Dissertations / Theses: 'Networking - Local Area Networks (LANs)'

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Foley, M. C. "Microprocessor based local area networks." Thesis, Bucks New University, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.381684.

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Lin, Xiaoyang. "Improving fairness in the 802.11 infrastructure wireless local area networks /." View abstract or full-text, 2005. http://library.ust.hk/cgi/db/thesis.pl?COMP%202005%20LIN.

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Shi, Junxiao, and Junxiao Shi. "Named Data Networking in Local Area Networks." Diss., The University of Arizona, 2017. http://hdl.handle.net/10150/625652.

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The Named Data Networking (NDN) is a new Internet architecture that changes the network semantic from packet delivery to content retrieval and promises benefits in areas such as content distribution, security, mobility support, and application development. While the basic NDN architecture applies to any network environment, local area networks (LANs) are of particular interest because of their prevalence on the Internet and the relatively low barrier to deployment. In this dissertation, I design NDN protocols and implement NDN software, to make NDN communication in LAN robust and efficient. My contributions include: (a) a forwarding behavior specification required on every NDN node; (b) a secure and efficient self-learning strategy for switched Ethernet, which discovers available contents via occasional flooding, so that the network can operate without manual configuration, and does not require a routing protocol or a centralized controller; (c) NDN-NIC, a network interface card that performs name-based packet filtering, to reduce CPU overhead and power consumption of the main system during broadcast communication on shared media; (d) the NDN Link Protocol (NDNLP), which allows the forwarding plane to add hop-by-hop headers, and provides a fragmentation-reassembly feature so that large NDN packets can be sent directly over Ethernet with limited MTU.

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Muriithi, Ndiritu. "Radio local area networks : protocol design and performance analysis." Thesis, University of York, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.296384.

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Jaiaree, Thoetsak. "The security aspects of wireless local area network (WLAN)." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2003. http://library.nps.navy.mil/uhtbin/hyperion-image/03sep%5FJaiaree.pdf.

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Thesis (M.S. in Information Technology Management)--Naval Postgraduate School, September 2003.
Thesis advisor(s): Norman F. Schneidewind, Douglas E. Brinkley. Includes bibliographical references (p. 75-78). Also available online.

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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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Onder, Hulusi. "Session hijacking attacks in wireless local area networks." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2004. http://library.nps.navy.mil/uhtbin/hyperion/04Mar%5FOnder.pdf.

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Siamarou, Andreas G. "Wireless local area radio networks : wideband characterisation and measurements at 62.4GHz." Thesis, University of South Wales, 2001. https://pure.southwales.ac.uk/en/studentthesis/wireless-local-area-radio-networks-wideband-characterisation-and-measurements-at-624ghz(025994b7-9a26-4ad2-9137-7946069d6900).html.

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The presence of multipath propagation in indoor environments limits the performance of wideband radio communication systems and also the maximum data rate that can be feasible. This thesis addresses the dynamics of propagation mechanisms needed to design and exploit future broadband wireless local area networks in the 60GHz millimetre-wave band. The frequency band between 62-63GHz with data rates up to 155Mb/s, has been provisionally assigned for Mobile Broadband Systems. The main emphasis of this study was to provide an original contribution to the development, design and planning of future broadband communication systems using new high-resolution wideband channel measurement data. Based on this data, spatial and temporal statistics of several line-of-sight radio paths in a University campus are presented and analysed. In order to enable measurement of the wideband propagation characteristics a high-resolution (Ins) wideband Frequency-swept channel sounder was designed and implemented at 62.4GHz. The channel sounder has been built around a Vector Network Analyser to measure the complex transfer function of the channel. The instantaneous coherence bandwidth is found to be highly variable with the location of the receiver with respect to the base station. With delay spread values ranging from 20 to 70ns the coherence bandwidth remains most of the times below 10MHz. Based on the maximum delay spread of 68ns obtained in a 41m long narrow corridor, a BER of 10" 3 and normalised delay spread of 0.1, the minimum data transmission rate is estimated at 1.47 Mb/s. For a 12.80m room environment with maximum delay spread of 20ns the minimum data transmission rate is 5Mb/s. To achieve higher data transmission rates channel protection countermeasures appears to be necessary. However limiting the extent of a picocell size and utilising the potential capability of frequency re-use at 62.4GHz can result in radio network implementation without the complexity of countermeasures. Results relating to coherence bandwidth variability in multipath conditions confirm that higher user mobility envisaged for MBS would present a real challenge to the achievement of data transmission rates of the order of 155Mb/s. The research work reported in the thesis has been able to identify and extract from extensive high resolution wideband propagation the necessary design characteristics for the development of realistic radio planning models. Using measured results obtained in a number of radio paths geometries, the objectives of the project have been largely achieved and further work is recommended.

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Dely, Peter. "Architectures and Algorithms for Future Wireless Local Area Networks." Doctoral thesis, Karlstads universitet, Avdelningen för datavetenskap, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-15393.

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Future Wireless Local Area Networks (WLANs) with high carrier frequencies and wide channels need a dense deployment of Access Points (APs) to provide good performance. In densely deployed WLANs associations of stations and handovers need to be managed more intelligently than today. This dissertation studies when and how a station should perform a handover and to which AP from a theoretical and a practical perspective. We formulate and solve optimization problems that allow to compute the optimal AP for each station in normal WLANs and WLANs connected via a wireless mesh backhaul. Moreover, we propose to use software defined networks and the OpenFlow protocol to optimize station associations, handovers and traffic rates. Furthermore, we develop new mechanisms to estimate the quality of a link between a station and an AP. Those mechanisms allow optimization algorithms to make better decisions about when to initiate a handover. Since handovers in today’s WLANs are slow and may disturb real-time applications such as video streaming, a faster procedure is developed in this thesis. Evaluation results from wireless testbeds and network simulations show that our architectures and algorithms significantly increase the performance of WLANs, while they are backward compatible at the same time.

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Zhai, Hongqiang. "Cross-layer design of networking protocols in wireless local area networks and mobile ad hoc networks." [Gainesville, Fla.] : University of Florida, 2006. http://purl.fcla.edu/fcla/etd/UFE0015668.

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Janse, van Rensburg Johanna Hendrina. "An investigation into the deployment of IEEE 802.11 networks." Thesis, Rhodes University, 2007. http://eprints.ru.ac.za/860/.

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Pereira, Rubem Kicis Torrents. "Token passing medium access control protocol performance under asymmetric service." Thesis, Manchester Metropolitan University, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.362694.

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Tian, Jun. "A speed adaptive mobile Internet protocol over wireless local area network." [Gainesville, Fla.] : University of Florida, 2005. http://purl.fcla.edu/fcla/etd/UFE0012700.

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Chan, Edward. "Supporting heterogeneous traffic in LANs and WANs : issues and techniques." Thesis, University of Sunderland, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.390607.

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Van, de Haar Paul. "Towards a wireless local area network security control framework for small, medium and micro enterprises in South Africa." Thesis, Nelson Mandela Metropolitan University, 2015. http://hdl.handle.net/10948/4001.

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There is little literature available that is specific to the use of wireless local area network [WLAN) security among small, medium and micro enterprises (SMMEs) in South Africa. This research study developed a framework which may be used by SMMEs for the purposes of securing their WLANs. In view of the fact that the aim of the study was to develop a system for improving information technology security, the study followed a design science approach. A literature review was conducted on security control framework standards and WLAN technologies. The needs of SMMEs regarding WLANs were also established. The result of this process was an artefact in the form of a WLAN Security Control Framework for securing WLANs for SMMEs in South Africa. The suitability of the framework was validated by means of a focus group.

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Wu, Haotian. "OpenFlow-enabled dynamic DMZ for local networks." Diss., Kansas State University, 2017. http://hdl.handle.net/2097/38231.

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Doctor of Philosophy
Department of Electrical and Computer Engineering
Don M. Gruenbacher
Caterina M. Scoglio
Cybersecurity is playing a vital role in today's network. We can use security devices, such as a deep packet inspection (DPI) device, to enhance cybersecurity. However, a DPI has a limited amount of inspection capability, which cannot catch up with the ever-increasing volume of network traffic, and that gap is getting even larger. Therefore, inspecting every single packet using DPI is impractical. Our objective is to find a tradeoff between network security and network performance. More explicitly, we aim at maximizing the utilization of security devices, while not decreasing network throughput. We propose two prototypes to address this issue in a demilitarized zone (DMZ) architecture. Our first prototype involves a flow-size based DMZ criterion. In a campus network elephant flows, flows with large data rate, are usually science data and they are mostly safe. Moreover, the majority of the network bandwidth is consumed by elephant flows. Therefore, we propose a DMZ prototype that we inspect elephant flows for a few seconds, and then we allow them to bypass DPI inspection, as long as they are identified as safe flows; and they can be periodically inspected to ensure they remain safe. Our second prototype is a congestion-aware DMZ scheme. Instead of determining whether a flow is safe or not by its size, we treat all flows identically. We measure the data rates of all flows, and use a global optimization algorithm to determine which flows are allowed to safely bypass a DPI. The objective is to maximize DPI utilization. Both prototypes are implemented using OpenFlow in this work, and extensive experiments are performed to test both prototypes' feasibility. The results attest that the two prototypes are effective in ensuring network security while not compromising network performance. A number of tools for SDN network configuring and testing are also developed.

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Samaras, Konstantinos. "Performance analysis of wireless infrared communication systems." Thesis, University of Oxford, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.300127.

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Wu, Di. "Performance studies of VoIP over Ethernet LANs a dissertation submitted to Auckland University of Technology in partial fulfillment [sic] of the requirements for the degree of Master of Computer and Information Sciences, 2008." Click here to access this resource online, 2008. http://hdl.handle.net/10292/677.

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Dissertation (MCIS - Computer and Information Sciences) -- AUT University, 2008.
Includes bibliographical references. Also held in print (ix, 65 leaves : ill. ; 30 cm.) in City Campus Theses Collection (T 621.385 WU)

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Kulyasov, Sergey. "Upgrading LAN infrastructure in manufacturing company to support wireless technology." Menomonie, WI : University of Wisconsin--Stout, 2005. http://www.uwstout.edu/lib/thesis/2005/2005kulyasovs.pdf.

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Fornaro, Antony. "Testbed evaluation of integrating ethernet switches in the differentiated services architecture using virtual LANs." Thesis, Georgia Institute of Technology, 2003. http://hdl.handle.net/1853/15684.

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Chung, Edward Chi-Fai. "Quality of service analysis for distributed multimedia systems in a local area networking environment." Ohio : Ohio University, 1996. http://www.ohiolink.edu/etd/view.cgi?ohiou1174610545.

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22

Karayakaylar, Selcuk. "Data link level interconnection of remote Fiber Distributed Data Interface Local Area Networks (FDDI LANs) through the Critical Data Link (CDL)." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1994. http://handle.dtic.mil/100.2/ADA284307.

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Chetty, Marshini. "Making infrastructure visible: a case study of home networking." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/41152.

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In this dissertation, I examine how making infrastructure visible affects users' engagement with that infrastructure, through the case study of home networking. I present empirical evidence of the visibility issues that home networks present to users and how these results informed the design of a prototype called Kermit to visualize aspects of the home network. Through my implementation and evaluation of Kermit, I derive implications for making infrastructure visible in ways that enable end-users to manage and understand the systems they use everyday. I conclude with suggestions for future work for making home networks, and infrastructure more generally, more visible.

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Yan, Ziguang. "On exploiting spatial reuse in wireless ad hoc networks." School of Electrical, Computer and Telecommunications Engineering - Faculty of Informatics, 2008. http://ro.uow.edu.au/theses/111.

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Wireless ad hoc networks have been increasingly popular in recent years with the development of mobile devices. However, both theoretical and simulation works show that the capacity of wireless ad hoc networks is bounded due to its nature of distributed and multihop. Spatial reuse is a promising technology to increase the capacity of wireless ad hoc networks by allowing more transmissions to occur simultaneously. In this thesis, we enhance 802.11 performances by exploiting the benefits of spatial reuse in wireless ad hoc networks which is achieved by transmission power control (TPC) and directional antennas. We first propose spatial TPC based on basic TPC to fully exploit the benefits of spatial reuse achieved by transmission range control. Simulation results show that spatial TPC achieves higher throughput and lower power consumption compared to 802.11 and basic TPC. We also develop four schemes of directional MAC protocols with the intention of overcoming the new hidden node problem faced by directional antennas. By extensive simulations under different topologies and traffic patterns, we find the directional RTS/CTS (DD) scheme outperforms 802.11 as well as other three schemes by fully exploiting the benefits of spatial reuse achieved by directional antennas.

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Zha, Wei. "An adaptive wireless LAN MAC scheme to achieve maximum throughput and service differentiation." Master's thesis, Mississippi State : Mississippi State University, 2005. http://sun.library.msstate.edu/ETD-db/ETD-browse/browse.

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Abdullah, Hanifa. "A risk analysis and risk management methodology for mitigating wireless local area networks (WLANs) intrusion security risks." Diss., Pretoria : [s.n.], 2006. http://upetd.up.ac.za/thesis/available/etd-10122006-155850.

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Almantheri, Hamed. "Computer wireless networks : a design plan for building wireless networks using IEEE 802.11 standard." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2003. http://library.nps.navy.mil/uhtbin/hyperion-image/03Mar%5FAlmantheri.pdf.

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Schmidt, Mark Bradley. "Development and analysis of a model for assessing perceived security threats and characteristics of innovating for wireless networks." Diss., Mississippi State : Mississippi State University, 2006. http://library.msstate.edu/etd/show.asp?etd=etd-04122006-130558.

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Kangude, Shantanu. "CSMA with Implicit Scheduling through State-keeping: A Distributed MAC Framework for QoS in Broadcast LANs." Diss., Available online, Georgia Institute of Technology, 2004:, 2004. http://etd.gatech.edu/theses/available/etd-05132004-132109/unrestricted/kangude%5Fshantanu%5F200407%5Fphd.pdf.

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Thesis (Ph. D.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2005. Directed by John Copeland.
Copeland, John, Committee Chair ; Owen, Henry, Committee Member ; Sivakumar, Raghupathy, Committee Member ; Lanterman, Aaron, Committee Member ; Dos Santos, Andre, Committee Member. Includes bibliographical references.

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Nagar, Bansi. "A theoretical study of wireless networks in local area networks." Thesis, 2014. http://hdl.handle.net/10210/12301.

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M.Com. (Computer Auditing)
With all the technology available in today’s world, people have become more connected to each other as well as to the world around them. This has been echoed by Rutledge (2009:1), who stated: “Emerging technologies are linking the world, but we no longer need wires and cables to connect people. People are no longer trapped by geography. We are, however, facing a digital tsunami as communications technology becomes cheaper, simpler, and more culturally-acceptable.” The new wireless technology has become an aid to most organizations, making networking simpler, cheaper and more effective, and has not only changed the way businesses operates but has changed the entire world of communications. It has not only caused a change in technology, but a change in the way of life. This is emphasized by Lawlor (2007:3), who stated: “Information technology has been a major driving force behind globalization and that information technology has now become a key component of a corporation’s global business strategy.” It is evident that the use of wireless technologies has changed the mode in which work is carried out and the manner in which communication takes place today. It has made it easier, more effective and efficient than before with wired technology. Wireless networks provide computing suppleness. It aids employees and individuals to take advantage of mobile networking for e-mail, Internet access, and sharing files regardless of where they are in the office or in a local area network (hereafter LAN). The advantage of the wireless setting is that it can be moved around at will, with no need for cables, leaving employees free to work from anywhere...

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"Voice-over-IP (VoIP) over wireless local area networks (WLAN)." 2004. http://library.cuhk.edu.hk/record=b5892251.

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Wang Wei.
Thesis (M.Phil.)--Chinese University of Hong Kong, 2004.
Includes bibliographical references (leaves 80-83).
Abstracts in English and Chinese.
Chapter Chapter 1 --- Introduction --- p.1
Chapter 1.1 --- Motivations and Contributions --- p.1
Chapter 1.2 --- Organization of the Thesis --- p.4
Chapter Chapter 2 --- Background --- p.6
Chapter 2.1 --- IEEE 802.11 --- p.6
Chapter 2.1.1 --- Distributed Coordination Function (DCF) / Point Coordination Function (PCF) --- p.7
Chapter 2.1.2 --- Types of Networks --- p.8
Chapter 2.1.3 --- The 802.11 MAC Sublayer Protocol --- p.9
Chapter 2.1.4 --- Why CSMA/CA for Wireless LAN? --- p.11
Chapter 2.2 --- Voice over IP (VoIP) --- p.13
Chapter 2.2.1 --- Speech Codec --- p.13
Chapter 2.2.2 --- The H.323 Standard --- p.13
Chapter 2.3 --- Related Work --- p.15
Chapter 2.3.1 --- Capacity limits of VoIP over WLAN --- p.16
Chapter 2.3.2 --- Methods for increasing VoIP capacity over WLAN --- p.16
Chapter 2.3.3 --- Interference between traffic of VoIP and other applications --- p.18
Chapter Chapter 3 --- VoIP Multiplex-Multicast Scheme --- p.20
Chapter 3.1 --- System Architecture --- p.20
Chapter 3.2 --- Packet Multiplexing and Multicasting --- p.22
Chapter 3.3 --- Header Compression --- p.24
Chapter 3.4 --- Connection Establishment --- p.29
Chapter Chapter 4 --- Capacity Analysis --- p.31
Chapter 4.1 --- VoIP Capacity Analysis for 802. 11b --- p.31
Chapter 4.1.1 --- Capacity of Ordinary VoIP over WLAN --- p.32
Chapter 4.1.2 --- Capacity of Multiplex-Multicast Scheme over WLAN --- p.33
Chapter 4.2 --- "VoIP Capacity Analysis for 802,11a and 802.11g" --- p.34
Chapter 4.3 --- VoIP Capacity with VBR Sources --- p.38
Chapter 4.4 --- Simulations --- p.38
Chapter Chapter 5 --- Delay Performance --- p.41
Chapter 5.1 --- Access Delay --- p.42
Chapter 5.2 --- Extra Delay Incurred by the Multiplex-Multicast Scheme --- p.47
Chapter Chapter 6 --- VoIP Co-existing with TCP Interference Traffic --- p.49
Chapter 6.1 --- Ordinary VoIP co-existing with TCP over WLAN --- p.49
Chapter 6.1.1 --- Problem Caused by TCP Interference --- p.49
Chapter 6.1.2 --- Solutions --- p.52
Chapter 6.2 --- M-M VoIP coexisting with TCP over WLAN --- p.53
Chapter 6.3 --- 802.11e --- p.56
Chapter 6.3.1 --- EDCA --- p.56
Chapter 6.3.2 --- ACK Policies --- p.58
Chapter 6.3.3 --- VoIP over EDCA --- p.58
Chapter Chapter 7 --- Experimental Validation --- p.61
Chapter 7.1 --- Transmission Errors --- p.61
Chapter 7.2 --- Prototype Implementation --- p.62
Chapter Chapter 8 --- VoIP over Ad Hoc Networks --- p.65
Chapter 8.1 --- Mobile Ad Hoc Networks (MANET) and Wireless Distributed System (WDS) --- p.65
Chapter 8.2 --- The M-M Scheme in WDS --- p.67
Chapter 8.2.1 --- Modified System Architecture --- p.67
Chapter 8.2.2 --- Delay Performance --- p.68
Chapter 8.2.3 --- Analysis of M-M Scheme in WDS --- p.69
Chapter 8.2.4 --- Capacity Improvement --- p.70
Chapter 8.2.5 --- Delay Improvement --- p.71
Chapter 8.2.6 --- Spectrum Reuse --- p.71
Chapter Chapter 9 --- Conclusions --- p.76
References --- p.80

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32

Makharia, Shivesh. "Video multicast over wireless local area networks." 2007. http://hdl.rutgers.edu/1782.2/rucore10001600001.ETD.17085.

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33

Sethakaset, Ubolthip. "Modulation and coding techniques for infrared wireless local area networks." Thesis, 2006. http://hdl.handle.net/1828/2190.

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Because of low-cost optical devices and virtually unlimited bandwidth, optical wireless communications (OWC) for indoor wireless local area networks (WLANs) have recently become an attractive alternative to radio frequency systems. Since optical signals cannot penetrate through walls or other opaque barriers, the security of infrared WLANs is very high and there is no interference between rooms. Subsequently, cell planning is simple and easy, and the potential capacity of an optical-based network in a building is extremely high. However, the system link is susceptible to path loss and multipath dispersion. In addition, the average transmit power is constrained by eye-safety regulations and power consumption concerns. Hence, most recent research deals with the physical layer aspects such as modulation, equalization and error-control coding in order to cope with these draw-backs, especially the effects of multipath dispersion. The objective of this thesis is to study practical signaling techniques capable of eliminating the effects of intersymbol interference (ISI). Regarding the drawbacks of OWC, modulation schemes which are power and band-width efficient are considered. Pulse-position modulation (PPM) has been employed for IrDA and IEEE802.11 standards because it offers high power efficiency. However, it re-quires high bandwidth so that its performance is considerably degraded when the channel is more corrupted by ISI. A number of modified PPM techniques have been proposed to improve bandwidth efficiency. This thesis introduces a hybrid between pulse-amplitude modulation (PAM) and differential pulse-position modulation (DPPM), named differential amplitude pulse-position modulation (DAPPM), in order to gain a better compromise be¬tween power and bandwidth efficiency. It yields better bandwidth and/or power efficiency than PAM, PPM and DPPM depending on the number of amplitude levels (A), and the maximum length (L) of a symbol. The channel capacity of PPM, DPPM and DAPPM systems is investigated. Since these modulation schemes over an ISI channel can be represented by a trellis diagram, their channel capacity is determined using a method for calculating the capacity of a Markov process channel. Over a soft-output channel, DAPPM achieves a higher capacity and is less sensitive to multipath dispersion than PPM and DPPM. Moreover, the comparison of hard-decision decoding (HDD) and soft-decision decoding (SDD) for PPM and DPPM systems shows that the performance of SDD is superior to that of HDD, especially when the channel is dispersive. Then, some soft-decision techniques for DPPM system are considered. Although maximum-likelihood sequence detection (MLSD) is the optimal SDD for DPPM system, its complexity is extremely high. This thesis examines SDDs which are less complex than MLSD, but have performance close to that with MLSD. As the DPPM system is a Markov pro¬cess, maximum a posteriori (MAP), Max-Log-MAP and the soft-output Viterbi algorithm (SOVA) are adopted. In addition, a novel very low complexity soft-decision decoding algorithm is introduced. The performance of the proposed algorithm is independent of the knowledge of the channel model, while the performance of the optimal and suboptimal MAP algorithms is impaired when the receiver has no information about the channel. Finally, to achieve lower power requirements, error-control coding in an OWC system is investigated. Because insertion and deletion errors exist in DPPM systems, conventional coding techniques cannot be used. This thesis presents the concatenation of marker and Reed-Solomon codes which is able to correct such errors. The coded systems with HDD and SDD are examined by analysis and simulation.

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Billapati, Venkata R. Foo Simon Y. "Security in wireless communications and wireless local area networks." 2004. http://etd.lib.fsu.edu/theses/available/etd-07172004-104054.

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Thesis (M.S.)--Florida State University, 2004.
Advisor: Dr. Simon Foo, Florida State University, College Engineering, Dept. of Electrical and Computer Engineering. Title and description from dissertation home page (viewed Sept. 29, 2004). Includes bibliographical references.

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Reid, Michael Edward. "Modeling and performance analysis of ATM LANs /." 1997.

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Madingoane, Kefilwe. "A Bragg grating Fabry-Perot filter for next-generation broadband wireless local area networks." Thesis, 2009. http://hdl.handle.net/10210/2170.

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M.Ing.
Over the past few years, fibre Bragg gratings have emerged as very important components in the photonics environment. Their discovery has greatly revolutionised the design of many complex devices, introducing simplicity and cost effectiveness. Extensive research has been invested into identifying possible areas of application for fibre Bragg gratings. This has resulted in fibre Bragg gratings finding a comfortable niche in the fields of sensors and optical communication systems. This study focuses on the possible application of fibre Bragg gratings in wireless local area networks. Wireless local area networks are rapidly becoming a market of great potential for the investor. To sustain the impressive image of this market, research initiatives should strive to secure cost-effective solutions for the implementation of wireless local area networks. With reduced costs on wireless local area network products, the demand for these products is expected to escalate. Research conducted at the COBRA Institute, has produced a novel concept of optically distributing data signals across a network, and later transmitting them at radio frequencies between antenna sites. This concept, earmarked for wireless local area networks, uses a fast tuneable laser source, graded index polymer optical fibre and a periodic optical filter to generate the radio frequency microwave signals. The periodic filter in this network system serves to up-convert the frequency of the signal to radio-frequency levels. The filter is an important component of the network and it is situated at the antenna site. For wireless local area networks that require broad coverage, the number of periodic optical filters deployed for the system can be high. This can have a negative impact on the cost of the network. This research proposes a low-cost Fabry-Perot filter designed from fibre Bragg gratings, to replace the optical periodic filter discussed in the network mentioned above. The work presented in this study consolidates the design theories of Fabry-Perot filters and fibre Bragg gratings. The grating-based Fabry-Perot filter is modelled using coupled-mode theory, simulated using the transfer matrix method and fabricated via the strain controlled phase mask technique. The figures of merit that describe the spectral performance of the Fabry-Perot filter (i.e. free spectral range, minimum resolvable bandwidth, finesse and contrast factor) are compared to calculations associated with classical designs. The final part of this study presents experimental measurements of the generated radio frequency microwave signal. The purpose of these measurements is firstly to demonstrate the feasibility of the entire concept of generating radio frequency microwave signals using optical frequency multiplication. The second goal for the measurements is to benchmark the performance of the new grating-based Fabry-Perot filter against expected results approximated through calculations. Both goals were achieved with encouraging observations.

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Ogunduyile, O. Oluwagbenga. "Integrating wireless body area networks with web services for ubiquitous healthcare service provisioning." 2013. http://encore.tut.ac.za/iii/cpro/DigitalItemViewPage.external?sp=1001110.

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M. Tech. Information Networks
This dissertation reports on a prototype implementation of an architecture that seamlessly integrates Wireless Body Area Networks with Web services for ubiquitous healthcare service provisioning. The prototype ubiquitous monitoring system proactively collects body physiological signals of remote patients to recommend diagnostic services. The technologies that are based upon Wireless Body Area Networks and Web services can provide ubiquitous accessibility to variety of services by allowing distributed healthcare resources to be massively reused. This contributes to improving quality of healthcare services and shields individuals from physically moving to locations where healthcare services are provided, except in a critical situation. In addition, the technology can reduce costs of healthcare services by allowing individuals to remotely access services to support their healthcare. Especially our system is designed for ubiquitous monitoring of elderly and patients in recovery (or rehabilitation). The Wireless Body Area Networks - Web services architecture is at crossroad of embedded engineering of hardware, software and networking protocols. Testing of the prototype was carried out on enthusiastic volunteers and it has shown to be an efficient, reliable and support state-of-art service provisioning of ubiquitous healthcare monitoring in health sector.

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(9828710), Sandaruvan Rajasinghege. "Optimal desired trajectories for local area networks of drones." Thesis, 2020. https://figshare.com/articles/thesis/Optimal_desired_trajectories_for_local_area_networks_of_drones/13405574.

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Mini and micro Unmanned Aerial Vehicles (UAVs) can provide a better service in commercial applications if they are used in networks. Flying Ad hoc Networks (FANETs) and Internet of Drones (IoD) are UAV networks where many UAVs belonging to different users coexist, and there are several routing protocols which have been developed to maintain communication in such networks. However, in application scenarios where only a limited number of UAV nodes are available, some communication paths cannot be established if an existing neighbour UAV node moves away and a new neighbour is not within reach. As response to this problem, LANs of Drones (LoDs) have been recently introduced to be used in these scenarios. A LoD is a star-connected relay network where the UAVs are connected serially in branches, in contrast to FANETs and IoDs. In a LoD, the movements of UAVs should be controlled in order to maintain the communication links. This thesis mainly focusses on the determination of desired trajectories of UAV nodes in a LoD when the leading UAV has to move to a given target. The trajectories were optimized to minimise the task completion time or the total energy consumed. Mathematical constraints were applied to the optimization problem in order to maintain the distances between the UAV nodes and between the closest UAV and the Ground Station (GS) so that they were less than the Wi-Fi communication distance. MATLAB simulations were used to verify the desired trajectory optimization method. Additional constraints were introduced to the optimization problem to derive the desired trajectories of UAVs in the presence of obstacles and image processing techniques were used to derive constraints of a realistic obstacle using an image of an obstacle. In addition, a secondary outcome of this research study was the determination of the minimum number of UAVs required to perform a given task and the minimum number of UAVs was determined for four categories of tasks. Finally, a purpose of this research was to determine the number of branches required in a LoD to obtain a given level of reliability. The reliability of a LoD was estimated by varying the number of branches and number of UAVs in each branch.

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Amer, Abdelsalam Bubaker. "Quality of service support with error control protocol in wireless local area networks." Thesis, 2010. http://hdl.handle.net/1828/2906.

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This dissertation discusses some techniques to improve the medium access control in infrastructure multi channel wireless local area networks. Medium Access Control protocols (MAC) coordinate the stations and resolve the channel contentions so that scarce radio resources are shared fairly and efficiently amongst participating users. We propose different models to improve the medium access control performance. The models deal with improving the channel access and allocation. By proposing some backoff strategies for the collided users to retransmit, the performance is improved. A comparison amongst the proposed models is shown. We also investigate the quality of service provisioning in infrastructure-based wireless local area networks medium access control. We propose a multiple class traffic model to support quality of service. This model is a cross-layer model as we consider the error in the transmitted state. We also propose models for uplink channel utilizations for data channel transmissions that can be applied to different WLANs. Finally, we propose an integrated model that deals with error in both the request and data transmissions. That model applies in the single class and quality of service support models we develop. In this dissertation, we propose four techniques to improve the medium access control frame utilization by developing four backoff strategies to reduce the collision on the request channels. We propose a cross-layer model for the error control protocol. We propose another model for uplink channel utilization for data transmission in one class of traffic. We also propose a quality of service support model so high priority users get better performance compared to low priority class traffic. Furthermore, we propose cross-layer design for data transmission to guarantee safe data delivery to the receiver for the QoS model. Finally, we propose a model for uplink channel utilization in the QoS model. This model can be applied to different WLANs standards. This model also includes the channel error in both the request and data channels.

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40

"A study of application of IBM-compatible personal computer local area networks (PC LANs) among computer professionals in Hong Kong." Chinese University of Hong Kong, 1990. http://library.cuhk.edu.hk/record=b5886360.

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Cheung Wing Kin, Chong Kwok Kwong, Daniel.
Thesis (M.B.A.)--Chinese University of Hong Kong, 1990.
Bibliography: leaf 133.
ABSTRACT --- p.ii
TABLE OF CONTENTS --- p.iv
LIST OF FIGURES --- p.vii
LIST OF EXHIBITS --- p.viii
LIST OF TABLES --- p.ix
PREFACE --- p.xi
Chapter
Chapter I. --- INTRODUCTION --- p.1
The World Market of LAN --- p.3
Local Market of LAN in Hong Kong --- p.7
The Research --- p.8
The Significance of Study Findings --- p.9
Chapter II. --- METHODOLOGY --- p.10
Target Population --- p.10
Unit of Analysis --- p.11
Population Size --- p.12
Sample Size --- p.14
Data Collection --- p.15
Objective --- p.15
Selection of Data Collection Method --- p.15
Questionnaires --- p.16
Design --- p.16
Contents --- p.18
Despatch Methods --- p.18
Research Aids --- p.20
Summary --- p.20
Chapter III. --- SURVEY FINDINGS --- p.21
Despatch and Collection of Questionnaries --- p.21
Company Data --- p.26
Classification --- p.26
Size in Terms of Number of Staff --- p.27
Degree of Computerization --- p.27
Number of PC in Use --- p.30
PC LAN Installed --- p.32
Hardware Particulars --- p.35
Type of Computers in Use --- p.35
PC LAN Hardware in Use --- p.35
Length of Use of PC LAN --- p.37
Assessment of Hardware in Use --- p.38
Software Particulars --- p.39
PC LAN Software in Use --- p.39
Applications in Use --- p.39
Assessment of Software in Use --- p.40
Criteria in Choosing PC LANs --- p.41
Job Function --- p.43
Role in Purchasing --- p.43
Report --- p.44
Chapter IV. --- ANALYSIS AND INTERPRETATION OF FINDINGS --- p.45
Response Rates --- p.45
Company Data --- p.46
Classification --- p.46
Degree of Computerization --- p.48
Size in Terms of Number of Staff --- p.50
Number of PC in Use --- p.52
PC LANs Installed --- p.54
Hardware Particulars --- p.55
Type of Computers in Use --- p.55
PC LAN Hardware in Use --- p.55
Length of Use of PC LAN --- p.57
Assessment of Hardware in Use --- p.57
Software Particulars --- p.57
PC LAN Software in Use --- p.57
Applications in Use --- p.59
Assessment of Software in Use --- p.59
Observation Relating to the Objectives of the Survey --- p.60
Objective 1 : PC LAN Market Segment in Hong Kong --- p.60
Objective 2 : Identify Market Characteristics --- p.63
Objective 3 : Selection Criteria of LANs --- p.66
Objective 4 : Gap between what are offered and what are needed --- p.66
Objective 5 : Major Applications of PC LANs in Hong Kong --- p.71
Job Function --- p.73
Role in Purchasing --- p.73
Report --- p.74
Chapter V. --- CONCLUSION AND RECOMMENDATION --- p.75
Conclusion --- p.75
Extent of Usage of PC LANs in Hong Kong --- p.76
PC LAN Market Segment in Hong Kong --- p.76
PC LAN Market Characteristics in Hong Kong --- p.77
Selection Criteria of PC LANs in Hong Kong --- p.78
Gap Between what are offered and what are needed for PC LAN in Hong Kong --- p.78
Major Applications of PC LANs in Hong Kong --- p.79
Recommendation --- p.79
Firms Already Installed PC LANs --- p.79
Firms Not Yet Installed PC LANs --- p.81
Marketeers --- p.82
APPENDIX --- p.85
BIBLIOGRAPHY --- p.133

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Van, Niekerk Albertus. "Paying for high speed networking services." 1997. http://hdl.handle.net/10500/17734.

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The idea of a free network is a myth of the past. Networking costs are expected to remain a burden to future IT budgets, no doubt raising questions regarding the payment of such services. Users do not normally pay to use local area networks, as companies tend to own their LANs. However, when wide area or international networks are considered, the situation is different. It is argued that in these cases the invoicing and payment system should be integral to the network's communication protocol. This implies changes to the networking protocol (to handle invoicing) as well as a new look at customary ideas of representing currency (to handle payment). In this dissertation, an invoicing and payment scheme that uses electronic cash and is implemented as part of the basic ATM protocols is discussed. The main advantages of this scheme can be summarized as a low administrative overhead and user privacy.
Computer Science
M. Sc. (Computer Science)

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Han, Yue. "The study of students['] perceptions of on-campus Wireless Local Area Networks (WLANs) usage. A thesis submitted in partial fulfilment of the requirements of the degree of Master of Computing, Unitec New Zealand. A research study /." Diss., 2008. http://www.coda.ac.nz/cgi/viewcontent.cgi?article=1011&context=unitec_scit_di.

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Peng, Fang. "Perceptions of travellers regarding wireless local area networks at international airports. A thesis submitted in partial fulfilment of the requirements of the degree of Master of Computing, Unitec Institute of Technology [i.e. Unitec New Zealand]. A research study /." Diss., 2008. http://www.coda.ac.nz/cgi/viewcontent.cgi?article=1013&context=unitec_scit_di.

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Pradeepa, B. K. "Performance Modelling Of TCP-Controlled File Transfers In Wireless LANs, And Applications In AP-STA Association." Thesis, 2011. http://etd.iisc.ernet.in/handle/2005/2121.

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Our work focuses on performance modelling of TCP-controlled file transfers in infrastructure mode IEEE 802.11 wireless networks, and application of the models in developing association schemes. A comprehensive set of analytical models is used to study the behaviour of TCP-controlled long and short file transfers in IEEE 802.11 WLANs. The results can provide insight into the performance of TCP-controlled traffic in 802.11 WLANs in a variety of different network environments. First, we consider several WLAN stations associated at rates r1, r2, ...,rk with an Access Point. Each station (STA) is downloading a long file from a local server, located on the LAN to which the AP is attached, using TCP. We assume that a TCP ACK will be produced after the reception of d packets at an STA. We model these simultaneous TCP-controlled transfers using a semi-Markov process. Our analytical approach leads to a procedure to compute aggregate download as well as per-STA throughputs numerically, and the results match simulations very well. Performance analysis of TCP-controlled long file transfers in a WLAN in infrastructure mode is available in the literature with one of the main assumptions being equal window size for all TCP connections. We extend the analysis to TCP-controlled long file uploads and downloads with different TCP windows. Our approach is based on the semi- Markov process considered in above work, but with arbitrary window sizes. We present simulation results to show the accuracy of the analytical model. Then, we obtain an association policy for STAs in an IEEE 802.11 WLAN by taking into account explicitly an aspect of practical importance: TCP controlled short file downloads interspersed with read times (motivated by web browsing). Our approach is based on two steps. First, we consider the analytical model mentioned above to obtain the aggregate download throughput. Second, we present a 2-node closed queueing network model to approximate the expected average-sized file download time for a user who shares the AP with other users associated at a multiplicity of rates. These analytical results motivate the proposed association policy, called the Estimated Delay based Association (EDA) policy: Associate with the AP at which the expected file download time is the least. Simulations indicate that for a web-browsing type traffic scenario, EDA outperforms other policies that have been proposed earlier; the extent of improvement ranges from 12.8% to 46.4% for a 9-AP network. We extend the performance model by considering _le sizes drawn from heavy-tailed distributions. We represent heavy-tailed distributions using a 1 mixture of exponential distributions (following Cox's method). We provide a closed queueing network model to approximate the expected average-sized file download time for a user who shares the AP with other users associated at a multiplicity of rates. Further, we analyze TCP-controlled bulk file transfers in a single station WLAN with nonzero propagation delay between the file server and the WLAN. Our approach is to model the flow of packets as a closed queueing network (BCMP network) with 3 service centres, one each for the Access Point and the STA, and the third for the propagation delay. The service rates of the first two are obtained by analyzing the WLAN MAC. We extend this work to obtain throughputs in multirate scenarios. Simulations show that our approach is able to predict observed throughputs with a high degree of accuracy.

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Dissertations / Theses on the topic 'Networking - Local Area Networks (LANs)'

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