With the proliferation of mobile devices and the advance of audio/video coding technologies, there is an increasing demand to provide quality-of-service (QoS) guarantees for multimedia applications. A WLAN (wireless local are network) typically consists of an access point (AP) and a finite set of mobile stations. Since the AP is generally more powerful and less physical constraint than mobile stations, it is of great interest to consider the use of sectorized multi-beam antennas at the AP to boost the network throughput by exploiting the benefit of spatial reuse. IEEE 802.11 is current the de facto standard for WLANs. However, if we directly apply 802.11 to the WLAN with multi-beam AP without any modification, we will encounter many challenging problems. Although existing solutions modify the 802.11 DCF (distributed coordination function) to solve these problems, yet DCF does not provide any QoS support. On the basis of 802.11e HCCA (hybrid channel control access), in this thesis, we propose a novel MAC protocol, named MPCF (multi-beam AP-assisted point coordination function), which is not only backward compatible with DCF, but also supports QoS functionalities, including non-reversal prioritization, time-bounded reservation, admission control, and cross-layer rate adaptation for multimedia streaming. Simulation results show that, in terms of throughput, frame delay dropped rate, and energy throughput, MPCF significantly outperforms existing protocols even in imperfect beam-forming and mobility environments.

It is a future trend to include the function of wireless networking in portable electronic devices, such as notebooks, tablet PC, PDA, mobile phone, and other information applicants. IEEE 802.11 is the most popular wireless LAN protocol that defines the functions in the medium access control (MAC) layer and physical layer. In this thesis, we design and implement a flexible and reusable soft IP (Intellectual Property) for wireless MAC that is compatible with AMBA system and can be used in SOC applications. The wireless MAC supports buffer descriptors, interrupt and DMA. The IP provides an AMBA-compatible interface for the host system bus, and provides a communication interface for the baseband processor in the physical layer.

In this thesis, we propose the predictive multicast polling scheme for medium access control in wireless networks with multipacket reception capability. We concentrate on the case in which the packet arrival process is general and the maximum queue size is finite but larger than one. We derive both analytical results and simulation results. We use the theory of discrete-time Markov chain to analyze the evolution of the system state. In addition, we propose to use Markov reward processes to calculate the throughput. Furthermore, we obtain the average system size, the packet blocking probability, and the average packet delay. The proposed analysis approach is applicable no matter whether perfect state information is available to the controller or not. We also use simulation results to justify the usage of the proposed approach. Our study shows that the system performance can be significantly improved with a few additional buffers in the queues. The proposed medium access control scheme can be used in the single-hop wireless local area networks and the multi-hop wireless mesh networks.

It is necessary to authenticate users when they want to access services in WLANs. Extensible Authentication Protocol (EAP) is an authentication framework widely used in WLANs. Authentication mechanisms built on EAP are called EAP methods. The requirements for EAP methods in WLAN authentication have been defined in RFC 4017. Besides, low computation cost and forward secrecy, excluded in RFC 4017, are noticeable requirements in WLAN authentication. However, all EAP methods and authentication schemes designed for WLANs so far do not satisfy all of the above requirements. Therefore, we will propose an EAP method which utilizes three factors, stored secrets, passwords, and biometrics, to verify users. Our proposed method fully satisfies 1) the requirements of RFC 4017, 2) forward secrecy, and 3) lightweight computation. Moreover, the privacy of biometrics is protected against the authentication server, and the server can flexibly decide whether passwords and biometrics are verified in each round or not.

<p>Användningen av trådlöst nätverk blev under början av 2000-talet mycket populärt bland privatpersoner, genom dess mobila fördelar, Tekniken medförde många fördelar, men också många nackdelar och frågan var hur många som verkligen hade blivit uppmärksammade på eller kände till dessa och därefter valt att skydda sina trådlösa nätverk.</p><p>Det främsta syftet med denna uppsats var därmed att undersöka på vilken nivå säkerhetsmedvetandet låg i samhället vid användning av trådlöst nätverk vid gällande tidpunkt. Vidare handlade det också om att reda ut gällande rättsläge , vid handlingar mot eller via ett trådlöst nätverk, och mäta hur utbredd säkerhetsanvändningen var bland trådlösa hemmanätverk. För att besvara detta utgick vi från ett positivistiskt och deduktivt synsätt, med kvalitativa intervjuer för att reda ut gällande rättsläge, pejling av trådlöst nätverk för att mäta säkerhetsläget och kvantitativa enkätintervjuer, för att få fram typer av säkerhetsmedvetande, bland användare av trådlöst hemmanätverk. Innehållet i alla intervjuer baserades på fastställd fakta kring trådlöst nätverk, risker med tekniken, riskförebyggande säkerhetsrutiner och Svensk lag.</p><p>Vi konstaterade slutligen att gällande rättsläge för närvarande var föråldrat och inte anpassat att hantera de risker som trådlöst nätverk hade medfört. Vidare visade resultatet på ökad säkerhetsanvändning bland trådlösa nätverk i samhället, och att det överlag var yngre användare som stod för denna ökning. Yngre användare visade sig även överlag ha ett högre säkerhetsmedvetande, än äldre, och då särskilt hög teknisk kunskap</p> / <p>The usage of Wireless local area networks (WLAN) became very popular amongst private citizens, during the beginning of the 21 century, because of its mobile advantages. The technology brought many advantages, but also many disadvantages and the question was how many had noticed or knew that these existed and afterwards had chosen to secure their WLAN.</p><p>The main purpose of this thesis was to examine the current level of security awareness, in the community, when using WLAN. Other goals were to investigate the current general legal context, about actions against or through a WLAN, and measure the widespread usage of security within WLAN. To answer this we used a positivistic and deductive approach, with qualitative interviews to sort out the current general legal context, Wardriving to find and measure the current state of security within WLAN's and quantitative questionnaires to find out the most common types of security awareness amongst users of WLAN. The content of all this was based on facts about the WLAN technology, the risks that comes with it, risk preventing security routines and the Swedish law.</p><p>Finally we established that the current general legal context was out-of-date and not adapted to handle the new risks that WLAN had brought. Further on the result also showed a increased usage of security amongst WLAN in the community and that the main reason for this was the younger WLAN owners. Younger users also turned out to have higher security awareness, than older users, and particularly very high technical knowledge.</p>

Thesis (M.S.)--Florida State University, 2003. / Advisor: Dr. Xin Yuan, Florida State University, College of Arts and Sciences, Dept. of Computer Science. Title and description from dissertation home page (viewed Apr. 7, 2004). Includes bibliographical references.

Thesis (M.S. in Computer Science)--Naval Postgraduate School, September 2003. / Thesis advisor(s): Geoffrey Xie, John Gibson. Includes bibliographical references (p. 75-76). Also available online.

Thesis (M.S.)--Worcester Polytechnic Institute. / Keywords: indoor geolocation; TOA. Includes bibliographical references (p. 97).

As wireless devices become more common, the ability to position a wireless device has become a topic of importance. Accurate positioning through technologies such as the Global Positioning System is possible for outdoor environments. Indoor environments pose a different challenge, and research continues to position users indoors. Due to the prevalence of wireless local area networks (WLANs) in many indoor spaces, it is prudent to determine their capabilities for the purposes of positioning. Signal strength and time based positioning systems have been studied for WLANs. Direction or angle of arrival (AOA) based positioning will be possible with multiple antenna arrays, such as those included with upcoming devices based on the IEEE 802.11n standard. The potential performance of such a system is evaluated. The positioning performance of such a system depends on the accuracy of the AOA estimation as well as the positioning algorithm. Two different maximum-likelihood (ML) derived algorithms are used to determine the AOA of the mobile user: a specialized simple ML algorithm, and the space- alternating generalized expectation-maximization (SAGE) channel parameter estimation algorithm. The algorithms are used to determine the error in estimating AOAs through the use of real wireless signals captured in an indoor office environment. The statistics of the AOA error are used in a positioning simulation to predict the positioning performance. A least squares (LS) technique as well as the popular extended Kalman filter (EKF) are used to combine the AOAs to determine position. The position simulation shows that AOA- based positioning using WLANs indoors has the potential to position a wireless user with an accuracy of about 2 m. This is comparable to other positioning systems previously developed for WLANs.

The dissertation addresses the communication issues of interconnecting the different government sectors LANs, and access to the global Internet. Network capacities are being purposely overengineered in today's commercial Internet. Any network provider, be it a commercial Internet Service Provider (ISP) or Information Technology Service department at government sector, company or university site, will design network bandwidth resources in such a way that there will be virtually no data loss, even during the worst possible network utilization scenario. Thus, the service delivered by today's end-to-end wide area Internet would be perfect if it wasn't for the inter-domain connections, such as Internet access link to the ISP, or peering points between ISPs. The thesis studies the performance of the network in Eritrea, displaying the problems of Local Area Networks (LANs) and Wide Area Networks (WAN) and suggesting initial solutions and investigating the performance of (WAN) through the measured traffic analysis between Asmara LAN and Massawa LAN, using queuing theory system (M/M/1 and M/M/2) solution. The dissertation also uses OPNET IT Guru simulation software program ·to study the performance of LAN and WLAN in Eritrea. The items studied include traffic, collision, packet loss, and queue delay. Finally in order to follow the current trends, we study the performance ofVOIP links in Eritrean WANs environment, with a focus on five different link capacities: 28 kbps, 33 kbps, 64 kbps, and 128 kbps for voice and 256/512 kbps for voice and data. Using the R value as a measure of mean opinion score (MOS), we determine that the 33 kbps link would be adequate for Eritrean WANs. / Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2006.