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1
Mallory, Patrick L. "Extending IEEE 802.11b Wireless Local Area Networks to the metropolitan area." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2001. http://handle.dtic.mil/100.2/ADA406344.
Повний текст джерела
2
Vokál, Martin. "Principy zabezpečení bezdrátových standardů." Master's thesis, Vysoké učení technické v Brně. Fakulta informačních technologií, 2007. http://www.nusl.cz/ntk/nusl-412795.
Повний текст джерелаАнотація:
Computer networks are in the scope of the IEEE organization normalized by the 802 board which currently comprises six working groups for wireless communications. IEEE 802.11 for wireless local area networks, IEEE 802.15 for wireless personal area networks, IEEE 802.16 for wireless metropolitan area networks, IEEE 802.20 for mobile broadband wireless access, IEEE 802.21 for media independent handover and IEEE 802.22 for wireless regional area networks. This master's thesis focuses on a security analysis of particular standards, describes threats, vulnerabilities, current security measures and mutually compares wireless specifications from a security point of view. The conclusion is devoted to overall evaluation of the project, to its contributions, possible enhancements and continuation in the form of consequential studies.
3
Wang, Peng. "Throughput optimization of urban wireless mesh networks." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 196 p, 2009. http://proquest.umi.com/pqdweb?did=1833647421&sid=6&Fmt=2&clientId=8331&RQT=309&VName=PQD.
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4
Gordejuela, Sánchez Fernando. "Practical design of optimal wireless metropolitan area networks : model and algorithms for OFDMA networks." Thesis, University of Bedfordshire, 2009. http://hdl.handle.net/10547/134373.
Повний текст джерелаАнотація:
This thesis contributes to the study of the planning and optimisation of wireless metropolitan area networks, in particular to the access network design of OFDMAbased systems, where different parameters like base station position, antenna tilt and azimuth need to be configured during the early stages of the network life. A practical view for the solution of this problem is presented by means of the development of a novel design framework and the use of multicriteria optimisation. A further consideration of relaying and cooperative communications in the context of the design of this kind of networks is done, an area little researched. With the emergence of new technologies and services, it is very important to accurately identify the factors that affect the design of the wireless access network and define how to take them into account to achieve optimally performing and cost-efficient networks. The new features and flexibility of OFDMA networks seem particularly suited to the provision of different broadband services to metropolitan areas. However, until now, most existing efforts have been focused on the basic access capability networks. This thesis presents a way to deal with the trade-offs generated during the OFDMA access network design, and presents a service-oriented optimization framework that offers a new perspective for this process with consideration of the technical and economic factors. The introduction of relay stations in wireless metropolitan area networks will bring numerous advantages such as coverage extension and capacity enhancement due to the deployment of new cells and the reduction of distance between transmitter and receiver. However, the network designers will also face new challenges with the use of relay stations, since they involve a new source of interference and a complicated air interface; and this need to be carefully evaluated during the network design process. Contrary to the well known procedure of cellular network design over regular or hexagonal scenarios, the wireless network planning and optimization process aims to deal with the non-uniform characteristics of realistic scenarios, where the existence of hotspots, different channel characteristics for the users, or different service requirements will determine the final design of the wireless network. This thesis is structured in three main blocks covering important gaps in the existing literature in planning (efficient simulation) and optimisation. The formulation and ideas proposed in the former case can still be evaluated over regular scenarios, for the sake of simplicity, while the study of latter case needs to be done over specific scenarios that will be described when appropriate. Nevertheless, comments and conclusions are extrapolated to more general cases throughout this work. After an introduction and a description of the related work, this thesis first focuses on the study of models and algorithms for classical point-to-multipoint networks on Chapter 3, where the optimisation framework is proposed. Based on the framework, this work: - Identifies the technology-specific physical factors that affect most importantly the network system level simulation, planning and optimization process. - It demonstrates how to simplify the problem and translate it into a formal optimization routine with consideration of economic factors. - It provides the network provider, a detailed and clear description of different scenarios during the design process so that the most suitable solution can be found. Existing works on this area do not provide such a comprehensive framework. In Chapter 4: - The impact of the relay configuration on the network planning process is analysed. - A new simple and flexible scheme to integrate multihop communications in the Mobile WiMAX frame structure is proposed and evaluated. - Efficient capacity calculations that allow intensive system level simulations in a multihop environment are introduced. In Chapter 5: - An analysis of the optimisation procedure with the addition of relay stations and the derived higher complexity of the process is done. - A frequency plan procedure not found in the existing literature is proposed, which combines it with the use of the necessary frame fragmentation of in-band relay communications and cooperative procedures. - A novel joint two-step process for network planning and optimisation is proposed. Finally, conclusions and open issues are exposed.
5
Ozturk, Huseyin Selcuk. "Evaluation of secure 802.1X port-based network access authentication over 802.11 wireless local area networks." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2003. http://library.nps.navy.mil/uhtbin/hyperion-image/03Mar%5FOzturk.pdf.
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6
Aziz, Farhan Muhammad. "Implementation and Analysis of Wireless Local Area Networks for High-Mobility Telematics." Thesis, Virginia Tech, 2003. http://hdl.handle.net/10919/33505.
Повний текст джерелаАнотація:
Wireless networks provide communications to fixed, portable and mobile users and offer substantial flexibility to both end-users and service providers. Current cellular/PCS networks do not offer cost effective high data rate services for applications, such as, telematics, traffic surveillance and rescue operations. This research studies the feasibility and behavior of outdoor implementation of low-cost wireless LANs used for high mobility telematics and traffic surveillance. A multi-hop experimental wireless data network is designed and tested for this purpose. Outdoor field measurements show the wireless coverage and throughput patterns for static and mobile users. The results suggest that multi-hop wireless LANs can be used for high mobility applications if some protocols are improved.Master of Science
7
Khan, Tehmina Karamat. "Resilience Routing in AdHoc Networks. A decision based routing tree mechanism that can establish routes in adhoc network, which may than be configured into logical dual ring. Also a system is proposed to embed the QoS mechanisms, resilience and reliability features from RPR." Thesis, University of Bradford, 2008. http://hdl.handle.net/10454/4871.
Повний текст джерелаАнотація:
As the number of people using wireless networks is increasing, the need to reduce the
vulnerability of wireless networks from node or link failures that cause loss of data is
becoming a priority. Also the present techniques and topologies used for wireless
networking are not sufficient to handle the traffic load even if we solve the issues of
reliability and resilience. Packet loss or delay is increasingly likely due to the increase in
the number of packets as technology is evolving and more video and voice packets along
with the data packets are being transmitted. Only the efficient and intelligent use of the
shared medium can solve the problem and help in avoiding the collision or delay among
the packets using a newly proposed intelligent topology.
Wireless technology offers the potential to replace wires from many applications,
particularly for the rapid deployment of networks for permanent or temporary use. Fiber_
optic metropolitan area networks (WAN) provide security and resilience. A target of the
research was to match this in the wireless environment. This research investigates the
suitability if using wireless technology for the establishment of a MAN by adding
features to enhance resilience. We proposed a mechanism that may be rapidly deployed
and provide automatic configuration.
Research work and simulation design has been used to develop a new wireless network
topology for an efficient and intelligent packet transmission by identifying reliable routes.
This novel idea will help give wireless as well as mobile technology a clear edge over
wired technology, not only in the case of mobility but also in the case of security of data
and other services. A decision based routing tree mechanism has been developed, that can
establish routes in an ad-hoc network which may than be configured into a logical dual
ring. At the same time the proposed system proposes to embed the quality of service
mechanisms, resilience, and reliability features from RPR.
The simulations were created using Microsoft Visual Studio.Net for the Decision based
routing algorithm. The results were compared with an existing LAR algorithm. We have
obtained 95% confidence intervals on all the performance analysis results to indicate
accuracy.
8
Kubota, Flávio Adalberto 1987. "Escalonamento e controle de admissão cross-layer para redes IEEE 802.16." [s.n.], 2013. http://repositorio.unicamp.br/jspui/handle/REPOSIP/275611.
Повний текст джерелаАнотація:
Orientadores: Nelson Luis Saldanha da Fonseca, Juliana Freitag BorinDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Computação
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Resumo: O padrão IEEE 802.16, também conhecido como WiMAX (Worldwide Interoperability for Microwave Access) e seu adendo, o IEEE 802.16-2005, apresentam uma solução de baixo custo para o acesso à Internet. A tecnologia é capaz de prover altas taxas de transferências de dados para amplas áreas geográficas, alto nível de escalabilidade e baixo custo de instalação e manutenção. Além disso, a tecnologia inclui uma arquitetura para provisão de Qualidade de Serviço (QoS) para aplicações de tempo real e aplicações que demandam altas taxas de transferências. Para garantir os requisitos de QoS, o padrão define um mecanismo de sinalização entre a estação base (BS) e a estação cliente (SS), cinco classes de serviço, um mecanismo de escalonamento e um mecanismo de controle de admissão de novas conexões. Entretanto, as políticas que devem ser utilizadas na implementação dos mecanismos de escalonamento e controle de admissão não foram especificadas no padrão. O mecanismo de escalonamento é responsável principalmente por garantir os requisitos de banda mínima das conexões, enquanto que o controle de admissão restringe o número de conexões para evitar a sobrecarga do enlace sem fio. Esta dissertação propõe dois mecanismos de escalonamento e um mecanismo de controle de admissão para redes baseadas no padrão IEEE 802.16. Os mecanismos propostos são totalmente compatíveis com o padrão IEEE 802.16 e são capazes de atender os requisitos de QoS das cinco classes de serviço. Devido a alta variabilidade do sinal do canal sem fio, os mecanismos de escalonamento para redes cabeadas não são adequados para dispositivos sem fio. Dessa forma, as duas políticas de escalonamento e o mecanismo de controle de admissão propostos utilizam informações sobre a qualidade do sinal, através de uma abordagem cross-layer, para promover um uso eficiente do enlace sem fio. As três soluções foram avaliadas através de experimentos de simulação utilizando um módulo para simulação de redes IEEE 802.16
Abstract: The IEEE 802.16 standard, also known as WiMAX (Worldwide Interoperability for Microwave Access) and its amendment, IEEE 802.16-2005, are a low cost solution for Internet access. The technology is capable of providing high data transfer rates for large geographic areas, high level of scalability and low cost of installation and maintenance. Furthermore, the technology includes an architecture for Quality of Service (QoS) provision for real-time applications and applications that require high transfer rates. To garantee the QoS requirements, the standard defines a signaling mechanism between Base Station (BS) and Subscriber Station (SS), five classes of service, a scheduling mechanism and an admission control mechanism for new connections. However, policies that must be used in the implementation of scheduling mechanisms and admission control mechanisms were not defined by the standard. The scheduling mechanism is responsible for guaranteeing the minimum reserved rate requirements for the connections, while the admission control mechanism restricts the number of connections in the network to avoid the wireless link saturation. This dissertation proposes two scheduling mechanisms and one admission control mechanism for IEEE 802.16 networks. The proposed mechanisms are fully-standard compliant and capable of meeting the QoS requirements of the five classes of service. Due to the high variability of wireless channel signal, the scheduling mechanisms for wired networks are not suitable for wireless networks. Thus, the two scheduling policies and admission control mechanism proposed use information about the quality of the signal, through a cross-layer approach, to promote an efficient use of the wireless link. The three solutions were evaluated through simulation experiments using a simulation module for IEEE 802.16 networks
Mestrado
Ciência da Computação
Mestre em Ciência da Computação
9
Shrestha, Sanjeeb. "Addressing the hidden terminal problem in MU-MIMO WLANs with relaxed zero-forcing approach." Thesis, Optimal ZF precoding vector, 2017. http://hdl.handle.net/10453/116766.
Повний текст джерелаАнотація:
University of Technology Sydney. Faculty of Engineering and Information Technology.An ever-increasing data rate demand, mainly due to the proliferation of numerous smart devices, enterprises’ mission critical networks, and industry automation, has mounted tremendous pressure on today’s Wireless Local Area Networks (WLANs). Several avenues such as bandwidth, constellation density, the Multiple Input Multiple Output (MIMO) technique, etc., have been explored, e.g., IEEE802.11n/ac standards, to keep up with the demand. Future WLAN standard, e.g., IEEE802.11ax, with potential technologies such as uplink Multi-User (MU)-MIMO, full duplex transmission, etc., is anticipated by 2019. Having said that, there has been a strong emphasis on solving the technical issues with WLANs along with the addition of new frontiers in order to cope with the data rate demanded. One such appending decade-long issue is the inevitable Hidden Terminal (HT) problem in a distributive, decentralised and densely deployed WLANs, which fundamentally arises because of the transmission time overlaps between different transmitters operating at a particular frequency. The consequence is that it causes collisions of signals, which sharply reduces the system throughput. In the context of MU-MIMO based WLANs, several designs for a general network scenario, without the consideration of the HT problem, have been proposed, bringing efficiency by avoiding the collision of signals. However, a dedicated design, which could effectively address the HT problem in MU-MIMO WLANs and also become interoperable (with legacy standards) and feasible with existing hardware, is lacking to the best of our knowledge. In this thesis, we propose a solution for the HT problem which has three fundamental attributes. First, a) at the Physical (PHY) layer, the Zero-forcing (ZF) transmission strategy with fairness and throughput aware precoding is proposed, b) a hybrid scheduling scheme, combining the packet position-based First In First Out (FIFO) and channel quality-based scheme, namely the Best of the Two Choices, is designed, c) at the Medium Access Control (MAC) layer, Degrees-of-Freedom (DoF) based Transmission Opportunity (TXOP) for Access Points (APs) is developed which is backed by an extended Point Coordination Function (PCF), d) an explicit channel acquisition framework is proposed for ZF which has a reduced signaling time overhead of 98.6740 μs compared to IEEE802.11ac. e) performance evaluation methodologies are: i) hardware testbed results of the PHY strategy, which shows a received SNR gain of about 6 dB on average, and about 10 dB in comparison to the HT scenario, ii) simulation results of the MAC design, which shows a constant throughput gain of 4 − 5 times w.r.t. the popular Request to Send/Clear to Send (RTS/CTS) solution. Second, to address the interoperability issue, we purposefully use the standard frame format except for some required logical changes. Notably, the transition mechanism of our design, and for any MAC that uses standard frame formats, is investigated meticulously. The transition condition, transition steps and transition frame formats are detailed. Third, to address a practical constraint of an imperfect Channel State Information (CSI) at APs, a) we incorporate the Finite Rate Feedback (FRF) model in our solution. The effects on system parameters such as quantisation error bounds, throughput loss w.r.t. perfect CSI, etc., are discussed with closed-form analytical expressions, b) instead of an ideal ZF technique, a Relaxed ZF (RZF) framework is considered, in which the interference and power constraints of the optimisation problem are relaxed to the interference upper bound and to the maximum transmit power respectively. Our results lead to a distributive algorithm for calculating the optimal ZF precoding vector which suits the distributive, decentralised and uncoordinated nature of MU-MIMO WLANs.
10
Figueiredo, Fabricio Lira. "Capacidade e roteamento em redes metropolitanas sem fio hibridas." [s.n.], 2008. http://repositorio.unicamp.br/jspui/handle/REPOSIP/261046.
Повний текст джерелаАнотація:
Orientador: Paulo CardieriTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação
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Resumo: As redes metropolitanas sem fio (Wireless Metropolitan Area Networks - WMAN) modernas representam uma tendência tecnológica que viabiliza a ampliação da disponibilidade de acesso a serviços banda larga em todo o mundo. Estas redes se baseiam principalmente nas tecnologias WiMAX e Wi-Fi ad hoc e mesh, que apresentam características complementares e ermitem, a partir de sua integração, construir uma rede metropolitana sem fio híbrida com suporte a múltiplos serviços, mais flexível e de custo otimizado. Esta é a solução de rede investigada nesta tese, que exige o tratamento de diversos desafios tecnológicos, principalmente com o intuito de maximizar cobertura e desempenho da rede. Para tanto, é proposta uma abordagem que consiste em adotar, ao mesmo tempo, metodologias de planejamento e protocolos eficientes para redes WMAN híbridas. Neste contexto, dois aspectos de grande relevância são tratados: esquemas de roteamento de pacotes eficientes para redes Wi-Fi ad hoc e mesh e o planejamento de redes WMAN híbridas. Os resultados obtidos nesta tese representam contribuições significativas para o tratamento destes aspectos, e podem ser adotados para aumentar a eficiência de soluções de redes WMAN híbridas.
Abstract: Modern wireless metropolitan area networks (WMAN) correspond to technological tendency that has contributed to the growth of broadband services availability all over the world. These networks are currently based on technologies WiMAX, Wi-Fi ad hoc e mesh, which support complimentary features, thus allowing the design of multi- service hybrid WMANs, which correspond to a more flexible and cost-effective solution. This approach is the key research subject of this thesis, which requires that several technological challenges are handled, aiming at maximizing network coverage and performance. In this thesis, this problem is addressed by adopting network planning techniques and protocols that jointly contribute to increase coverage and efficiency of hybrid WMAN. In this context, two major aspects are considered: routing in Wi-Fi ad hoc and mesh and planning of hybrid WMAN. The results from this work correspond to significant contributions for each subject and can be adopted for increasing efficiency of hybrid WMAN solutions.
Doutorado
Telecomunicações e Telemática
Doutor em Engenharia Elétrica
11
Svoboda, Jan. "Bezdrátové spoje pro metropolitní sítě." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2011. http://www.nusl.cz/ntk/nusl-219290.
Повний текст джерелаАнотація:
This Master’s thesis analizes technologies suitable for metropolitan area networks. In this thesis there are mentioned technologies used for wireless transfer with speeds above 1 Gbps. There are described basic features and parameters of microwave radio relay links in 70/80GHz range and free space optic links. These technologies are compared with classic optical networks. Practical part of thesis was focused on development of application which calculates signal attenuation caused by the passage of the atmosphere for both technologies. Results gained from this application are mentioned in this Master’s thesis.
12
Naidoo, Deshree. "WiMAX performance analysis in a selected rural area in South Africa." Thesis, 2006. http://hdl.handle.net/10413/2226.
Повний текст джерелаАнотація:
Bringing broadband access to rural and remote communities has been a very difficult task due to the high cost of installation and complete lack of infrastructure in certain areas. Options currently under serious consideration to enable this access have included GSM, CDMA, Power line telecommunications, and DSL technologies. However, with the addition of the IEEE 802.16 standard - commonly referred to as WiMAX - with its various advantages, another serious option is now being considered. WiMAX is standard developed to provide wireless broadband access to metropolitan area networks. It is capable of providing LOS and NLOS coverage in the range of 350 km with data rates up to 75 Mbps. This research therefore looks at the WiMAX standard MAC and PHY layers with special focus on the PHY layer properties enabling provision ofNLOS coverage (WirelessMAN OFDM PHY). The research evaluates the performance of WiMAX in a rural environment in terms of coverage and traffic analysis. Other aspects include multipath fading and channel estimation. The traffic analysis is carried out using traffic projection formulated over a period often years for Nkandla, a typical rural area in South Africa. This is done to evaluate the sustainability of the designed base stations over the ten-year period with the growing traffic.Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2006.
13
Perera, B. E. Shehan. "VoIP and best effort service enhancement on fixed WiMAX : a thesis submitted in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Electrical and Computer Engineering in the University of Canterbury /." 2008. http://hdl.handle.net/10092/1575.
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Wang, Kuan-Wu, and 王冠武. "Study of Multi-Channel Technique for Wireless Metropolitan Area Networks." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/06589683060146083629.
Повний текст джерелаАнотація:
碩士國立雲林科技大學
電機工程系碩士班
93
WMANs(Wireless Metropolitan Area Networks) is a portable, wireless network that is favorably employed often used in wide-area transmission applications. Its advantages include wider coverage, higher throughput, and the flexible bandwidth on demand. Despite above advantages, the transmission environment of WMANs is much more complicated than that of WLANs(Wireless Local Area Networks), for example, dynamic multi-path fading and the Doppler effect. Based on the 802.16 specifications, this study proposes a new transmission scheme that combines the adaptive QAM and the characteristic of the binary Gray code to construct multiple sub-channels with different transmission quality respectively. Based on this scheme, we also analyze the capability of sub-channels under different modulation methods and channel coding in various transmission environment. In addition, we also propose an algorithm to improve the low quality of transmission caused by the Doppler Shift. The simulation results show our proposed algorithm can improve the transmission efficiency over various channel conditions and system parameters.
15
Lin, Chia-ching, and 林家慶. "Energy Efficient Multicast Scheduling for IEEE 802.16e Wireless Metropolitan Area Networks." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/67753619125732053999.
Повний текст джерелаАнотація:
碩士國立中山大學
電機工程學系研究所
97
In this thesis, we proposed a simple yet novel multicast scheduling scheme for IEEE 802.16e wireless metropolitan area networks. Specifically, we want to solve the problem that how the base station schedules data messages in a multicast superframe such that mobile stations can receive their required multicast data and the total awake time of mobile stations is minimal. We first prove that this problem is NP-complete, and then propose a greedy k-approximation algorithm, named G-EEMS, whose running time is , where n is the total number of multicast data messages and k is the size of MBS (multicast and broadcast service) zone in a frame. Simulation results show that, in terms of energy throughput, G-EEMS significantly outperforms the existing scheme, called SMBC-D.
16
Tsai, Ming-huei, and 蔡明惠. "Condensed Downlink MAP Structures for IEEE 802.16e Wireless Metropolitan Area Networks (MANs)." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/70211545410239194778.
Повний текст джерелаАнотація:
碩士國立中央大學
通訊工程研究所
97
The new mobile wireless metropolitan area network (WMAN) architecture imposes a demanding performance requirement on the radio resource to provide broadband internet access. The radio resource is partitioned as bursts in time and frequency domains and used by mobile stations (MS) in an exclusive manner. The base station (BS) functionally serves as a resource controller for traffic to and from the MSs associated with it, and thus naturally generates the proper downlink (DL) and uplink (UL) MAPs for active MSs based on service and traffic requirements. However, the DL-MAP construction scheme in IEEE 802.16e OFDMA standard, which was designed for handling irregular traffic pattern of MS, often produces a large DL-MAP, as a certain small amount of data distribution to each MS will render a potential overhead of information elements (IE) in DL-MAP and limit the overall capacity. Moreover, the robustness requirement on MAP broadcasting would further cause severe system overhead. As a solution, we propose four exclusive condensed DL-MAP structures, which only carry partial information of each rectangular burst in order to reduce the size of IE in DL-MAP. For each condensed DL-MAP structure, the algorithm for BS to produce the condensed DL-MAP structure and the algorithm for MS to precisely reconstruct the original DL-MAP structure are provided. As confirmed by the analysis results, the proposed condensed DL-MAP can achieve significant DL-MAP size reduction compared with standard DL-MAP structure.
17
Benade, Jacobus Retief. "The use of wireless technology to overcome bandwidth constraints by constructing a secure wireless metropolitan area network." Thesis, 2008. http://hdl.handle.net/10210/369.
Повний текст джерелаАнотація:
The Internet has influenced our lives greatly. The way we communicate evolved with the arrival of the Internet and has continued to evolve along with the Internet. While initially being used by Academia and large organizations such as the American Department of Defense, the Internet soon became a buzzword in the average home. E-mail has changed the way companies and individuals communicate, and the World Wide Web has changed the way all Internet users access information. Lately the ability to communicate globally and instantly via text services such as MSN, audio services such as Skype, or audio and video services such as Microsoft NetMeeting has become popular. These new services consume ever-increasing amounts of bandwidth; in turn these high quality services have driven the need for high-speed always-on Internet connections to businesses and homes. The development of 802.11b and later on 802.11g wireless local area network (LAN) standards have brought wireless networking to the home user. Cheap Wi- Fi-certified hardware has enabled many people to access their high-speed Internet connections from anywhere within their home, or even on the move. The convenience that Wi-Fi has brought has resulted in the increased use of the broadband services mentioned above. The end result is that the Internet changed the way we communicate, and continues to do so with the help of Wi-Fi.Dr. E. Marais
18
Yin, Hua-Chiang, and 尹華強. "Study of Efficient Data Forwarding in Heterogeneous and Multihop Wireless Metropolitan Area Networks." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/10328790442966667417.
Повний текст джерелаАнотація:
博士淡江大學
電機工程學系博士班
96
Recent wireless access technology has been about to launch various services for mobile users. The main development consideration of the trend is to provide broadband services for mobile users. Although the coverage of the general packet radio service (GPRS) or third generation (3G) is larger than the wireless fidelity (WiFi) system adopting IEEE 802.11 specification as the wireless local area network (WLAN) solution, the system throughput and the data transmission rate are significantly lower than the WLAN. Comparing GPRS/3G with the worldwide interoperability for microwave access (WiMAX) system, which uses IEEE 802.16 specification to deploy the wireless metropolitan area network (WMAN), the system throughput of GPRS/3G is lower than that of WiMAX which also can provide wide coverage cell. This dissertation mainly focuses on the strategies of providing high throughput for every mobile user and proposes three efficient strategies to increase the system performance of wireless network services. First, this dissertation proposes a heterogeneous handover solution for the existing wireless service environment between GPRS and WiFi. Considering the system coverage and the data transmission rate, four mechanisms are implemented for the authorization and fast seamless handover via the proposed circular probe strategy (CPS). By using the received signal strength indication (RSSI), delay time, and jitter as the system performance criteria, it verifies that the performance of the proposed handover strategy can provide higher throughput for mobile users. Secondly, the IEEE 802.16j task group has designed a multihop relay network for amending the existing 802.16e network to have better coverage and higher system throughput. This dissertation analyzes the orthogonal frequency division multiple access (OFDMA) permutations used in the 802.16j frame and then proposes a metric named radio resource utilization index (RRUI) for evaluating the useful radio resource as well as selecting a path with mimial cost in a multihop relay network. Finally, this dissertation proposes three fast forwarding schemes in order to reduce the overheads existed in the IEEE 802.16j draft. The proposed CID-translated forwarding scheme can relay broadcast messages without appending any relay medium access control (MAC) header. The proposed enhanced CID-translated forwarding scheme classifies the content of the relayed broadcast messages and then uses efficient relaying method to relay the messages. For a moving station that may change the data path frequently, the proposed burst-based forwarding scheme can relay data directly without negotiating any dynamic service flow, updating a forwarding table, appending any relay MAC header, and parsing every relayed MAC protocol data unit (PDU).
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Lee, Nien-tsung, and 李念聰. "An Integrated Power Saving Scheduling Algorithm in IEEE 802.16e Wireless Metropolitan Area Networks." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/26511420971561292968.
Повний текст джерелаАнотація:
碩士大同大學
資訊經營學系(所)
96
In mobile WiMAX (IEEE 802.16e), with the popularization of multimedia services, multicast and unicast services are coexisted in one mobile subscriber stations (MSS). In such network, power saving is a very important issue for battery powered mobile computing devices. In this paper we have proposed a Multicast Services Based Scheduling (MSBS) algorithm that improves energy efficiency for both unicast and multicast services, and conforms QoS requirements of MSSs in 802.16e wireless networks. MSBS schedules as many MSSs as possible into adjacent interval of their multicast data transmission periods and combines the unicast data of the remaining MSSs based on their deadline. Our scheme controls packets based on a deadline for each packet determined from QoS parameters and reduces energy consumption of MSSs by minimizing the energy for switching. Simulation results show that, MSBS can produce significant overall energy saving and prolonged lifetime of the MSSs.
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Faraj, Khaldoun Esmaeil. "Security technologies for wireless access to local area networks." Master's thesis, 2019. http://hdl.handle.net/10400.1/15018.
Повний текст джерелаАнотація:
In today’s world, computers and networks are connected to all life aspects and professions.
The amount of information, personal and organizational, spread over the network
is increasing exponentially. Simultaneously, malicious attacks are being developed at the
same speed, which makes having a secure network system a crucial factor on every level
and in any organization. Achieving a high protection level has been the goal of many
organizations, such as the Wi-Fi Alliance
R , and many standards and protocols have been
developed over time.
This work addresses the historical development of WLAN security technologies, starting
from the oldest standard, WEP, and reaching the newly released standard WPA3, passing
through the several versions in between,WPA, WPS, WPA2, and EAP. Along with WPA3,
this work addresses two newer certificates, Enhanced OpenTM and Easy ConnectTM. Furthermore,
a comparative analysis of the previous standards is also presented, detailing
their security mechanisms, flaws, attacks, and the measures they have adopted to prevent
these attacks. Focusing on the new released WPA3, this work presents a deep study
on both WPA3 and EAP-pwd. The development of WPA3 had the objective of providing
strong protection, even if the network’s password is considered weak. However, this
objective was not fully accomplished and some recent research work discovered design
flaws in this new standard.
Along with the above studies, this master thesis’ work builds also a network for penetration
testing using a set of new devices that support the new standard. A group of possible
attacks onWi-Fi latest security standards was implemented on the network, testing the response
against each of them, discussing the reason behind the success or the failure of the
attack, and providing a set of countermeasures applicable against these attacks. Obtained results show that WPA3 has overcome many of WPA2’s issues, however, it is still unable to overcome some major Wi-Fi vulnerabilities.No mundo de hoje, os computadores e as redes estão conectados praticamente a todos os aspectos da nossa vida pessoal e profissional. A quantidade de informações, pessoais e organizacionais, espalhadas pela rede está a aumentar exponencialmente. Simultaneamente, também os ataques maliciosos estão a aumentar à mesma velocidade, o que faz com que um sistema de rede seguro seja um fator crucial a todos os níveis e em qualquer organização. Alcançar altos níveis de proteção tem sido o objetivo de trabalho de muitas organizações, como a Wi-Fi Alliance R , tendo muitos standards e protocolos sido desenvolvidos ao longo do tempo. Este trabalho aborda o desenvolvimento histórico das tecnologias de segurança para WLANs, começando pelo standard mais antigo, WEP, e acabando no recém-chegado WPA3, passando pelas várias versões intermedias, WPA, WPS, WPA2 e EAP. Juntamente com o WPA3, este trabalho aborda os dois certificados mais recentes, Enhanced OpenTM e Easy ConnectTM. Além disso, também é apresentada uma análise comparativa dos standards anteriores, detalhando os seus principais mecanismos de segurança, falhas, ataques a que são susceptíveis e medidas adotadas para evitar esses ataques. Quanto ao novo WPA3 e EAP-pwd, este trabalho apresenta um estudo aprofundado sobre os seus modos "Personal" e "Enterprise". O desenvolvimento do WPA3 teve por objetivo fornecer proteção forte, mesmo que a password de rede seja considerada fraca. No entanto, esse objetivo não foi totalmente alcançado e alguma investigação realizada recentemente detectou falhas de desenho nesse novo padrão. Juntamente com os estudo dos standards acima referidos, o trabalho realizado para esta tese de mestrado também constrói uma rede para testes de penetração usando um conjunto de novos dispositivos que já suportam o novo standard. São aplicados vários ataques aos mais recentes padrões de segurança Wi-Fi, é testada a sua resposta contra cada um deles, é discutindo o motivo que justifica o sucesso ou a falha do ataque, e são indicadas contramedidas aplicáveis a esses ataques. Os resultados obtidos mostram que o WPA3 superou muitos dos problemas do WPA2 mas que, no entanto, ainda é incapaz de superar algumas das vulnerabilidades presentes nas redes Wi-Fi.
First, I would like to express my deepest appreciation to those who gave me the possibility to complete my study and get my Master degree, the Aga Khan Foundation, who has supported me financially
21
Cobbold, Christopher M. "Voice transport, capacity and signaling improvements for integrated wireless personal communications over metropolitan area networks." Thesis, 1995. http://hdl.handle.net/2429/4372.
Повний текст джерелаАнотація:
Networks for Personal Communication Services (PCS) are currently being deployed in
various parts of the world. A wide range of wireless voice and data service offerings is promised,
and consumer participation is expected to be high. The IEEE 802.6 Metropolitan Area Network
(MAN) has previously been proposed to provide for the distributed control of such networks.
This work continues investigations in call transport on the MAN using pre-arbitrated (PA)
bandwidth, and for signaling using queue arbitrated (QA) bandwidth. A scheme for the transport
of low bit-rate encoded voice, which is characteristic of mobile voice coders, is proposed that
attempts to balance packetization delay with network complexity. Capacity gains are realized with
PA access by locating a gateway, which provides interconnection to the Public Switched Telephone
Network (PSTN), at the Head of Bus (HOB) in a closed-bus MAN. A two-dimensional
Markov Chain and resulting blocking probabilities are derived which result in the determination
of the Erlang and subscriber capacity of a Personal Communications Network (PCN) based on a
single MAN. This provides the basis for extracting reductions in signaling delays on the MAN by
applying the Preemptive Priority Mechanism (PPM), a recently proposed improvement to the
MAN media access control protocol. In summary, improvements to the PA and QA transport
mechanisms, as applied to PCNs, are developed and assessed.
Architectures of single and multiple MAN-based PCNs are presented in the context of the
Intelligent Network (IN). The IEEE 802.6 MAN is viewed as being an evolutionary step towards
the introduction of the Broadband Integrated Services Digital Network (B-ISDN). Issues arising
from the migration of such architectures towards Asynchronous Transfer Mode (ATM) networks
are considered in depth.
22
Chiao-Chun, Hsu, and 許喬鈞. "Design and Implementation of High Performance Bandwidth Allocation Scheme for IEEE 802.16 Wireless Metropolitan Area Networks." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/75288520765283073116.
Повний текст джерелаАнотація:
碩士淡江大學
電機工程學系碩士班
94
IEEE 802.16 is considered today as the most promising technology to build a simple, high performance and high bandwidth wireless network into metropolitan areas. For providing a high performance services in complicated environments, QoS (Quality of Service) architecture are designed in IEEE 802.16 for scheduling services for different requests. However, the corresponding mechanisms for scheduling are not described in detail in the standard. In this paper, we designed an allocation mechanism for different services that could satisfy the requests of SS (Subscriber Station) by the connection conditions. In the allocation mechanism, the bandwidth allocation, services classification and bandwidth request schedule policy are considered. In the simulation, we have a comparison of the WFQ (Weight Fair Queue) and our algorithm. By the result, it could be observed that our algorithm could not only satisfy the fairness and QoS, but also has better efficiency in scheduling.
23
Hsu, Chao-Yuan, and 許朝淵. "Energy Efficient Multicast Scheduling with Adaptive Modulation and Coding for IEEE 802.16e Wireless Metropolitan Area Networks." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/31170201666190562184.
Повний текст джерелаАнотація:
碩士國立中山大學
電機工程學系研究所
99
One of the major applications driving wireless network services is video streaming, which is based on the ability to simultaneously multicast the same video contents to a group of users, thus reducing the bandwidth consumption. On the other hand, due to slow progress in battery technology, the investigation of power saving technologies becomes important. IEEE 802.16e (also known as Mobile WiMAX) is currently the international MAC (medium access control) standard for wireless metropolitan area networks. However, in 802.16e, the power saving class for multicast traffic is designed only for best-effort-based management operations. On the other hand, SMBC-AMC adopts the concepts of “multicast superframe” and “logical broadcast channel” to support push-based multicast applications. However, SMBC-AMC requires that (1) the number of frames in each logical broadcast channel must be equal, (2) all mobile stations must have the same duty cycle, and (3) the base station must use the same modulation to send data in a frame. These imply that SMBC-AMC is too inflexible to reach high multicast energy throughput. In this thesis, we propose cross-layer energy efficient multicast scheduling algorithms, called EEMS-AMC, for scalable video streaming. The goal of EEMS-AMC is to find a multicast data scheduling such that the multicast energy throughput of a WiMAX network is maximum. Specifically, EEMS-AMC has the following attractive features: (1) By means of admission control and the restriction of the multicast superframe length, EEMS-AMC ensures that the base layer data of all admitted video streams can be delivered to mobile stations in timeliness requirements. (2) EEMS-AMC adopts the greedy approach to schedule the base layer data such that the average duty cycle of all admitted stations can approach to the theoretical minimum. (3) EEMS-AMC uses the metric “potential multicast throughput” to find the proper modulation for each enhancement layer data and uses the metric “multicast energy throughput gain” to find the near-optimal enhancement layer data scheduling. Simulation results show that EEMS-AMC significantly outperforms SMBC-AMC in terms of average duty cycle, multicast energy throughput, multicast packet loss rate, and normalized total utility.
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Lu, Shao-jung, and 呂紹榮. "Smart Strategy for Configuring Parameters of Power Saving Classes in IEEE 802.16 Mobile Wireless Metropolitan Area Networks." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/87497596938388987543.
Повний текст джерелаАнотація:
碩士國立中央大學
通訊工程研究所
95
Recently, mobile communication technologies have been developed rapidly. The IEEE 802.16e wireless metropolitan area network (WMAN) standard is an emerging technology to support roaming mobility of mobile stations (MSs) in outdoor environment. For MSs powered by batteries, the standard supports power saving mode to conserve battery power meanwhile fulfilling the requirements of quality of services. Regarding to different service types, standard defines three different power saving types for them and each type has its own power saving parameters. By setting appropriate parameters, single type of power saving will work well for extending the battery life. However, if the number of established connections of MS is more than one and the number of associated power saving type is more than one, the sleeping behavior is not following the setting parameters because that the MS will enter sleep mode only when all of connections decide to enter sleep at a same time. In other words, for a time frame, if there is any one connection is in listening mode, the MS shall not turn down the wireless transceiver. Therefore, such multi-connection case may degrade power saving efficiency. In this dissertation, we propose a smart strategy for base station (BS) to configure the parameters of power saving classes for MSs with multiple connections. At first, we explain and discuss the features of IEEE 802.16e sleep modes and then propose a smart strategy for merging parameters of different power saving classes in order to extend the battery life. Performance of proposed strategy is evaluated by simulations and simulation results illustrate that the proposed strategy with single parameter set outperforms the standard strategy with multiple parameter sets.