Along with the huge growth of mobile devices in recent years we have seen a matching growth in interest for mobile applications, with location-aware applications experiencing rapid growth for mobile devices. Radiolocation from measurements of radio received signal strength has demonstrated excellent precision, although despite a decade of research there have been no wide-spread deployments of indoor location systems. The majority of the existing research has been focused towards producing improved precision at the cost of increased time requirements for system configuration and maintenance. This thesis proposes taking a step back from increasing complexity by giving up precision in exchange for simplicity and speed of deployment, while still providing sufficient accuracy for many indoor location tasks. This is accomplished by putting aside the standard x, y, z coordinate systems and by using a method based on defined areas. Carefully choosing the defined areas to include Wi-Fi access points and to have signal attenuating walls separating the area from the next, this work demonstrates locational accuracy of over 90% in most cases. While this method is not applicable to wide open areas that lack signal attenuating features, it is highly applicable to many indoor environments. / Graduate

Mobile phones are becoming a primary platform for information access. More and more people use their mobile devices as one of their major communication access tools. Commuters are increasingly carrying their mobile devices with them almost everywhere. Mobile devices fit perfectly into an ideal environment for realizing ubiquitous computing. A major aspect of ubiquitous computing is context-aware applications where the applications collect information about the environment that the user is in and use this information to achieve their goals or improve performance. The location of the device is one of the most important pieces of context information. Location awareness makes certain applications possible, e.g., recommending nearby businesses and tracking estimated routes, and greatly improves the performance of other applications, for example it can be associated with automobile navigation devices. A feature available to mobile applications in the Android platform makes it possible to determine a device's location without any additional hardware or sensor mechanisms, by simply using the native capability of the built-in wireless network card. Since the release of Android systems, there have been numerous applications developed to introduce new ways of tracking locations. Recently, there have been many papers on location estimation leveraging ubiquitous wireless networks. In this thesis, we develop an Android application to collect useful Wi-Fi information without registering a location listener with a network-based provider, such as Wi-Fi connections or data connections. Therefore it provides a passive, privacy-preserving, non-intrusive and power-saving way of achieving location awareness to Android mobile users. Accurate estimation of the location information can bring a more contextual experience to mobile users. We save the passively collected data of the IDs of Wi-Fi access points and the received signal strengths to a database in order to help us structure the data and analyse it. We employ some heuristics to infer the location information from the data. Our work presents a location tracking technique mainly based on Basic Service Set identification (BSSID) and/or Received Signal Strength Indicator (RSSI) using Wi-Fi information. It falls into one of the most active fields in mobile application development --location-based or location-aware applications.

This thesis assesses the impact of Wi-Fi radio frequency interference (RFI) on mobile application quality of experience (QoE). Wi-Fi is a wireless radio network for transferring data between two end points and is based on the IEEE 802.11 standards and operates in the unlicensed 2.4 GHz and 5 GHz radio frequency bands. This thesis explores the QoE of mobile applications when considering the impact of RFI caused by Wi-Fi access points (WAPs) within a campus Wi-Fi network. The research was conducted to assess the effect of RFI on mobile application network performance metrics. This is evaluated by collecting broadcasted WAPs within a campus network, assessing the experienced RFI, and evaluating the mobile application QoE at specific locations to assess the impact of the experienced interference. / Graduate

The Cash in Transit (CIT) industry demands reliable and innovative products from its suppliers to ensure safety and reliability within the industry. Product innovation has been directed at a bespoke tracking system for the Cash in Transit industry, which can meet its stringent requirements and excel above the capabilities of standard, readily available tracking systems. The presented research has investigated the state of the art in tracking and localisation systems and has highlighted Wi-Fi as a potential novel Cash in Transit tracking solution. With research into 2.4GHz Wi-Fi and the effects in a CIT environment, the technology has been understood and demonstrated in terms of its advantages and weaknesses when applied to CIT. The research has shown that 2.4GHz Wi-Fi is a novel and viable solution for both wide area tracking and localised tracking of a Cash in Transit security box by testing innovative ways of detecting theft using 2.4GHz Wi-Fi in a set of specific real-world scenarios. An embedded tracking system was developed and a thorough evaluation undertaken using a series of practical usage scenarios. The results show the proposed tracking capability is very effective and ready for initial effective use within a Cash in Transit security box.

El objetivo de esta memoria es el diseño de una plataforma inalámbrica que permita soportar una serie de servicios previamente determinados, como transmisión de datos y Voz sobre IP (VoIP); para posteriormente, probar el desempeño de esta maqueta con el fin de evaluar su funcionamiento. La plataforma está basada en la utilización de equipamiento específico de dispositivos S trixSystems y en una topología de red inalámbrica Mesh, también conocida como sistema de malla. Esta topología permite un aumento en el ancho de banda del sistema y un mayor respaldo ante fallas de los enlaces inalámbricos entre equipos, gracias a su sistema de troncales inalámbricas de comunicación que interconecta los nodos de la malla.

With the development of Wi-Fi networks, Wi-Fi connection become a very important part of people‟s life, it seems that Wi-Fi networks are everywhere, especially in China. However, Wi-Fi networks not only bring convenience to users, but also bring some security threats. Nowadays, Wi-Fi security problems become increasingly acute. This thesis investigates the differences between male and female users regarding Wi-Fi network security. By distributing a questionnaire in China, specific questions have been asked about key factors within the area of Wi-Fi security. The questions focus on the usage situation, information security awareness and the knowledge level in Wi-Fi related fields. The found result is: Wi-Fi security issues are more prominent for female users than for male users.

Submitted by Pedro Barros (pedro.silvabarros@ufpe.br) on 2018-09-14T22:19:42Z No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) DISSERTAÇÃO Eric Ribas Moraes Machado.pdf: 4900184 bytes, checksum: c948644abc8216ef6e5e18dedb37a22f (MD5) / Approved for entry into archive by Alice Araujo (alice.caraujo@ufpe.br) on 2018-09-18T16:02:00Z (GMT) No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) DISSERTAÇÃO Eric Ribas Moraes Machado.pdf: 4900184 bytes, checksum: c948644abc8216ef6e5e18dedb37a22f (MD5) / Made available in DSpace on 2018-09-18T16:02:00Z (GMT). No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) DISSERTAÇÃO Eric Ribas Moraes Machado.pdf: 4900184 bytes, checksum: c948644abc8216ef6e5e18dedb37a22f (MD5) Previous issue date: 2017-06-05 / Redes Wi-Fi estão presentes desde as residências aos ambientes corporativos e instituições de ensino e pesquisa. Contudo, a qualidade de serviço (QoS) percebida pelo usuário pode ser degradada quando em ambientes congestionados, como em lugares confinados com grande quantidade de usuários. Para lidar com esse problema várias empresas oferecem soluções verticalmente integradas e fechadas, no entanto, os custos de capital (CAPEX), com a aquisição de equipamentos e licenças, e operacionais (OPEX) decorrente do seu gerenciamento são muito altos. O surgimento das redes definidas por software (SDN) viabilizou o desenvolvimento de varias soluções abertas para melhorar o gerenciamento das redes em geral, possibilitando ao administrador da rede programar rotinas dinâmicas de monitoramento, correção de problemas e otimização do uso dos recursos disponíveis, através de um controlador centralizado com visão geral da rede. Considerando a necessidade de soluções abertas para os Institutos Federais de Educação, Ciência e Tecnologia e o potencial da programabilidade das redes sem fio definidas por software, várias soluções foram desenvolvidas para lidar com o problema da degradação do QoS, entretanto, das inúmeras soluções existentes na literatura para o gerenciamento e balanceamento de carga nestas redes, a maioria delas não visam ambientes confinados com baixa mobilidade e/ou requerem modificações no dispositivo móvel, criando burocracia para o setor de tecnologia da informação e gerando desconforto aos usuários, que muitas vezes possuem dispositivos que não suportam as mudanças necessárias. Diante deste cenário esta dissertação propõe um arcabouço para balanceamento de carga em redes sem fio (Wi-Fi) utilizando a arquitetura SDN. Existem outras propostas que promovem o balanceamento de carga em redes Wi-Fi, mas são, normalmente, orientadas ao usuário. O foco do arcabouço proposto nesta dissertação é prover uma solução orientada à infraestrutura para ambientes de rede sem fio confinados, densos e com baixa mobilidade como auditórios, salas de aula, anfiteatros, dentre outros. O modelo promove a melhoria da QoS das aplicações dos usuários através do monitoramento de dados estatísticos da rede, coletados a partir da controladora SDN e de rádios de baixo custo com firmware modificado (OpenWRT) e da análise da carga gerada por cada usuário, mitigando assim a assimetria de rede por meio da realocação da carga. Para analisar o arcabouço proposto foi desenvolvido um software, utilizado o controlador SDN Ryu, foram configurados pontos de acesso (AP) e definidos cenários de congestionamento e assimetria em um ambiente de redes sem fio. A partir dos experimentos, foi observado que, os usuários tiveram uma melhoria de QoS considerável enquanto o sistema estava ativado. / Wi-Fi networks are present from residences to corporate environments and education and research institutions. However, user perceived quality of service (QoS) can be degraded when in congested environments, such as in confined spaces with large numbers of users. To deal with this problem several companies offer vertically integrated and closed solutions, but, the capital expenditure (CAPEX), with the acquisition of equipment and licenses, and operational expenditure (OPEX) due to its management are very high. The emergence of software-defined networking (SDN) enabled the development of several open solutions to improve network management, enabling the network administrator to program dynamic monitoring routines, problem correction and optimization of the use of available resources through centralized controller with network overview. Considering the need for open solutions for federal institutes and the potential for programmability of SDN, several solutions have been developed to deal with the QoS degradation problem, nevertheless, of the numerous solutions in the literature for managing and balancing the load on these networks, most of them do not target confined environments with low mobility and / or require modifications in the mobile device, creating bureaucracy for the IT sector and generating discomfort to the users, which often have devices that do not support the necessary changes. Considering this scenario, this dissertation proposes a framework for load balancing in wireless networks (Wi-Fi) using the SDN architecture. There are other proposals that promote load balancing on Wi-Fi networks, they are usually user-oriented. In this dissertation the proposed framework focus is to provide an infrastructure-oriented solution for confined, dense, low mobility wireless network environments such as auditoriums, classrooms and amphitheaters. The proposal improves the QoS of the users’ applications by the monitoring of statistical data from network, collected through the controller SDN and low cost radios with modified firmware (OpenWRT) and analysis of the load generated by each user, thus mitigating the asymmetry through load reallocation. In order to analyze the proposed framework, a software was developed, using the Ryu SDN controller, configured access points (AP) and defined congestion and asymmetry scenarios in a wireless environment. From the experiments, it was observed that, users had a considerable QoS improvement while the system was activated.

The diploma thesis gives the overall information about the field of wireless networks of standards 802.11 and Quality of Service (QoS). The practical measurements describe the reactions of multimedia dataflows in the networks 802.11a/b/g/n. The individual standards, offered services, access methods and the network architecture are analyzed in the theoretical part. In the following part there is written about QoS and its basic parameters. Moreover, the standard 802.11e and the question of QoS in the wireless networks are explained in a detailed way. The first part of the practical measurement is focused on the networks 802.11b/g/n. All main network statistics are measured when using the wireless stations and routers. The projection and implementation of the wireless network in the Opnet Modeler is included in the next part. The individual simulations WLAN in the Opnet Modeler are comparing the networks 802.11a/b/g. The analysis of the key QoS statistics is undertaken; the measured data are clearly displayed in the charts and schemes. The interpreted results are concluded and justified.

This thesis is focused on the design of panel antennas for band 5,6 GHz. Antennas have been examined and optimized with a view to impedance, broadband and directional characteristics by using designing software CST Design Environment. Optimized antennas were produced, and their measured parameters achieved required values.

This project is concerned with the security of Wi-Fi network. It defines security and introduces the principles of some security systems which are consequently instructed for its breakthrough, out of which follows the nature of security failures. The main emphasis is put on the current security issue of Wi-Fi Protected Setup (WPS) technology. Consequently, it is concerned with the putting into service of this technology in GNU/Linux distribution OpenWrt on Wi-Fi router TP-LINK TL-WR1043ND. The project is concluded with the suggestions for the correction of the security failure.