14 research outputs found
Investigation of Vehicle-to-Everything (V2X) Communication for Autonomous Control of Connected Vehicles
Autonomous Driving Vehicles (ADVs) has received considerable attention in recent years by academia and industry, bringing about a paradigm shift in Intelligent Transportation Systems (ITS), where vehicles operate in close proximity through wireless communication. It is envisioned as a promising technology for realising efficient and intelligent transportation systems, with potential applications for civilian and military purposes. Vehicular network management for ADVs is challenging as it demands mobility, location awareness, high reliability, and low latency data traffic.
This research aims to develop and implement vehicular communication in conjunction with a driving algorithm for ADVs feedback control system with a specific focus on the safe displacement of vehicle platoon while sensing the surrounding environment, such as detecting road signs and communicate with other road users such as pedestrian, motorbikes, non-motorised vehicles and infrastructure. However, in order to do so, one must investigate crucial aspects related to the available technology, such as driving behaviour, low latency communication requirement, communication standards, and the reliability of such a mechanism to decrease the number of traffic accidents and casualties significantly. To understand the behaviour of wireless communication compared to the theoretical data rates, throughput, and roaming behaviour in a congested indoor line-of-sight heterogeneous environment, we first carried out an experimental study for IEEE 802.11a, 802.11n and 802.11ac standards in a 5 GHz frequency spectrum. We validated the results with an analytical path loss model as it is essential to understand how the client device roams or decides to roam from one Access Point to another and vice-versa. We observed seamless roaming between the tested protocols irrespective of their operational environment (indoor or outdoor); their throughput efficiency and data rate were also improved by 8-12% when configured with Short Guard Interval (SGI) of 400ns compared to the theoretical specification of the tested protocols.
Moreover, we also investigated the Software-Defined Networking (SDN) for vehicular communication and compared it with the traditional network, which is generally incorporated vertically where control and data planes are bundled collectively. The SDN helped gain more flexibility to support multiple core networks for vehicular communication and tackle the potential challenges of network scalability for vehicular applications raised by the ADVs. In particular, we demonstrate that the SDN improves throughput efficiency by 4% compared to the traditional network while ensuring efficient bandwidth and resource management. Finally, we proposed a novel data-driven coordination model which incorporates Vehicle-to-Everything (V2X) communication and Intelligent Driver Model (IDM), together called V2X Enabled Intelligent Driver Model (VX-IDM). Our model incorporates a Car-Following Model (CFM), i.e., IDM, to model a vehicle platoon in an urban and highway traffic scenario while ensuring the vehicle platoon's safety with the integration of IEEE 802.11p Vehicle-to-Infrastructure (V2I) communication scheme. The model integrates the 802.11p V2I communication channel with the IDM in MATLAB using ODE‐45 and utilises the 802.11p simulation toolbox for configuring vehicular channels. To demonstrate model functionality in urban and highway traffic environments, we developed six case studies. We also addressed the heterogeneity issue of wireless networks to improve the overall network reliability and efficiency by estimating the Signal-to-Noise Ratio (SNR) parameters for the platoon vehicle's displacement and location on the road from Road-Side-Units (RSUs). The simulation results showed that inter-vehicle spacing could be steadily maintained at a minimum safe value at all the time. Moreover, the model has a fault-tolerant mechanism that works even when communication with infrastructure is interrupted or unavailable, making the VX-IDM model collision-free
A Survey on platoon-based vehicular cyber-physical systems
Vehicles on the road with some common interests can cooperatively form a platoon-based driving pattern, in which a vehicle follows another one and maintains a small and nearly constant distance to the preceding vehicle. It has been proved that, compared to driving individually, such a platoon-based driving pattern can significantly improve the road capacity and energy efficiency. Moreover, with the emerging vehicular adhoc network (VANET), the performance of platoon in terms of road capacity, safety and energy efficiency, etc., can be further improved. On the other hand, the physical dynamics of vehicles inside the platoon can also affect the performance of VANET. Such a complex system can be considered as a platoon-based vehicular cyber-physical system (VCPS), which has attracted significant attention recently. In this paper, we present a comprehensive survey on platoon-based VCPS. We first review the related work of platoon-based VCPS. We then introduce two elementary techniques involved in platoon-based VCPS: the vehicular networking architecture and standards, and traffic dynamics, respectively. We further discuss the fundamental issues in platoon-based VCPS, including vehicle platooning/clustering, cooperative adaptive cruise control (CACC), platoon-based vehicular communications, etc., and all of which are characterized by the tight coupled relationship between traffic dynamics and VANET behaviors. Since system verification is critical to VCPS development, we also give an overview of VCPS simulation tools. Finally, we share our view on some open issues that may lead to new research directions
Open Platforms for Connected Vehicles
L'abstract è presente nell'allegato / the abstract is in the attachmen
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
VANET Applications Under Loss Scenarios & Evolving Wireless Technology
In this work we study the impact of wireless network impairment on the performance of VANET applications such as Cooperative Adaptive Cruise Control (CACC), and other VANET applications that periodically broadcast messages. We also study the future of VANET application in light of the evolution of radio access technologies (RAT) that are used to exchange messages. Previous work in the literature proposed fallback strategies that utilizes on-board sensors to recover in case of wireless network impairment, those methods assume a fixed time headway value, and do not achieve string stability. In this work, we study the string stability of a one-vehicle look-ahead CACC platoon under different network loss scenarios, and propose to adapt the time headway parameter of the model according to a network reliability metric that we defined based on packet burst loss length to maximize traffic flow efficiency while maintaining a string stable platoon. Our findings show that careful adjustment of headway value according to the wireless network reliability allows the platoon to maintain string stable operation while maximizing traffic flow. We also study the impact that evolving wireless technology can have on VANET applications such as CACC, where we study the performance when using DSRC and 5G NR V2X. In addition, we study the evolution of RATs used in VANET application, and we propose DSRC+, as a possible enhancement to traditional DSRC, that utilizes modern modulation/coding schemes and performs random blind retransmission to improve packet delivery ratio. We finally study the trade-offs in the choice of RAT in VANET applications such as CACC, concluding that RATs with time-division channel access can be reliable with lower packet loss, but performs poorly when needing to disseminate messages over longer CACC platoons
VANET-enabled eco-friendly road characteristics-aware routing for vehicular traffic
There is growing awareness of the dangers of climate change caused by greenhouse gases. In the coming decades this could result in numerous disasters such as heat-waves, flooding and crop failures. A major contributor to the total amount of greenhouse gas emissions is the transport sector, particularly private vehicles. Traffic congestion involving private vehicles also causes a lot of wasted time and stress to commuters.
At the same time new wireless technologies such as Vehicular Ad-Hoc Networks (VANETs) are being developed which could allow vehicles to communicate with each other. These could enable a number of innovative schemes to reduce traffic congestion and greenhouse gas emissions.
1) EcoTrec is a VANET-based system which allows vehicles to exchange messages regarding traffic congestion and road conditions, such as roughness and gradient. Each vehicle uses the messages it has received to build a model of nearby roads and the traffic on them. The EcoTrec Algorithm then recommends the most fuel efficient route for the vehicles to follow.
2) Time-Ants is a swarm based algorithm that considers not only the amount of cars in the spatial domain but also the amoumt in the time domain. This allows the system to build a model of the traffic congestion throughout the day. As traffic patterns are broadly similar for weekdays this gives us a good idea of what traffic will be like allowing us to route the vehicles more efficiently using the Time-Ants Algorithm.
3) Electric Vehicle enhanced Dedicated Bus Lanes (E-DBL) proposes allowing electric vehicles onto the bus lanes. Such an approach could allow a reduction in traffic congestion on the regular lanes without greatly impeding the buses. It would also encourage uptake of electric vehicles.
4) A comprehensive survey of issues associated with communication centred traffic management systems was carried out
Development and Performance Evaluation of Urban Mobility Applications and Services
L'abstract è presente nell'allegato / the abstract is in the attachmen