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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

Comparison of Wireless Ad-Hoc Sensor Networks

Spinden, David, Jasper, Jeffrey, Kosbar, Kurt 10 1900 (has links)
International Telemetering Conference Proceedings / October 18-21, 2004 / Town & Country Resort, San Diego, California / There are a number of telemetry applications where it would be helpful to have networks of sensors that could autonomously discover their connectivity, and dynamically reconfigure themselves during use. A number of research groups have developed wireless ad-hoc sensor network systems. This paper reviews the state-of-the-art in wireless ad-hoc networks, examining the features, assumptions, limitations and unique attributes of some of the more popular solutions to this problem.
52

DESIGN AND DEVELOPMENT OF ADVANCED TRANSCEIVER UNIT FOR WIRELESS MOBILE SENSING SYSTEMS

Doonan, Daniel, Iltis, Ronald, Lee, Hua, Kastner, Ryan 10 1900 (has links)
International Telemetering Conference Proceedings / October 20-23, 2003 / Riviera Hotel and Convention Center, Las Vegas, Nevada / Sensor technology is continually advancing to meet demands of a wide range of potential applications. Many of these applications could be better served by distributed sensing than by traditional centralized sensing. To support these emerging applications, it is important to design and develop a unified framework for communication and network infrastructure capable of supporting various sensing functions. A research prototype operating in the 915 MHz Industrial, Scientific, and Medical band (ISM band) has been developed as potentially the core component of this infrastructure. In this paper, we will present the design and optimization of the system, data processing procedures, system parameters, network protocols, and experimental results.
53

Distributed scheduling in multihop ad hoc networks

Sun, Yijiang, 孫一江 January 2008 (has links)
published_or_final_version / abstract / Electrical and Electronic Engineering / Master / Master of Philosophy
54

Capacity and coverage of mmWave ad hoc networks

Thornburg, Andrew Scott 07 October 2014 (has links)
Ad hoc networks provide a flexible, infrastructure-free means to communicate between soldiers in war zones, aid workers in disaster areas, or consumers in device-to-device (D2D) applications. Ad hoc networks, however, are stilled plagued by interference. Communication with millimeter-wave (mmWave) devices offers hope to ad hoc networks through higher bandwidth, reduced interference due to directional antennas, and a lighter interference field due to blockage. This report uses a stochastic geometry approach to characterize the one-way and two-way coverage probability of a mmWave ad hoc network with directional antennas and random blockages. The coverage probability in the presence of noise and both line-of-sight and non-line-of-sight interference is analyzed and used to derive the transmission capacity. Several reasonable simplifications are used to derive the transmission capacity. Performance of mmWave is then analyzed in terms of area spectral efficiency and rate coverage. The results show that mmWave networks support larger densities, higher area spectral efficiencies, and better rate coverage compared to microwave ad hoc networks. / text
55

Cognitive Radio Ad Hoc Networks: A Local Control Approach

Hu, Peng 06 February 2013 (has links)
Cognitive radio is an important technology which aims to improve the spectrum resource utilization and allows a cognitive radio transceiver to detect and sense spectrum holes without causing interference to the primary users (PUs). As a result of the development of cognitive radio technology, the concept of cognitive radio ad hoc networks (CRAHNs) has recently been proposed in the literature, which aims to apply the cognitive radio to traditional ad hoc networks. However, this new network paradigm creates more research challenges than those in classical cognitive radio networks (CRNs). These research challenges in CRAHNs are due to the variable radio environments caused by spectrum-dependent communication links, hop-by-hop transmission, and changing topology. This study will focus on important research topics in spectrum management in scalable CRAHNs driven by local control, such as spectrum sharing, allocation, and mobility. To conduct this study, a local control approach is proposed to enable system-level analysis and protocol-level design with distributed protocols for spectrum sharing. In the local control approach, we can evaluate the system dynamics caused by either protocol-specific parameters or application-specific parameters in CRAHNs, which is hard to explore using existing methods. Moreover, combining the previous evaluations and scaling law analysis based on local control concept, we can design new distributed protocols based on the features of the medium access control (MAC) layer and the physical layer. In this study, the proposed research themes and related research issues surrounding spectrum sharing are discussed. Moreover, justification of the research has been made by experimental and analytical results. / Thesis (Ph.D, Electrical & Computer Engineering) -- Queen's University, 2013-02-04 14:37:45.883
56

Multi-Access Edge Computing Assisted Mobile Ad-hoc Cloud

Bhuchhada, Jay Kumar 05 September 2019 (has links)
Mobile Ad-hoc Cloud offers users the capability to offload intensive tasks on a cloud composed of voluntary mobile devices. Due to the availability of these devices in the proximity, intensive tasks can be processed locally. In addition, the literature referred to in the text, distinguishes a specific class of application to be well addressed when processed at the user level. However, due to lack of commitment, mobility, and unpredictability of the mobile devices, providing a rich ad-hoc cloud service is challenging. Furthermore, the resource availability of these devices impacts the service offered to the requester. As a result, this thesis aims to address the challenges mentioned above. With the support of Multi-Access Edge Computing, a mobile ad-hoc Infrastructure as a Service composition framework is proposed. An ad-hoc application server is designed to operate over the MEC platform to compose and manage the mobile ad-hoc cloud. The server uses the information provided by the MEC services to compose volunteer resources for a given request. As well, a heuristic approach for a multi-dimensional bin packing technique is considered, while extending the Euclidean distance for sub-tasks selection. In addition, to address the lack of resource availability, an architecture for MAC using SDN is proposed. The logically centralized controller works with the application server to migrate requests seamlessly from one region to another. Inspired by the benefits of the MEC, a mobility mechanism is introduced to address the movement of the participants. Finally, based on the evaluation, it was observed that the proposed MAC framework not only provided better use of resources but also provided a consisted and scalable service.
57

Effective beam width of directional antennas in wireless ad hoc networks.

January 2006 (has links)
Zhang Jialiang. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (leaves 51-52). / Abstracts in English and Chinese. / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Motivation and Related Work --- p.1 / Chapter 1.2 --- Organization of the Thesis --- p.3 / Chapter Chapter 2 --- Interference Modeling for Directional Antennas --- p.5 / Chapter 2.1 --- Pair-wise Physical Link Interference Model of Generic Directional Antenna --- p.6 / Chapter 2.2 --- Potential Interference Region --- p.8 / Chapter 2.3 --- Antenna Pattern and Phased Array Antenna --- p.9 / Chapter Chapter 3 --- Null Width of Directional Antennas --- p.12 / Chapter 3.1 --- Concept of Null Width --- p.12 / Chapter 3.2 --- Effective Null Width and Interference --- p.14 / Chapter 3.2.1 --- Probability of Interference --- p.14 / Chapter 3.2.2 --- Scenario of Directional Transmission and Omni-directional Reception --- p.15 / Chapter 3.2.3 --- Scenario of Directional Transmission and Directional Reception --- p.17 / Chapter 3.3 --- Properties of General Effective Beam Width --- p.18 / Chapter 3.4 --- Numerical Scaling Law of Effective Beam Width of Some Particular Antenna Patterns --- p.23 / Chapter 3.5 --- Summary --- p.26 / Chapter Chapter 4 --- Scaling Law of Network Capacity of Wireless Random Networks with Directional Antennas --- p.27 / Chapter 4.1 --- Random Network Model and Network Capacity --- p.27 / Chapter 4.2 --- Node distribution and MAC Protocol --- p.29 / Chapter 4.3 --- Scenario of Directional Transmission and Omni-directional Reception --- p.30 / Chapter 4.3.1 --- Probability of Transmission to be Success and Per-Link (Transport) Throughput --- p.30 / Chapter 4.3.2 --- Scaling Law of Network Capacity --- p.32 / Chapter 4.3.3 --- Concluding Remark --- p.37 / Chapter 4.4 --- Scenario of Directional Transmission and Directional Reception --- p.38 / Chapter 4.4.1 --- Antenna Steering Protocol --- p.39 / Chapter 4.4.2 --- Probability of Transmission to be Success --- p.40 / Chapter 4.4.3 --- Scaling Law of Network Capacity --- p.41 / Chapter 4.4.4 --- Scaling Law of Phased Array Antennas --- p.42 / Chapter Chapter 5 --- Conclusion --- p.44 / Appendix A: Proof of equation (22) --- p.47 / Appendix B: Proof of equation (28) --- p.49 / Appendix C: Constraint on Region of Optimality for pt and r --- p.50 / References --- p.51
58

Power saving mechanisms in wireless ad hoc networks.

January 2006 (has links)
Lau Ka Ming. / Thesis submitted in: August 2005. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (leaves 69-72). / Abstracts in English and Chinese. / Abstract --- p.i / Acknowledgements --- p.iii / Table of Contents --- p.iv / List of Figures --- p.vi / List of Tables --- p.viii / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Introduction --- p.1 / Chapter 1.2 --- Wireless Ad Hoc Networks --- p.2 / Chapter 1.2.1 --- Wireless Sensor Network --- p.3 / Chapter 1.2.2 --- IEEE802.11 Ad Hoc Network --- p.3 / Chapter 1.2.3 --- Bluetooth Personal Area Network --- p.4 / Chapter 1.3 --- Power Saving in Wireless Ad Hoc Networks --- p.4 / Chapter 1.4 --- Contributions of the Thesis --- p.8 / Chapter 1.5 --- Outline of the Thesis --- p.9 / Chapter 2 --- Power Saving Mechanisms in Wireless Ad hoc Networks --- p.10 / Chapter 2.1 --- Recent Research Proposals --- p.10 / Chapter 2.1.1 --- Synchronous Power Saving Schemes --- p.11 / Chapter 2.1.2 --- Asynchronous Power Saving Schemes --- p.12 / Chapter 2.2 --- Existing Standards --- p.17 / Chapter 2.2.1 --- IEEE802.1l Ad Hoc Power Saving Mode --- p.17 / Chapter 2.2.2 --- Bluetooth Low Power Modes --- p.20 / Chapter 3 --- Analytical Framework for Designing Synchronous Wakeup Patterns --- p.22 / Chapter 3.1 --- System Model --- p.23 / Chapter 3.1.1 --- Vacation Model --- p.23 / Chapter 3.1.2 --- Optimal Wakeup Pattern --- p.25 / Chapter 3.2 --- Analytical analysis of different wakeup patterns --- p.27 / Chapter 3.2.1 --- Exhaustive Wakeup Pattern --- p.27 / Chapter 3.2.2 --- Gated Wakeup Pattern --- p.31 / Chapter 3.2.3 --- Gated Wakeup With Constant Cycle Time --- p.34 / Chapter 3.3 --- Discussion of results --- p.43 / Chapter 3.3.1 --- Performances impacts of various system parameters --- p.43 / Chapter 3.3.2 --- Performances comparison of different wakeup patterns --- p.47 / Chapter 3.4 --- Chapter Summary --- p.48 / Chapter 4 --- An improved IEEE802.1l Power Saving Mode --- p.49 / Chapter 4.1 --- Related Proposals --- p.50 / Chapter 4.2 --- Proposed Scheme --- p.52 / Chapter 4.2.1 --- Overview --- p.52 / Chapter 4.2.2 --- Beacon Sending Station --- p.53 / Chapter 4.2.3 --- Beacon Receiving Station --- p.55 / Chapter 4.2.4 --- Computing the Transmission Schedule --- p.55 / Chapter 4.2.5 --- Data Transmission Specifications --- p.56 / Chapter 4.2.6 --- Failure Conditions --- p.58 / Chapter 4.3 --- Performances Evaluation --- p.58 / Chapter 4.3.1 --- Simulation Model --- p.60 / Chapter 4.3.2 --- Simulation Results --- p.60 / Chapter 4.4 --- Chapter Summary --- p.64 / Chapter 5 --- Conclusion --- p.66
59

Design and Optimization of Wireless Networks for Large Populations / Planification et optimisation des réseaux sans fil pour des grandes populations

Silva Allende, Alonso Ariel 07 June 2010 (has links)
La croissance explosive des réseaux sans fil et l’augmentation du nombre de dispositifs sans fil ont soulevé de nombreuses difficultés techniques dans la planification et l’analyse de ces réseaux. Nous utilisons la modélisation continue, utile pour la phase initiale de déploiement et l’analyse à grande échelle des études régionales du réseau. Nous étudions le problème de routage dans les réseaux ad hoc, nous définissons deux principes d’optimisation du réseau: le problème de l’utilisateur et du système. Nous montrons que les conditions d’optimalité d’un problème d’optimisation construit d’une manière appropriée coïncide avec le principe de l’optimisation de l’utilisateur. Pour fonctions de coût différentes, nous résolvons le problème de routage pour les antennes directionnelles et omnidirectionnelles. Nous trouvons également une caractérisation des voies du coût minimum par l’utilisation extensive du Théorème de Green dans le cas d’antennes directionnelles. Dans de nombreux cas, la solution se caractérise par une équation aux dérivés partielles. Nous proposons l’analyse numérique par éléments finis qui donne les limites de la variation de la solution par rapport aux données. Lorsque nous permettons la mobilité des origines et destinations, on trouve la quantité optimale de relais actif. Dans les réseaux MIMO, nous montrons que, même lorsque la chaîne offre un nombre infini de degrés de liberté, la capacité est limitée par le rapport entre la taille du réseau d’antennes, la station de base, la position des mobiles et la longueur d’onde du signal. Nous constatons également l’association optimale mobile pour différentes politiques et distributions des utilisateurs. / The growing number of wireless devices and wireless systems present many challenges on the design and operation of these networks. We focus on massively dense ad hoc networks and cellular systems. We use the continuum modeling approach, useful for the initial phase of deployment and to analyze broad-scale regional studies of the network. We study the routing problem in massively dense ad hoc networks, and similar to the work of Nash, and Wardrop, we define two principles of network optimization: user- and system-optimization. We show that the optimality conditions of an appropriately constructed optimization problem coincides with the user-optimization principle. For different cost functions, we solve the routing problem for directional and omnidirectional antennas. We also find a characterization of the minimum cost paths by extensive use of Green’s theorem in directional antennas. In many cases, the solution is characterized by a partial differential equation. We propose its numerical analysis by finite elements method which gives bounds in the variation of the solution with respect to the data. When we allow mobility of the origin and destination nodes, we find the optimal quantity of active relay nodes. In Network MIMO systems and MIMO broadcast channels, we show that, even when the channel offers an infinite number of degrees of freedom, the capacity is limited by the ratio between the size of the antenna array at the base station and the mobile terminals position and the wavelength of the signal. We also find the optimal mobile association for the user- and system-optimization problem under different policies and distributions of the users.
60

Bluetooth information exchange network

Liu, Xiaoning January 2008 (has links)
Bluetooth is a low cost and low power wireless technology for connecting portable and / or fixed Bluetooth enabled devices to form short-range wireless ad hoc personal area networks (PANs). As the Bluetooth specification does not specify a protocol to form ad hoc Bluetooth networks, a method for forming an efficient Bluetooth network under a practical networking scenario is still an open research problem. This thesis introduces an approach to implement an indoor ad hoc Bluetooth wireless network, Bluetooth information exchange network (BIEN). This network formation is based on Bluetooth and Java technologies. A set of Bluetooth enabled devices configured with the BIEN software application are able to spontaneously establish a dynamic multi-hop wireless network using Bluetooth technology without the need of formal network infrastructure, centralized administration, fixed routers or access points. In this study, the performance evaluation focuses on the relation between network capacity and topology by testing end-to-end performance in terms of throughput and the latency of communication links with various parameters, including the hop number between nodes and the number of slaves in piconets. The evaluation results show that the throughput reduces with the increased length of a path, and with an increase in the number of slaves in a piconet in the network. The latency also increases with path length, and with the number of slaves in a piconet in the different experimental BIENs, whether if there is traffic or not in the networks. Experimental results have further confirmed the necessity to minimize the number of bridge nodes in the Bluetooth networks due to their traffic bottleneck effect. This work is an attempt at implementation of a distributed multi-hop scatter net with an integrated routing protocol in the practical environments, while most of the literature focuses on covering the modelling of it. It intends to demonstrate how Bluetooth technology with Java technology can be used to design, develop and deploy ad hoc wireless networks with the commercial Bluetooth devices, and examine how well Bluetooth technology supports ad hoc multi-hop wireless network technology.

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