Exploiting Layered Multi-Path Routing Protocols to avoid void hole regions for reliable data delivery and efficient energy management for IoT-enabled underwater WSNs

The key concerns to enhance the lifetime of IoT-enabled Underwater Wireless Sensor Networks (IoT-UWSNs) are energy-efficiency and reliable data delivery under constrained resource. Traditional transmission approaches increase the communication overhead, which results in congestion and affect the reliable data delivery. Currently, many routing protocols have been proposed for UWSNs to ensure reliable data delivery and to conserve the node’s battery with minimum communication overhead (by avoiding void holes in the network). In this paper, adaptive energy-efficient routing protocols are proposed to tackle the aforementioned problems using the Shortest Path First (SPF) with least number of active nodes strategy. These novel protocols have been developed by integrating the prominent features of Forward Layered Multi-path Power Control One (FLMPC-One) routing protocol, which uses 2-hop neighbor information, Forward Layered Multi-path Power Control Two (FLMPC-Two) routing protocol, which uses 3-hop neighbor information and ’Dijkstra’ algorithm (for shortest path selection). Different Packet Sizes (PSs) with different Data Rates (DRs) are also taken into consideration to check the dynamicity of the proposed protocols. The achieved outcomes clearly validate the proposed protocols, namely: Shortest Path First using 3-hop neighbors information (SPF-Three) and Breadth First Search with Shortest Path First using 3-hop neighbors information (BFS-SPF-Three). Simulation results show the effectiveness of the proposed protocols in terms of minimum Energy Consumption (EC) and Required Packet Error Rate (RPER) with a minimum number of active nodes at the cost of affordable delay

Self-organizing Fast Routing Protocols for Underwater Acoustic Communications Networks

To address this problem, in this thesis we propose a cross-layer proactive routing initialization mechanism that does not require additional measurements and, at the same time, is energy efficient. Two routing protocols are proposed: Self-Organized Fast Routing Protocol for Radial Underwater Networks (SOFRP) for radial topology and Self-organized Proactive Routing Protocol for Non-uniformly Deployed Underwater Networks (SPRINT) for a randomly deployed network. SOFRP is based on the algorithm to recreate a radial topology with a gateway node, such that packets always use the shortest possible path from source to sink, thus minimizing consumed energy. Collisions are avoided as much as possible during the path initialization. The algorithm is suitable for 2D or 3D areas, and automatically adapts to a varying number of nodes. In SPRINT the routing path to the gateway is formed on the basis of the distance, measured by the signal strength received. The data sending node prefers to choose the neighbor node which is closest to it. It is designed to achieve high data throughput and low energy consumption of the nodes. There is a tradeoff between the throughput and the energy consumption: more distance needs more transmission energy, and more relay nodes (hops) to the destination node affects the throughput. Each hop increases the packet delay and decreases the throughput. Hence, energy consumption requires nearest nodes to be chosen as forwarding node whereas the throughput requires farthest node to be selected to minimize the number of hops. Fecha de lectura de Tesis Doctoral: 11 mayo 2020Underwater Wireless Sensor Networks (UWSNs) constitute an emerging technology for marine surveillance, natural disaster alert and environmental monitoring. Unlike terrestrial Wireless Sensor Networks (WSNs), electromagnetic waves cannot propagate more than few meters in water (high absorption rate). However, acoustic waves can travel long distances in underwater. Therefore, acoustic waves are preferred for underwater communications, but they travel very slow compare to EM waves (typical speed in water is 1500 m/s against 2x10^8 m/s for EM waves). This physical effect makes a high propagation delay and cannot be avoided, but the end-to-end packet delay it can be reduced. Routing delay is one of the major factors in end-to-end packet delay. In reactive routing protocols, when a packet arrives to a node, the node takes some time to select the node to which the data packet would be forwarded. We may reduce the routing delay for time-critical applications by using proactive routing protocols. Other two critical issues in UWSNs are determining the position of the nodes and time synchronization. Wireless sensor nodes need to determine the position of the surrounding nodes to select the next node in the path to reach the sink node. A Global Navigation Satellite System (GNSS) cannot be used because of the very short underwater range of the GNSS signal. Timestamping to estimate the distance is possible but the limited mobility of the UWSN nodes and variation in the propagation speed of the acoustic waves make the time synchronization a challenging task. For these reasons, terrestrial WSN protocols cannot be readily used for underwater acoustic networks

Analysis of Security Attacks & Taxonomy in Underwater Wireless Sensor Networks

Abstract: Underwater Wireless Sensor Networks (UWSN) have gained more attention from researchers in recent years due to their advancement in marine monitoring, deployment of various applications, and ocean surveillance. The UWSN is an attractive field for both researchers and the industrial side. Due to the harsh underwater environment, own capabilities, open acoustic channel, it's also vulnerable to malicious attacks and threats. Attackers can easily take advantage of these characteristics to steal the data between the source and destination. Many review articles are addressed some of the security attacks and Taxonomy of the Underwater Wireless Sensor Networks. In this study, we have briefly addressed the Taxonomy of the UWSNs from the most recent research articles related to the well-known research databases. This paper also discussed the security threats on each layer of the Underwater Wireless sensor networks. This study will help the researcher’s design the routing protocols to cover the known security threats and help industries manufacture the devices to observe these threats and security issues

THREE DIMENSIONAL REAL-TIME GEOGRAPHICAL ROUTING PROTOCOLS FOR WIRELESS SENSOR NETWORKS

One of the most important concerns in the operation of Wireless Sensor Network(WSN) is the real-time data delivery. This dissertation addresses the problem of real-time data delivery and void node problem in three dimensional WSN, which has a signicant impact on the network performance. In order to provide an accurate route calculation for reliable data delivery the third coordinate of the location sensor nodes is considered in this dissertation. Additionally, two dierent heuristic solutions for void node problem in three dimensional space have been provided to elevate the eect of long route and spares regions on assurance of real-time data delivery. In order to provide a wide applicable soft real-time routing protocol two decentralized geographical routings are proposed: Three Dimensional Real-Time Geographical Routing Protocol (3DRTGP) and Energy-Aware Real-Time Routing Protocol for Wireless Sensor Networks (EART). 3DRTGP and EART are designed to t with WSNs that are deployed in 3D space. Both protocols benet from utilizing the third coordinate of nodes\u27 locations to achieve less packet end to end (E2E) delay and packet miss ratio.In 3DRTGP, void node problem in 3D space was solved based on adaptive packet forwarding (PFR) region. 3D-VNP solution solely was done locally and without any messaging overhead. In EART, 3D-VNP was solved based on an adaptive spherical forwarding wedge (SFW)

QoSRP: A cross-layer QoS channel-aware routing protocol for the internet of underwater acoustic sensor networks

Quality of service (QoS)-aware data gathering in static-channel based underwater wireless sensor networks (UWSNs) is severely limited due to location and time-dependent acoustic channel communication characteristics. This paper proposes a novel cross-layer QoS-aware multichannel routing protocol called QoSRP for the internet of UWSNs-based time-critical marine monitoring applications. The proposed QoSRP scheme considers the unique characteristics of the acoustic communication in highly dynamic network topology during gathering and relaying events data towards the sink. The proposed QoSRP scheme during the time-critical events data-gathering process employs three basic mechanisms, namely underwater channel detection (UWCD), underwater channel assignment (UWCA) and underwater packets forwarding (UWPF). The UWCD mechanism finds the vacant channels with a high probability of detection and low probability of missed detection and false alarms. The UWCA scheme assigns high data rates channels to acoustic sensor nodes (ASNs) with longer idle probability in a robust manner. Lastly, the UWPF mechanism during conveying information avoids congestion, data path loops and balances the data traffic load in UWSNs. The QoSRP scheme is validated through extensive simulations conducted by NS2 and AquaSim 2.0 in underwater environments (UWEs). The simulation results reveal that the QoSRP protocol performs better compared to existing routing schemes in UWSNs

A Virtual Infrastructure for Mitigating Typical Challenges in Sensor Networks

Sensor networks have their own distinguishing characteristics that set them apart from other types of networks. Typically, the sensors are deployed in large numbers and in random fashion and the resulting sensor network is expected to self-organize in support of the mission for which it was deployed. Because of the random deployment of sensors that are often scattered from an overflying aircraft, the resulting network is not easy to manage since the sensors do not know their location, do not know how to aggregate their sensory data and where and how to route the aggregated data. The limited energy budget available to sensors makes things much worse. To save their energy, sensors have to sleep and wake up asynchronously. However, while promoting energy awareness, these actions continually change the underlying network topology and make the basic network protocols more complex. Several techniques have been proposed in different areas of sensor networks. Most of these techniques attempt to solve one problem in isolation from the others, hence protocol designers have to face the same common challenges again and again. This, in turn, has a direct impact on the complexity of the proposed protocols and on energy consumption. Instead of using this approach we propose to construct a lightweight backbone that can help mitigate many of the typical challenges in sensor networks and allow the development of simpler network protocols. Our backbone construction protocol starts by tiling the area around each sink using identical regular hexagons. After that, the closest sensor to the center of each of these hexagons is determined—we refer to these sensors as backbone sensors. We define a ternary coordinate system to refer to hexagons. The resulting system provides a complete set of communication paths that can be used by any geographic routing technique to simplify data communication across the network. We show how the constructed backbone can help mitigate many of the typical challenges inherent to sensor networks. In addition to sensor localization, the network backbone provides an implicit clustering mechanism in which each hexagon represents a cluster mud the backbone sensor around its center represents the cluster head. As cluster heads, backbone sensors can be used to coordinate task assignment, workforce selection, and data aggregation for different sensing tasks. They also can be used to locally synchronize and adjust the duty cycle of non-backbone sensors in their neighborhood. Finally, we propose “Backbone Switching”, a technique that creates alternative backbones and periodically switches between them in order to balance energy consumption among sensors by distributing the additional load of being part of the backbone over larger number of sensors

Energy Efficiency in Green Internet of Things (IoT) Networks

Internet of Things (IoT) is having a major impact on the digital world and how we interact with the internet. The wireless sensor network (WSN) is a promising wireless communication system for enabling IoT networks. But these networks have limited energy (battery) resources and energy-saving has become a pressing need in such networks and there have been increasing efforts to minimise energy consumption via message scheduling, optimal routing, clustering formation, aggregation techniques, etc. However, significant improvement is still required and this study has produced algorithms which have been shown to reduce energy consumption and prolong network life. Increasing the number of neighbour nodes around a node has a negative impact on the network lifetime of WSNs. This is due to the adverse effects caused by overhearing and interference. This thesis presents a new routing technique that considers the transmission distances from one node to all neighbouring nodes within its transmission range. The interference measurement approach is adopted to select the next-hop node. The cluster head (CH) node selection is based on transmission distances to the base station (BS) with the nearest node to the BS in a sub-cluster elected as CH node for that sub-cluster. The thesis also introduces a novel scheduling algorithm called the “long hop” (LH) which assigns high priority to messages coming from sensor nodes that are located farthest away and have accessed a high number of hops, to be served first at CH nodes. This minimised energy consumption caused by the retransmission process. Redundant data increases the unnecessary/unwanted processing and transmission of data. Thus, the thesis introduces a new method that reduces redundant data transmission and lowers the communication costs related to sending unnecessary data. The study also provides a remote monitoring system for the end-user that can check and track the performance of the sensors/IoT devices during real-time communication. Extensive simulation tests on randomly situated WSNs show the potential of the solutions proposed in this thesis to reduce energy consumption and extend network lifetime

Design, analysis and implementation of a spatial-temporal, adaptive and multi-replication data centric storage framework for wireless sensor and actor networks

This PhD Thesis presents a novel framework for Data-Centric Storage(DCS) in a Wireless Sensor and Actor Network(WSAN) that enables the use of a multiple set of data replication nodes, which also change over the time. This allows reducing the average network traffic and energy consumption by adapting the number of replicas to applications’ traffic, while balancing energy burdens by varying their location. To that end we propose and validate a simple model to determine the optimal number of replicas, in terms of minimizing average traffic/energy consumption, from the measured applications’ production and consumption traffic. Simple mechanisms are proposed to decide when the current set of replication nodes should be changed, to enable new applications and sensor nodes to efficiently bootstrap into a working sensor network, to recover from failing nodes, and to adapt to changing conditions. Extensive simulations demonstrate that our approach can extend a sensor network’s lifetime by at least a 60%, and up to a factor of 10x depending on the lifetime criterion being considered. Furthermore, we have implemented our framework in a real testbed with 20 motes that validates in a small scenario those results obtained via simulation for large WSANs. Finally, we present a heuristic that adapts our framework to scenarios with spatially heterogeneous consumption and/or production traffic distributions providing an effective reduction in the overall traffic, as well as reducing the number of nodes that die over the time. --------------------------------------------------------------------------------------------------------------------------------------------Esta Tesis se enmarca en el campo de la redes de sensores y actuadores inalámbricas. Para este tipo de redes existe un sistema de almacenamiento y entrega de información totalmente distribuido denominado Data-Centric Storage (DCS). En dicho sistema se selecciona un nodo en la red para almacenar toda la información relativa a una aplicación o tipo de evento. Dicha elección se realiza mediante el uso de una función de hash que, usando como argumento el propio nombre de la aplicación (o tipo de evento), devuelve el identificador (e.g. coordenadas geográficas, identificador de nodo, etc) del nodo responsable de almacenar toda la información que deesa aplicación (o tipo de evento). El uso de un único nodo para almacenar todos los datos de un mismo tipo generados en la red tiende a generar un punto de saturación en la red (especialmente en términos energéticos) ya que una gran cantidad de tráfico es encaminada hacia un único punto. De hecho, no sólo el nodo seleccionado como nodo de almacenamiento, sino también todos aquellos que le rodean, experimentan un mayor gasto de recursos ya que son los encargados de rutar los mensajes hacia el nodo de almacenamiento. Este problema ha dado lugar a sistemas que utilizan multiples réplicas para aliviar la generacióon de un punto de congestión y elevado consumo energético en la red. Situando varios puntos de almacenamiento para un tipo de evento dado, es posible aliviar la congestión de un único punto. Sin embargo la generación de nuevas réplicas tiene un coste asociado, y por tanto existe un número de réplicas óptimo que minimiza el tráfico total en la red, que a su vez tiene un impacto directo en la reducción del consumo energético y la extensión del tiempo de vida de la red. En esta Tesis se proponen dos esquemas de replicación para redes de sensores que usan DCS como sistema de almacenamiento distribuido. Para ambos casos se han desarrollado modelos matemáticos que permiten conocer el número óptimo de réplicas que deben ser utilizadas (para minimizar el tráfico total en la red) en función de la intensidad de producción y consumo de un tipo de evento. El primer mecanismo, denominado Quadratic Adaptive Replication (QAR), propone el uso de una estructura mallada para la colocación de las réplicas. QAR mejora trabajos previos que ya proponían un esquema de replicación en grid, ya que es más adaptativo a las condiciones de tráfico en la red. El segundo mecanismo simplemente genera localizaciones aleatorias donde situar las replicas. Sorprendentemente, esta Tesis demuestra que es el mejor sistema de replicación, incluso por delante de QAR, ya que es el más adaptativo a las condiciones de tráfico. Además, tiene la gran ventaja de que es extremadamente simple y puede aplicarse en redes irregulares o que utlizan diferentes protocolos de enrutamiento. Los sistemas de replicación alivian el problema del punto único de congestión, pero no lo solucionan completamente, ya que siguen apareciendo puntos de congestión menores, tantos como réplicas sean usadas. Por tanto, la red sigue presentando una gran desigualdad en el consumo energético, ya que aquellos puntos seleccionados como réplicas (y sus vecinos) usan una mayor energía para desarrollar su actividad. Frente a este problema, se propone como solución el cambio de las réplicas a lo largo del tiempo. Esecialmente, se limita el tiempo que un nodo puede permanecer desempeñando el papel de réplica, de tal forma que, una vez pasado ese tiempo, otro nodo tomará esa responsabilidad. Aplicando esta propuesta se consigue un equilibrio en el consumo energético de los nodos de la red, lo que tiene un gran impacto en la extensión del tiempo de vida de la red. En los experimentos realizados, dicha extensión tiene un valor m´ınimo de un 60%, llegándose a extender el tiempo de la vida hasta 10 veces bajo ciertas definiciones de tiempo de vida de la red. La principal contribución de esta Tesis es la presentación de un marco de trabajo adaptativo tanto espacial como temporalmente que, basado en un modelo teórico, indica cuál es el número óptimo de replicas que deben ser usadas en un determinado periodo. En esta Tesis se propone un protocolo completo que cubre todas las funcionalidades para que dicho sistema pueda ser implementado y desplegado en el mundo real. Para demostrar que el sistema propuesto puede ser implementado en ndoos de sensores comerciales, esta Tesis presenta la implementación realizada en 20 motas del fabricante Jennic. Asimismo, se ha empleado un pequeño test de pruebas para confirmar la validez de los modelos matemáticos para la obtención del número óptimo de réplicas, así como para demostrar que el cambio de las réplicas a lo largo del tiempo genera una mejor distribución del consumo energético en la red

Routing and Mobility on IPv6 over LoWPAN

The IoT means a world-wide network of interconnected objects based on standard communication protocols. An object in this context is a quotidian physical device augmented with sensing/actuating, processing, storing and communication capabilities. These objects must be able to interact with the surrounding environment where they are placed and to cooperate with neighbouring objects in order to accomplish a common objective. The IoT objects have also the capabilities of converting the sensed data into automated instructions and communicating them to other objects through the communication networks, avoiding the human intervention in several tasks. Most of IoT deployments are based on small devices with restricted computational resources and energy constraints. For this reason, initially the scientific community did not consider the use of IP protocol suite in this scenarios because there was the perception that it was too heavy to the available resources on such devices. Meanwhile, the scientific community and the industry started to rethink about the use of IP protocol suite in all IoT devices and now it is considered as the solution to provide connectivity between the IoT devices, independently of the Layer 2 protocol in use, and to connect them to the Internet. Despite the use of IP suite protocol in all devices and the amount of solutions proposed, many open issues remain unsolved in order to reach a seamless integration between the IoT and the Internet and to provide the conditions to IoT service widespread. This thesis addressed the challenges associated with the interconnectivity between the Internet and the IoT devices and with the security aspects of the IoT. In the interconnectivity between the IoT devices and the Internet the problem is how to provide valuable information to the Internet connected devices, independently of the supported IP protocol version, without being necessary accessed directly to the IoT nodes. In order to solve this problem, solutions based on Representational state transfer (REST) web services and IPv4 to IPv6 dual stack transition mechanism were proposed and evaluated. The REST web service and the transition mechanism runs only at the border router without penalizing the IoT constrained devices. The mitigation of the effects of internal and external security attacks minimizing the overhead imposed on the IoT devices is the security challenge addressed in this thesis. Three different solutions were proposed. The first is a mechanism to prevent remotely initiated transport level Denial of Service attacks that avoids the use of inefficient and hard to manage traditional firewalls. It is based on filtering at the border router the traffic received from the Internet and destined to the IoT network according to the conditions announced by each IoT device. The second is a network access security framework that can be used to control the nodes that have access to the network, based on administrative approval, and to enforce security compliance to the authorized nodes. The third is a network admission control framework that prevents IoT unauthorized nodes to communicate with IoT authorized nodes or with the Internet, which drastically reduces the number of possible security attacks. The network admission control was also exploited as a management mechanism as it can be used to manage the network size in terms of number of nodes, making the network more manageable, increasing its reliability and extending its lifetime.A IoT (Internet of Things) tem suscitado o interesse tanto da comunidade académica como da indústria, uma vez que os campos de aplicação são inúmeros assim como os potenciais ganhos que podem ser obtidos através do uso deste tipo de tecnologia. A IoT significa uma rede global de objetos ligados entre si através de uma rede de comunicações baseada em protocolos standard. Neste contexto, um objeto é um objeto físico do dia a dia ao qual foi adicionada a capacidade de medir e de atuar sobre variáveis físicas, de processar e armazenar dados e de comunicar. Estes objetos têm a capacidade de interagir com o meio ambiente envolvente e de cooperar com outros objetos vizinhos de forma a atingirem um objetivo comum. Estes objetos também têm a capacidade de converter os dados lidos em instruções e de as comunicar a outros objetos através da rede de comunicações, evitando desta forma a intervenção humana em diversas tarefas. A maior parte das concretizações de sistemas IoT são baseados em pequenos dispositivos autónomos com restrições ao nível dos recursos computacionais e de retenção de energia. Por esta razão, inicialmente a comunidade científica não considerou adequado o uso da pilha protocolar IP neste tipo de dispositivos, uma vez que havia a perceção de que era muito pesada para os recursos computacionais disponíveis. Entretanto, a comunidade científica e a indústria retomaram a discussão acerca dos benefícios do uso da pilha protocolar em todos os dispositivos da IoT e atualmente é considerada a solução para estabelecer a conetividade entre os dispositivos IoT independentemente do protocolo da camada dois em uso e para os ligar à Internet. Apesar do uso da pilha protocolar IP em todos os dispositivos e da quantidade de soluções propostas, são vários os problemas por resolver no que concerne à integração contínua e sem interrupções da IoT na Internet e de criar as condições para a adoção generalizada deste tipo de tecnologias. Esta tese versa sobre os desafios associados à integração da IoT na Internet e dos aspetos de segurança da IoT. Relativamente à integração da IoT na Internet o problema é como fornecer informação válida aos dispositivos ligados à Internet, independentemente da versão do protocolo IP em uso, evitando o acesso direto aos dispositivos IoT. Para a resolução deste problema foram propostas e avaliadas soluções baseadas em web services REST e em mecanismos de transição IPv4 para IPv6 do tipo pilha dupla (dual stack). O web service e o mecanismo de transição são suportados apenas no router de fronteira, sem penalizar os dispositivos IoT. No que concerne à segurança, o problema é mitigar os efeitos dos ataques de segurança internos e externos iniciados local e remotamente. Foram propostas três soluções diferentes, a primeira é um mecanismo que minimiza os efeitos dos ataques de negação de serviço com origem na Internet e que evita o uso de mecanismos de firewalls ineficientes e de gestão complexa. Este mecanismo filtra no router de fronteira o tráfego com origem na Internet é destinado à IoT de acordo com as condições anunciadas por cada um dos dispositivos IoT da rede. A segunda solução, é uma framework de network admission control que controla quais os dispositivos que podem aceder à rede com base na autorização administrativa e que aplica políticas de conformidade relativas à segurança aos dispositivos autorizados. A terceira é um mecanismo de network admission control para redes 6LoWPAN que evita que dispositivos não autorizados comuniquem com outros dispositivos legítimos e com a Internet o que reduz drasticamente o número de ataques à segurança. Este mecanismo também foi explorado como um mecanismo de gestão uma vez que pode ser utilizado a dimensão da rede quanto ao número de dispositivos, tornando-a mais fácil de gerir e aumentando a sua fiabilidade e o seu tempo de vida