Festag et
al. investigate the performance of FleetNet in IVC systems.
The paper compares greedy position-based routing with the
Dynamic Source Routing (DSR) protocol [35] which is purely
topology based. The experiment used real cars equipped with
IEEE 802.11b wireless LAN modules as well as Linux-based
FleetNet routers. The results show that position-based routing,
which forwards routes on the fly without the need for route
discovery and maintenance, is more efficient than DSR in a
highly mobile environment. However, in city scenarios, simple
greedy forwarding proved not to be very efficient due to the
lack of correlation with available ”streets” to the destination.
On the other hand, very good results could be obtained by
combining position-based and map-based (i.e. topological)
routing strategies. This gain in efficiency comes at the cost
of more demanding processing requirements from the routing
module. In another paper [36], Tian et al. propose a spatially
aware packet routing protocol for inter-vehicular MANETs
which is optimized to perform better in this environment. The
protocol relies on geographic information to predict permanent
topology holes caused by spatial constraints (roads, etc.) and
avoid them. This strategy can significantly improve routing
performance over existing generic MANET routing protocols
in IVC network environments where geographic holes are very
frequent.
In the broadcasting category, a specialized broadcast algo-
rithm for IVC systems is presented in [37]. Using this algo-
rithm, each node that receives a broadcast message forwards it
after a back-off delay that is dependent upon its distance from
the source. The algorithm relies on GPS information available
to a typical vehicle with IVC technology in order to increase
reliability and message propagation speed, as well as reduce
redundancy. As mentioned earlier, broadcasting is important
and essential to IVC systems for self-organization, manage-
ment, control, and data exchange functions. For example, an
efficient and rapid broadcast is essential for the propagation
of alert messages to upcoming vehicles.
Finally, in the delay-tolerant network category, Virtual Ferry
Networking (VFN) is presented in [38] and represent another
routing strategy that is proposed for use in IVC systems. This
strategy uses a store and forward approach which relies on
the expected mobility of vehicles to forward messages across
a network that might even be disconnected at a particular
instance of time. The VFN protocol is designed to function
between the application and routing layer of the networking
stack, and assumes that the network uses a geolocation system
such as GLS [39] to map vehicles to locations. VFN improves
the message delivery ratio by allowing delivery of messages
that would otherwise fail due to the fact that the source
and destination might belong to different temporary partitions
of the network. This form of forwarding of messages can
be useful for some applications such as publish/subscribe
messaging, geostationary messaging, advertisement of travel-
time notifications, and safety warnings (e.g. slippery roads,
crashed vehicle ahead). However, it is limited to delay-tolerant
services due to the store-and-forward nature of the mechanism
that is used. Consequently, this approach might not be efficient
in the fast response services that were described earlier. As
can be seen some research has been done at the network layer
but much more is still needed in order to adapt the message
routing and broadcasting strategies to the special nature and
characteristic of various services in IVC systems depending
on the type of traffic supported and the applications that are
involved.
C. Transport layer
The transport layer is responsible for process-to-process
communication between hosts in different vehicles in V2V
communication or between vehicles and servers in V2I com-
munication. In most IVC systems, the common transport
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layer protocols are the TCP and UDP protocols. The first is
used to provide reliable connection-oriented services, and the
latter provides light weight connectionless services. Since IVC
systems are mostly wireless, these transport protocols usually
rely on lower layers provided by common wireless protocols
such as IEEE 802.11. Such protocols try to handle most of the
problems and challenges of the wireless medium (e.g. noise,
fading, high bit error rates, etc.) at the lower layers instead
of passing it over to these transport layer protocols which
were originally designed for wired systems. The IEEE 802.11p
protocol is a new specialized version of the IEEE 802.11
protocol which is tailored specifically for the IVC systems
environment. This adapted protocol works well in a mobile
ad hoc networking environment with a high number of nodes,
moving at high speeds, and using the frequency spectrum that
is appropriate for IVC systems. More research is needed in
this area in order to test and optimize the current transport
layer protocols to work more efficiently under the conditions
and specifications that exist in IVC systems.
In [40] Schmilz et al. study the characteristics of communi-
cation paths in VANETs in a typical highway scenario. They
analyze parameters such as connectivity, disruption duration,
packet loss, packet ordering, round trip time (RTT), and RTT
jitter. They found that steady connectivity where interruptions
do not last longer than 10 s is feasible for distances up to 2000
m. However, the packet loss ratio can be substantial. Below
distances of 700 m the RTT and RTT jitter are acceptable but
increase drastically for higher distances. Based on the results,
the paper presents a design for a unicast transport protocol
for VANETs with objectives of maximizing throughput with
reliable in-sequence segment delivery along with flow and
congestion control that are adapted to the characteristics of
the VANET communication environment. The main idea is to
use information about the elapsed V2V connectivity duration
and other statistical parameters to predict current and future
connectivity states to better adjust to the special conditions in
VANETs. Even though the paper does a reasonable analysis of
the end-to-end and session oriented challenges of the VANET
environment, they do not provide details of how these these
important challenges can be overcome by a new adaptable
transport layer protocol. Specific solutions that address these
issues are yet to be provided.
The authors in [41] investigate the performance of TCP in
ad hoc networks and determine the various significant draw-
backs including slow start, window-based transmissions, loss-
based congestion detection, linear increase and multiplicative
decrease of the sender window, and use of transmission time
outs. In order to remedy these problems they present the
ad hoc transport protocol (ATP), which relies on layer-based
coordination with link information feedback from the lower
layers which clearly identify the cause of dropped packets,
and decoupling of congestion control and reliability. While
the paper presents a good evaluation of the ATP protocol
which show significant improvements over TCP several issues
remain to be considered. ATP relies on several configurable
parameters which are critical for good performance. More
research is needed to adapt this protocol to the VANET
environment which have specific mobility patters in city and
rural areas. The protocol does not consider very lossy links
which is a characteristic that can be prevalent in VANETs
exiting in city scenarios.
MRTP, A Multiflow Real-Time Transport protocol for ad
hoc networks in presented in [42]. The protocol is design
to improve the performance of QoS traffic in ad hoc net-
work through the use of traffic partitioning which is shown
to improve the queueing performance of multimedia data
resulting in less congestion, reduced delay and better link
utilization. Although this protocol is designed for a mobile
node environment it would be useful to take advantage of
the findings of this research to improve transport protocols
for VANETs which have the specific mobility characteristics
which were mentioned earlier. Such a protocol would be useful
for V2V multimedia audio/video communication with more
demanding and stringent QoS requirements. It does not cover
the V2I case which would be more likely to be used for real-
time and multimedia communication between vehicles and
fixed infrastructures including the Internet.
In [43] a Persistent Connection Management Protocol
(PCMP) is used as a key component in a Drive-thru Internet
architecture. PCMP operates at the session layer on top of
the TCP protocol in the presence of intermittent connectivity
and address changes in order to maintain reliable transport
layer sessions. The objective is to provide Internet access for
mobile users in moving vehicles such as cars and trains on
WLAN technology deployed on the side of the road. The
PCMP architecture reliers on the use ofa Drive-thru proxy
operating at the transport and application layers as interme-
diaries to maintain persistent connections between the mobile
node and the destination application. The paper provides good
detail about the implementation and demonstrates acceptable
operation of the protocol. However, the architecture relies on
the availability of a sufficient density of hot spots (in the area
of travel of the mobile user, which may not be available in a
large number of areas.
D. Application layer
Numerous applications have been designed to take ad-
vantage of the capabilities and features that IVC systems
offer. The paper in [44], discusses the use of IVC systems
and exchanged data to provide distributed intelligence among
vehicles, which when combined with the use of intelligent
speed adaptation controller technology can enhance traffic per-
formance, increase effective highway capacity, reduce traffic
congestion, and increase safety. The IVC-based controller uses
mildly perceptible acceleration modifications to trigger send-
ing warning messages to other vehicles in the same geographic
area. In all of these systems, multihop communication through
retransmissions via intermediate vehicles is used to increase
the effective range and further magnify the impact of the stated
services and their benefits.
The paper in [45], presents a Railway Collision Avoidance
System (RCAS). The proposed system is similar to the aero-
nautical Traffic Alert and Collision Avoidance System (TCAS)
[46] and the maritime Automatic Identification System (AIS)
[47]. It requires relatively limited infrastructure components
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and has been shown to significantly reduce the probability of
collisions. RCAS consists mainly of ad hoc networking com-
ponents without requiring extensions to the railway infrastruc-
ture. Individual trains determine their position, direction and
speed using the European global navigation system GALILEO
[48], and thus broadcast this data along with other important
information such as dangerous goods classifications, in the
region of its current location. The information is received
and evaluated by other trains. This information analysis may
lead to traffic alerts, resolution advisories, or even direct
intervention (e.g. applying brakes) if the possibility of collision
is detected.
In [23], Bechler et al. propose a communication architecture
called MOCCA (MObile CommuniCation Architecture), as
an Internet integration approach for future IVC systems.
MOCCA uses an IPv6-based proxy architecture along with
Mobile IP for handling vehicle mobility. The proxy allows
inter-operability with Internet protocols by separating end-
to-end connections. Additionally, optimized communication
protocols as well as a more scalable service discovery protocol
are included in MOCCA in order to improve the efficiency
of communication between the vehicles and the proxy. The
system also includes a second proxy in the vehicle to interface
with common IP-based applications running on passenger
mobile devices.
In [49], the authors present a Vehicular Collision Warning
Communication (VCWC) protocol to support V2V communi-
cation in emergency situations. It defines a vehicle involved
in an emergency as an Abnormal Vehicle (AV) and provides
a congestion control mechanism to support stringent delay
requirements for emergency situations. In such situations,
vehicles communicate rapidly to inform other vehicles/drivers
in the same group of interest in order to take corrective action
to avoid imminent collisions. Such congestion conditions can
arise rapidly once an abnormal event is detected by the AV
sensors and is quickly propagated to nearby vehicles which
forward related messages. The flooding of the propagated
messages can involve a good amount of redundancy. The paper
identifies three states that a vehicle involved in the abnormal
situation might have and builds the congestion control mecha-
nism based on transitions between these states in combination
with a traffic priority and redundancy elimination strategy. The
simulation shows improvements in message delay when the
number of vehicles involved increases.
V. OTHE R ISS UES A ND CHALLENGES IN IVC SYS TEM S
A. Security
In [50], Papadimitratos et al. consider the security is-
sues in IVC systems. The authors provide an analysis of
the different types of threats to which such systems can
be susceptible from anti-social and criminal attackers. For
example, an attacker might ”contaminate” a large part of
the network with false information: A vehicle can transmit
false warnings, or messages in order to masquerade as an
emergency vehicle to cause other vehicles to slow down and
yield. In addition, messages transmitted from vehicles using
IVC systems can be used to track down a vehicle’s location
and transactions which can lead to information about the
driver and passengers. In order to protect IVC systems from
such possible attacks, various security requirements should be
implemented such as: message authentication and integrity,
message non-repudiation, entity authentication, access control,
accountability, and privacy protection. Furthermore, security
measures must be taken in order to ensure secure beaconing,
neighbor discovery, and geocasting processes which constitute
important functional parts of IVC systems.
In [51], Dressler et al. outline security requirements and
objectives for Traffic Information Systems (TIS) and provide
some possible solutions for such systems. They discuss the
issues related to centralized TIS, Floating Car Data (FCD),
and distributed TIS. The latter model is also referred to
as decentralized Self-Organizing Traffic Information System
(SOTIS) [52]. The authors identify security objectives such as
confidentiality, data integrity, availability, and access control.
In addition, they provide different attacker models for IVC
systems including insider versus outsider, malicious versus
rational, active versus passive, and global versus local. The
paper proposes solutions related to confidentiality, message
integrity/authentication, key management/security updates, se-
cure positioning, and privacy.
B. The linear nature of most IVC systems
In addition to the above, the special characteristics of
IVC systems provide further research opportunities [53]. For
example, linear ad hoc and sensor networks is a new area
of research which can contribute to the optimization of IVC
systems and protocols. In such networks, the nodes are aligned
in a linear formation which characterizes the node positions
in IVC systems. Vehicles on a long highway constitute a good
example of such an alignment. Figure 2 shows a vehicular
linear ad hoc network that is not connected to roadside
infrastructure. In the figure, vehicles S1 and S2 are sending
data to vehicles D1 and D2 respectively. Both sessions are
using the intermediate vehicles between them as routers.
Figure 3 shows a vehicular linear network that is connected
to roadside infrastructure nodes that serve as gateways to
infrastructure networks including the Internet. In the figure,
node S1 is communicating with access point A1, which is
the closest one to it in number of hops. Similarly, node S2
is communicating with access point A2. As vehicles continue
to move, they will continuously switch to the nearest access
point using a hand over mechanism. The two figures also
show the possibility of having three types of nodes: Basic
Sensor Nodes (BSNs), Data Relay Nodes (DRNs), and Data
Dissemination Nodes (DDNs). The function of the BSN nodes
is to perform their designated and possibly diversified sensing
operations. Then, they communicate their information to the
DRN nodes. The DRN nodes are responsible for routing the
information to the nearest DDN node. The DDN nodes are
the gateway nodes which provide connectivity to the control
center, the Internet, or any other backbone network depending
on the application involved. More details about these types
of nodes and the related framework can be found in [54].
The paper presents related research that has been done on
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Fig. 2. A vehicular linear ad hoc network with V2V communication.
Fig. 3. A vehicular linear ad hoc network with V2I communication.
Linear Sensor Networks (LSNs) and linear ad hoc networks,
which, as indicated earlier, share a lot of common requirements
and characteristics with IVC systems. The results of this
research as well as future work to optimize and enhance the
performance of such networks can be beneficial and useful to
IVC systems design leading to increased network performance
and reliability.
C. Middleware support for IVC systems
Middleware platforms offer many novel approaches and
enhancements in developing and operating inter-vehicle ap-
plications. Middleware is defined as a software layer between
applications and multiple distributed resources such as net-
worked vehicles. It masks the heterogeneity and distribution
of these underlying resources and provides advanced services
for implementing and operating V2V applications. It simplifies
the communication among the distributed components of ve-
hicle applications and provides a unified programming model
to application developers. It can provide common services
needed by different V2V applications. These services could be
for interoperability support, real-time communication support,
communication reliability enhancements, security enhance-
ment and management, and efficient resource utilization and
management. A number of middleware platforms and services
were developed to provide support for both V2V and V2I
communications and applications. Some research was done
in the generic area of mobile ad hoc networks [60] where
V2V communication is a special case. In this section, we
will cover only the middleware platforms and architectures
are specifically designed for inter-vehicle systems. These have
been designed to respond to the dynamic nature of the envi-
ronment they serve as well as fulfilling the need for real-time
support for vehicle applications. An example of a middleware
that provides real-time communication support is RT-STEAM
[55]. RT-STEAM is an event-based middleware that provides
guaranteed real-time message propagation for vehicular ad hoc
networks. It supports hard real-time event delivery and filtering
mechanism. The filtering can be based on subject, content,
and proximity. Unlike other event middleware systems, there
is no centralized event broker or look-up service. Another
middleware example that provides real-time communication
support in heterogeneous environments is Seaware [56]. Sea-
ware is a publish-subscribe middleware that was developed
to support heterogeneous vehicles including autonomous un-
derwater vehicles, remotely operated vehicles, unmanned air
vehicles, and autonomous surface vehicles. Seaware uses Real-
Time Publish-Subscribe messaging (RTPS) and other transport
protocols. RTPS is a standard protocol for communicating
over lightweight unreliable network transport such as UDP.
Seaware can support other heterogeneous transport vehicles
such as acoustic modems for underwater communications,
raw UDP transport, and HTTP transport. Another middleware
that provides advanced real-time support is MARCHES [57].
MARCHES is a context-aware reflective middleware for adap-
tive real-time vehicle applications. This framework was created
with the motivation to improve vehicle safety and reduce traffic
congestion. The created context-aware reflective middleware
can measure real-time contexts and accordingly reconfigure
the behavior of supported applications. This is very important
to improve the flexibility, adaptability, and affordability of the
future vehicle safety systems. Unlike other context-aware re-
flective middleware, the suggested middleware can provide fast
reconfiguration time to satisfy the strict real-time requirements
of vehicle applications. Other types of middleware systems are
designed to enable efficient V2V as well as V2I communica-
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TABLE II
SUMMARY OF TYPICAL IVC SYS TE MS R ES EA RC H AT VARIO US L AYER S O F TH E NE TW OR KI NG S TACK .
Protocol/Sys. Comm.
Layer/Cat.
Description Protocol/Spec. V2V V2I
Festag et al.
[24]
Network/ rout-
ing
Position-based routing is compared with typical ad hoc network routing protocol
such as DSR. Better results can be achieved by combining position-based and
map-based strategies.
Position-based routing, IEEE
802.11b, and Linux-based
FleetNet routers
√
Bechler et al.
[23]
Application MOCCA (Mobile CommuniCation Architecture) as an Internet integration
approach for IVC systems. Interoperability with Internet protocols. IP-based
applications in vehicles running on top of FleetNet Data link and Physical layers
access the Internet via roadside Internet Gateways (IGWs) using predefined
Global addresses.
IPv6-based proxy, Mobile IP,
FleetNet Data link and Physi-
cal layers
√ √
Subramanian
et al. [25]
Physical Use of steerable beam directional antennas with IEEE 802.11b in V2V systems.
GPS used for beam direction.
IEEE 802.11b √
OISHI et al.
[26]
Physical A communication model for radio wave propagation for IVC systems in urban
areas. Building density is proposed to be used for simpler and more accurate
IVC system simulations.
2.2 GHz radio frequency √
Khaled et al.
[28]
Data link/MAC Authors study the performance of IEEE 802.11b protocols in the IVC networking
environment. With current protocol, slower data rates would have to be used.
Adaptable transmission heuristics needed to improve performance in delay and
data loss.
IEEE 802.11b √
Fasolo et al.
[37]
Network/ rout-
ing
Specialized broadcast algorithm for IVC systems. Relies on GPS information to
increase message propagation speed and reduce redundancy
Smart Broadcast, IEEE
802.11, GPS
√
Choffnes et al.
[38]
Network/ rout-
ing
Virtual Ferry Networking (VFN). Store and forward approach to routing mes-
sages in IVC systems. Not suitable for fast response services. Only suitable for
delay-tolerant applications.
VFN √
Tian et al. [36] Network/ rout-
ing
Spatially aware packet routing for Inter-vehicular MANETs. Protocol uses
geographic information to avoid predictable and permanent topology holes
caused by road structures in IVC systems and improve routing performance
over generic MANET protocols.
Spatially Aware Routing
(SAR), Geographic Source
Routes (GSR) and GSR-based
forwarding
√
Kates et al.
[44]
Application Intelligent speed adaptation controller technology in vehicles to enhance traf-
fic performance, increase effective highway capacity, reduce congestion, and
increase safety.
ACC controller, BMW
XFACE
√ √
Strang et al.
[45]
Application Railway Collision Avoidance System (RCAS). Uses Ad hoc networking com-
ponents without the need for extension to railway infrastructure. Provide traffic
alerts, or direct system intervention if collision possibility is detected.
GALILEO/GPS, Global
Navigation Satellite System
(GNSS)
√
Yang et al.
[49]
Application Vehicle Collision Warning Communication (VCWC) protocol to support V2V
communication in emergency situations. Data traffic congestion control mecha-
nism to prevent delays due to sudden abnormal events in vehicles.
DSRC (Dedicated Short
Range Communications)
services with IEEE 802.11
DCF, GPS
√
Papadimitratos
et al. [50]
Security Security issues in IVC systems. Types of threats from anti-social and criminal
attackers. Security requirements and measures that should be implemented.
Position-based routing, Geo-
cast, GPRS, TCP/IP
√ √
Dressler et al.
[51]
Security Outline challenges and objectives of different models of IVC systems including
centralized and distributed ones. Propose some solutions to the different attack
types.
GPS-based systems. Central-
ized and distributed Traffic In-
formation System (TIS).
√ √
Jawhar et al.
[53]
Application/
Routing
Architectural model taking advantage of the linear alignment of nodes in most
IVC systems. Research to use this characteristic to optimize the performance
of the different protocols at the various layers of the networking stack in IVC
systems.
Linear ad hoc network rout-
ing protocols, IEEE 802.11,
WIMAX, Zigbee, GPRS
√ √
Hughes et al.
[55]
Application/
Middleware
Event-based middleware. Provide guaranteed real-time message propagation in
IVC systems
RT-STREAM event-based
middleware
√
Marques et al.
[56]
Application/
Middleware
Publish-subscribe middleware. Developed to support heterogeneous vehicles in-
cluding underwater, surface, and air autonomous vehicles. Support for accoustic
modems. Use Real Time Publish and Subscribe (RTPS) network protocol.
Seaware, support UDP and
HTTP transport.
√
Liu et al. [57] Application/
Middleware
MARCHES: a context-aware reflective middleware for adaptive real-time ve-
hicule operations. Improve vehicle safety and traffic congestion.
MARCHES, XML. √ √
Guo et al. [58] Application/
Middleware
Mobile agent-based middleware architecture for distributed V2V coordination. JNomad, Sun Microsystems
Jini platform
√
Manasseh et
al. [59]
Application/
Middleware
Middleware architecture for traffic-related data and traffic operation and safety.
Data collected from sensors in vehicles and intersections. Provide Geo-spatial
query interface for locating sensors.
GPS, different distributed
platforms (CORBA, Java
RMI, etc.)
√ √
tion. Middleware can be used to improve communication relia-
bility in dynamic environments. Resources such as bandwidth
and error rates can change dynamically due to the ad hoc
nature of V2V communication environments. Mobile agent-
based middleware was used to support distributed coordination
and communication in vehicle systems [58]. In addition, a
middleware architecture for producing traffic related data for
traffic operations and safety was developed [59]. This data
can be collected from a mobile sensor network comprised of
vehicles and intersections. The developed architecture reduces
the complexities of the heterogeneous communication layer
and data sources by providing a uniform interface to collect
data from the sensors. It also provides a geo-spatial query
interface that allows locating the sensors.
Table II offers a summary of IVC systems research at
various layers of the networking stack that was discussed in
this paper.
VI. OPEN RE S EA RCH A ND FUT URE DIRECTIONS
Despite the research that has been done on IVC systems,
a good amount of open problems remain and need to be
addressed. In this section, we outline some of these problems
and the most important future directions for research in this
area:
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•Design of distributed systems and protocols that do not
rely on fixed roadside infrastructures, in order to provide
reliable communication which is possible in metropolitan
as well as rural areas.
•Adopting consistent IVC networking standards and pro-
tocols which enable the manufacturing and deployment
of hardware and software components with common in-
terface that are able to interconnect to provide dependable
communication for IVC services.
•Researchers and designers must provide protocols that are
highly adaptable to the frequent and highly variable link
state changes and short link lifetime due to the mobility
of the nodes in IVC systems.
•While providing best effort and delay-tolerant communi-
cation services in IVC systems is feasible with relatively
good performance, it is quite challenging to provide
support for real-time and multimedia application that
have stringent QoS requirements such as delay, delay
jitter, bandwidth and low packet loss. Consequently, more
research work is needed to provide QoS support for IVC
systems at all of the layers of the networking stack.
•A lot of the research in IVC systems focuses on particular
applications. There is a real need to design protocols,
services, and architectures which can be used by most
IVC applications
•A good amount of research have been done at the data
link, and routing layer. However a lot of this work deals
with short-range local communication. In addition, the
research done at the transport layer is very limited. Much
more work is needed across these layer in order to provide
reliable end-to-end communication which support the
wide range of promising applications of IVC systems.
•Various wireless networking protocols are used as a part
of a vehicle as well as might be transported by vehicles.
For example vehicles might have a mixture of devices that
use protocols such as IEEE 802.15.4 (Zigbee), Bluetooth,
IEEE 802.11, Wimax, GSM, and others. One aspect of a
successful VANET system is the ability to interconnect
these devices seamlessly among themselves as well as to
infrastructure networks and the Internet. More research is
needed in order to achieve this important goal which can
go a long way to achieve true ubiquitous computing.
VII. CONCLUSIONS
IVC communication is rapidly becoming a very important
area of research due to the considerable advancements in
in-vehicle computing and processing capabilities as well as
the significant improvement in the capacity of mobile and
wireless communication systems. In this paper, a survey of
IVC systems was presented. It included two categories of
communication: V2V and V2I. The latest IVC projects were
offered along with a description of the features and services
that are supported by each one. In addition, a discussion of
the current research in each layer of the networking stack
was presented along with motivations to address some of
the important open issues and future research challenges in
this area. IVC systems are expected to play a powerful role
in providing safer and more convenient driving as well as
greatly contribute to reaching the goal of ”computing anytime
anywhere” of today’s society. A good amount of research has
been done in this field. However, a lot more is still needed
to tackle the characteristic and distinctive challenges that IVC
systems offer at each layer of the networking model.
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Imad Jawhar is an associate professor at The
College of Information Technology, UAE University,
Alain, UAE. He has a BS and an MS in electrical
engineering from the University of North Carolina
at Charlotte, USA, an MS in computer science,
and a Ph.D. in computer engineering from Florida
Atlantic University, USA, where he also served as a
faculty member for several years. He has published
numerous papers in international journals, confer-
ence proceedings and book chapters. He worked at
Motorola as engineering task leader involved in the
design and development of IBM PC based software used to program the
world’s leading portable radios, and cutting-edge communication products
and systems. He was also the president and owner of Atlantic Computer
Training and Consulting, which is a company based on South Florida (USA).
His current research focuses on the areas of wireless networks and mobile
computing, sensor networks, routing protocols, distributed and multimedia
systems. He is the editor of several international journals in his field of
research, and served on numerous international conference committees. He
is a member of IEEE, ACM, and ACS organizations.
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Nader Mohamed is an associate professor at The
College of Information Technology, UAE University,
Alain, UAE. He obtained his Ph.D. in Computer
Science from University of Nebraska-Lincoln, Ne-
braska, USA in 2004. He was an assistant profes-
sor of Computer Engineering at Stevens Institute
of Technology in New Jersey, USA. His current
professional interest focuses on middleware, Inter-
net computing, sensor networks, and cluster, Grid,
and Cloud computing. He published more than 90
refereed articles in these fields.
Hafsa Usmani is working as a research assistant
at The College of Information Technology, UAE
University, Alain, UAE. The main area of research
is wireless networking, wireless sensors networks,
and inter-vehicular communication. She was an as-
sistant professor in Hamdard University. She taught
courses in various engineering and computer science
subjects in the Faculty of Engineering Sciences and
Technology. Before joining Hamdard University, she
had worked as an assistant manager in the Systems
Division of the State Life Insurance Corporation of
Pakistan. Earlier, she worked in Pakistan International Airlines working as
a programming analyst in the Information Systems Department. She also
worked at Siemens Pakistan, as a trainee engineer in its Organization and
Information Systems Department. She has a BE in Computer Engineering
from NED University, and a Masters in Information Technology from Ham-
dard University.
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