Thesis (M.S.)--Rochester Institute of Technology, 2007. / Typescript. Includes bibliographical references (leaves 57-59).

This thesis presents a framework for investigating opportunistic routing in Delay Tolerant Mobile Ad hoc Networks (DTMANETs), and introduces the concept of an Opportunistic Confidence Index (OCI). The OCI enables multiple opportunistic routing protocols to be applied as an adaptive group to improve DTMANET routing reliability, performance, and efficiency. The DTMANET is a recently acknowledged networkarchitecture, which is designed to address the challenging and marginal environments created by adaptive, mobile, and unreliable network node presence. Because of its ad hoc and autonomic nature, routing in a DTMANET is a very challenging problem. The design of routing protocols in such environments, which ensure a high percentage delivery rate (reliability), achieve a reasonable delivery time (performance), and at the same time maintain an acceptable communication overhead (efficiency), is of fundamental consequence to the usefulness of DTMANETs. In recent years, a number of investigations into DTMANET routing have been conducted, resulting in the emergence of a class of routing known as opportunistic routing protocols. Current research into opportunistic routing has exposed opportunities for positive impacts on DTMANET routing. To date, most investigations have concentrated upon one or other of the quality metrics of reliability, performance, or efficiency, while some approaches have pursued a balance of these metrics through assumptions of a high level of global knowledge and/or uniform mobile device behaviours. No prior research that we are aware of has studied the connection between multiple opportunistic elements and their influences upon one another, and none has demonstrated the possibility of modelling and using multiple different opportunistic elements as an adaptive group to aid the routing process in a DTMANET. This thesis investigates OCI opportunities and their viability through the design of an extensible simulation environment, which makes use of methods and techniques such as abstract modelling, opportunistic element simplification and isolation, random attribute generation and assignment, localized knowledge sharing, automated scenario generation, intelligent weight assignment and/or opportunistic element permutation. These methods and techniques are incorporated at both data acquisition and analysis phases. Our results show a significant improvement in all three metric categories. In one of the most applicable scenarios tested, OCI yielded a 31.05% message delivery increase (reliability improvement), 22.18% message delivery time reduction (performance improvement), and 73.64% routing depth decrement (efficiency improvement). We are able to conclude that the OCI approach is feasible across a range of scenarios, and that the use of multiple opportunistic elements to aid decision-making processes in DTMANET environments has value.

ABSTRACT Wireless networks are gaining popularity day by day, as users want wireless connectivity irrespective of their geographic position. There is an increasing threat of malicious nodes attacks on the Mobile Ad-hoc Networks (MANET). Black hole attack is one of the security threat in which the traffic is redirected to such a node that actually does not exist in the network. It’s an analogy to the black hole in the universe in which things disappear. MANETs must have a secure way for transmission and communication which is quite challenging and vital issue. In order to provide secure communication and transmission, researcher worked specifically on the security issues in MANETs, and many secure routing protocols and security measures within the networks were proposed. The scope of this thesis is to study the effects of Black hole attack in MANET using both Proactive routing protocol i.e. Optimized Link State Routing (OLSR) and Reactive routing protocol Ad-Hoc on Demand Distance Vector (AODV). Comparative analysis of Black Hole attack for both protocols is taken into account. The impact of Black Hole attack on the performance of MANET is evaluated finding out which protocol is more vulnerable to the attack and how much is the impact of the attack on both protocols. The measurements were taken in the light of throughput, end-to-end delay and network load. Simulation is done in Optimized Network Engineering Tool (OPNET). Previously the works done on security issues in MANET were based on reactive routing protocol like Ad-Hoc on Demand Distance Vector (AODV). Different kinds of attacks were studied, and their effects were elaborated by stating how these attacks disrupt the performance of MANET.

Wireless networks are gaining popularity to its peak today, as the users want wireless connectivity irrespective of their geographic position. There is an increasing threat of attacks on the Mobile Ad-hoc Networks (MANET). Black hole attack is one of the security threat in which the traffic is redirected to such a node that actually does not exist in the network. It’s an analogy to the black hole in the universe in which things disappear. The node presents itself in such a way to the node that it can attack other nodes and networks knowing that it has the shortest path. MANETs must have a secure way for transmission and communication which is quite challenging and vital issue. In order to provide secure communication and transmission, researcher worked specifically on the security issues in MANETs, and many secure routing protocols and security measures within the networks were proposed. Previously the works done on security issues in MANET were based on reactive routing protocol like Ad-Hoc On Demand Distance Vector (AODV). Different kinds of attacks were studied, and their effects were elaborated by stating how these attacks disrupt the performance of MANET. The scope of this thesis is to study the effects of Black hole attack in MANET using both Proactive routing protocol i.e. Optimized Link State Routing (OLSR) and Reactive routing protocol Ad-Hoc On Demand Distance Vector (AODV). Comparative analysis of Black Hole attack for both protocols is taken into account. The impact of Black Hole attack on the performance of MANET is evaluated finding out which protocol is more vulnerable to the attack and how much is the impact of the attack on both protocols. The measurements were taken in the light of throughput, end-to-end delay and network load. Simulation is done in Optimized Network Engineering Tool (OPNET).

Cette thèse traite de l'optimisation des communications dans les réseaux véhiculaires à l'aided'une plate-forme de simulation réaliste. Un environnement réaliste implique des modèles demobilité adaptés aux véhicules ainsi que des modèles de couche physique détaillés (modèles decanaux et chaîne de transmission numérique).Notre travail a d'abord consisté à concevoir une plate-forme de simulation réaliste dédiée auxVANETs (Vehicular Ad hoc NETworks). Cette plate-forme a été complétée par un modèle depropagation semi-déterministe que nous avons conçu. L'avantage de ce modèle, appelé UMCRT,est d'avoir un réalisme équivalent à un modèle déterministe tout en réduisantsignificativement le temps de calcul. Ce modèle a été validé par comparaison avec unsimulateur déterministe à tracé de rayons.Nous avons ensuite utilisé cette plate-forme pour évaluer des protocoles de routage.L'efficacité de ces différents protocoles ad hoc testés en conditions réalistes nous a permis defocaliser notre étude sur les protocoles réactifs. De cette évaluation, nous avons retenu AODV(Ad hoc On demand Distance Vector) auquel nous avons notamment appliqué une métriquecross layer pour pallier la baisse de performance induite par le réalisme. Nous avons ensuiteutilisé une technique de tuning appliquée à des protocoles réactifs. Finalement, nous avonsévalué différentes couches physiques, SISO (Simple Input Simple Output) et MIMO (MultipleImput Multiple Output).Ces travaux montrent que seules des améliorations combinées à différents niveaux (physique etréseau) permettraient d'apporter une amélioration significative des performances. / This thesis deals with the optimization of communications in vehicular networks by using arealistic simulation platform. A realistic environment implies the usage of mobility modelsadapted to vehicles and also highly detailed physical models (channel models and digitaltransmission chain).The first part of our work has consisted in the design of a realistic simulation platformdedicated to VANETs (Vehicular Ad hoc NETworks). This platform has been completed by asemi-deterministic propagation model which we have designed. This model called UM-CRThas the advantage to have the same level of realism than a deterministic model while requiringmuch less computation time. This model has been validated by comparison with a deterministicray tracing simulator.We then have used this platform to evaluate routing protocols. The efficiency of different adhoc routing protocols in realistic conditions has led us to focus our study on the family ofreactive protocols. From this evaluation we have selected AODV (Ad hoc On demandDistance Vector) to which we have applied a cross-layer metric in order to reduce theperformance degradation caused by the realistic environment. We then have used a tuningtechnique with reactive protocols. Finally, we have evaluated several SISO and MIMOphysical layers. This work shows that only improvements combined at different levels (physicaland network) can yield a significant increase in performance.

Les réseaux de capteurs sans fil (RCSFs) ont suscité un grand intérêt scientifique durant cette dernière décennie. Un des grands défis des RCSFs est d'assurer une communication avec la Qualité de Service (QoS) exigée par l'application tout en prenant en considération les contraintes intrinsèques des capteurs. Un autre défi est relatif à la génération des trafics hétérogènes avec des priorités diverses, ce qui impose des contraintes supplémentaires aux différents protocoles de communication. Dans cette thèse, nous nous intéressons aux protocoles de routage dédiés aux RCSFs. Dans un premier temps, nous proposons des améliorations de deux protocoles appartenant à deux catégories différentes de routage. L'objectif est de surmonter les contraintes liées aux caractéristiques des capteurs sans fil et d'assurer de meilleure performance. Dans un deuxième temps, nous proposons une solution pour remédier à la vulnérabilité de la technique des chemins multiples aussi bien dans le cas d'une seule source ou que dans le cas de plusieurs sources. Ainsi, nous avons proposé un protocole de routage à chemins multiples, capable de créer des chemins tout en évitant l'effet du rayon de détection de porteuse. Ce protocole nommé « Carrier Sense Aware Multipath Geographic Routing (CSA-MGR) », satisfait la QoS exigée par les RCSFs. Comme application directe de notre solution, nous avons étudié un scénario d'irrigation par goutte-à-goutte en utilisant les RCSFs. Principalement, nous nous sommes intéressés au cas d'un dysfonctionnement de système, tel que la rupture des tuyaux d'irrigation ou bien le blocage des émetteurs. Ainsi, nous distinguons deux niveaux de priorité pour les informations transmises par le réseau, et en utilisant le protocole CSA-MGR, nous concevons un routage selon la priorité exigée. Notre travail a été validé avec NS2 et TOSSIM ainsi par une implémentation réelle sur des noeuds capteurs TelosB. Les résultats des simulations numériques et des tests expérimentaux montrent l'apport de nos contributions par rapport aux solutions existantes. / Wireless Sensor Networks (WSNs) have aroused great scientific interest during the last decade. One of the greatest challenge of WSNs is to ensure communication with the Quality of Service (QoS) required by the application while taking into account the inherent constraints of the sensor nodes. Another challenge is related to the generation of heterogeneous traffic with different priorities, which imposes additional constraints on different communication protocols. In this thesis, we are interested specifically to routing protocols dedicated to WSNs. First, we propose improvements of protocols based on combinatorial optimization techniques and those based on nodes geographic positions to overcome the related constraints of WSNs. Secondly, we propose a solution to address the vulnerability of the multiple paths technique, whether for the case of a single source or several sources in the network. Thus, our main contribution is to provide a multi-path routing protocol, able to creating paths while avoiding the carrier sense range effect. This protocol denoted "Carrier Sense Aware Multipath Geographic Routing (CSA-MGR)" meets the QoS required by WSNs. As direct application of our solution, we studied a drip irrigation scenario using WSNs. Mainly, we studied the case where a system dysfunctioning occurs, such as irrigation pipe rupture or the emitters blocking. Also, we distinguish two priority levels for the data transmitted over the network, and based on the CSA-MGR, we design routing according to the required priority. Our work in this thesis has been validated through NS2 and TOSSIM simulators and also through a real implementation over the TelosB motes. The results of numerical simulations and experimental results show the advantage of our contributions compared to existing solutions.

Thesis (MSc.) -- University of Limpopo, 2017 / The notion of ubiquitous computing, Internet of things (IoT), big data, cloud computing and other emerging technologies has brougt forward the innovative paradigms and incredible developments in wireless communication technologies. The Wireless Mesh Networks (WMNs) technology has recently emerged as the promising high speed wireless technology to provide the last mile broadband Internet access and deliver flexible and integrated wireless communication solutions. The WMNs has the potential to enable people living in rural, peri-urban areas and small businesses to interconnect their networks and share the affordable Internet connectivity. The recent multimedia applications developed, such as voice over Internet protocol (VoIP), online gaming, cloud storage, instant messaging applications, and video sharing applications require high speed communication media and networks. These applications have witnessed enormous growth in the recent decade and continue to enhance communication amongst the users. Hence, the WMNs must have adequate capacity to support high bandwidth and real-time and multimedia applications. While the wireless communications networks are dependent on the radio frequency (RF) spectrum, the traditional wireless technologies utilise the RF spectrum bands inefficiently, resulting in sporadic and underutilisation of the RF spectrum. This inefficient usage of RF spectrum calls for novel techniques to leverage the available RF spectrum amongst different players in the wireless communication arena. There have been developments on integration of the WMNs with cognitive ratios to allow unlicensed users of RF spectrum to operate in the licensed portions of spectrum bands. This integration will provide the required bandwidth to support the required high speed broadband communication infrastructure. In this dissertation, we focus our research on the routing layer in a multi-hop wireless network environment. We addressed the routing challenges in both the WMNs and the cognitive radio based wireless mesh networks (CR-WMNs). The primary focus was to identify the routing protocols most suitable for the dynamic WMN environment. Once identified, the routing protocol was then ported to the CR-WMN environment to evaluate its performance given all the dynamics of cognitive radio environment. vi We further proposed the routing protocol called the extended weighted cumulative expected transmission time (xWCETT) routing protocol for the CR-WMNs. The design of our proposed xWCETT routing protocol is based on the multi-radio multi-channel architecture as it gives the base framework matching the cognitive radio environment. The xWCETT integrates features from the Ad-hoc On-demand Distance Vector (AODV) routing protocol and the weighted cumulative expected transmission time (WCETT) routing metric. The xWCETT was implemented using the Cognitive Radio Cognitive Network (CRCN) patch ported in network simulator (NS2) to incorporate the shared and dynamic spectrum access features. We compared the performance of our proposed xWCETT routing protocol with the AODV, dynamic source routing (DSR), the optimised link source routing (OLSR), Destination Sequences Distance Vector (DSDV), and the CRCN-WCETT routing protocols. The extensive simulation and numerical results show that the proposed xWCETT protocol obtained on average, around 10% better performance results in the CR-WNNs as compared to its routing counterparts. The comparative analysis and evaluation was performed in terms of the average end-to-end latency, throughput, jitter, packet delivery ratio, as well as the normalised routing load. The performance results obtained indicates that the proposed xWCETT routing protocol is a promising routing solution for dynamic CR-WMNs environment. / National Research Foundation (NRF)

The diploma thesis "QoS model for Mobile ad hoc network" focuses on the quality of services in MANET (Mobile Ad-hoc) networks. It describes MANET networks and covers the theoretical analysis of routing protocols with QoS (Quality of Service) support. Furthermore, there is processed the creation process of model MANET networks with the routing protocol DSDV (Destination-Sequenced Distance Vector) in the simulation environment NS-3 (Network Simulator 3) and its extension of QoS support. The used QoS model is subsequently modified to improve core operating parameters. The implementation of QoS parameters as well as the improvement of delay and jitter (the delay between selected packets) is verified by the functional simulation.

In recent years, the development of a large variety of mobile computing devices has led to wide scale deployment and use of wireless ad hoc and sensor networks. Wireless Sensor Networks consist of battery powered, tiny and cheap "motes", having sensing and wireless communication capabilities. Although wireless motes have limited battery power, communication and computation capabilities, the range of their application is vast. In the first part of the dissertation, we have addressed the specific application of Biomedical Sensor Networks. To solve the problem of data routing in these networks, we have proposed the Adaptive Least Temperature Routing (ALTR) algorithm that reduces the average temperature rise of the nodes in the in-vivo network while routing data efficiently. For delay sensitive biomedical applications, we proposed the Hotspot Preventing Routing (HPR) algorithm which avoids the formation of hotspots (regions having very high temperature) in the network. HPR forwards the packets using the shortest path, bypassing the regions of high temperature and thus significantly reduces the average packet delivery delay, making it suitable for real-time applications of in-vivo networks. We also proposed another routing algorithm suitable for being used in a network of id-less biomedical sensor nodes, namely Routing Algorithm for networks of homogeneous and Id-less biomedical sensor Nodes (RAIN). Finally we developed Biocomm, a cross-layer MAC and Routing protocol co-design for Biomedical Sensor Networks, which optimizes the overall performance of an in-vivo network through cross-layer interactions. We performed extensive simulations to show that the proposed Biocomm protocol performs much better than the other existing MAC and Routing protocols in terms of preventing the formation of hotspots, reducing energy consumption of nodes and preventing network congestion when used in an in-vivo network. In the second part of the dissertation, we have addressed the problems of habitat-monitoring sensor networks, broadcast algorithms for sensor networks and the congestion problem in sensor networks as well as one non-sensor network application, namely, on-chip communication networks. Specifically, we have proposed a variation of HPR algorithm, called Hotspot Preventing Adaptive Routing (HPAR) algorithm, for efficient data routing in Networks On-Chip catering to their specific hotspot prevention issues. A protocol similar to ALTR has been shown to perform well in a sensor network deployed for habitat monitoring. We developed a reliable, low overhead broadcast algorithm for sensor networks namely Topology Adaptive Gossip (TAG) algorithm. To reduce the congestion problem in Wireless Sensor Networks, we proposed a tunable cross-layer Congestion Reducing Medium Access Control (CRMAC) protocol that utilizes buffer status information from the Network layer to give prioritized medium access to congested nodes in the MAC layer and thus preventing congestion and packet drops. CRMAC can also be easily tuned to satisfy different application-specific performance requirements. With the help of extensive simulation results we have shown how CRMAC can be adapted to perform well in different applications of Sensor Network like Emergency Situation that requires a high network throughput and low packet delivery latency or Long-term Monitoring application requiring energy conservation.

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