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Hybrid token-CDMA MAC protocol for wireless networks.Liu, Yi-Sheng. January 2009 (has links)
Ad hoc networks are commonly known to implement IEEE 802.11 standard as their medium
access control (MAC) protocol. It is well known that token passing MAC schemes
outperform carrier-sense-multiple-access (CSMA) schemes, therefore, token passing MAC
protocols have gained popularity in recent years. In recent years, the research extends the
concept of token passing ' scheme to wireless settings since they have the potential of
achieving higher channel utilization than CSMA type schemes.
In this thesis, a hybrid Token-CDMA MAC protocol that is based on a token passing scheme
with the incorporation of code division multiple access (CDMA) is introduced. Using a
dynamic code distribution algorithm and a modified leaky-bucket policing system, the
hybrid protocol is able to provide both Quality of Service (QoS) and high network resource
utilization, while ensuring the stability of a network. This thesis begins with the introduction
of a new MAC protocol based on a token-passing strategy. The input traffic model used in
the simulation is a two-state Markov Modulated Poisson Process (MMPP). The data rate
QoS is enforced by implementing a modified leaky bucket mechanism in the proposed MAC
scheme. The simulation also takes into account channel link errors caused by the wireless
link by implementing a multi-layered Gilbert-Elliot model. The performance of the proposed
MAC scheme is examined by simulation, and compared to the performance of other MAC
protocols published in the literature. Simulation results demonstrate that the proposed hybrid
MAC scheme is effective in decreasing packet delay and significantly shortens the length of
the queue.
The thesis continues with the discussion of the analytical model for the hybrid Token CDMA
protocol. The proposed MAC scheme is analytically modelled as a multiserver
multiqueue (MSMQ) system with a gated service discipline. The analytical model is
categorized into three sections viz. the vacation model, the input model and the buffer model.
The throughput and delay performance are then computed and shown to closely match the
simulation results. Lastly, cross-layer optimization between the physical (PHY) and MAC
layers for the hybrid token-CDMA scheme is discussed. The proposed joint PHY -MAC
approach is based on the interaction between the two layers in order to enable the stations to
dynamically adjust the transmission parameters resulting in reduced mutual interference and
optimum system performance. / Thesis (Ph.D.)-University of KwaZulu-Natal, Durban, 2009.
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Energy efficient medium access protocol for DS-CDMA based wireless sesor networks.Thippeswamy, Muddenahalli Nagendrappa. January 2012 (has links)
Wireless Sensor Networks (WSN), a new class of devices, has the potential to revolutionize
the capturing, processing, and communication of critical data at low cost. Sensor networks
consist of small, low-power, and low-cost devices with limited computational and wireless
communication capabilities. These sensor nodes can only transmit a finite number of
messages before they run out of energy. Thus, reducing the energy consumption per node for
end-to-end data transmission is an important design consideration for WSNs.
The Medium Access Control (MAC) protocols aim at providing collision-free access to the
wireless medium. MAC protocols also provide the most direct control over the utilization of
the transceiver, which consumes most of the energy of the sensor nodes.
The major part of this thesis is based on a proposed MAC protocol called Distributed
Receiver-oriented MAC (DRMACSN) protocol for code division multiple access (CDMA)
based WSNs. The proposed MAC protocol employs the channel load blocking scheme to
reduce energy consumption in the network. The performance of the proposed MAC protocol is verified through simulations for average
packet throughput, average delay and energy consumption. The performance of the proposed
MAC protocol is also compared to the IEEE 802.15.4 MAC and the MAC without the channel load sensing scheme via simulations.
An analytical model is derived to analyse the average packet throughput and average energy consumption performance for the DRMACSN MAC protocol. The packet success probability, the message success and blocking probabilities are derived for the DRMACSN
MAC protocol. The discrete-time multiple vacation queuing models are used to model the delay behaviour of
the DRMACSN MAC protocol. The Probability Generating Functions (PGF) of the arrivals
of new messages in sleep, back-off and transmit states are derived. The PGF of arrivals of
retransmitted packets of a new message are also derived. The queue length and delay expressions for both the Bernoulli and Poisson message arrival models are derived. Comparison between the analytical and simulation results shows that the analytical model is accurate. The proposed MAC protocol is aimed at having an improved average packet throughput, a reduced packet delay, reduced energy consumption performance for WSN. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2012.
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Secure Key Establishment for Mobile NetworksTin, Yiu Shing (Terry) January 2005 (has links)
Informal analysis of authenticated key establishment (ake) protocols was commonly accepted as the valid argument for their security in the past. Although it can provide some confidence in protocol correctness, experience has shown time and again that ake protocols are likely to contain flaws even after an informal analysis is completed. Therefore, it has become increasingly common to expect a formal analysis, and preferably a mathematical proof, of any published ake protocol in order to obtain increased confidence in its security. In this research we use an appropriate model for analysing ake protocols based on its features and properties. The model allows us to design ake protocols modularly and reuse existing protocol components. We provide a detailed description of its formalisation, operations and usage. This description also includes ways of extracting new protocol components from existing ake protocols. Following the description of the model, we propose a new unauthenticated key establishment protocol for two-party communications. By composing this protocol with authentication protocols, we can construct several new secure ake protocols. These new protocols are compared with existing protocols for their computational efficiency. The comparison shows that our new proven secure protocols are as efficient as the existing protocols with an informal security analysis. We then propose a three-party key establishment protocol which involves a trusted server and two users. We also propose a non-interactive authentication protocol and discuss it and a variant of it. These components are used to construct a secure three-party ake protocol that supports a privacy framework. This framework allows users to remain anonymous while conducting electronic transactions with an independent service provider. A new password-based authentication protocol is proposed to address the problem of authentication using passwords. This protocol carries a proof of security and satisfies a slightly relaxed definition of security. We demonstrate its application by composing it with existing key establishment protocols. To maximise its use, we modified a two-party key establishment protocol to become three-party server based. By using the server for authentication, two users within a common network domain can establish a secure session key. Only a small number of ake protocols are demonstrated in this thesis. There exist many more provably secure ake protocols that can be constructed using the protocol components presented by applying the approach of "mix and match". That is, each new component results in a number of new ake protocols depending on the number of existing components.
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High quality video streaming with SCTP over CDMA2000 : a thesis submitted in partial fulfilment of the requirements for the degree of Master of Science in the University of Canterbury /Begg, C. Lee January 2007 (has links)
Thesis (M. Sc.)--University of Canterbury, 2007. / Typescript (photocopy). Includes bibliographical references (p. 105-108). Also available via the World Wide Web.
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Global hot swapping in the SNMP system /Liu, Changsong, January 1900 (has links)
Thesis (M. Sc.)--Carleton University, 2002. / Includes bibliographical references (p. 117-122). Also available in electronic format on the Internet.
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Design and implementation of lightweight SNMP for micro-satellites using generative programming /Qi, Huan, January 1900 (has links)
Thesis (M. Sc.)--Carleton University, 2003. / Includes bibliographical references (p. 115-117). Also available in electronic format on the Internet.
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Vertical handoff in heterogeneous wireless networks with mSCTPTsang, Cheuk-kan, Ken. January 2008 (has links)
Thesis (Ph. D.)--University of Hong Kong, 2008. / Includes bibliographical references (p. 243-251) Also available in print.
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Mobile commerce over GSM a banking perspective on security /Van der Merwe, Pieter Ben. January 2003 (has links)
Thesis (M. Sc.)(Electronic Engineering)--University of Pretoria, 2004. / Summaries in English and Afrikaans. Includes bibliographical references (125-128).
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The use of ISDN signaling for real-time applications at homes and small businessesPrakash, Nisheeth. January 1900 (has links) (PDF)
Thesis (M.Sc.)--Acadia University, 1998. / Includes bibliographical references. (leaves 98-99). Also available on the Internet via the World Wide Web.
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Congestion control for streaming mediaChung, Jae Won. January 2005 (has links)
Dissertation (Ph.D.) -- Worcester Polytechnic Institute. / Keywords: streaming media; streaming transport protocol; active queue management (AQM); Internet congestion control. Includes bibliographical references (p. 236-248).
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