A interferência espectral gera patologias nos sistemas de comunicação sem fio (wireless), como por exemplo, quedas na comunicação e degradação na vazão. O espectro de RF (rádio frequência) é fiscalizado e controlado por órgãos governamentais, no entanto as redes sem fio padrão IEEE 802.11, conhecidas por WLANs (Wireless Local Area Networks), trabalham em faixas espectrais não licenciadas, conhecidas por ISM. Estas redes estão cada vez mais presentes nos ambientes comerciais e residenciais, contribuindo para questões de ubiquidade e acesso à Internet. Com este aumento expressivo, a cobertura espectral está cada vez mais densa. A densidade elevada de sinais aponta para a saturação do espectro ISM, causando interferências mútuas das redes IEEE 802.11. O objetivo deste trabalho é analisar a cobertura do espectro, por redes WLANs, e avaliar quedas de vazão ocasionadas por interferências espectrais, variando no espaço e no tempo. Dois cenários foram mapeados para analisar as degradações, um com baixa a média e outro com alta densidade e complexidade. O objetivo da criação desses cenários foi comparar as degradações causadas pelas interferências em ambientes diferentes, na ocupação, na utilização e na propagação de sinais de redes WLANs. Através dos resultados obtidos, um ciclo de vida de gerenciamento do espectro de redes padrão 802.11 foi proposto. Este ciclo contribui para avaliar e classificar o estado de uma rede em densa, não densa, complexa e não complexa, visto que alterações de ocupação do espectro no espaço e no tempo são plausíveis de ocorrerem. Conclui-se que os impactos da sobreposição total do canal, por fontes 802.11, não são suficientes para a substancial degradação da vazão em ambientes de baixa a média complexidade. Em ambientes com alta densidade e complexidade as degradações são mais evidentes, principalmente quando ocorrem perturbações vindas de duas fontes adjacentes / The spectral interference generates pathologies in wireless communication systems (wireless), such as declines in communication and degradation in flow. The spectrum of RF (radio frequency) is supervised and controlled by government agencies, however the wireless standard IEEE 802.11, known as WLANs (Wireless Local Area Networks), work in unlicensed spectrum bands, known as ISM. These networks are increasingly involved in commercial and residential environments, contributing to issues and ubiquity of Internet access. With the significant increase in these networks, the spectral coverage is increasingly dense. The high density of signals pointing to the saturation of the ISM spectrum, causing mutual interference of IEEE 802.11 networks. The aim of this study is to analyze the coverage of the spectrum, for WLANs, and evaluate the flow falls caused by spectral interferences, varying in space and time. Two scenarios were mapped to examine the degradations, with a low to medium and one with high density and complexity. The purpose of creating these scenarios was to compare the degradation caused by interference in different environments, occupation, use and spread of signals WLANs. Through the results, a life cycle management of the spectrum of standard 802.11 networks was proposed. This cycle helps to evaluate and classify the state of a dense network, not dense, complex and not complex, since changes in occupation of the spectrum - in space and time - are plausible to occur. It is concluded that the impacts of the complete overlap of the channel, sources 802.11, are not sufficient to the substantial degradation of the flow in low to medium complexity. In environments with high density and complexity of the degradation is more evident, especially when there are disturbances coming from two adjacent sources

A vantagem das redes locais sem fios, as quais permitem que uma estação móvel possa deslocar-se livremente dentro da área de abrangência da rede, possui uma contrapartida em termos de segurança. A possibilidade dos sinais de microondas atravessarem paredes e sofrerem atenuação, reflexão, refração, difração e dispersão, dependendo dos obstáculos, torna a definição dos limites da área de abrangência da rede sem fios uma tarefa difícil. Sem o conhecimento dos limites de abrangência, o administrador não tem como delimitar fisicamente o acesso à rede. Além disso, o padrão IEEE 802.11 não define um mecanismo capaz de localizar a posição física de estações móveis. Sem a possibilidade de localização de estações, é impossível restringir o acesso à rede baseando-se em limitações físicas definidas pelo administrador. Quando a rede sem fios é utilizada em ambientes internos, os diversos obstáculos e seu comportamento dinâmico (como pessoas em movimento, por exemplo), fazem com que os sinais de microondas alterem as características da área de abrangência da rede. Este trabalho propõe uma nova abordagem para localização de estações sem fios em ambientes internos, baseada no comportamento dinâmico dos obstáculos e conseqüentes alterações na rede, e, de acordo com este comportamento, tenta ampliar a eficiência da localização de estações. Por fim, é proposto um novo sistema de autenticação de estações baseado na sua localização. / The advantage of wireless local area networks, giving the mobile stations the possibility of moving free inside the network access range comes with a security drawback. The fact that microwave signals can cross walls and behave with attenuation, reflections, refraction, diffraction and dispersion, depending of the obstacles, makes very difficult to define the network access range. Without the knowledge of the network boundaries, the network administrator cannot define a physical delimiter to network access. Besides this issue, there is no default user-location mechanism in the IEEE 802.11 standard. Without the user-location, it is impossible to restrict the network access based on the physical access boundaries defined by the administrator. When the wireless network operates indoor the many obstacles and the dynamic behavior of these obstacles (some people moving around, for instance) make the microwave signal behavior change the range and aspect of the network. This work proposes a new approach to indoor user-location mechanism, based on the dynamic behavior of the obstacles and consequent changes on network range. This approach focus on the dynamic obstacles behavior analysis and according to this behavior tries to increase the user-location system efficiency. Finally a new authentication system based on the user location is proposed.

Les réseaux sans fil sont en plein développement du fait de la flexibilité de leur interface, qui permet aux utilisateurs de se communiquer directement entre eux ou de se connecter facilement à Internet en onde radio sans mettre en place préalablement d'infrastructures lourdes, telles que des câbles filaires. Parmi les différentes technologies de réseaux sans fil, l'IEEE 802.11/Wi-Fi est devenu une technologie plus connue et plus utilisée pour construire des réseaux sans fil à haut débit dans une zone à forte concentration d'utilisateurs, telle que les aéroports, les campus ou les sites industriels. L'engouement pour les réseaux sans fil et notamment pour les réseaux Wi-Fi a fait émerger de nouvelles nécessités, tel que se déplace dans les réseaux sans fil tout en restant connecté à Internet. Dans les réseaux sans fil, le déplacement d’un utilisateur implique parfois un changement de Point d’accès (AP) au réseau. On désigne généralement ce fait un handover de niveau 2, du fait que le changement d'AP n’implique que les deux premières couches du modèle OSI. Si les deux APs se situent dans des réseaux différents, le changement d'AP implique aussi le changement de réseau pour cet utilisateur. On dénomme généralement cette situation un handover de niveau 3, par le fait que cet utilisateur devrait changer son réseau d’attachement et son adresse IP pour maintenir la connexion à Internet et que ce changement intervient sur la couche réseau du model OSI. La procédure du handover de niveau 2 dans les réseaux Wi-Fi est gérée par la norme IEEE 802.11 et celle de niveau 3 est gérée par le protocole IP Mobile. Le protocole IP Mobile est un protocole standardisé par l'IETF qui permet à l'utilisateur de maintenir ses communications en cours et de rester connecté à Internet tout en masquant d'une manière transparente le changement de réseau. Ainsi, l'utilisateur peut se déplace dans les réseaux Wi-Fi tout en maintenant les communications en cours et restant connecté à Internet grâce à la norme IEEE 802.11 et au protocole IP Mobile. Cependant, le délai introduit par ces deux procédures du handover est trop long, les communications en cours sont interrompus pendant ces procédures, naturellement, cela ne peut pas répondre aux exigences qualitatives des applications temps réel comme la vidéo conférence ou la voix sur IP. Diverses propositions qui ont été faites pour réduire le délai de ces procédures du handover et améliorer leur performance. Cependant, ces propositions sont soit imparfaites, soit non-implémentables à cause de leur complexité. En partant du principe que les réseaux Wi-Fi et les routeurs d'accès sont déjà massivement implantés dans le monde universitaire et dans les entreprises, nous proposons d'ajouter une nouvelle fonctionnalité, appelé E-HCF (Extended Handover Control Function) dans un routeur sans modifier les autres équipements du réseau. Le routeur pourvu de cette fonctionnalité est dénommé le routeur E-HCF. Pour réduire le délai des procédures du handover, la fonctionnalité E-HCF permet au routeur de générer une topologie des APs en utilisant la théorie des graphes de voisinage et de maintenir un pool d'adresses IP disponibles dans sa base de données. Quand le Nœud mobile (MN) a besoin de changer son AP, le routeur E-HCF peut proposer au MN une liste des APs potentiellement utilisables qui sont choisis et classés par un algorithme de sélection et de classement que nous avons élaboré dans la thèse. Si le changement d'AP implique un changement de réseau, le MN doit changer d'adresse IP. Dans ce cas, le routeur E-HCF peut attribuer une adresse IP unique à ce MN. Le MN peut donc utiliser cette adresse sans exécuter la phase d'Auto-configuration d'adresses ni exécuter la procédure de Détection d'adresse dupliquée. Avec cette nouvelle fonctionnalité E-HCF, nous pouvons réduire le délai des procédures du handover de quelques secondes à une centaine de millisecondes. / Wireless networks are in full development because of the flexibility of their interfaces, which allow users to be easily connected to the Internet. Among various technologies of wireless networks, IEEE 802.11/Wi-Fi technology is becoming better known and more used to construct high speed wireless networks in areas with high concentration of users, such as airports, campuses or industrial sites. The passion for wireless networks and in particular for Wi-Fi networks has given rise to new uses of the Internet, such as moving in wireless networks while still being connected. In Wi-Fi networks, the user's movement may sometimes lead to a change of Access Points (APs) to the network. This fact is generally named the handover of layer 2 because this change involves only the first two layers of the OSI model. If the two APs are located in different networks, the change of AP would entail a change of network for the user. This situation is generally termed, the handover of layer 3 because the user should change his network and his IP address to maintain connection to the Internet. Therefore, this change intervenes on the network layer of the OSI model. The process of the handover of layer 2 is handled by the IEEE 802.11 standard and that of layer 3 is controlled by the Mobile IP protocol. The Mobile IP protocol is a protocol standardized by IETF, which allows users to change network, while maintaining their actual connection to the Internet. Consequently, users can connect to the Internet, while keep moving in Wi-Fi networks in control of the IEEE 802.11 standard and the Mobile IP protocol. However, the delay induced by these procedures of handover is too long. As such, this generally leads to the cut-off of current communications, hence impacting adversely on the qualitative requirements of real-time applications, such as video conferencing or voice over IP. Various proposals have been made to reduce the delay of handover procedures and to improve their performances. However, these proposals are either imperfect, or non-implementable because of their complexity. Based on the premise that Wi-Fi networks and access routers are already massively implanted in academia and in industry, we propose to add a new functionality, called E-HCF (Extended Handover Control Function) in routers, without modifying other network equipments. A router equipped with this functionality is called an E-HCF router. To reduce the delay of handover procedures, the E-HCF functionality allows a router to generate a topology of APs by using the neighbourhood graph theory and to maintain a pool of available IP addresses in its database. When a Mobile Node (MN) needs to change its AP, the E-HCF router may propose to the latter a list of potentially usable APs, which are selected and classified by an algorithm of selection and classification that we developed in the thesis. If the change of APs involves a change of network, the MN must change its IP address. In this case, the E-HCF router can assign a unique IP address to this MN. The MN can thus use this address without engaging in the process of Stateless Address Autoconfiguration or the procedure of Duplicate Address Detection. With this new E-HCF functionality, we can reduce the delay of handover procedures from a few seconds to one hundred milliseconds.

Le protocole IEEE 802.11, basé sur les principes CMSA/CA, est largement déployé dans les communications sans fil actuelles, principalement en raison de sa simplicité et sa mise en œuvre à faible coût. Une utilisation intéressante de ce protocole peut être trouvée dans les réseaux sans fil multi-sauts, où les communications entre les nœuds peuvent impliquer l'emploi de nœuds relais. Une topologie simple de ces réseaux impliquant une source et une destination est communément connue en tant que chaîne. Dans cette thèse, un modèle hiérarchique, composé de deux niveaux, est présenté dans le but d'analyser la performance associée à ces chaînes. Le niveau supérieur modélise la topologie de la chaîne et le niveau inférieur modélise chacun de ses nœuds. On estime les performances de la chaîne, en termes de débit obtenu et de pertes de datagrammes, en fonction de différents modes de qualité du canal. En termes de précision, le modèle offre, en général, des résultats justes. Par ailleurs, le temps nécessaire à sa résolution reste très faible. Le modèle proposé est ensuite appliqué aux chaînes avec deux, trois et quatre nœuds, en présence de stations cachées potentielles, de tampons finis et d'une couche physique non idéale. Par ailleurs, l'utilisation du modèle proposé permet de mettre en évidence certaines propriétés inhérentes à ces réseaux. Par exemple, on peut montrer que la chaîne présente un maximum de performance (en ce qui concerne le débit atteint) en fonction du niveau de charge de du système, et que cette performance s'effondre par l'augmentation de cette charge. Cela représente un comportement non trivial des réseaux sans fil et il ne peut pas être facilement identifié. Cependant, le modèle capture cet effet non évident. Finalement, certains impacts sur les performances des chaînes occasionnés par les mécanismes IEEE 802.11 sont analysés et détaillés. La forte synchronisation entre les nœuds d'une chaîne et comment cette synchronisation représente un défi pour la modélisation de ces réseaux sont décrites. Le modèle proposé permet de surmonter cet obstacle et d'assurer une évaluation facile des performances de la chaîne / The IEEE 802.11 protocol, based on the CMSA/CA principles, is widely deployed in current communications, mostly due to its simplicity and low cost implementation. One common usage can be found in multi-hop wireless networks, where communications between nodes may involve relay nodes. A simple topology of these networks including one source and one destination is commonly known as a chain. In this thesis, a hierarchical modeling framework, composed of two levels, is presented in order to analyze the associated performance of such chains. The upper level models the chain topology and the lower level models each of its nodes. It estimates the performance of the chain in terms of the attained throughput and datagram losses, according to different patterns of channel degradation. In terms of precision, the model delivers, in general, accurate results. Furthermore, the time needed for solving it remains very small. The proposed model is then applied to chains with 2, 3 and 4 nodes, in the presence of occasional hidden nodes, finite buffers and non-perfect physical layer. Moreover, the use of the proposed model allows us to highlight some inherent properties to such networks. For instance, it is shown that a chain presents a performance maximum (with regards to the attained throughput) according to the system workload level, and this performance collapses with the increase of the workload. This represents a non-trivial behavior of wireless networks and cannot be easily identified. However, the model captures this non-trivial effect. Finally, some of the impacts in chains performance due to the IEEE 802.11 mechanisms are analyzed and detailed. The strong synchronization among nodes of a chain is depicted and how it represents a challenge for the modeling of such networks. The proposed model overcomes this obstacle and allows an easy evaluation of the chain performance

The goal of this thesis is an exploration of the possibilities of Espressif's ESP32 chips in combination with Espressif IoT Development Framework with intention of implementing well-known Wi-Fi attacks on this platform. In this work, multiple implementation proposals were done for deauthentication attack in two variants followed by WPA/WPA2 handshake capture, attack on PMKID, creation of rogue MitM access point, or brute-force attack on WPS PIN, and more. A universal penetration tool ESP32 Wi-Fi Penetration Tool was proposed and implemented, including deauthentication attacks with WPA/WPA2 handshake capture. This tool provides an easy way to configure and run malicious Wi-Fi attacks without any domain knowledge required from the user. The outcome of this work opens new attack vectors for the attacker, thanks to cheap, ultra-low powered, and lightweight ESP32 chips.

Automation of the forest industry has for over 30 years been an important subject of research, which could reduce the human workload and costs significantly. However, there are still many problems to be solved, such as enabling the communication between the heavy machinery in a forest and a remote base. High speed and reliable communication is the key to automated operations and remote control of machinery. This thesis investigates the feasibility and performance of IEEE 802.11n/ac WiFi hardware to provide high-bandwidth connection in a forest. In this project, the propagation of WiFi signals in the2.4 GHz and 5 GHz bands in a typical Nordic forest environment has been simulated using specialized radio propagation software employing ray-tracing and different diffraction models to evaluate the path loss and signal strength. The simulations show that the idea is feasible if high-gain directional antennas are employed, as connections of sufficiently high speed (400+ Mbps for the 5 GHz band) can potentially be established for typical working distances,i.e. 300m. We then designed a directional antenna system and evaluated it in a real Nordic forest environment. We found that by manually aligning the antennas in a forest, reliable connections could be achieved up to 50 m without line-of-sight, however higher distances result in significantly lower speeds (13.3 Mbps at 80 m and 1.21 Mbps at 100 m) due to antenna misalignment. It is however possible to construct a more accurate, automated alignment system, which could replicate the simulation results and fully solve the problem of communication. / Automatiseringen av skogsindustrin har i över 30 år varit ett viktigt forskningsämne, med potential att kraftigt minska människans arbetsbelastning samt kostnader. Det finns dock fortfarande flera problem som behöver lösas inom ämnet, såsom kommunikationen mellan en tung skogsmaskin och en basstation. En stabil höghastighetsuppkoppling är nyckeln till automatiserad drift och fjärrstyrning av maskiner. Det här projektet undersöker möjligheterna och prestandan när IEEE 802.11n/ac WiFi-hårdvara används till att skapa ett högbandbreddsuppkoppling in en skog. Projektet examinerar hur WiFi-signaler i 2.4 GHzsamt 5 GHz-banden sprids i en typisk nordisk skog. Detta görs med hjälp av simulationer utförda i specialiserad radiovågsspridnings mjukvara som använder sig av ray-tracing och olika spridningsmodeller till analyser av signalförluster och uppkopplingens stabilitet. Simulationerna visar att lösningen kan realiseras om riktade antenner med hög förstärkning används då kan uppkopplingar med tillräckligt hög hastighet (400+ Mbps för 5 GHz-bandet) potentiellt erhållas för typiska arbetsavstånd 300 m. Därefter byggdes det ett antennsystem som examinerades i en verklig nordisk skogsmiljö. Då antennerna riktades manuellt, kunde systemet erhålla stabil och snabb uppkoppling på avstånd av upp till 50m i skogsmiljö utan sikte mellan basstation och mottagare. Vid längre avstånd blev dock hastigheterna lägre (13.3 Mbps vid 80 m och 1.21 Mbps vid 100 m) på grund av antennernas felorientering gentemot varandra. Det är dock potentiellt möjligt att kostruera ett mer exakt, automatiserad system som kan återskapa simulationsresultaten och fullständigt lösa kommunikationsproblemet.

This work comprises an approximation of the energy consumption of the transceiver circuit in a single board computer. Single board computers, such as the Raspberry Pi 4 Model B that is used here, are usually cheap and therefore more accessible. This method of estimation does not use any other hardware which gives it an advantage compared to many other methods that use expensive measurement equipment, but it unfortunately comes with certain trade-offs, like accuracy, to name one example. One area where this approximation method could be applied is for optimizing the energy efficiency of wireless sensor networks. The method can be divided into two main parts, firstly the transceiver’s active transmission and reception states are profiled and then a power model is chosen and adapted to suit the transceiver as well as possible. These two steps are then combined and results in an energy consumption approximation. The evaluation of the results showed that the estimations are reasonable according to the most relevant findings on measuring a similar transceiver circuit, but there are also limitations that brings uncertainty to the results. More relevant studies are needed to properly assess the method of estimation and some further improvements are suggested. / Olika typer av elektroniska enheter utgör idag en stor del av många människors vardag och samhället i stort. Mobiltelefoner, laptops och olika sensorer är bara några exempel på dessa enheter som fyller viktiga funktioner i både vardag och arbete. En stor del av dem använder ett protokoll som heter IEEE 802.11ac för att kommunicera och de bör gärna göra det så energi-effektivt som möjligt. Det här arbetet undersöker energikonsumtionen hos en transceiverkrets som använder det nämnda protokollet för att skicka och ta emot datapaket. Målet med arbetet är uppskatta energikonsumtionen så väl som möjligt, med hjälp av billig och lättillgänglig hårdvara. Av den anledningen används en enkortsdator för att göra uppskattningen, mer specifikt en Raspberry Pi 4 Model B (RPi). Eftersom energiåtgången för transceiverkretsen inte kan mätas direkt från strömmen som dras av datorn, måste mjukvara skrivas för att göra uppskattningen. På det sättet undviker man behovet av dyr mätutrustning, men man måste göra avkall på till exempel noggrannhet i utbyte. Ett område där metoden eventuellt kan appliceras är för att göra trådlösa sensornätverk mer energi-effektiva. Metoden som användes för energiuppskattningen kan delas upp i två huvuddelar, förutom litteraturstudien som gjordes för att få en djupare förståelse för ämnet. Först profilerades transceiverkretsens aktiva tillstånd för transmission (TX) och mottagning (RX), som ligger i fokus för det här arbetet. Till detta användes mjukvaran perf som är ett prestandaanalyseringsverktyg som finns tillgängligt för Linuxsystem. Med hjälp av perf fick man fram längden av varje TX och RX operation i millisekunder. Sedan valdes en passande kraftmodell som anpassades för att efterlikna egenskaperna i RPi datorns transceiver så noga som möjligt. Modellen gav två olika formler för att beräkna kraftåtgången för TX respektive RX, vilket sedan multiplicerades med tidsåtgången för varje operation för att få fram energikonsumtionen. Metoden testades genom att skicka och ta emot datapaket med en storlek på 256 byte, mäta tidsåtgången, och sist räkna ut hur mycket energi som gick åt för varje enskilt paket. Resultaten presenterades med olika grafer samt en rimlighetsanalys. Slutsatsen var att resultaten verkar rimliga utgående från de mest relevanta fynden som gjordes inom ramen för litteraturstudien, men även att fler relevanta studier och mätningar behövs för att kunna göra en bättre bedömning av metodens tillförlitlighet. Slutligen framfördes förslag på eventuella förbättringar av arbetet samt områden för vidareutveckling.

ITC/USA 2007 Conference Proceedings / The Forty-Third Annual International Telemetering Conference and Technical Exhibition / October 22-25, 2007 / Riviera Hotel & Convention Center, Las Vegas, Nevada / An rfNET solution based on IEEE 802.11 wireless network is presented to perform one-way remote transmission of airborne instrumentation data and multi-channel video images in flight test by modifying the wireless network bridge and UDP protocol. Its architecture and structure is introduced briefly and the results of ground transmission test and flight demonstration transmission are provided. It also points out the major problems of this solution for engineering application and their solutions.

International Telemetering Conference Proceedings / October 23-26, 2000 / Town & Country Hotel and Conference Center, San Diego, California / Wireless data acquisition began with sensors connected to some form of radio. Emergence of the IEEE 802.11 specification made possible the evolution of a high-speed, multi-channel, wireless data acquisition system using COTS, Commercial Off-The-Shelf, technology. After developing a sub-miniature telemetry system in the S-band for the US Air Force, the system delivered to the Air Force evolved into a high-speed, wireless data acquisition system for the commercial market.

In this thesis we have focused in the wireless environment and how to run voice application over it. Conducive environment that makes it possible for the voice services to run in wireless is necessary. As we know this well that wireless is a contemporary technology due to it low cost and its effectiveness, and one major advantage of it is the mobility that is one fell free to move anywhere but have the access to the resource. So this makes wireless networks of great value, we in this thesis have focused on wireless LAN’s. In second part of the thesis we have shed some light on the VoIP showing how it works in the wireless environment. Analysis phase is relatively more important phase then the previous section which shows issues or hindrances in carrying voice over wireless environment. This analysis shows that these issues still prevails and should be addresses and the corresponding results are also discussed and by looking at those results we have derived a summery out of it. Next chapter we firstly tried to explain why we have chosen specific protocols and then showing some graphical representation measurements that are to address the problem based on the work done. We tried to evaluate EDCF and DCF as these play important role in handling real time applications like voice. After that we proposed a scheme through which these effects can be minimized and to enhance the method is necessary to avoid the issues still in effect. / Thesis is Part for Master program in Electrical Engineering with Emphasis on Telecommunication(2007-2009).We have had a very nice time doing this thesis as there was alot of learning. Our examinator was allways there to help us, we are thankfull to Richard for his endless support.