119 research outputs found
PERFORMANCE STUDY FOR CAPILLARY MACHINE-TO-MACHINE NETWORKS
Communication technologies witness a wide and rapid pervasiveness of wireless machine-to-machine (M2M) communications. It is emerging to apply for data transfer among devices without human intervention. Capillary M2M networks represent a candidate for providing reliable M2M connectivity. In this thesis, we propose a wireless network architecture that aims at supporting a wide range of M2M applications (either real-time or non-real-time) with an acceptable QoS level. The architecture uses capillary gateways to reduce the number of devices communicating directly with a cellular network such as LTE. Moreover, the proposed architecture reduces the traffic load on the cellular network by providing capillary gateways with dual wireless interfaces. One interface is connected to the cellular network, whereas the other is proposed to communicate to the intended destination via a WiFi-based mesh backbone for cost-effectiveness. We study the performance of our proposed architecture with the aid of the ns-2 simulator. An M2M capillary network is simulated in different scenarios by varying multiple factors that affect the system performance. The simulation results measure average packet delay and packet loss to evaluate the quality-of-service (QoS) of the proposed architecture. Our results reveal that the proposed architecture can satisfy the required level of QoS with low traffic load on the cellular network. It also outperforms a cellular-based capillary M2M network and WiFi-based capillary M2M network. This implies a low cost of operation for the service provider while meeting a high-bandwidth service level agreement. In addition, we investigate how the proposed architecture behaves with different factors like the number of capillary gateways, different application traffic rates, the number of backbone routers with different routing protocols, the number of destination servers, and the data rates provided by the LTE and Wi-Fi technologies. Furthermore, the simulation results show that the proposed architecture continues to be reliable in terms of packet delay and packet loss even under a large number of nodes and high application traffic rates
Joint Scheduling and Duty Cycle Control Framework for Hierarchical Machine-to-Machine Communication Networks.
PhDThis thesis presents a novel distributed optimisation framework for machine-tomachine
(M2M) communication networks with dynamic traffic generation, heterogeneous
applications and different device capabilities. The aim of the framework is
to effectively manage the massive access of energy constrained M2M devices while
satisfying different application requirements. The proposed framework has three
control blocks which run at cluster heads and M2M gateways:
i) The distributed duty cycle control that adapts to dynamic network traffics
for IEEE 802.15.4 MAC layer protocol with stop-and-wait automatic repeat
request (ARQ) and Go-Back-N ARQ schemes.
ii) The cluster head control that applies dynamic programming (DP) and approximate
dynamic programming (ADP) techniques to maximise single cluster
utility while balancing the tradeoff between system performance and algorithm
complexity.
iii) The gateway control that applies network utility optimisation (NUM) and
mixed integer programming (MIP) techniques to maximise the aggregated
long-term network utility while satisfying different application requirements
among clusters.
Both theoretical and practical concerns are addressed by the proposed control
framework. Simulation results show that the proposed framework effectively improve
the overall network performance in terms of network throughput, energy
efficiency, end-to-end delay and packet drop ratio.Chinese Scholarship Council (CSC)
A Survey on LoRaWAN Technology: Recent Trends, Opportunities, Simulation Tools and Future Directions
Low-power wide-area network (LPWAN) technologies play a pivotal role in IoT applications, owing to their capability to meet the key IoT requirements (e.g., long range, low cost, small data volumes, massive device number, and low energy consumption). Between all obtainable LPWAN technologies, long-range wide-area network (LoRaWAN) technology has attracted much interest from both industry and academia due to networking autonomous architecture and an open standard specification. This paper presents a comparative review of five selected driving LPWAN technologies, including NB-IoT, SigFox, Telensa, Ingenu (RPMA), and LoRa/LoRaWAN. The comparison shows that LoRa/LoRaWAN and SigFox surpass other technologies in terms of device lifetime, network capacity, adaptive data rate, and cost. In contrast, NB-IoT technology excels in latency and quality of service. Furthermore, we present a technical overview of LoRa/LoRaWAN technology by considering its main features, opportunities, and open issues. We also compare the most important simulation tools for investigating and analyzing LoRa/LoRaWAN network performance that has been developed recently. Then, we introduce a comparative evaluation of LoRa simulators to highlight their features. Furthermore, we classify the recent efforts to improve LoRa/LoRaWAN performance in terms of energy consumption, pure data extraction rate, network scalability, network coverage, quality of service, and security. Finally, although we focus more on LoRa/LoRaWAN issues and solutions, we introduce guidance and directions for future research on LPWAN technologies
A Survey and Future Directions on Clustering: From WSNs to IoT and Modern Networking Paradigms
Many Internet of Things (IoT) networks are created as an overlay over traditional ad-hoc networks such as Zigbee. Moreover, IoT networks can resemble ad-hoc networks over networks that support device-to-device (D2D) communication, e.g., D2D-enabled cellular networks and WiFi-Direct. In these ad-hoc types of IoT networks, efficient topology management is a crucial requirement, and in particular in massive scale deployments. Traditionally, clustering has been recognized as a common approach for topology management in ad-hoc networks, e.g., in Wireless Sensor Networks (WSNs). Topology management in WSNs and ad-hoc IoT networks has many design commonalities as both need to transfer data to the destination hop by hop. Thus, WSN clustering techniques can presumably be applied for topology management in ad-hoc IoT networks. This requires a comprehensive study on WSN clustering techniques and investigating their applicability to ad-hoc IoT networks. In this article, we conduct a survey of this field based on the objectives for clustering, such as reducing energy consumption and load balancing, as well as the network properties relevant for efficient clustering in IoT, such as network heterogeneity and mobility. Beyond that, we investigate the advantages and challenges of clustering when IoT is integrated with modern computing and communication technologies such as Blockchain, Fog/Edge computing, and 5G. This survey provides useful insights into research on IoT clustering, allows broader understanding of its design challenges for IoT networks, and sheds light on its future applications in modern technologies integrated with IoT.acceptedVersio
Edge Offloading in Smart Grid
The energy transition supports the shift towards more sustainable energy
alternatives, paving towards decentralized smart grids, where the energy is
generated closer to the point of use. The decentralized smart grids foresee
novel data-driven low latency applications for improving resilience and
responsiveness, such as peer-to-peer energy trading, microgrid control, fault
detection, or demand response. However, the traditional cloud-based smart grid
architectures are unable to meet the requirements of the new emerging
applications such as low latency and high-reliability thus alternative
architectures such as edge, fog, or hybrid need to be adopted. Moreover, edge
offloading can play a pivotal role for the next-generation smart grid AI
applications because it enables the efficient utilization of computing
resources and addresses the challenges of increasing data generated by IoT
devices, optimizing the response time, energy consumption, and network
performance. However, a comprehensive overview of the current state of research
is needed to support sound decisions regarding energy-related applications
offloading from cloud to fog or edge, focusing on smart grid open challenges
and potential impacts. In this paper, we delve into smart grid and
computational distribution architec-tures, including edge-fog-cloud models,
orchestration architecture, and serverless computing, and analyze the
decision-making variables and optimization algorithms to assess the efficiency
of edge offloading. Finally, the work contributes to a comprehensive
understanding of the edge offloading in smart grid, providing a SWOT analysis
to support decision making.Comment: to be submitted to journa
On Supporting Small M2M Data Transmissions in LTE/LTE-A Networks
In Machine-to-Machine (M2M) applications, devices monitor events (e.g., temperature, inventory
level), which is relayed through a communication network infrastructure (e.g. Internet, LTE) to an
application (software program running on a server connected to the Internet), that translates the
monitored event into some meaningful information to be able to take collaborative decisions with
limited or no human intervention.
With the availability of IPv6 address, it is possible to interconnect everything in this universe.
By using the concept of interconnecting things, several applications can be envisioned to make the
world smarter. Internet of Things (IoT) is a paradigm whose aim is to implement the concept of
interconnection of everything by using all possible technologies and others means. M2M communica-
tion is one of the components of Internet of Things (IoT) whose goal is to make the communication
smooth and seamless between any two networking enabled devices. According to the researchers by
the end of 2014, 1.5 billion devices and by the end of 2020, 20 billion devices will be part of M2M
communication
Tecnologias IoT para pastoreio e controlo de postura animal
The unwanted and adverse weeds that are constantly growing in vineyards,
force wine producers to repeatedly remove them through the use of mechanical
and chemical methods. These methods include machinery such
as plows and brushcutters, and chemicals as herbicides to remove and
prevent the growth of weeds both in the inter-row and under-vine areas.
Nonetheless, such methods are considered very aggressive for vines, and, in
the second case, harmful for the public health, since chemicals may remain
in the environment and hence contaminate water lines. Moreover, such
processes have to be repeated over the year, making it extremely expensive
and toilsome. Using animals, usually ovines, is an ancient practice used
around the world. Animals, grazing in vineyards, feed from the unwanted
weeds and fertilize the soil, in an inexpensive, ecological and sustainable
way. However, sheep may be dangerous to vines since they tend to feed
on grapes and on the lower branches of the vines, which causes enormous
production losses. To overcome that issue, sheep were traditionally used to
weed vineyards only before the beginning of the growth cycle of grapevines,
thus still requiring the use of mechanical and/or chemical methods during the
remainder of the production cycle.
To mitigate the problems above, a new technological solution was investigated
under the scope of the SheepIT project and developed in the
scope of this thesis. The system monitors sheep during grazing periods on
vineyards and implements a posture control mechanism to instruct them to
feed only from the undesired weeds. This mechanism is based on an IoT
architecture, being designed to be compact and energy efficient, allowing it to
be carried by sheep while attaining an autonomy of weeks.
In this context, the thesis herein sustained states that it is possible to
design an IoT-based system capable of monitoring and conditioning sheep’s
posture, enabling a safe weeding process in vineyards. Moreover, we support
such thesis in three main pillars that match the main contributions of this
work and that are duly explored and validated, namely: the IoT architecture
design and required communications, a posture control mechanism and
the support for a low-cost and low-power localization mechanism. The
system architecture is validated mainly in simulation context while the posture
control mechanism is validated both in simulations and field experiments.
Furthermore, we demonstrate the feasibility of the system and the contribution
of this work towards the first commercial version of the system.O constante crescimento de ervas infestantes obriga os produtores a manter
um processo contínuo de remoção das mesmas com recurso a mecanismos
mecânicos e/ou químicos. Entre os mais populares, destacam-se o uso de
arados e roçadores no primeiro grupo, e o uso de herbicidas no segundo
grupo. No entanto, estes mecanismos são considerados agressivos para as
videiras, assim como no segundo caso perigosos para a saúde pública, visto
que os químicos podem permanecer no ambiente, contaminando frutos e
linhas de água. Adicionalmente, estes processos são caros e exigem mão de
obra que escasseia nos dias de hoje, agravado pela necessidade destes processos
necessitarem de serem repetidos mais do que uma vez ao longo do
ano. O uso de animais, particularmente ovelhas, para controlar o crescimento
de infestantes é uma prática ancestral usada em todo o mundo. As ovelhas,
enquanto pastam, controlam o crescimento das ervas infestantes, ao mesmo
tempo que fertilizam o solo de forma gratuita, ecológica e sustentável. Não
obstante, este método foi sendo abandonado visto que os animais também
se alimentam da rama, rebentos e frutos da videira, provocando naturais
estragos e prejuízos produtivos.
Para mitigar este problema, uma nova solução baseada em tecnologias
de Internet das Coisas é proposta no âmbito do projeto SheepIT, cuja espinha
dorsal foi construída no âmbito desta tese. O sistema monitoriza as ovelhas
enquanto estas pastoreiam nas vinhas, e implementam um mecanismo de
controlo de postura que condiciona o seu comportamento de forma a que se
alimentem apenas das ervas infestantes. O sistema foi incorporado numa
infraestrutura de Internet das Coisas com comunicações sem fios de baixo
consumo para recolha de dados e que permite semanas de autonomia,
mantendo os dispositivos com um tamanho adequado aos animais.
Neste contexto, a tese suportada neste trabalho defende que é possível
projetar uma sistema baseado em tecnologias de Internet das Coisas,
capaz de monitorizar e condicionar a postura de ovelhas, permitindo que
estas pastem em vinhas sem comprometer as videiras e as uvas. A tese
é suportada em três pilares fundamentais que se refletem nos principais
contributos do trabalho, particularmente: a arquitetura do sistema e respetivo
sistema de comunicações; o mecanismo de controlo de postura; e o suporte
para implementação de um sistema de localização de baixo custo e baixo
consumo energético. A arquitetura é validada em contexto de simulação,
e o mecanismo de controlo de postura em contexto de simulação e de
experiências em campo. É também demonstrado o funcionamento do
sistema e o contributo deste trabalho para a conceção da primeira versão
comercial do sistema.Programa Doutoral em Informátic
ENABLING SMART CITY SERVICES FOR HETEROGENEOUS WIRELESS NETWORKS
A city can be transformed into a smart city if there is a resource-rich and reliable communication infrastructure available. A smart city in effect improves the quality of life of citizens by providing the means to convert the existing solutions to smart ones. Thus, there is a need for finding a suitable network structure that is capable of providing sufficient capacity and satisfactory quality-of-service in terms of latency and reliability. In this thesis, we propose a wireless network structure for smart cities. Our proposed network provides two wireless interfaces for each smart city node. One is supposed to connect to a public WiFi network, while the other is connected to a cellular network (such as LTE). Indeed, Multi-homing helps different applications to use the two interfaces simultaneously as well as providing the necessary redundancy in case the connection of one interface is lost. The performance of our proposed network structure is investigated using comprehensive ns-2 computer simulations. In this study, high data rate real-time and low data rate non-real-time applications are considered. The effect of a wide range of network parameters is tested such as the WiFi transmission rate, LTE transmission rate, the number of real-time and non-real-time nodes, application traffic rate, and different wireless propagation models. We focus on critical quality-of-service (QoS) parameters such as packet delivery delay and packet loss. We also measured the energy consumed in packet transmission. Compared with a single-interface WiFi-based or an LTE-based network, our simulation results show the superiority of the proposed network structure in satisfying QoS with lower latency and lower packet loss. We found also that the proposed multihoming structure enables the smart city sensors and other applications to realize a greener communication by consuming a lesser amount of transmission power rather than single interface-based networks
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