Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 36 for “"Channel Access"”.
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Voice Interactive Classroom, a service-oriented software architecture to enable cross-platform multi-channel access to Internet-based learning
… systems has evolved from using the traditional access from a personal computer or laptop‟s web browser to more flexible access from mobile devices. However, in both cases, e-learning systems have created a context in which interaction with the user is carried out mainly by using visual …
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Enhanced Collision Resolution for the IEEE 802.11 Distributed Coordination Function
… Function (DCF) as the fundamental medium access control method. DCF uses the Binary Exponential Backoff (BEB) algorithm to regulate channel access. The backoff period determined by BEB depends on a contention window (CW) whose size is doubled if a station suffers a collision and reset to …
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Secure protocols for wireless availability
… medium, multiple transmissions on the same channel cause interference to each other and degrade the channel quality, much as multiple people talking at the same time make for inefficient meetings. To avoid transmission collision, the network divides the medium into multiple orthogonal …
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A hardware testbed for measuring IEEE 802.11g DCF performance
… most widely-used IEEE 802.11 contention-based channel access control protocol. DCF adds a significant amount of overhead in the form of preambles, frame headers, randomised binary exponential back-off and inter-frame spaces. Having accurate and verified performance models for DCF is thus …
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Efficient Packet Scheduling in Wireless Multihop Networks
… to support differentiated service, the medium access control protocol must provide certain mechanisms to incorporate differentiated priority scheduling, such that higher priority traffic can be transmitted in preference to lower priority traffic. The ""location dependent channel contention"" …
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Performance Evaluation of MU-MIMO WLANs Under the Impact of Traffic Dynamics
… under TCP flows. Moreover, the contention based channel access reduces the user set size for downlink transmission thereby affecting the multiplexing gain as well. Consequently, the downlink performance is extremely poor. Unfortunately we find that even under an ideal network and channel …
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Performance Analysis of Coexistence Schemes for LTE in Unlicensed Bands
… that could be employed to ensure a fair channel access. First, we consider coexistence mechanism fundamentals, and then downlink system performance of two coexistence mechanisms are analyzed for multi-operator LTE-Unlicensed (LTE-U) deployments with different simulation scenarios, using …
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A quality of service architecture for WLAN-wired networks to enhance multimedia support
… quality of service (QoS). Because WLAN users access multimedia services usually over a wired backbone, attention must be paid to QoS over the integrated WLAN-wired network. This research focuses on the provision of QoS to WLAN users accessing multimedia services over a wired backbone. In this …
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Personal communications services: improving theater deployable communications for the 21st century
… such as frequency reuse, cell splitting, channel access methods, and propagation factors are also addressed. Finally, a framework for comparison of the candidate MSS systems is proposed as a baseline for further studies into the most beneficial implementation of PCS into theater deployable …
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Distributed Algorithms for Resource Allocation in Multi-Hop Random Access Wireless Networks
We then present a distributed flow-based access scheme for slotted-time protocols that provides proportional fairness with respect to flow-throughput under constraints on the buffer overflow probabilities at each node. We model the end-to-end flows in an ad hoc wireless network using a tandem of …
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Design and Implementation of a MAC protocol for Wireless Distributed Computing
… it is imperative and necessary to have a medium access control (MAC) protocol for such networks which is capable of scheduling channel access by multiple radios in the network, ensuring reliable data transfer, incorporating rate adaptation as well as handling link failures. The thesis presented …
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Analysis and improvement of medium access control protocols in wireless networks. Performance modelling and Quality-of-Service enhancement of IEEE 802.11e MAC in wireless local area networks under heterogeneous multimedia traffic.
… technologies and protocols. The Medium Access Control (MAC) protocol, which coordinates the channel access and data transmission of wireless stations, plays a pivotal role in wireless networks. Performance modelling and analysis has been and continues to be of great theoretical and …
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Modelling, analysis and design of MAC and routing protocols for wireless body area sensor networks.
… modeling, analysis, and design for Medium Access Control (MAC) and link-quality based routing protocols of Wireless Body Area Sensor Networks (WBASNs) for remote patient monitoring applications by considering saturated and un-saturated traffic scenarios. The design of these protocols has …
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Scalable network localization
… an objective function. Node Activation controls channel access through the calculation of a optimal binary activation probability. Node Localization is developed in the context of a globally optimum Bayesian estimation problem and solved by means of the sigma point belief propagation (SPBP) …
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Learning-based Decision Making in Wireless Communications
… learning based framework for dynamic multichannel access. We consider both a single-user case and a scenario in which multiple users attempt to access channels simultaneously. In the single-user model, in order to evaluate the performance of the proposed channel access policy and the …
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Efficient channel allocation and medium access organization algorithms for vehicular networking
… Networks (VANETs), organizing the wireless channel access to efficiently use the bandwidth is one of the main challenges in VANET. In this dissertation, we focus on channel allocation and media access organization for Vehicle-to-Roadside Units (V2R) and Vehicle-to-Vehicle (V2V) …
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Efficient Communication Protocols for Underwater Acoustic Sensor Networks
… a model characterizing the underwater acoustic channel utilization efficiency is introduced. The model allows setting the optimal packet size for underwater communications. Two distributed routing algorithms are proposed for delay-insensitive and delay-sensitive applications. The proposed …
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