Approved for public release, distribution is unlimited / In today's navy, it is becoming more and more important to reach all areas onboard a ship with key technical resources. In order to accomplish this goal, the already existing physical networks need to be complemented with wireless capability. A sophisticated Wireless Local Area Network (WLAN) can provide that vital connectivity to the ship's network resources from almost anywhere on the ship. It would allow sailors to access critical information and immediately communicate with others throughout the ship from any standard wireless device (PDA, laptop and many other hand-held devices). In addition, WLANs greatly mitigate problems due to physical damage to wires or fiber optic cables that are used today. Because the navy's emphasis is on building ships with reduced manning, advanced technology, and lower cost in mind, the idea of a WLAN, which has a deep impact on all those areas, has been of a growing interest to the Navy. The purpose of this thesis is to analyze, model, and simulate a wireless environment on board a variety of naval ship compartments, using the Urbana code. Starting from known inputs (frequency, ship compartment geometry, material properties, propagation computation model, and antenna type), analytical results reflecting the propagation mechanisms, coverage area, and security posture of the WLAN are presented. Variable inputs can then be optimized to achieve a desired signal distribution and to meet security requirements for a specific shipboard environment. / Lieutenant Junior Grade, Tunisian Navy

Approved for public release; distribution in unlimited. / In spite of the fact that wireless network technology has been available for long period of time, there has been very limited wireless networks deployments around the world before 1997 due to the lack of widely recognized standard for wireless networks. Thanks to the approval of the IEEE 802.11 family of standards in 1997, the world has witnessed tremendous deployment and proliferation of wireless networks in all aspects of life. Although the IEEE 802.11 family of standards has been ratified to design radio transceivers for wireless computer stations capable of interconnecting with other wireless computer stations in close proximity, the technology has been successfully employed to design and implement wireless networks with great number of distant wireless computer stations with reasonable data throughput and flexibility. This thesis explores the wireless network technology and the primary building blocks and components of a wireless network. It also explores the IEEE 802.11 standard and its technical specifications including the Physical layer (PHY), the Media Access Control layer (MAC) and the ongoing task forces. Additionally, the thesis examines the wireless network security including the vulnerabilities, ongoing improvements and recommendations. Next, it investigates the market for available wireless devices compatible with the IEEE 802.11 standard that can be used to build a wireless network with high data throughput and high level of security. Subsequently, the thesis formulates a design plan for civilian wireless network with different scenarios in order to provide a speedy solution to the limited broadband service availability in the Sultanate of Oman. Additionally, the thesis formulates a generic design plan for a military wireless network with different scenarios that can be rapidly deployed in the field of operations. / Computer Engineer, Royal Army of Oman

L'objectif de nos travaux de recherche est de concevoir une architecture simple et efficace veiller à deux exigences suivantes: une grande précision (au niveau de la pièce) ; une adaptation aux plusieurs scénarios. La thèse contribue aux études pour les systèmes de localisation en intérieur en combinant des approches basées sur la caractérisation de mouvement, la communication courte portée et de l'intensité du signal. La combinaison de ces approches proposées permettent de minimiser la défaillance de chacune approche. En effet, notre système de localisation propose une combinaison des technologies qui sont actuellement équipé en terminaux mobiles, y compris la technologie de WLAN, NFC et des capteurs (accéléromètre et magnétomètre). Voici nos trois approches proposées : Premièrement, nous proposons l'approche basée sur NFC-étiquetage qui fournit un service simple et efficace pour une localisation en intérieur. En touchant une étiquette disséminées dans l'environnement intérieur, l'utilisateur peut connaître sa position réelle qui est même à celle d’étiquette. Cette approche est très pratique car la localisation se fait automatiquement en approchant le terminal mobile de l'utilisateur à l’étiquette. L'approche basée sur NFC-étiquetage, cependant, nécessite l'intervention régulière de l'utilisateur qui n'est pas prédictive et donc peut poser des problèmes sur la validité des informations. Alors, l'information de localisation n’est fiable que dans un certain intervalle de temps depuis le dernier étiquetage. La valeur de cet intervalle de temps (ex. t secondes) sera ajustée selon les scénarios de déploiement. Deuxièmement, nous améliorons la qualité de l'approche précédente en développant la deuxième approche basée sur des capteurs qui combine l'accéléromètre et le magnétomètre pour estimer la distance de déplacement de l'utilisateur. Avec l'objectif de permettre à l'utilisateur de tenir son terminal mobile commodément dans la main (multi-positions), la deuxième approche fournit un service de localisation caractérisant le degré de mouvement à l'utilisateur pour déterminer si l'utilisateur est au même endroit depuis le dernier étiquetage. Pour une longue trajectoire, cette approche permet de détecter que l'utilisateur a déjà déplacé à un autre endroit. Finalement, afin de surmonter les inconvénients de deux approches précédentes, nous proposons la troisième approche basée sur l'intensité du signal en utilisant la similarité des conditions radio entre proches voisins. Nous proposons une combinaison de la technologie NFC et WLAN pour construire la cartographie d'intensité du signal. La communication à courte portée NFC permet au système d’obtenir correctement les informations de position. Cette combinaison peut récupérer les données de l'intensité du signal radio à et les attribuer à une position connue sur la cartographie, sans exiger de phases hors ligne pour enregistrer l'intensité du signal radio. / Ubiquitous computing refers to providing a global computing service where the user access seamlessly resources. User tracking is one of the most important location-aware applications for maintaining the service even with the users' mobility.Unlike outdoor localization technologies like GPS, indoor localization systems have to encounter many problems such as interferences from external sources, low cost and low latency infrastructure requirements, and high accuracy in a limited space.Our localization approaches associate with technologies that are currently equipped in mobile devices, including NFC technology and inertial sensors and Wireless LAN. The aim of this thesis is to design simple and effective architecture ensuring two requirements: a high accuracy and an adaptation to the multiple scenarios. Therefore, our proposed system does not address to the fingerprint technique and learning machine algorithms. In this thesis, we propose three approaches as follows:- The NFC-tagging approach is an instant on-the-spot localization with almost zero-latency- A combination of accelerometer and magnetometer in the sensors-based approach permits to characterize the user's movement- The signal-strength-based approach using the similarity of radio conditions between the neighbors can update in real time the radio map for long period localization.We analyze the performance of the proposed approaches based on rigorous simulation and experimentation tests. We then implement the proposed approaches in a wireless testbed with Android smartphone. Although the implementation is not a final product, the current application can be used to evaluate the feasibility and the performance of the proposed approaches.

This work presents the implementation of the the IEEE 1609.2 WAVE Security Services Standard. This implementation provides the ability to generate a message signature, along with the capability to verify that signature for wave short messages transmitted over an unsecured medium. Only the original sender of the message can sign it, allowing for the authentication of a message to be checked. As hashing is used during the generation and verification of signatures, message integrity can be verified because a failed signature verification is a result of a compromised message. Also provided is the ability to encrypt and decrypt messages using AES-CCM to ensure that sensitive information remains safe and secure from unwanted recipients. Additionally this implementation provides a way for the 1609.2 specific data types to be encoded and decoded for ease of message transmittance. This implementation was built to support the Smart Drive initiative’s VANET testbed, supported by the National Science Foundation and is intended to run on the Vehicular Multi-technology Communication Device (VMCD) that is being developed. The VMCD runs on the embedded Linux operating system and this implementation will reside inside of the Linux kernel. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2016. / FAU Electronic Theses and Dissertations Collection

We present an implementation of the IEEE WAVE (Wireless Access in Vehicular Environments) 1609.4 standard, Multichannel Operation. This implementation provides concurrent access to a control channel and one or more service channels, enabling vehicles to communicate among each other on multiple service channels while still being able to receive urgent and control information on the control channel. Also included is functionality that provides over-the-air timing synchronization, allowing participation in alternating channel access in the absence of a reliable time source. Our implementation runs on embedded Linux and is built on top of IEEE 802.11p, as well as a customized device driver. This implementation will serve as a key compo- nent in our IEEE 1609-compliant Vehicular Multi-technology Communication Device (VMCD) that is being developed for a VANET testbed under the Smart Drive initiative, supported by the National Science Foundation. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2014. / FAU Electronic Theses and Dissertations Collection

As a result of rapid progress in research and development, today's wireless world exhibits several heterogeneous communication networks, such as cellular networks, satellite networks, wireless local area networks (WLAN), mobile ad hoc networks (MANET), and sensor networks. These networks are complementary to each other. Hence, their integration can realize a unified wireless system that has the best features of the individual networks. This has spurred much research interest in designing integrated next-generation of wireless systems (NGWS). While existing wireless networks have been extensively studied individually, the integrated wireless system brings new challenges in architecture design, system management, and protocol design. The different wireless networks use different communication technologies and are based on different networking paradigms. Therefore, it is challenging to integrate these networks such that their heterogeneities are hidden from each other and a harmonious inter-operation among them is achieved. The objective of this research is to design a scalable, secure, and robust architecture and to develop seamless mobility management protocols for NGWS. More specifically, an architecture that integrates the heterogeneous wireless systems is first proposed for NGWS. Next, a cross-layer (Layer 2 + 3) handoff management protocol is developed for NGWS. Afterward, analytical modeling is developed to investigate the handoff performance of the existing mobility management protocols for different types of applications. Finally, a framework for multi-layer mobility management is developed to support the seamless handoff support to all types of applications in NGWS.

The area of deterministic noise cancellation in mobile radio communication systems is investigated and analyzed. Several interoperation problems in the mobile wireless radio space are identified and interference concerns for the Bluetooth - WLAN networks are characterized and quantified in the physical layer. A mathematical framework has been created for describing interference in the 2.4 GHz band. An adaptive noise suppression system has been developed that is able to alleviate the encroachment of the aggressor signal on the victim without sacrificing any of the original signal. This system is demonstrated to improve the victim SNR in a spread spectrum communication scenario. The research is extended to construct an interference canceller that is easy to assimilate into existing RF front-ends. A low-power small form-factor analog active canceller has been designed in 0.18-ìm Si-CMOS IC technology that delivers adequate noise suppression performance while operating in the RF domain. This includes novel implementations of phase rotator circuits based on delay interpolation and an integrated low-current quadrature modulator-based continuously variable analog phase shifter. This canceller is capable of up to 30 dB of in-band cancellation for the Bluetooth - WLAN problem. Other versions of the canceller are configured to protect GPS and DVB-H receivers from unintentional radiators transmitting in the vicinity. These demonstrate noise mitigation of at least 15 dB in their respective bands while generating very low broadband noise at the output. A simple low-power mixed-signal automatic control mechanism is also developed to operate the canceller adaptively. The work described in this dissertation advances the state-of-the-art in the area of mobile wireless radio coexistence.

Current wireless network solutions are based on a link abstraction where a single co-channel transmitter transmits in any time duration. This model severely limits the performance that can be obtained from the network. Being inherently an extension of a wired network model, this model is also incapable of handling the unique challenges that arise in a wireless medium. The prevailing theme of this research is to explore wireless link abstractions that incorporate the broadcast and space-time varying nature of the wireless channel. Recently, a new paradigm for wireless networks which uses the idea of 'cooperative transmissions' (CT) has garnered significant attention. Unlike current approaches where a single transmitter transmits at a time in any channel, with CT, multiple transmitters transmit concurrently after appropriately encoding their transmissions. While the physical layer mechanisms for CT have been well studied, the higher layer applicability of CT has been relatively unexplored. In this work, we show that when wireless links use CT, several network performance metrics such as aggregate throughput, security and spatial reuse can be improved significantly compared to the current state of the art. In this context, our first contribution is Aegis, a framework for securing wireless networks against eavesdropping which uses CT with intelligent scheduling and coding in Wireless Local Area networks. The second contribution is Symbiotic Coding, an approach to encode information such that successful reception is possible even upon collisions. The third contribution is Proteus, a routing protocol that improves aggregate throughput in multi-hop networks by leveraging CT to adapt the rate and range of links in a flow. Finally, we also explore the practical aspects of realizing CT using real systems.

Transmission of medical images, that mandate lossless transmission of content over WLANs, presents a great challenge. The large size of these images coupled with the low acceptance of traditional image compression techniques within the medical community compounds the problem even more. These factors are of enormous significance in a hospital setting in the context of real-time image collaboration. However, recent advances in medical image compression techniques such as diagnostically lossless compression methodology, has made the solution to this difficult problem feasible. The growing popularity of high speed wireless LAN in enterprise applications and the introduction of the new 802.11n draft standard have made this problem pertinent. The thesis makes recommendations on the degree of compression to be performed for specific instances of image communication applications based on the image size and the underlying network devices and their topology. During our analysis, it was found that for most cases, only a portion of the image; typically the region of interest of the image will be able to meet the time deadline requirement. This dictates a need for adaptive method for maximizing the percentage of the image delivered to the receiver within the deadline. The problem of maximizing delivery of regions of interest of image data within the deadline has been effectively modeled as a multi-commodity flow problem in this work. Though this model provides an optimal solution to the problem, it is NP hard in computational complexity and hence cannot be implemented in dynamic networks. An approximation algorithm that uses greedy approach to flow allocation is proposed to cater to the connection requests in real time. While implementing integer programming model is not feasible due to time constraints, the heuristic can be used to provide a near-optimal solution for the problem of maximizing the reliable delivery of regions of interest of medical images within delay deadlines. This scenario may typically be expected when new connection requests are placed after the initial flow allocations have been made.

Thesis (PhD)--Macquarie University, Faculty of Science, Dept. of Physics & Engineering, 2008. / "March, 2009". Bibliography: p. 145-158.