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|Título:||Performance assessment of vehicular delay-tolerant networks|
|Autor:||Soares, Vasco Nuno da Gama de Jesus|
|Orientador:||Rodrigues, Joel José Puga Coelho|
|Palavras-chave:||Redes veiculares com ligações intermitentes|
Vehicular Delay-Tolerant Networking
Vehicular Ad-Hoc Networking
|Data de Defesa:||Jul-2011|
|Editora:||Universidade da Beira Interior|
|Resumo:||Vehicular networks have attracted considerable attention in the last few years, both in
academia and industry. One of the main reasons for their growing popularity can be
attributed to the various applications that they make possible. Road safety, traffic
monitoring, driving assistance, entertainment, and delivering connectivity to rural/remote
communities or catastrophe-hit areas are just a few examples of the many applications
envisioned for these networks. Nevertheless, the special characteristics of vehicular networks
such as high mobility, highly dynamic network topology, short contact durations, disruption,
intermittent connectivity, significant loss rates, variable node density, and network
partitioning introduce unique challenges, which greatly impact the deployment of these
Such challenges make data dissemination and routing interesting research topics within the
vehicular networking area, which are addressed by this research. The work presented in this
thesis is motivated by the need to find new solutions to the communication problems arising
in disconnected opportunistic vehicular networking scenarios. A new network architecture for
vehicular communications is therefore proposed in this work, called vehicular delay-tolerant
network (VDTN). Its layered structure is introduced and the corresponding performance
analysis is conducted. This architecture differs from other proposals in the literature in
several respects. Briefly, it adopts a store-carry-and-forward paradigm combined with an IP
over VDTN approach and out-of-band signaling with control and data plane separation.
This thesis presents studies on the impact of stationary relay nodes, node density, vehicles
movement patterns, and storage constraints on the VDTN network performance, in terms of
bundle delivery probability and bundle average delivery delay. Of particular interest to this
thesis is the performance improvement of these networks. In particular, node localization
information is exploited to improve and optimize the use of data plane resources. It is
demonstrated the performance gains attainable in a VDTN through the cooperation between
network nodes, in terms of bundle delivery probability and bundle average delivery delay.
These performance metrics are also used to investigate the impact of non-priority and
priority-based queueing disciplines.
Finally, a detailed analysis is performed with the proposed routing protocol for VDTNs, called
GeoSpray, against popular single-copy (Direct Delivery, First Contact, GeOpps), and multiplecopy
(Epidemic, Spray and Wait, PRoPHET) routing protocols. Such protocols are considered
reference in the literature of DTN networks and were deployed in VDTNs. It is shown that
GeoSpray yields significant performance gains in terms of the bundle delivery probability and the bundle average delivery delay. The proposed protocol proves to be efficient in terms of
storage and bandwidth resources utilization.
The results presented in this thesis are based on computer simulations and testbed
experiments. The lack of a simulator specialized for VDTN layered network architecture,
created the necessity to propose, develop, and implement a simulation tool for VDTNs, called
VDTNsim. VDTNsim was used as a basis for the creation of a prototype of a VDTN laboratory
testbed, named VDTN@Lab.
This thesis aims to contribute to the advance of the state-of-the-art on techniques for
tackling the challenges that arise from the unique properties of vehicular networks. Further,
this thesis highlights important guidelines for the improvement and design of new protocols,
algorithms, services, and applications for vehicular delay-tolerant networks.|
O presente resumo alargado em língua portuguesa sintetiza a tese de Doutoramento intitulada “Avaliação do Desempenho de Redes Veiculares com Ligações Intermitentes” (Performance Assessment of Vehicular Delay-Tolerant Networks). Começa-se por enumerar os objectivos e referir as principais contribuições desta investigação. Depois são sintetizadas as principais conclusões e apontadas direcções para trabalho futuro.
|Aparece nas colecções:||FE - DI | Dissertações de Mestrado e Teses de Doutoramento|
Ficheiros deste registo:
|vsoares_phd_thesis.pdf||11,93 MB||Adobe PDF||Ver/Abrir|
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