On the Energy Efficiency of Dynamic Spectrum Access in the Ad-hoc Wireless LAN Scenario PDF Download

Author: Anm Badruddoza
Publisher:
ISBN:
Category : Electronic dissertations
Languages : en
Pages : 81

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Book Description
Wireless data communications, especially to and from portable mobile devices, is one of the fastest growing paradigms in the field of computer communications. This fast paced growth of wireless communication devices is making some communication frequency bands overcrowded. There exists legacy frequency spectrum that remains under utilized. As a result, there are great inefficiencies in how the overall available frequency spectrum is utilized, motivating the need for new technologies to solve this issue. Cognitive Radio (CR) is an emerging technology proposed over the past decade in order to deal with spectrum inefficiency and to help improving wireless communication performance. A CR has the capability to scan across the spectrum to find under utilized channels and use them for communications under some stipulated conditions. A key aspect of CRs is the "cognition" gained through a spectrum scanning process. The benefit of this cognition is apparent and well studied in terms of achieving better communication performance on selected spectrum and detecting the presence of primary users of licensed spectrum. The benefits in terms of reduced energy consumption in secondary users, however, due to easier channel access and less contention have not been quantified in prior work. Spectrum scanning to gain cognition is a power intensive process and the costs incurred in terms of energy lost need to be accounted for. Thus, it is not clear whether a cognitive radio based node would be more energy efficient than any conventional radio node, and if so, under what circumstances. As a result, the focus of this work is on the ad hoc Wireless LAN scenario that works in the highly congested ISM bands. In this dissertation three important contributions to research on ad-hoc WLAN cognitive radios are presented. First, a comprehensive survey on prior research in cognitive radio networks with a focus on the implications for energy consumption is presented. Second, the energy consumption of a radio that uses the CR technique is modeled and analyzed for a static scenario with fixed channel conditions and node populations. As part of this work four novel spectrum scanning algorithms are proposed and analytically evaluated for their energy consumption. Finally, the energy consumption of a radio that employs the CR technique through one of our four spectrum scanning schemes is studied through simulations for dynamic scenarios that include diverse channel conditions and varying node populations.

Author: Kamal Rahimi Malekshan
Publisher:
ISBN:
Category : Ad hoc networks (Computer networks)
Languages : en
Pages : 137

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Book Description
The increasingly growing number of mobile devices and volume of mobile data traffic necessitate establishing an effective self-organizing wireless ad hoc network to efficiently utilize radio spectrum and energy. The transmissions time and bandwidth should be dynamically coordinated based on instantaneous traffic load of the links in the network. Energy consumption in a mobile device can be reduced by putting the radio interface into a sleep mode. However, the mobile device cannot receive incoming data packets in the sleep mode. Thus, awake and sleep times of radio interfaces should be carefully planned to avoid missing incoming packets. In a wireless network, links that are far apart in distance can simultaneously transmit using the same bandwidth without interfering reception at destination nodes. Concurrent transmissions should be properly scheduled to maximize spatial spectrum utilization. Also, the transmission power level of each link should be optimized to enhance spectrum and energy efficiencies. First, we present a new energy-efficient medium access control (MAC) scheme for a fully connected wireless ad hoc network. Energy consumption is reduced by periodically putting radio interfaces in the sleep mode and by reducing transmission collisions. The network throughput and average packet transmission delay are also improved because of lower collision and contention overhead. The proposed MAC scheme can achieve energy saving for realtime traffic which requires a low packet transmission delay. An analytical model is established to evaluate the performance of the proposed MAC scheme. Analytical and simulation results demonstrate that the proposed scheme has a significantly lower energy consumption, achieves higher throughput, and has a lower packet transmission delay in comparison with existing power saving MAC protocols. Second, we present a novel distributed MAC scheme based on dynamic space-reservation to effectively coordinate transmissions in a wireless ad hoc network. A set of coordinator nodes distributed over the network area are employed to collect and exchange local network information and to periodically schedule links for transmission in a distributed manner. For each scheduled transmission, a proper space area around the receiver node is reserved to enhance spatial spectrum reuse. Also, the data transmission times are deterministic to minimize idle-listening radio interface energy consumption. Simulation results demonstrate that the proposed scheme achieves substantially higher throughput and has significantly lower energy consumption in comparison with existing schemes. We study joint scheduling and transmission power control in a wireless ad hoc network. We analyze the asymptotic joint optimal scheduling and transmission power control, and determine the maximum spectrum and energy efficiencies in a wireless network. Based on the asymptotic analysis, we propose a novel scheduling and transmission power control scheme to approach the maximum spectrum efficiency, subject to an energy consumption constraint. Simulation results show that the proposed distributed scheme achieves 40% higher throughput than existing schemes. Indeed, the scheduling efficiency of our proposed scheme is about 70% of the asymptotic optimal scheduling and transmission power control. Also, the energy consumption of the proposed scheme is about 20% of the energy consumed using existing MAC protocols. The proposed MAC, scheduling and transmission power control schemes provide effective spectrum sharing and energy management for future wireless hotspot and peer-to-peer communication networks. The presented asymptotic analysis determines the maximum spectrum and energy efficiencies in a wireless network and provides an effective means to efficiently utilize spectrum and energy resources based on network traffic load and energy consumption constrains.

Author: George F. Elmasry
Publisher: John Wiley & Sons
ISBN: 1119573777
Category : Technology & Engineering
Languages : en
Pages : 752

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Book Description
Optimize your dynamic spectrum access approach using the latest applications and techniques Dynamic Spectrum Access Decisions: Local, Distributed, Centralized and Hybrid Designs prepares engineers to build optimum communications systems by describing at the outset what type of spectrum sensing capabilities are needed. Meant for anyone who has a basic understanding of wireless communications and networks and an interest in the physical and MAC layers of communication systems, this book has a tremendous range of civilian and military applications. Dynamic Spectrum Access Decisions provides fulsome discussions of cognitive radios and networks, but also DSA technologies that operate outside the context of cognitive radios. DSA has applications in: Licensed spectrum bands Unlicensed spectrum bands Civilian communications Military communications Consisting of a set of techniques derived from network information theory and game theory, DSA improves the performance of communications networks. This book addresses advanced topics in this area and assumes basic knowledge of wireless communications.

Author: Ishfaq Ahmad
Publisher: CRC Press
ISBN: 1466501138
Category : Computers
Languages : en
Pages : 621

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Book Description
This book provides basic and fundamental knowledge of various aspects of energy-aware computing at the component, software, and system level. It provides a broad range of topics dealing with power-, energy-, and temperature-related research areas for individuals from industry and academia.

Author: Ishfaq Ahmad
Publisher: CRC Press
ISBN: 1482254441
Category : Computers
Languages : en
Pages : 1284

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Book Description
Implementing energy-efficient CPUs and peripherals as well as reducing resource consumption have become emerging trends in computing. As computers increase in speed and power, their energy issues become more and more prevalent. The need to develop and promote environmentally friendly computer technologies and systems has also come to the forefront

Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 300

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Book Description
Resource allocation strategies, including power control, rate adaptation, and dynamic spectrum access, have been the keys to improving the performance of dynamic (mobile) wireless networks. In this dissertation, we propose several resource optimization schemes for various wireless network architectures, with the goal of maximizing the system throughput and/or minimizing the total energy consumption. These schemes are integrated into the design of distributed medium-access control (MAC) protocols. We propose a game theoretic power control scheme for single-channel ad-hoc networks, and design an efficient MAC protocol, called GMAC, that implements such a scheme in a distributed fashion. GMAC allows for multiple potential transmitters to contend for the channel through an admission phase that these transmitters to determine their appropriate transmission powers. Successful contenders proceed concurrently following the admission phase. We then study the operation of spectrum-agile (cognitive) radios in multi-channel, multi-hop wireless network setting. Two principal cases are considered: exclusive-occupancy and interference-based channel models. For the case of exclusive-occupancy channel models, we design a MAC protocol that exploits the "dual receive" capabilities of the radios to maximize the network throughput. We then propose a cross-layer framework for joint adaptive load/medium access controls. Under this framework, the traffic loads of individual node are adapted based on local MAC parameters. For the case of interference-based channel models, when system throughput is the primary performance metric, we apply "price-based" iterative water-filling (PIWF) algorithms for resource allocation. When energy consumption is the primary metric, we propose a selfish update algorithm and an incentive-based update algorithm for minimizing the power consumption while satisfying the rate and power mask requirements. These algorithms are implemented by having nodes repeatedly negotiate their best power/spectrum to reach a good Nash Equilibrium. An efficient multi-channel MAC protocol is proposed to facilitate the radio negotiation and convergence phase. Simulation results indicate that our proposed protocols achieve significant throughput/energy improvements over existing protocols.

Author: Jaime Lloret Mauri
Publisher: CRC Press
ISBN: 1482236990
Category : Technology & Engineering
Languages : en
Pages : 518

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Book Description
A cognitive network makes use of the information gathered from the network in order to sense the environment, plan actions according to the input, and make appropriate decisions using a reasoning engine. The ability of cognitive networks to learn from the past and use that knowledge to improve future decisions makes them a key area of interest for anyone whose work involves wireless networks and communications. Cognitive Networks: Applications and Deployments examines recent developments in cognitive networks from the perspective of cutting-edge applications and deployments. Presenting the contributions of internationally renowned experts, it supplies complete and balanced treatment of the fundamentals of both cognitive radio communications and cognitive networks—together with implementation details. The book includes case studies and detailed descriptions of cognitive radio platforms and testbeds that demonstrate how to build real-world cognitive radio systems and network architectures. It begins with an introduction to efficient spectrum management and presents a survey on joint routing and dynamic spectrum access in cognitive radio networks. Next, it examines radio spectrum sensing and network coding and design. It explores intelligent routing in graded cognitive networks and presents an energy-efficient routing protocol for cognitive radio ad hoc networks. The book concludes by considering dynamic radio spectrum access and examining vehicular cognitive networks and applications. Presenting the latest standards and spectrum policy developments, the book’s strong practical orientation provides you with the understanding you will need to participate in the development of compliant cognitive systems.

Author: Habib F. Rashvand
Publisher: IET
ISBN: 1849196478
Category : Computers
Languages : en
Pages : 504

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Book Description
Dynamic Ad-Hoc Networks is a compilation of key research papers and contributions from experts and researchers in the field considers that under the Ad-Hoc-based distributed systems, we can envision a whole new emerging distributed style of features that have never been experienced before. Motivated by a new exciting application paradigm using both internet and wireless technologies, Ad-Hoc networking and its association with emerging technologies is discussed across a range of systems ranging from surveillance systems up to road traffic control systems. Improved features of Ad-Hoc networking are discussed in this book to lead the way for new approaches for higher reliability, security, energy efficiency and application-specific optimized performance. The book is organized into four interrelated parts: Concepts and Principles; Networking Techniques; Ad-Hoc Network Management; and Applications of Ad-Hoc Networking. Examples are supported by a variety of algorithms. Dynamic Ad-Hoc Networks features three areas of new advanced solutions; advancements in Mobile Ad Hoc Networks (MANET), Vehicular Adhoc Networking (VANET) and distributed sensor systems (DSS), specific networking topologies such as Mesh, WLAN, WiMAX and Vehicular-to-Vehicle Communication and ad-hoc specific networking solutions such as network control, routing, scheduling and application samples such as wireless sensor networks (WSN) and Telematic Computing.

Author: Shweta Pandit
Publisher: Springer
ISBN: 3319531476
Category : Technology & Engineering
Languages : en
Pages : 270

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Book Description
This book discusses the use of the spectrum sharing techniques in cognitive radio technology, in order to address the problem of spectrum scarcity for future wireless communications. The authors describe a cognitive radio medium access control (MAC) protocol, with which throughput maximization has been achieved. The discussion also includes use of this MAC protocol for imperfect sensing scenarios and its effect on the performance of cognitive radio systems. The authors also discuss how energy efficiency has been maximized in this system, by applying a simple algorithm for optimizing the transmit power of the cognitive user. The study about the channel fading in the cognitive user and licensed user and power adaption policy in this scenario under peak transmit power and interference power constraint is also present in this book.

Author: Tansu Alpcan
Publisher: Cambridge University Press
ISBN: 1107034124
Category : Computers
Languages : en
Pages : 604

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Book Description
An innovative and comprehensive book presenting state-of-the-art research into wireless spectrum allocation based on game theory and mechanism design.