Routing Protocol Performance Evaluation for Mobile Ad-hoc Networks

Currently, MANETs are a very active area of research, due to their great potential to provide networking capabilities when it is not feasible to have a fixed infrastructure in place, or to provide a complement to the existing infrastructure. Routing in this kind of network is much more challenging than in conventional networks, due to its mobile nature and limited power and hardware resources. The most practical way to conduct routing studies of MANETs is by means of simulators such as GloMoSim. GloMoSim was utilized in this research to investigate various performance statistics and draw comparisons among different MANET routing protocols, namely AODV, LAR (augmenting DSR), FSR (also known as Fisheye), WRP, and Bellman-Ford (algorithm). The network application used was FTP, and the network traffic was generated with tcplib [Danzig91]. The performance statistics investigated were application bytes received, normalized application bytes received, routing control packets transmitted, and application byte delivery ratio. The scenarios tested consisted of an airborne application at a high (26.8 m/s) and a low speed (2.7 m/s) on a 2000 m x 2000 m domain for nodal values of 36, 49, 64, 81, and 100 nodes, and radio transmit power levels of 7.005, 8.589, and 10.527 dBm. Nodes were paired up in fixed client-server couples involving 10% and 25% of the nodes being V111 clients and the same quantity being servers. AODV and LAR showed a significant margin of performance advantage over the remaining protocols in the scenarios tested

Information distribution and recharging dispatch strategy in large wireless networks

Large wireless networks are envisioned to play increasingly important roles as more and more mobile wireless devices and Internet of Things (IoT) devices are put in use. In these networks, it is often the case that some critical information needs to be readily accessible, requiring a careful design of the information distribution technique. In this work, we at first propose PeB, Periodic Broadcast, that takes advantage of periodic broadcast from the information server(s) to leave traces for nodes requesting for the information while maintaining a low overhead. Similar to swarm intelligence, PeB requires each node to keep track of traces, or past records of information flow, through itself toward information servers. We present our extensive investigation of the PeB scheme on cost and network dynamics as compared to other state-of-the-art techniques. When the devices run out of battery, they become static and need to be recharged by the wireless charging vehicles (WCVs). Often times, WCV receives a number of charging requests and form a Hamiltonian cycle and visit these nodes one-by-one. We also propose a heuristic algorithm, termed Quad, that generates a Hamiltonian cycle in a square plane. We then focus on the theoretical study of the length of the Hamiltonian cycles in such networks

Efficient broadcasting by selective forwarDing

A major challenge faced in MANETs is locating the devices for communication, especially with high node mobility and sparse node density. Present solutions provided by the ad hoc routing protocols range from flooding [1] the entire network with route requests, to deploying a separate location management scheme to maintain a device location database. Many applications as well as various unicast routing protocols such as Dynamic Source Routing (DSR), Ad Hoc On Demand Distance Vector (AODV), Zone Routing Protocol (ZRP), and Location Aided Routing (LAR) use broadcasting or a derivation of it. Flooding, which is often deployed to achieve the above objective, is expensive in terms of overhead and wastes valuable resources such as bandwidth and power. We propose to develop a strategy to reduce the redundant transmission of packets in normal flooding used in broadcasting, and we describe strategies for choosing only an optimal set of nodes for rebroadcast in a grid network. The main contribution is to reduce the redundant transmission of packets and to forward packets with minimum transmissions. To determine the minimal set of nodes for efficient transmission, we propose a new algorithm, Efficient Broadcasting by Selective Forwarding, using a distance-based approach; The distance-based approach [2] is implemented for broadcast and rebroadcast to a set of nodes with the help of a threshold value [3] that is taken to be threshold = n* transmission-radius, where n is a real number. This reduces the number of redundant transmission. This threshold value can be tuned to show performance enhancement

Provision of adaptive and context-aware service discovery for the Internet of Things

The IoT concept has revolutionised the vision of the future Internet with the advent of standards such as 6LoWPAN making it feasible to extend the Internet into previously isolated environments, e.g., WSNs. The abstraction of resources as services, has opened these environments to a new plethora of potential applications. Moreover, the web service paradigm can be used to provide interoperability by offering a standard interface to interact with these services to enable WoT paradigm. However, these networks pose many challenges, in terms of limited resources, that make the adaptability of existing IP-based solutions infeasible. As traditional service discovery and selection solutions demand heavy communication and use bulky formats, which are unsuitable for these resource-constrained devices incorporating sleep cycles to save energy. Even a registry based approach exhibits burdensome traffic in maintaining the availability status of the devices. The feasible solution for service discovery and selection is instrumental to enable the wide application coverage of these networks in the future. This research project proposes, TRENDY, a new compact and adaptive registry-based SDP with context awareness for the IoT, with more emphasis given to constrained networks, e.g., 6LoWPAN It uses CoAP-based light-weight and RESTful web services to provide standard interoperable interfaces, which can be easily translated from HTTP. TRENDY's service selection mechanism collects and intelligently uses the context information to select appropriate services for user applications based on the available context information of users and services. In addition, TRENDY introduces an adaptive timer algorithm to minimise control overhead for status maintenance, which also reduces energy consumption. Its context-aware grouping technique divides the network at the application layer, by creating location-based groups. This grouping of nodes localises the control overhead and provides the base for service composition, localised aggregation and processing of data. Different grouping roles enable the resource-awareness by offering profiles with varied responsibilities, where high capability devices can implement powerful profiles to share the load of other low capability devices. Thus, it allows the productive usage of network resources. Furthermore, this research project proposes APPUB, an adaptive caching technique, that has the following benefits: it allows service hosts to share their load with the resource directory and also decreases the service invocation delay. The performance of TRENDY and its mechanisms is evaluated using an extensive number of experiments performed using emulated Tmote sky nodes in the COOJA environment. The analysis of the results validates the benefit of performance gain for all techniques. The service selection and APPUB mechanisms improve the service invocation delay considerably that, consequently, reduces the traffic in the network. The timer technique consistently achieved the lowest control overhead, which eventually decreased the energy consumption of the nodes to prolong the network lifetime. Moreover, the low traffic in dense networks decreases the service invocations delay, and makes the solution more scalable. The grouping mechanism localises the traffic, which increases the energy efficiency while improving the scalability. In summary, the experiments demonstrate the benefit of using TRENDY and its techniques in terms of increased energy efficiency and network lifetime, reduced control overhead, better scalability and optimised service invocation time

Supporting Collaboration in Mobile Environments

Continued rapid improvements in the hardware capabilities of mobile computing devices is driving a parallel need for a paradigm shift in software design for such devices with the aim of ushering in new classes of software applications for devices of the future. One such class of software application is collaborative applications that seem to reduce the burden and overhead of collaborations on human users by providing automated computational support for the more mundane and mechanical aspects of a cooperative effort. This dissertation addresses the research and software engineering questions associated with building a workflow-based collaboration system that can operate across mobile ad hoc networks, the most dynamic type of mobile networks that can function without dependence on any fixed external resources. While workflow management systems have been implemented for stable wired networks, the transition to a mobile network required the development of a knowledge management system for improving the predictability of the network topology, a mobility-aware specification language to specify workflows, and its accompanying algorithms that help automate key pieces of the software. In addition to details of the formulation, design, and implementation of the various algorithms and software components. this dissertation also describes the construction of a custom mobile workflow simulator that can be used to conduct simulation experiments that verify the effectiveness of the approaches presented in this document and beyond. Also presented are empirical results obtained using this simulator that show the effectiveness of the described approaches

Performance improvement of ad hoc networks using directional antennas and power control

Au cours de la dernière décennie, un intérêt remarquable a été éprouvé en matière des réseaux ad hoc sans fil capables de s'organiser sans soutien des infrastructures. L'utilisation potentielle d'un tel réseau existe dans de nombreux scénarios, qui vont du génie civil et secours en cas de catastrophes aux réseaux de capteurs et applications militaires. La Fonction de coordination distribuée (DCF) du standard IEEE 802.11 est le protocole dominant des réseaux ad hoc sans fil. Cependant, la méthode DCF n'aide pas à profiter efficacement du canal partagé et éprouve de divers problèmes tels que le problème de terminal exposé et de terminal caché. Par conséquent, au cours des dernières années, de différentes méthodes ont été développées en vue de régler ces problèmes, ce qui a entraîné la croissance de débits d'ensemble des réseaux. Ces méthodes englobent essentiellement la mise au point de seuil de détecteur de porteuse, le remplacement des antennes omnidirectionnelles par des antennes directionnelles et le contrôle de puissance pour émettre des paquets adéquatement. Comparées avec les antennes omnidirectionnelles, les antennes directionnelles ont de nombreux avantages et peuvent améliorer la performance des réseaux ad hoc. Ces antennes ne fixent leurs énergies qu'envers la direction cible et ont une portée d'émission et de réception plus large avec la même somme de puissance. Cette particularité peut être exploitée pour ajuster la puissance d'un transmetteur en cas d'utilisation d'une antenne directionnelle. Certains protocoles de contrôle de puissance directionnel MAC ont été proposés dans les documentations. La majorité de ces suggestions prennent seulement la transmission directionnelle en considération et, dans leurs résultats de simulation, ces études ont l'habitude de supposer que la portée de transmission des antennes omnidirectionnelles et directionnelles est la même. Apparemment, cette supposition n'est pas toujours vraie dans les situations réelles. De surcroît, les recherches prenant l'hétérogénéité en compte dans les réseaux ad hoc ne sont pas suffisantes. Le présent mémoire est dédié à proposer un protocole de contrôle de puissance MAC pour les réseaux ad hoc avec des antennes directionnelles en prenant tous ces problèmes en considération. ______________________________________________________________________________ MOTS-CLÉS DE L’AUTEUR : Réseaux ad hoc, Antennes directives, Contrôle de puissance

Producer mobility support scheme for indirection-based mobility approach in named data networking

Named Data Networking (NDN) is a clean-slate future Internet architecture proposed to support content mobility by using hierarchical naming instead of IP addresses for routing. The hierarchical naming structure of NDN offers more benefits in supporting consumer mobility. However, the movements of producer inflict changes in routing name prefix hierarchy, which makes the entire network unaware of the new location of the producer. Thus, it causes some significant challenges, such as unnecessary Interest packet losses, high handoff latency, high signaling overhead cost, poor utilization of bandwidth, and path stretching. The aim of this research is to propose a Producer Mobility Support Scheme (PMSS) in order to minimize the handoff latency, signaling cost, improve data packets delivery via optimal path once a content producer relocated. The proposed PMSS model includes the formulated Mobility Weighted Function to incorporate movement behavior of the mobile producer. Also, Mobility Interest packet was designed to convey binding information and Broadcasting Strategy to facilitate handoff processes by updating the intermediate routers. Therefore, modeling and simulation methodologies were used in the design and performance evaluation of PMSS for rigorous investigation. The analytical result of PMSS scheme outperforms Optimal Producer Mobility for Larger-scale scheme with 50% lower handoff latency and signaling cost. Moreover, it minimizes 46% handoff signaling cost and improves 32% data path optimization as compared to the Kite scheme. The simulation results show that the proposed PMSS scheme minimizes 40% handoff latency, 28% packets delay, 28% unnecessary Interest packets loss, and improves 20% throughput. This study contributes to the development of the movement behavior model and mobility update packets. The findings have significant implication to support seamless mobility and the integration of NDN with other networks without additional mechanism

Service Replication in Wireless Mobile Ad Hoc Networks

Die vorliegende Arbeit beschäftigt sich mit dem Management von Diensten im mobilen ad-hoc Netzwerken (MANETs). MANETs sind drahtlose Netzverbände mobiler Einheiten die sich dezentral ohne eine übergeordnete Organisation selbst verwalten. Die Netztopologie eines MANET verändert sich dabei dynamisch mit der Bewegung der autonomen Teilnehmer. Sensor Netzwerke, Personal Area Networks und Satelliten Netzwerke sind typische Beispiele für derartige MANETs. Mit der wachsenden Bedeutung der drahtlosen Vernetzung mobiler Geräte haben sich MANETs in den vergangenen Jahren zu einem wichtigen Forschungsgebiet entwickelt. Im Katastrophenmanagement, bei zivilen Rettungsfällen oder in militärischen Szenarien kann ihre infrastrukturlose Selbstorganisation MANETs zum einzig möglichen Kommunikationsmittel machen. Die mobilen Knoten eines MANETs kooperieren um essenzielle Netzwerkdienste wie das Routing und den Datentransport gemeinschaftlich zu gewährleisten. Ressourcen wie die Bandbreite zwischen Knoten, die Rechenleistung der mobilen Geräte und ihre Batterieleistung sind dabei typischerweise stark begrenzt und zudem wechselnd. Das Teilen der verfügbaren Ressourcen ist daher eine Notwendigkeit für das effiziente Funktionieren eines MANETs. Dienstorientierte Architekturen (SOAs) stellen ein geeignetes Paradigma dar, um geteilte Ressourcen zu verwalten. Wenn verfügbare Ressourcen als Dienst aufgefasst werden, lässt sich ihre Nutzung als Dienstabfrage bearbeiten. In diesem Zusammenhang ermöglichen SOAs Abstraktion, Kapselung, lose Koppelung, Auffindbarkeit von Ressourcen und dir für MANETs essenzielle Autonomie. Die Anwendung von SOAs auf MANETs findet daher zunehmend Beachtung in der Forschung