Performance Comparison of AODV and OLSR in
VANETs Urban Environments under Realistic
Mobility Patterns
J´erˆome Haerri
Institut Eur´ecom
‡
Department of Mobile Communications
B.P. 193
06904, Sophia Antipolis, France
Email: Jerome.Haerri@eurecom.fr
Fethi Filali
Institut Eur´ecom
‡
Department of Mobile Communications
B.P. 193
06904, Sophia Antipolis, France
Email: Fethi.Filali@eurecom.fr
Christian Bonnet
Institut Eur´ecom
‡
Department of Mobile Communications
B.P. 193
06904, Sophia Antipolis, France
Email: Christian.Bonnet@eurecom.fr
Abstract— A Vehicular Ad Hoc Network (VANET) is an in-
stance of MANETs that establishes wireless connections between
cars. In VANETs, routing protocols and other techniques must
be adapted to vehicular-specific capabilities and requirements. As
many previous works have shown, routing performance is greatly
dependent to the availability and stability of wireless links, which
makes it a crucial parameter that should not be neglected in
order to obtain accurate performance measurements in VANETs.
Although routing protocols have already been analyzed and
compared in the past, simulations and comparisons have almost
always been done considering random motions. But could we
assess that those results hold if performed using realistic urban
vehicular motion patterns ?
In this paper, we evaluate AODV and OLSR performance
in realistic urban scenarios. We study those protocols under
varying metrics such as node mobility and vehicle density, and
with varying traffic rates. We show that clustering effects created
by cars aggregating at intersections have remarkable impacts on
evaluation and performance metrics. Our objective is to provide
a qualitative assessment of the applicability of the protocols in
different vehicular scenarios.
Index Terms— Urban Environment, Realistic Vehicular Mobil-
ity Models, OLSR, AODV, Performance.
I. INTRODUCTION
Vehicular Ad-hoc Networks (VANETs) represent a rapidly
emerging, particularly challenging class of Mobile Ad
Hoc Networks (MANETs). VANETs are distributed, self-
organizing communication networks built up by moving vehi-
cles, and are thus characterized by a very high node mobility
and limited degrees of freedom in the mobility patterns.
Hence, ad hoc routing protocols must adapt continuously to
these unreliable conditions, whence the growing effort in the
development of communication protocols which are specific
to vehicular networks.
One of the critical aspects when evaluating routing protocols
for VANETs is the employment of mobility models that reflect
as closely as possible the real behavior of vehicular traffic.
‡
Institut Eur´ecom’s research is partially supported by its industrial mem-
bers: BMW Group Research & Technology - BMW Group Company,
Bouygues T´el´ecom, Cisco Systems, France T´el´ecom , Hitachi Europe, SFR,
Sharp, STMicroelectronics, Swisscom, Thales.
This notwithstanding, using simple random-pattern, graph-
constrained mobility models is a common practice among
researchers working on VANETs. There is no need to say that
such models cannot describe vehicular mobility in a realistic
way, since they ignore the peculiar aspects of vehicular traffic,
such as cars acceleration and deceleration in presence of
nearby vehicles, queuing at roads intersections, traffic bursts
caused by traffic lights, and traffic congestion or traffic jams.
All these situations greatly affect the network performance,
since they act on network connectivity, and this makes ve-
hicular specific performance evaluations fundamental when
studying routing protocols for VANETs. Initial works [1],
[2] on performance evaluation considered simple pseudo-
random motion patterns and lacked any interaction between
cars, generally referred as micro-mobility. Following the recent
interest in realistic mobility models for VANETs, new studies
appeared on performance evaluations of VANETs in urban
traffic or highway traffic conditions [3], [4]. However, their
models were quite limited, notably the macro-model, which
also limited the scope of their results.
In this paper, our objective is to evaluate AODV and OLSR
in realistic urban traffic environment. In order to model real-
istic vehicular motion patterns, we make use of the Vehicular
Mobility Model (VMM), which is part on the VanetMobiSim
tool we previously developed (see [5]). This model is able
to closely reflect spatial and temporal correlations between
cars, and between cars and urban obstacles. Notably, the tool
illustrates clustering effects obtained at intersection, also is
more commonly called traffic jam, or drastic speed decays.
Accordingly, it becomes possible to more realistically evaluate
ad hoc routing performances for vehicular networks. We
configure VMM to model urban environment then evaluate
the performance of AODV and OLSR in terms of (i) Packet
Delivery Ratio (PDR) (ii) Control Traffic Overhead (RO), (iii)
Delay, and (iv) Number of Hops. We test AODV and OLSR
in three different conditions (i) variable velocity (ii) variable
density (iii) variable data traffic rate. We show first that the
clustering effect obtained at intersection has a major effect
on the effective average velocity during the simulation. We