Seamless connectivity:investigating implementation challenges of multibroker MQTT platform for smart environmental monitoring

Abstract. This thesis explores the performance and efficiency of MQTT-based infrastructure Internet of Things (IoT) sensor networks for smart environment. The study focuses on the impact of network latency and broker switching in distributed multi-broker MQTT platforms. The research involves three case studies: a cloud-based multi-broker deployment, a Local Area Network (LAN)-based multi-broker deployment, and a multi-layer LAN network-based multi-broker deployment. The research is guided by three objectives: quantifying and analyzing the latency of multi-broker MQTT platforms; investigating the benefits of distributed brokers for edge users; and assessing the impact of switching latency at applications. This thesis ultimately seeks to answer three key questions related to network and switching latency, the merits of distributed brokers, and the influence of switching latency on the reliability of end-user applications

Adaptive Quality of Service Control for MQTT-SN

Internet of Things and wireless sensor networks applications are becoming more and more popular nowadays, supported by new communication technologies and protocols tailored to their specific requirements. This paper focuses on improving the performance of a Wireless Sensor Network operated by the MQTT-SN protocol, one of the most popular publish/subscribe protocols for IoT applications. In particular, we propose a dynamic Quality of Service (QoS) controller for the MQTT-SN protocol, capable of evaluating the status of the underlying network in terms of end-to-end delay and packet error rate, reacting consequently by assigning to a node the best QoS value. We design and implement the QoS controller in a simulated environment based on the ns-3 network emulator and we perform extensive experiments to prove its effectiveness compared to a non-controlled scenario. The reported results show that, by controlling the Quality of Service, it is possible to manage effectively the number of packets successfully received by each device and their average latency, to improve the quality of the communication of each end node

Performance evaluation of CoAP and MQTT with security support for IoT environments

World is living an overwhelming explosion of smart devices: electronic gadgets, appliances, meters, cars, sensors, camera and even traffic lights, that are connected to the Internet to extend their capabilities, constituting what is known as Internet of Things (IoT). In these environments, the application layer is decisive for the quality of the connection, which has dependencies to the transport layer, mainly when secure communications are used. This paper analyses the performance offered by these two most popular protocols for the application layer: Constrained Application Protocol (CoAP) and Message Queue Telemetry Transport (MQTT). This analysis aims to examine the features and capabilities of the two protocols and to determine their feasibility to operate under constrained devices taking into account security support and diverse network conditions, unlike the previous works. Since IoT devices typically show battery constraints, the analysis is focused on bandwidth and CPU use, using realistic network scenarios, since this use translates to power consumption.This work was supported in part by the Ministry of Economy and Competitiveness (Spain) under the project MAGOS (TEC2017-84197-C4-1-R) and by the Comunidad de Madrid (Spain) under the projects: CYNAMON (P2018/TCS-4566), co-financed by European Structural Funds (ESF and FEDER), and the Multiannual Agreement with UC3M in the line of Excellence of University Professors (EPUC3M21), in the context of the V PRICIT (Regional Programme of Research and Technological Innovation)

Safe Intelligent Driver Assistance System in V2X Communication Environments based on IoT

In the modern world, power and speed of cars have increased steadily, as traffic continued to increase. At the same time highway-related fatalities and injuries due to road incidents are constantly growing and safety problems come first. Therefore, the development of Driver Assistance Systems (DAS) has become a major issue. Numerous innovations, systems and technologies have been developed in order to improve road transportation and safety. Modern computer vision algorithms enable cars to understand the road environment with low miss rates. A number of Intelligent Transportation Systems (ITSs), Vehicle Ad-Hoc Networks (VANETs) have been applied in the different cities over the world. Recently, a new global paradigm, known as the Internet of Things (IoT) brings new idea to update the existing solutions. Vehicle-to-Infrastructure communication based on IoT technologies would be a next step in intelligent transportation for the future Internet-of-Vehicles (IoV). The overall purpose of this research was to come up with a scalable IoT solution for driver assistance, which allows to combine safety relevant information for a driver from different types of in-vehicle sensors, in-vehicle DAS, vehicle networks and driver`s gadgets. This study brushed up on the evolution and state-of-the-art of Vehicle Systems. Existing ITSs, VANETs and DASs were evaluated in the research. The study proposed a design approach for the future development of transport systems applying IoT paradigm to the transport safety applications in order to enable driver assistance become part of Internet of Vehicles (IoV). The research proposed the architecture of the Safe Intelligent DAS (SiDAS) based on IoT V2X communications in order to combine different types of data from different available devices and vehicle systems. The research proposed IoT ARM structure for SiDAS, data flow diagrams, protocols. The study proposes several IoT system structures for the vehicle-pedestrian and vehicle-vehicle collision prediction as case studies for the flexible SiDAS framework architecture. The research has demonstrated the significant increase in driver situation awareness by using IoT SiDAS, especially in NLOS conditions. Moreover, the time analysis, taking into account IoT, Cloud, LTE and DSRS latency, has been provided for different collision scenarios, in order to evaluate the overall system latency and ensure applicability for real-time driver emergency notification. Experimental results demonstrate that the proposed SiDAS improves traffic safety

Contribution to the publish/subscribe communication model for the development of ubiquitous services in wireless sensor networks

Advances in wireless technologies and the rapid development of integrated electronics have made wireless sensor networks (WSN) one of the key technologies of the Internet of Things (IoT). Thanks to the ability of these networks to measure the physical phenomena of their environment, process and communicate this information using wireless technologies, they have excelled in the development of applications that respond or adapt to the context of a user, as is the case of ubiquitous environments such as smart cities, industrial automation, e-health among others. In addition, the IoT has opened the possibility that intelligent objects or devices are also capable of exchanging status information, conditions and capacity in order to interact with each other, in the same way that human beings have done through systems based on presence. These systems require information of an event in real time to react in a timely manner to the conditions or context of the user or device. These applications open new challenges in the management of WSN resources, since these networks operate in environments that are generally prone to packet loss and consist of generally small nodes with limited resources in memory, processing, bandwidth and power. The main objective of this thesis is the development of several mechanisms that allow the adaptation of the Publish/Subscribe protocols to the characteristics and limitations of the WSN for the provision of ubiquitous services in the context of the IoT. In addition, QoS support is supplied through mechanisms that provide reliability and timeliness in the delivery of packets and data aggregation techniques are applied to be efficient in the power consumption and the WSN bandwidth. Our research proposes an architecture to provide a presence service for WSN based on a Publish/ Subscribe model distributed and focused on mechanisms such as the aggregation of data and the publication of messages on demand to achieve energy efficiency and bandwidth. All these mechanisms have been applied in the design of a system called PASH aimed at home control based on the concept of Ambient Assisted Living (AAL). The reliability provided by Publish/Subscribe protocols in WSN is of great importance in the design of applications that require receiving a message to react on time or in real time to an event. Initially, we focused our study on increasing the proportion of packet delivery (PDR) in the destination node through the improvement of reliability mechanisms. We evaluated the reliability mechanism of the MQTT-SN protocol and several proposed mechanisms of the CoAP protocol. From this evaluation, we propose a new and simple adaptive retransmission mechanism to respond to packet loss in the most appropriate way. Finally, we consider that applications such as: e-health, critical infrastructure control and monitoring, among others, must meet different QoS requirements, such as reliability and timeliness for each type of message received. In addition, data aggregation techniques play an important role in WSN to reduce power consumption and bandwidth. In this thesis, we propose a mechanism that provides the application with three different levels of QoS: we provide an improvement of our previous relay mechanism for reliability, we include the data aggregation in our reliability mechanism and we provide a timeliness mechanism in the delivery of packets.Els avenços en les tecnologies sense fils i al ràpid desenvolupament de l'electrònica integrada, ha convertit les xarxes de sensors sense fils (WSN) en una de les tecnologies claus de l'Internet de les Coses (Iot). Gràcies a la capacitat que tenen aquestes xarxes de mesurar els fenòmens físics del seu entorn, processar i comunicar aquesta informació utilitzant tecnologies sense fils, s'han destacat en el desenvolupament d'aplicacions que responguin o s'adaptin al context d'un usuari, com és el cas dels entorns ubics com a ciutats intel·ligents, automatització industrial, salut electrònica entre d'altres. A més, el IOT ha obert la possibilitat que els objectes o dispositius intel·ligents també siguin capaços d'intercanviar informació d'estat, condicions i capacitat per tal d'interactuar entre si, de la mateixa manera que els éssers humans ho han fet a través de sistemes basats en presència. Aquests sistemes requereixen informació d'un esdeveniment en temps real per reaccionar de manera oportuna a les condicions o al context de l'usuari o dispositiu. Aquestes aplicacions obren nous desafiaments en l'administració dels recursos de WSN, ja que aquestes xarxes operen en entorns que generalment són propensos a la pèrdua de paquets i consten de nodes generalment petits amb recursos limitats en memòria, processament, ample de banda i alimentació. El principal objectiu d'aquesta tesi és el desenvolupament de diversos mecanismes que permetin l'adequació dels protocols d'Publish / Subscribe a les característiques i limitacions de la WSN per a la provisió de serveis ubics en el context de la IOT. A més, es brinda suport de QoS a través de mecanismes que proporcionen fiabilitat i puntualitat en el lliurament de paquets i s'apliquen tècniques d'agregació de dades per a ser eficients en el consum d'energia i l'ample de banda de la WSN. La nostra investigació proposa una arquitectura per a proporcionar un servei de presència per WSN basat en un model de Publish / Subscribe distribuït i centrat en mecanismes com ara l'agregació de dades i la publicació de missatges en demanda per aconseguir eficiència en l'energia i l'ample de banda . Tots aquests mecanismes han estat aplicats en el disseny d'un sistema anomenat Pash dirigit al control de la llar basat en el concepte de Vida Assistida (AAL). La fiabilitat proporcionada pels protocols de Publish / Subscribe WSN és de gran importància en el disseny d'aplicacions que requereixen rebre un missatge per reaccionar a temps o en temps real davant un esdeveniment. Inicialment enfoquem el nostre estudi en augmentar la proporció de lliurament de paquets (PDR) en el node de destinació a través de la millora dels mecanismes de fiabilitat. Avaluem el mecanisme de fiabilitat del protocol MQTT-SN i diversos mecanismes proposats del protocol COAP. A partir d'aquesta avaluació, proposem un nou i senzill mecanisme de retransmissió adaptable per respondre a la pèrdua de paquets de la manera més adequada. Finalment, considerem que les aplicacions com: salut electrònica, control d'infraestructura crítica i monitoratge, entre d'altres, han de complir diferents requisits de QoS, com la fiabilitat i la puntualitat per a cada tipus de missatge rebut. A més, les tècniques d'agregació de dades tenen un paper important en WSN per reduir el consum d'energia i l'ample de banda. En aquesta tesi, proposem un mecanisme que proporciona a la aplicació tres nivells de QoS diferents: proporcionem una millora del nostre mecanisme de retransmissió anterior per a la fiabilitat, incloem l'agregació de dades en el nostre mecanisme de fiabilitat i proporcionem un mecanisme de puntualitat en el lliurament de paquets.Postprint (published version

Contribution to the publish/subscribe communication model for the development of ubiquitous services in wireless sensor networks

Advances in wireless technologies and the rapid development of integrated electronics have made wireless sensor networks (WSN) one of the key technologies of the Internet of Things (IoT). Thanks to the ability of these networks to measure the physical phenomena of their environment, process and communicate this information using wireless technologies, they have excelled in the development of applications that respond or adapt to the context of a user, as is the case of ubiquitous environments such as smart cities, industrial automation, e-health among others. In addition, the IoT has opened the possibility that intelligent objects or devices are also capable of exchanging status information, conditions and capacity in order to interact with each other, in the same way that human beings have done through systems based on presence. These systems require information of an event in real time to react in a timely manner to the conditions or context of the user or device. These applications open new challenges in the management of WSN resources, since these networks operate in environments that are generally prone to packet loss and consist of generally small nodes with limited resources in memory, processing, bandwidth and power. The main objective of this thesis is the development of several mechanisms that allow the adaptation of the Publish/Subscribe protocols to the characteristics and limitations of the WSN for the provision of ubiquitous services in the context of the IoT. In addition, QoS support is supplied through mechanisms that provide reliability and timeliness in the delivery of packets and data aggregation techniques are applied to be efficient in the power consumption and the WSN bandwidth. Our research proposes an architecture to provide a presence service for WSN based on a Publish/ Subscribe model distributed and focused on mechanisms such as the aggregation of data and the publication of messages on demand to achieve energy efficiency and bandwidth. All these mechanisms have been applied in the design of a system called PASH aimed at home control based on the concept of Ambient Assisted Living (AAL). The reliability provided by Publish/Subscribe protocols in WSN is of great importance in the design of applications that require receiving a message to react on time or in real time to an event. Initially, we focused our study on increasing the proportion of packet delivery (PDR) in the destination node through the improvement of reliability mechanisms. We evaluated the reliability mechanism of the MQTT-SN protocol and several proposed mechanisms of the CoAP protocol. From this evaluation, we propose a new and simple adaptive retransmission mechanism to respond to packet loss in the most appropriate way. Finally, we consider that applications such as: e-health, critical infrastructure control and monitoring, among others, must meet different QoS requirements, such as reliability and timeliness for each type of message received. In addition, data aggregation techniques play an important role in WSN to reduce power consumption and bandwidth. In this thesis, we propose a mechanism that provides the application with three different levels of QoS: we provide an improvement of our previous relay mechanism for reliability, we include the data aggregation in our reliability mechanism and we provide a timeliness mechanism in the delivery of packets.Els avenços en les tecnologies sense fils i al ràpid desenvolupament de l'electrònica integrada, ha convertit les xarxes de sensors sense fils (WSN) en una de les tecnologies claus de l'Internet de les Coses (Iot). Gràcies a la capacitat que tenen aquestes xarxes de mesurar els fenòmens físics del seu entorn, processar i comunicar aquesta informació utilitzant tecnologies sense fils, s'han destacat en el desenvolupament d'aplicacions que responguin o s'adaptin al context d'un usuari, com és el cas dels entorns ubics com a ciutats intel·ligents, automatització industrial, salut electrònica entre d'altres. A més, el IOT ha obert la possibilitat que els objectes o dispositius intel·ligents també siguin capaços d'intercanviar informació d'estat, condicions i capacitat per tal d'interactuar entre si, de la mateixa manera que els éssers humans ho han fet a través de sistemes basats en presència. Aquests sistemes requereixen informació d'un esdeveniment en temps real per reaccionar de manera oportuna a les condicions o al context de l'usuari o dispositiu. Aquestes aplicacions obren nous desafiaments en l'administració dels recursos de WSN, ja que aquestes xarxes operen en entorns que generalment són propensos a la pèrdua de paquets i consten de nodes generalment petits amb recursos limitats en memòria, processament, ample de banda i alimentació. El principal objectiu d'aquesta tesi és el desenvolupament de diversos mecanismes que permetin l'adequació dels protocols d'Publish / Subscribe a les característiques i limitacions de la WSN per a la provisió de serveis ubics en el context de la IOT. A més, es brinda suport de QoS a través de mecanismes que proporcionen fiabilitat i puntualitat en el lliurament de paquets i s'apliquen tècniques d'agregació de dades per a ser eficients en el consum d'energia i l'ample de banda de la WSN. La nostra investigació proposa una arquitectura per a proporcionar un servei de presència per WSN basat en un model de Publish / Subscribe distribuït i centrat en mecanismes com ara l'agregació de dades i la publicació de missatges en demanda per aconseguir eficiència en l'energia i l'ample de banda . Tots aquests mecanismes han estat aplicats en el disseny d'un sistema anomenat Pash dirigit al control de la llar basat en el concepte de Vida Assistida (AAL). La fiabilitat proporcionada pels protocols de Publish / Subscribe WSN és de gran importància en el disseny d'aplicacions que requereixen rebre un missatge per reaccionar a temps o en temps real davant un esdeveniment. Inicialment enfoquem el nostre estudi en augmentar la proporció de lliurament de paquets (PDR) en el node de destinació a través de la millora dels mecanismes de fiabilitat. Avaluem el mecanisme de fiabilitat del protocol MQTT-SN i diversos mecanismes proposats del protocol COAP. A partir d'aquesta avaluació, proposem un nou i senzill mecanisme de retransmissió adaptable per respondre a la pèrdua de paquets de la manera més adequada. Finalment, considerem que les aplicacions com: salut electrònica, control d'infraestructura crítica i monitoratge, entre d'altres, han de complir diferents requisits de QoS, com la fiabilitat i la puntualitat per a cada tipus de missatge rebut. A més, les tècniques d'agregació de dades tenen un paper important en WSN per reduir el consum d'energia i l'ample de banda. En aquesta tesi, proposem un mecanisme que proporciona a la aplicació tres nivells de QoS diferents: proporcionem una millora del nostre mecanisme de retransmissió anterior per a la fiabilitat, incloem l'agregació de dades en el nostre mecanisme de fiabilitat i proporcionem un mecanisme de puntualitat en el lliurament de paquets.Postprint (published version

On Information-centric Resiliency and System-level Security in Constrained, Wireless Communication

The Internet of Things (IoT) interconnects many heterogeneous embedded devices either locally between each other, or globally with the Internet. These things are resource-constrained, e.g., powered by battery, and typically communicate via low-power and lossy wireless links. Communication needs to be secured and relies on crypto-operations that are often resource-intensive and in conflict with the device constraints. These challenging operational conditions on the cheapest hardware possible, the unreliable wireless transmission, and the need for protection against common threats of the inter-network, impose severe challenges to IoT networks. In this thesis, we advance the current state of the art in two dimensions. Part I assesses Information-centric networking (ICN) for the IoT, a network paradigm that promises enhanced reliability for data retrieval in constrained edge networks. ICN lacks a lower layer definition, which, however, is the key to enable device sleep cycles and exclusive wireless media access. This part of the thesis designs and evaluates an effective media access strategy for ICN to reduce the energy consumption and wireless interference on constrained IoT nodes. Part II examines the performance of hardware and software crypto-operations, executed on off-the-shelf IoT platforms. A novel system design enables the accessibility and auto-configuration of crypto-hardware through an operating system. One main focus is the generation of random numbers in the IoT. This part of the thesis further designs and evaluates Physical Unclonable Functions (PUFs) to provide novel randomness sources that generate highly unpredictable secrets, on low-cost devices that lack hardware-based security features. This thesis takes a practical view on the constrained IoT and is accompanied by real-world implementations and measurements. We contribute open source software, automation tools, a simulator, and reproducible measurement results from real IoT deployments using off-the-shelf hardware. The large-scale experiments in an open access testbed provide a direct starting point for future research

IoT Content Object Security with OSCORE and NDN: A First Experimental Comparison

The emerging Internet of Things (IoT) challenges the end-to-end transport of the Internet by low power lossy links and gateways that perform protocol translations. Protocols such as CoAP or MQTT-SN are degraded by the overhead of DTLS sessions, which in common deployment protect content transfer only up to the gateway. To preserve content security end-to-end via gateways and proxies, the IETF recently developed Object Security for Constrained RESTful Environments (OSCORE), which extends CoAP with content object security features commonly known from Information Centric Networks (ICN). This paper presents a comparative analysis of protocol stacks that protect request-response transactions. We measure protocol performances of CoAP over DTLS, OSCORE, and the information-centric Named Data Networking (NDN) protocol on a large-scale IoT testbed in single- and multi-hop scenarios. Our findings indicate that (a) OSCORE improves on CoAP over DTLS in error-prone wireless regimes due to omitting the overhead of maintaining security sessions at endpoints, and (b) NDN attains superior robustness and reliability due to its intrinsic network caches and hop-wise retransmissions

APPLICATION FOR FUNCTIONALITY AND REGISTRATION IN THE CLOUD OF A MICROCONTROLLER DEVELOPMENT BOARD FOR IOT IN AWS

The use of the Amazon Web Services cloud enables new functionalities that are not possible with traditional solutions: low latency, local data processing and storage, and direct connectivity to other cloud services. Reimagining the way IoT connectivity services are presented by combining AWS cloud technology with mobile connectivity offers rapid prototyping to help connect devices natively over Wi-Fi. For this, the MQTT communication protocol is used to interact with the IoT device and exchange data, which allows controlling the basic functions of a sensor node. The installation is realized through a software development kit (SDK), which allows the creation of an application for Android devices. This solution gives the option to integrate together, improving the connectivity of the IoT system. The results enable board logging and network configuration, and can also be used to control the IoT device. The embedded firmware provides the required security functions