As Industry 4.0 keeps approaching, the quality of data communication in industrial scenarios is increasingly important to support a high degree of automation and intelligence in factories. Wi-Fi 6E, the latest advanced wireless local-area network standard, comes with new 6 GHz unlicensed spectrum, a new access method named Orthogonal Frequency Division Multiple Access, and even more features. Accordingly, Wi-Fi 6E can be a promising candidate technology for an industrial wireless network. To fulfill industrial applications, Wi-Fi 6E is challenged with high communication requirements and a massive number of devices to support. Since the cutting-edge Wi- Fi 6E systems have not been widely deployed practically, simulations are required to evaluate the performance of Wi-Fi 6E in industrial scenarios. Based on an event-based simulator from Ericsson, we performed simulations covering not only single access point scenarios with periodic traffic, but also scenarios where multiple applications and generations of Wi-Fi systems coexist. Finally, a large-area industry scenario with frequency planning applied was evaluated. Through simulation results and analysis, we conclude that Wi-Fi 6E performs well in most of our tested scenarios. Compared to legacy Wi-Fi 5,Wi-Fi 6E performs better when subject to uplink traffic, and is more suitable for handling a massive number of devices or high packet rate traffic due to its unique multi-user accessing. However, Wi-Fi 6E can have poor performance when performing multi-user transmission with applications that have complex traffic and millisecond-level latency requirement. In some cases, Wi-Fi 6E performs worse than Wi-Fi 5 while handling multiple applications whose packet sizes vary a lot. Moreover, with the increase in factory scales, Wi-Fi 6E can have a magnificent performance drop, almost 100%, through the regulatory requirements in the new 6 GHz unlicensed band. / När Industri 4.0 fortsätter att närma sig blir datakommunikationens kvalitet i industriella scenarier allt viktigare för att stödja en hög grad av automatisering och intelligens i fabriker. Wi-Fi 6E, den senaste avancerade standarden för trådlöst lokalt nätverk, kommer med ett nytt 6 GHz olicensierat spektrum, en ny åtkomstmetod som heter Orthogonal Frequency Division Multiple Access och ännu fler funktioner. Följaktligen kan Wi-Fi 6E vara en lovande kandidatteknik för ett industriellt trådlöst nätverk. För att uppfylla industriella applikationer utmanas Wi-Fi 6E med höga kommunikationskrav och ett stort antal enheter att stödja. Eftersom de banbrytande Wi-Fi 6E systemen inte har använts i stor utsträckning praktiskt taget, krävs simuleringar för att utvärdera prestandan för Wi-Fi 6E i industriella scenarier. Baserat på en händelsebaserad simulator från Ericsson utförde vi simuleringar som inte bara omfattar enstaka åtkomstpunktsscenarier med periodisk trafik, utan också scenarier där flera applikationer och generationer av Wi-Fi-system samexisterar. Slutligen utvärderades ett storindustriscenario med tillämpad frekvensplanering. Genom simuleringsresultat och analys drar vi slutsatsen att Wi-Fi 6E fungerar bra i de flesta av våra testade scenarier. Jämfört med äldre Wi-Fi 5, fungerar Wi-Fi 6E bättre när den utsätts för upplänkstrafik och är mer lämpad för att hantera ett stort antal enheter eller hög pakettrafik på grund av dess unika åtkomst för flera användare. Wi-Fi 6E kan dock ha dålig prestanda vid överföring av fleranvändare med applikationer som har komplex trafik och krav på latens på millisekundnivå. I vissa fall fungerar Wi-Fi 6E sämre än Wi-Fi 5 när hanterar flera applikationer vars paketstorlekar varierar mycket. Med ökningen av fabriksskalor kan Wi-Fi 6E dessutom ha en fantastisk prestandaförlust, nästan 100%, genom lagkraven för det nya 6 GHz-bandet utan licens.

Indiana University-Purdue University Indianapolis (IUPUI) / The Internet of Things (IoT) is a natural evolution of the Internet and is becoming more and more ubiquitous in our everyday home, enterprise, healthcare, education, and many other aspects. The data gathered and processed by IoT networks might be sensitive and that calls for feasible and adequate security measures. The work in this thesis describes the use of the Wi-Fi technology in the IoT connectivity, then proposes a new approach, the Proactive Wireless Protected Access (PWPA), to protect the access networks. Then a new end to end (e2e) IoT security model is suggested to include the PWPA scheme. To evaluate the solutions security and performance, rstly, the cybersecurity triad: con dentiality, integrity, and availability aspects were discussed, secondly, the solutions performance was compared to a counterpart e2e security solution, the Secure Socket Layer security. A small e2e IoT network was set up to simulate a real environment that uses HTTP protocol. Packets were then collected and analyzed. Data analysis showed a bandwidth e ciency increase by 2% (Internet links) and 12% (access network), and by 344% (Internet links) and 373% (access network) when using persistent and non-persistent HTTP respectively. On the other hand, the analysis showed a reduction in the average request-response delay of 25% and 53% when using persistent and non-persistent HTTP respectively. This scheme is possibly a simple and feasible solution that improves the IoT network security performance by reducing the redundancy in the TCP/IP layers security implementation.

This study investigates how Swedish internet service providers (ISP) choose a Wi-Fi-Router for use by private customers. The study investigates the process of choosing a Wi-Fi-Router and what features the companies prioritize during the process. These features can be aspects such as security, speed, capacity, Wi-Fi standard and price. The study seeks to answer how the decision-making process is carried out in the companies, but also how the Wi-Fi-Routers features are prioritized during the decision-making process.  This was investigated using qualitative methods in the form of semi-structured interviews. The interviews were held remotely, which allowed for a larger spread of respondents. After the interviews, the data was coded using thematic analysis to arrive at the results of the study.  The study identified several different phases during the decision-making process that ISP’s go through. After identifying the phases, they were placed in a model which seeks to describe the decision-making process for all ISPs.  The most important aspect during the decision-making process was the price. The remaining aspects were decided by the Wi-Fi-Router's price and compromises had to be made to lower the price to a reasonable level for both the company and the customer. In addition to the price, the companies aimed to find a balance between the other features, where compromises can be made for features they consider to be less important.

<p>The growing demand for faster, more reliable wireless connectivity has brought about the development of the 802.11ax (Wi-Fi 6/6E) amendment, which aims to satisfy the increasing need for seamless wireless connectivity and improved traffic handling. The 802.11ax amendment introduces noteworthy improvements to the 802.11 wireless standard that should greatly improve the efficiency of wireless networks. The body of existing research has seen several simulated 802.11ax environments and found great success, however, these additions remain largely untested in physical environments. This thesis undertakes the testing for 802.11ax MU-MIMO to determine if these simulated successes translate into real-world improvements. By using a classroom scenario, the study investigates the performance improvements purported by 802.11ax, specifically the updated and expanded DL and UL MU-MIMO in an environment with high client numbers and density. </p>

Wi-Fi Sensing is becoming a prominent field with a wide range of potential applications. Using existing hardware on a wireless network such as access points, cell phones, and smart home devices, important information can be inferred about the current physical environment. Through the analysis of Channel State Information collected in the Neighborhood Discovery Protocol process, the wireless network can detect disturbances in Wi-Fi signals when the physical environment changes. This results in a system that can sense motion within the Wi-Fi network, allowing for movement detection without any wearable devices. The goal of this thesis is to answer whether Wi-Fi Sensing can enable useful applications at the enterprise level. The main applications we will focus on are presence detection and in-zone movement detection. Our contributions include: 1. A scalable, statistical analysis system that generates a heatmap and detects movement in a 12 x 9 meter zone with 98 percent accuracy, as well as a 6 x 9 meter zone with 88 percent accuracy. 2. A broad dataset collected for evaluation in an enterprise setting. 3. An end-to-end CSI data visualization and analysis application.

Kleine, flache Gewässer gelten als sogenannte „hotspots“ der Primärproduktion und Kohlenstoffbindung. Diese Doktorarbeit zielt darauf ab, die Primärproduktion verschiedener kleiner Gewässer zu quantifizieren sowie die Mechanismen, die den Kohlenstoffkreislauf dieser Systeme beeinflussen, zu analysieren. Der Fokus liegt dabei auf dem Einfluss globaler Veränderungen, die diese Mechanismen verändern können Im ersten Abschnitt wurde die Primärproduktion (PP) in kleinen, temporären Söllen untersucht, die sehr anfällig für Störungen sind. Ich konnte zeigen, dass die PP der Sölle im Sommer außergewöhnlich hoch ist, was hauptsächlich auf eine hohe Makrophytenproduktion zurückzuführen ist Im zweiten Teil analysiere ich die Ergebnisse eines Experiments zum Einfluss erhöhter Temperaturen auf die benthische PP kleiner Gewässer im Frühjahr. Acht Mesokosmen wurden bei normalen und um 4°C erhöhten Wassertemperaturen gemäßigter Breiten betrieben. In der ersten Hälfte des Experiments konnte ich eine erhöhte benthische PP in den erwärmten Mesokosmen feststellen, die auf direkte Temperatureffekte und indirekte Auswirkungen einer höheren Nährstoffverfügbarkeit zurückzuführen war. Anfang Juni stieg jedoch der Einfluss der Makroinvertebraten auf das Periphyton in den erwärmten Mesokosmen, so dass keine Unterschiede in der PP mehr auftraten. Schließlich, untersuche ich die Resilienz eines Sees gegenüber einem plötzlichen Eintrag gelösten organischen Kohlenstoffs (DOC) aus dem terrestrischen Umland, der zu einer starken Braunfärbung des Wassers führte. Der Fokus liegt dabei auf Veränderungen der Wasserqualität und der aquatischen PP des Sees, nachdem sich die DOC-Konzentration verfünffacht hatte. Drei Jahren nach Erreichen der maximalen DOC- und Gesamt-Phosphor im See sanken diese signifikant, lagen jedoch noch immer 1,5- bzw. 2-fach oberhalb der Ausgangskonzentrationen vor dem DOC-Eintrag. Die benthische PP zeigte eine teilweise Erholung, erreichte jedoch ebenfalls nicht die Ausgangswerte. / Small, shallow freshwater ecosystems are now considered hotspots of primary production & carbon sequestration. Yet till recently they’ve been mostly neglected. This thesis aims at explaining the underlying mechanisms affecting carbon cycling in these systems, particularly focusing on how contemporary global changes alter ecological equilibria. In the first section, using a compartmental approach, I study primary production in small, temporary ponds (kettle holes) within agricultural fields that are highly susceptible to environmental & anthropogenic disturbances. I show that summertime gross primary production (GPP) in kettle holes is exceptionally high, mostly driven by a strong macrophyte production. In winter, periphyton contributes to the majority of the systems’ GPP. High summertime deposition, correlated to GPP, and low sediment mineralization rates, signified a high potential for carbon burial. In the second experiment, I test the impact of increased temperatures on periphyton production during spring. I use eight mesocosms running at normal & +4°C temperatures. Initially, I recorded elevated periphyton GPP in the warmed treatment driven by direct temperature effects & indirect effects of higher nutrient availability. By late spring, the trend is reversed due to increased grazing pressure in the warm treatment. In the third study, I investigate a lake’s resilience to a sudden brownification event: A 5-fold increase in dissolved organic carbon (DOC) concentrations. Within three years after peak brownification, the lake DOC & total phosphorous concentrations dropped significantly but seem to have plateaued at 1.5 & 2-fold their pre-brownification levels, respectively. Consequently, benthic GPP, which had collapsed due to light limitation at peak brownification, marked only a partial recovery, while phytoplankton (& whole-lake) GPP remained higher than pre-brownification levels. Phytoplankton & periphyton exhibited an inverse response to DOC & TP concentrations.

No description available.

Yes / This study presents a wideband multiple-input-multiple-output (MIMO) antenna for Wifi/WLAN/LTE applications. The antenna consists of two triangular patches as the radiating elements placed orthogonally to each other. Two T-slots and a rectangular slot were etched on the ground plane to improve return loss and isolation. The total dimension of the proposed antenna is 30 x 30 mm2. The antenna yields impedance bandwidth of 101.7% between 2.28 GHz up to 7 GHz with a reflection coefficient of < -10 dB, and mutual coupling of < -14 dB. The results including S-Parameters, MIMO characteristics with analysis of envelope correlation coefficient (ECC), total active reflection coefficient (TARC), capacity loss, channel capacity, VSWR, antenna gain and radiation patterns are evaluated. These characteristics indicate that the proposed antenna is suitable for MIMO wireless applications.

O consumo de dados em dispositivos móveis cresce em taxas que dobram a cada ano. Tal crescimento demonstra como os dispositivos móveis ganham importância e como eles têm sido usados no dia a dia da população. Entretanto, o acesso à Internet ainda possui alto custo e nem sempre está disponível. Esse cenário apresenta o desafio de mantermos o uso dos dispositivos móveis acessível e viável, mesmo quando a Internet não esteja disponível. A comunicação direta entre os dispositivos é vista como alternativa para comunicação sem Internet e, consequentemente, para a redução do tráfego de dados nas redes de celulares. Além disso, ela pode ser útil para manter os dispositivos comunicando entre si mesmo desconectados da Internet. O protocolo Wi-Fi Direct (WD) é uma referência para esse tipo de comunicação, uma vez que seu protocolo não demanda infraestrutura de rede pré-estabelecida para que a comunicação aconteça e utiliza hardware padrão para comunicação Wi-Fi. Apesar dessas vantagens, seu uso é pouco difundido, o que o torna desconhecido pelos usuários, sendo uma das possíveis causas a complexidade de uso. De forma diferente, a conexão com a Internet, que acontece de forma quase espontânea, no WD as partes envolvidas precisam se envolver ativamente, na escolha e autorização, para que a conexão seja estabelecida. A complexidade da comunicação entre dispositivo pode ser constatada quando os usuários utilizam a Internet para enviar dados mesmo que o dispositivo alvo esteja ao lado da origem. Para superar esse obstáculo, a conexão entre os dispositivos deve ser tão ou mais simples do que a ação de enviar um e-mail ou uma mensagem instantânea usando a Internet. Para lidar com esse cenário, este trabalho propõe uma alternativa para comunicação entre dispositivos próximos que não demanda autorização manual prévia a cada conexão com um dispositivo, e que, ainda assim, permita que o usuário decida se quer ou não usar os dados transmitidos por uma conexão. Para isso definimos uma arquitetura que possibilite a conexão e transferência de dados entre os dispositivos próximos sem a necessidade de intervenção prévia do usuário e implementamos o conceito proposto no sistema operacional para dispositivos móveis Android / The consumption data on mobile devices is growing at rates double every year. This growth demonstrates how mobile devices gain importance and how they have been used in everyday life of the population. However, the internet also has high cost and is not always available. This scenario presents the challenge of maintaining the use of affordable and viable mobile devices even when the Internet is not available. Direct communication between the devices is regarded as no alternative for internet communication and, consequently, to reduce the data traffic in cellular networks. Furthermore, it can be useful to keep the devices communicating among themselves disconnected from the Internet. The Wi-Fi Direct (WD) protocol is a reference to this type of communication, since its protocol does not require pre-established network infrastructure for communication to happen and uses standard hardware for Wi-Fi communication. Despite these advantages, its use is not widespread, making it unknown to the users, one of the possible causes of the complexity of use. Differently, the connection to the Internet, which happens almost spontaneously, the WD parties need to engage actively in the selection and authorization for the connection to be established. The complexity of communication between device can be found when users use the Internet to send data even if the target device is adjacent to the source. To overcome this obstacle, the connection between the devices should be as or more simple than the action of sending an email or an instant message using the Internet. To handle this scenario, this paper proposes an alternative for communication between nearby devices that does not require prior manual authorization for each connection to a device, and that still allow the user to decide whether or not to use the data transmitted by a connection. For this we define an architecture that enables the connection and data transfer between nearby devices without the need for prior user intervention and implement the concept proposed in the Android operating system for mobile devices

Made available in DSpace on 2016-04-04T18:31:32Z (GMT). No. of bitstreams: 1 Aturo Jose Fenile Peris.pdf: 4348655 bytes, checksum: 34479e7af136c0f06a1b46d21b30c1c4 (MD5) Previous issue date: 2012-06-22 / The design of the IEEE 802.11 standard allows, in certain situations, competition for access to the transmission medium results in an anomaly. As a result of this anomaly, mobile stations that should achieve high rates of transmission are impaired and don t get those rates. The consequence is the transmission capacity low utilization of the wireless system and the natural increasing of the time mobile stations stays on (and consuming energy); because of this, the increase in energy consumption is another effect of this anomaly. From this scenario, one way to deal with this anomaly is to have a better utilization of the wireless transmission medium. In this context, this work proposes a bench for studies of flow control in IEEE 802.11; this bench allows the management of bandwidth and the collection of traffic statistics from users sessions connected to the wireless network. As a resulting study from the bench using, there is a proposal to mitigate the anomaly through the user traffic management. The results indicate that the controlling the traffic from users who are in poor wireless transmission may produce a better utilization of transmission capacity of an IEEE 802.11 access point. / A concep??o do padr?o IEEE 802.11 permite que, em determinadas situa??es, a competi??o pelo acesso ao meio de transmiss?o resulte em uma anomalia. Como resultado dessa anomalia, esta??es m?veis que deveriam conseguir altas taxas de transmiss?o s?o prejudicadas e acabam por n?o conseguir essas taxas. A consequ?ncia ? o baixo aproveitamento da capacidade de transmiss?o do sistema sem fio e o natural aumento do tempo em que as esta??es m?veis permanecem ligadas e consumindo energia; por conta disso, o aumento no consumo de energia ? outro efeito dessa anomalia. A partir desse cen?rio, uma forma de combater essa anomalia ? a melhoria da utiliza??o do meio de transmiss?o sem fio. Nesse contexto, este trabalho apresenta uma proposta de bancada para estudos de controle de vaz?o em redes IEEE 802.11; essa bancada permite gerenciar a largura de banda e coletar dados estat?sticos relativos ao tr?fego das sess?es dos usu?rios conectados ? rede sem fio. Como estudo resultante da utiliza??o da bancada, h? uma proposta de mitiga??o da anomalia por meio da gest?o do tr?fego dos usu?rios. Os resultados indicam que o controle do tr?fego de usu?rios que est?o em m?s condi??es de transmiss?o sem fio pode melhorar o aproveitamento da capacidade de transmiss?o de um ponto de acesso IEEE 802.11.