3,751 research outputs found
Soft-Defined Heterogeneous Vehicular Network: Architecture and Challenges
Heterogeneous Vehicular NETworks (HetVNETs) can meet various
quality-of-service (QoS) requirements for intelligent transport system (ITS)
services by integrating different access networks coherently. However, the
current network architecture for HetVNET cannot efficiently deal with the
increasing demands of rapidly changing network landscape. Thanks to the
centralization and flexibility of the cloud radio access network (Cloud-RAN),
soft-defined networking (SDN) can conveniently be applied to support the
dynamic nature of future HetVNET functions and various applications while
reducing the operating costs. In this paper, we first propose the multi-layer
Cloud RAN architecture for implementing the new network, where the multi-domain
resources can be exploited as needed for vehicle users. Then, the high-level
design of soft-defined HetVNET is presented in detail. Finally, we briefly
discuss key challenges and solutions for this new network, corroborating its
feasibility in the emerging fifth-generation (5G) era
The State-of-the-art of Coordinated Ramp Control with Mixed Traffic Conditions
Ramp metering, a traditional traffic control strategy for conventional
vehicles, has been widely deployed around the world since the 1960s. On the
other hand, the last decade has witnessed significant advances in connected and
automated vehicle (CAV) technology and its great potential for improving
safety, mobility and environmental sustainability. Therefore, a large amount of
research has been conducted on cooperative ramp merging for CAVs only. However,
it is expected that the phase of mixed traffic, namely the coexistence of both
human-driven vehicles and CAVs, would last for a long time. Since there is
little research on the system-wide ramp control with mixed traffic conditions,
the paper aims to close this gap by proposing an innovative system architecture
and reviewing the state-of-the-art studies on the key components of the
proposed system. These components include traffic state estimation, ramp
metering, driving behavior modeling, and coordination of CAVs. All reviewed
literature plot an extensive landscape for the proposed system-wide coordinated
ramp control with mixed traffic conditions.Comment: 8 pages, 1 figure, IEEE INTELLIGENT TRANSPORTATION SYSTEMS CONFERENCE
- ITSC 201
Vision-Based Lane-Changing Behavior Detection Using Deep Residual Neural Network
Accurate lane localization and lane change detection are crucial in advanced
driver assistance systems and autonomous driving systems for safer and more
efficient trajectory planning. Conventional localization devices such as Global
Positioning System only provide road-level resolution for car navigation, which
is incompetent to assist in lane-level decision making. The state of art
technique for lane localization is to use Light Detection and Ranging sensors
to correct the global localization error and achieve centimeter-level accuracy,
but the real-time implementation and popularization for LiDAR is still limited
by its computational burden and current cost. As a cost-effective alternative,
vision-based lane change detection has been highly regarded for affordable
autonomous vehicles to support lane-level localization. A deep learning-based
computer vision system is developed to detect the lane change behavior using
the images captured by a front-view camera mounted on the vehicle and data from
the inertial measurement unit for highway driving. Testing results on
real-world driving data have shown that the proposed method is robust with
real-time working ability and could achieve around 87% lane change detection
accuracy. Compared to the average human reaction to visual stimuli, the
proposed computer vision system works 9 times faster, which makes it capable of
helping make life-saving decisions in time
Infraestrutura de beira de estrada para apoio a sistemas cooperativos e inteligentes de transportes
The growing need of mobility along with the evolution of the automotive industry
and the massification of the personal vehicle amplifies some of the road-related
problems such as safety and traffic congestion. To mitigate such issues, the evolution
towards cooperative communicating technologies and autonomous systems
is considered a solution to overcome the human physical limitations and the limited
perception horizon of on-board sensors. Short-range vehicular communications
such as Vehicle-to-Vehicle or Vehicle-to-Infrastructure (ETSI ITS-G5) in conjunction
with long-range cellular communications (LTE,5G) and standardized messages,
emerge as viable solutions to amplify the benefits that standalone technologies can
bring to the road environment, by covering a wide array of applications and use
cases. In compliance with the standardization work from European Telecommunications
Standards Institute (ETSI), this dissertation describes the implementation of
the collective perception service in a real road infrastructure to assist the maneuvers
of autonomous vehicles and provide information to a central road operator. This
work is focused on building standardized collective perception messages (CPM)
by retrieving information from traffic classification radars (installed in the PASMO
project) for local dissemination using ETSI ITS-G5 radio technology and creating
a redundant communication channel between the road infrastructure and a central
traffic control centre, located at the Instituto de Telecomunicações - Aveiro, taking
advantage of cellular, point-to-point radio links and optical fiber communications.
The output of the messages are shown to the user by a mobile application. The
service is further improved by building an algorithm for optimizing the message
dissemination to improve channel efficiency in more demanding scenarios. The results
of the experimental tests showed that the time delay between the production
event of the collective perception message and the reception by other ITS stations
is within the boundaries defined by ETSI standards. Moreover, the algorithm for
message dissemination also shows to increase radio channel efficiency by limiting
the number of objects disseminated by CPM messages. The collective perception
service developed and the road infrastructure are therefore, a valuable asset to
provide useful information for improving road safety and fostering the deployment
of intelligent cooperative transportation systems.A crescente necessidade de mobilidade em paralelo com a evolução da indústria automóvel
e com a massificação do uso de meios de transportes pessoais, têm vindo
a amplificar alguns problemas dos transportes rodoviários, tais como a segurança
e o congestionamento do tráfego. Para mitigar estas questões, a evolução das
tecnologias de comunicação cooperativas e dos sistemas autónomos é vista como
uma potencial solução para ultrapassar limitações dos condutores e do horizonte
de perceção dos sensores veículares. Comunicações de curto alcance, tais como
Veículo-a-Veículo ou Veículo-a-Infrastrutura (ETSI ITS-G5), em conjunto com comunicações
móveis de longo alcance (LTE,5G) e mensagens padrão, emergem como
soluções viáveis para amplificar todos os beneficios que tecnologias independentes
podem trazer para o ambiente rodoviário, cobrindo um grande leque de aplicações
e casos de uso da estrada. Em conformidade com o trabalho de padronização
da European Telecommunications Standards Institute, esta dissertação descreve
a implementação do serviço de perceção coletiva, numa infrastrutura rodoviária
real, para suporte a manobras de veículos autónomos e para fornecer informações
aos operadores de estradas. Este trabalho foca-se na construção de mensagens
de perceção coletiva a partir de informação gerada por radares de classificação de
tráfego (instalados no âmbito do projeto PASMO) para disseminação local usando
a tecnologia rádio ETSI ITS-G5 e criando um canal de comunicação redundante
entre a infraestrutura rodóviaria e um centro de controlo de tráfego localizado no
Instituto de Telecomunicações - Aveiro, usando para isso: redes móveis, ligações
rádio ponto a ponto e fibra ótica. O conteúdo destas messagens é mostrado ao
utilizador através de uma aplicação móvel. O serviço é ainda melhorado, tendo-se
para tal desenvolvido um algoritmo de otimização de disseminação das mensagens,
tendo em vista melhorar a eficiência do canal de transmissão em cenários mais exigentes.
Os resultados dos testes experimentais efetuados revelaram que o tempo
de atraso entre o evento de produção de uma mensagem de perceção coletiva e a
receção por outra estação ITS, usando comunicações ITS-G5, se encontra dentro
dos limites definidos pelos padrões da ETSI. Além disso, o algoritmo para disseminação
de mensagens também mostrou aumentar a eficiência do canal de rádio,
limitando o número de objetos disseminados pelas mesmas. Assim, o serviço de
perceção coletiva desenvolvido poderá ser uma ferramenta valiosa, contribuindo
para o aumento da segurança rodóviaria e para a disseminação da utilização dos
sistemas cooperativos de transporte inteligente.Mestrado em Engenharia Eletrónica e Telecomunicaçõe
On the Experimental Evaluation of Vehicular Networks: Issues, Requirements and Methodology Applied to a Real Use Case
One of the most challenging fields in vehicular communications has been the
experimental assessment of protocols and novel technologies. Researchers
usually tend to simulate vehicular scenarios and/or partially validate new
contributions in the area by using constrained testbeds and carrying out minor
tests. In this line, the present work reviews the issues that pioneers in the
area of vehicular communications and, in general, in telematics, have to deal
with if they want to perform a good evaluation campaign by real testing. The
key needs for a good experimental evaluation is the use of proper software
tools for gathering testing data, post-processing and generating relevant
figures of merit and, finally, properly showing the most important results. For
this reason, a key contribution of this paper is the presentation of an
evaluation environment called AnaVANET, which covers the previous needs. By
using this tool and presenting a reference case of study, a generic testing
methodology is described and applied. This way, the usage of the IPv6 protocol
over a vehicle-to-vehicle routing protocol, and supporting IETF-based network
mobility, is tested at the same time the main features of the AnaVANET system
are presented. This work contributes in laying the foundations for a proper
experimental evaluation of vehicular networks and will be useful for many
researchers in the area.Comment: in EAI Endorsed Transactions on Industrial Networks and Intelligent
Systems, 201
Computational Intelligence Inspired Data Delivery for Vehicle-to-Roadside Communications
We propose a vehicle-to-roadside communication protocol based on distributed clustering where a coalitional game approach is used to stimulate the vehicles to join a cluster, and a fuzzy logic algorithm is employed to generate stable clusters by considering multiple metrics of vehicle velocity, moving pattern, and signal qualities between vehicles. A reinforcement learning algorithm with game theory based reward allocation is employed to guide each vehicle to select the route that can maximize the whole network performance. The protocol is integrated with a multi-hop data delivery virtualization scheme that works on the top of the transport layer and provides high performance for multi-hop end-to-end data transmissions. We conduct realistic computer simulations to show the performance advantage of the protocol over other approaches
The Dynamics of Vehicular Networks in Urban Environments
Vehicular Ad hoc NETworks (VANETs) have emerged as a platform to support
intelligent inter-vehicle communication and improve traffic safety and
performance. The road-constrained, high mobility of vehicles, their unbounded
power source, and the emergence of roadside wireless infrastructures make
VANETs a challenging research topic. A key to the development of protocols for
inter-vehicle communication and services lies in the knowledge of the
topological characteristics of the VANET communication graph. This paper
explores the dynamics of VANETs in urban environments and investigates the
impact of these findings in the design of VANET routing protocols. Using both
real and realistic mobility traces, we study the networking shape of VANETs
under different transmission and market penetration ranges. Given that a number
of RSUs have to be deployed for disseminating information to vehicles in an
urban area, we also study their impact on vehicular connectivity. Through
extensive simulations we investigate the performance of VANET routing protocols
by exploiting the knowledge of VANET graphs analysis.Comment: Revised our testbed with even more realistic mobility traces. Used
the location of real Wi-Fi hotspots to simulate RSUs in our study. Used a
larger, real mobility trace set, from taxis in Shanghai. Examine the
implications of our findings in the design of VANET routing protocols by
implementing in ns-3 two routing protocols (GPCR & VADD). Updated the
bibliography section with new research work
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