Approved for public release, distribution is unlimited / The objective of this research is to analyze the network performance and sensor functionality, efficacy and usability of IEEE 802.x wireless MESH networks within a DoD Tactical network environment. Multiple sensor configurations operating with wireless MESH network technologies will be researched and analyzed for performance in expeditionary environment situations. Specifically, this thesis will attempt establish the foundation for the development of wireless MESH "network health" models by examining the performance of sensors operating within a MESH network and define which network performance metrics equate to good quality of service. This research will experiment with different application, sensor, and network configurations of currently available COTS components, such as, voice, video and data hardware. This thesis will lay the groundwork for wireless network MESH predictability, which will enable the optimal use of sensors within a tactical network environment. / Lieutenant Commander, United States Navy

IEEE 802.16 是一支援都會型無線網路的協定，IEEE 802.16支援PMP模式(點對多點)和網狀模式兩種。在網狀模式中，所有節點的構成仿如ad-hoc方式，並依據在控制性子框中的排程資訊來計算下次遞送時間。在資料傳送之前，會有一段設定連線的時間。這段時間，每一個節點都必須跟鄰節點競爭，以取得廣播它的排程資訊給鄰節點的機會。這樣的行為跟它過去的歷史無關。換句話說，它具有”時間同質性”而適合以隨機程序來模擬。在這篇論文中，我們將用排隊程序來建立排程行為的模型，然後以馬可夫鏈來估計它的平均延遲時間，也就是一節點持續地競爭直到贏為止的這段等待時間。 / The IEEE 802.16 standard is a protocol for wireless metropolitan networks. IEEE 802.16 MAC protocol supports both of PMP (point to multipoint) and Mesh mode. In the mesh mode, all nodes are organized in a fashion similar ad-hoc and calculate their next transmission time based on the scheduling information performed in the control subframe. Before data transmission for a certain node, there is a period of time to setup the connection. During this period, each node has to compete with each other for the opportunity to advertise scheduling messages to its neighbors. This behavior does not depend on past history. In other words, it is a “Time Homogeneous” and suitable for being modeled by stochastic process. In this thesis, we will model this scheduling behavior by queuing process, and apply the Markov Chain to estimate its average delay time which a node keep waiting until it win the competition.

Les travaux de cette thèse s'inscrivent dans le contexte des réseaux sans fil et des réseaux d'accès par Satellite en particulier, qui facilitent l'installation d'infrastructures réseau dans les zones géographiquement reculées et faiblement peuplées. Cependant, ces derniers présentent certains inconvénients lorsqu'il s'agit de déployer des applications multimédia interactives. En effet, de telles applications requièrent un délai de bout en bout aussi faible que possible et plus généralement exigent une meilleure Qualité de Service (QdS) du système de communication que le classique Meilleur-Effort (BE) afin de fonctionner correctement. Or, les réseaux d'accès par satellite géostationnaires souffrent déjà d'un délai de propagation non négligeable d'autant plus accru que la transmission des données est assurée par des mécanismes d'allocation dynamique, par exemple dans un système DVB-S2/RCS. Dans ces travaux de thèse, nous proposons d'utiliser les informations de signalisation de session des applications multimédia basées sur le protocole de session SIP afin d'ajuster le paramétrage du système de communication selon une approche " cross-layer " qui permet alors d'améliorer de façon significative la réactivité du système. Nous avons proposé plusieurs solutions pour, d'abord réduire le temps entre la demande de communication et le démarrage effectif du transfert des flux multimédia, ensuite réduire le délai de transmission des données multimédia durant la communication (tout en utilisant de manière optimale les ressources réseau disponibles sur la voie retour), et enfin accroître le nombre de flux multimédia admissibles dans le réseau satellite tout en leur garantissant un niveau de QdS satisfaisant. Afin de faciliter l'intégration et l'implémentation des solutions proposées dans un système de communication réel, un mécanisme de communication inter-couches d'optimisation est proposé et développé. De plus, une architecture orientée web services est utilisée afin de faciliter la découverte et l'invocation des différentes niveaux de services de communication présents dans de tels réseaux d'accès. Les solutions proposées ont été évaluées dans des environnements sans fil émulés et réels

In recent years, there has been a rapid growth in deployment and usage of realtime network applications, such as Voice-over-IP, video calls/video conferencing, live network seminars, and networked gaming. The continued increase in the popularity of realtime applications requires a more intense focus on the provision of strict guarantees for Quality of Service (QoS) parameters such as delay, jitter and packet loss in access networks. At the same time, wireless networking technologies have become increasingly popular with a wide array of devices such as laptop computers, Personal Digital Assistants (PDAs), and cellular phones being sold with built-in WiFi and WiMAX interfaces. For realtime applications to be popular over wireless networks, simple, robust and effective QoS mechanisms suited for a variety of heterogeneous wireless networks must be devised. Implementing the same QoS mechanisms across multiple neighbouring networks aids seamless handover by ensuring that a flow will be treated in the same way, both before and after handover. To provide guaranteed QoS, an access network should limit load using an admission control algorithm. In this research, we propose a method to provide effective admission control for variable bit rate realtime flows, based on the Central Limit Theorem. Our objective is to estimate the percentage of packets that will be delayed beyond a predefined delay threshold, based on the mean and variance of all the flows in the system. Any flow that will increase the percentage of delayed packets beyond an acceptable threshold can then be rejected. Using simulations we have shown that the proposed method provides a very effective control of the total system load, guaranteeing the QoS for a set of accepted flows with negligible reductions in the system throughput. To ensure that flow data is transmitted according to the QoS requirements of a flow, a scheduling algorithm must handle data intelligently. We propose methods to allow more efficient scheduling by utilising existing Medium Access Control mechanisms to exchange flow information. We also propose a method to determine the delay-dependent "value" of a packet based on the QoS requirements of the flow. Using this value in scheduling is shown to increase the number of packets sent before a predetermined deadline. We propose a measure of fairness in scheduling that is calculated according to how well each flow's QoS requirements are met. We then introduce a novel scheduling paradigm, Delay Loss Controlled-Earliest Deadline First (DLC-EDF), which is shown to provide better QoS for all flows compared to other scheduling mechanisms studied. We then study the performance of our admission control and scheduling methods working together, and propose a feedback mechanism that allows the admission control threshold to be tuned to maximise the efficient usage of available bandwidth in the network, while ensuring that the QoS requirements of all realtime flows are met. We also examine heterogeneous/vertical handover, providing an overview of the technologies supporting seamless handover. The issues studied in this area include a method of using the Signal to Noise Ratio to trigger handover in heterogeneous networks and QoS Mapping between heterogeneous networks. Our proposed method of QoS mapping establishes the minimum set of QoS parameters applicable to individual flows, and then maps these parameters into system parameter formats for both 802.11e and 802.16e networks.

In recent years, immense effort has been channelled towards the Information and Technological development of rural areas. To support this development, telecommunication networks have been deployed. The availability of these telecommunication networks is expected to improve the way people share ideas and communicate locally and globally, reducing limiting factors like distance through the use of the Internet. The major problem for these networks is that very few of them have managed to stay in operation over long periods of time. One of the major causes of this failure is the lack of proper monitoring and management as, in some cases, administrators are located far away from the network site. Other factors that contribute to the frequent failure of these networks are lack of proper infrastructure, lack of a constant power supply and other environmental issues. A telecommunication network was deployed for the people of Dwesa by the Siyakhula Living Lab project. During this research project, frequent visits were made to the site and network users were informally interviewed in order to gain insight into the network challenges. Based on the challenges, different network monitoring systems and other solutions were deployed on the network. This thesis analyses the problems encountered and presents possible and affordable solutions that were implemented on the network. This was done to improve the network‟s reliability, availability and manageability whilst exploring possible and practical ways in which the connectivity of the deployed telecommunication network can be maintained. As part of these solutions, a GPRS redundant link, Nagios and Cacti monitoring systems as well as Simple backup systems were deployed. v Acronyms AC Access Concentrators AMANDA Automatic Marylyn Network Disk Archiver CDMA Code Divison Multiple Access CGI Common Gateway Interface.

Approved for public release, distribution is unlimited / This thesis analyzes the potential impact of incorporating wireless technologies, specifically an 802.11 mesh layer architecture and 802.16 Orthogonal Frequency Division Multiplexing, in order to effectively and more efficiently transmit data and create a symbiotic operational picture between Coast Guard Cutters, their boarding teams, Coast Guard Operation Centers, and various external agencies. Two distinct collaborative software programs, Groove Virtual Office and the Naval Postgraduate School's Situational Awareness Agent, are utilized over the Tactical Mesh and OFDM network configurations to improve the Common Operating Picture of involved units within a marine environment to evaluate their potential impact for the Coast Guard. This is being done to increase the effectiveness and efficiency of Coast Guard units while they carry out their Law Enforcement and Homeland Security Missions. Through multiple field experiments, including Tactical Network Topology and nuclear component sensing with Lawrence Livermore National Laboratory, we utilize commercial off the shelf (COTS) equipment and software to evaluate their impact on these missions. / Lieutenant Commander, United States Coast Guard / Lieutenant, United States Coast Guard

Submitted by Irvana Coutinho (irvana@ufpa.br) on 2013-01-23T13:08:05Z No. of bitstreams: 2 license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) Dissertacao_SwImaxSimuladorRealidade.pdf: 3330765 bytes, checksum: 7c92ceee8132c39701de5e5926670e7f (MD5) / Approved for entry into archive by Ana Rosa Silva(arosa@ufpa.br) on 2013-01-25T13:15:59Z (GMT) No. of bitstreams: 2 license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) Dissertacao_SwImaxSimuladorRealidade.pdf: 3330765 bytes, checksum: 7c92ceee8132c39701de5e5926670e7f (MD5) / Made available in DSpace on 2013-01-25T13:15:59Z (GMT). No. of bitstreams: 2 license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) Dissertacao_SwImaxSimuladorRealidade.pdf: 3330765 bytes, checksum: 7c92ceee8132c39701de5e5926670e7f (MD5) Previous issue date: 2012 / O padrão IEEE 802.16, também chamado de WiMAX, é uma tecnologia da rede banda larga sem fio para áreas metropolitanas, utilizado como alternativa para transmissão de sinal de Internet a regiões que não possuem infraestrutura de rede cabeada. Atualmente, o ensino desta tecnologia em sala de aula é meramente teórico, o que dificulta a compreensão dos alunos com relação a determinadas funcionalidades do WiMAX. Nesse sentido, a presente dissertação aborda o projeto de desenvolvimento de um simulador em Realidade Virtual, chamado SwImax, voltado para auxílio do ensino do padrão IEEE 802.16. Assim, o SwImax simula algumas características do funcionamento deste padrão, quais sejam: faixas de frequência de operação, área de cobertura, procedimento de handover, transmissão sem linha de visada, entre outros. A dissertação apresenta os trabalhos correlatos que influenciaram o desenvolvimento do projeto, além de um resumo acerca do padrão IEEE 802.16. O texto apresenta também as ferramentas utilizadas no desenvolvimento do SwImax e a implementação do simulador. Ao final do desenvolvimento, o software foi submetido a uma avaliação dos usuários, de modo que os resultados também são abordados nesta dissertação. / The IEEE 802.16 standard, also known as WiMAX, is a network technology for broadband wireless metropolitan areas, used as an alternative for streaming Internet signal to regions that do not have wired network infrastructure. Currently, the teaching of technology in the classroom is only theoretical, which hinders students understanding to certain features of WiMAX. Accordingly, this work discusses the design development of a virtual reality simulator, called SwImax, facing the aid teaching of IEEE 802.16. Thus, SwImax simulates some features of the functioning of this pattern, which are: operating frequency bands, coverage area, handover procedure, non-line of sight transmission, among others. The dissertation presents the related work that influenced the development of the project as well as a summary on the IEEE 802.16 standard. The text also presents the tools used in the development and implementation of SwImax simulator. At the end of development, the software was subject to an assessment of the users, so that the results are also discussed in this dissertation.

Computer networks are in the scope of the IEEE organization normalized by the 802 board which currently comprises six working groups for wireless communications. IEEE 802.11 for wireless local area networks, IEEE  802.15 for wireless personal area networks, IEEE 802.16 for wireless metropolitan area networks, IEEE 802.20 for mobile broadband wireless access, IEEE 802.21 for media independent handover and IEEE 802.22 for wireless regional area networks. This master's thesis focuses on a security analysis of particular standards, describes threats, vulnerabilities, current security measures and mutually compares wireless specifications from a security point of view. The conclusion is devoted to overall evaluation of the project, to its contributions, possible enhancements and continuation in the form of consequential studies.