Download or read book Cross layer Framework for Interference Avoidance in Cognitive Radio Ad hoc Networks written by Minh thao Quach and published by . This book was released on 2015 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: A fixed spectrum assignment scheme has a problem with resource deficiency in a wireless network. In 2002, the US Federal Communication Commission (FCC) reported that the radio spectrum was 20% to 85% under-utilized. The insufficient use of the spectrum is a critical issue for radio communication; as communication grows, a fixed spectrum becomes more limiting. The FCC then changed its spectrum management policy to make it more flexible by investigating the cognitive radio (CR) approach. Cognitive radio is a type of intelligent radio that explores the radio frequency environment, learns, and decides to use the unused portion of the frequency. The main functions of a CR are sensing, decision making, and sharing. However, these radios have to respect the standard wireless infrastructures by ensuring the least impact with their devices, also known as primary radios. Coexistence between CR systems and primary systems requires dedicated observation processes and interference management. In this thesis, observation from a CR point of view is presented. The overlapping area between a CR transmitter and primary radio (PR) transmitter is analysed so that it can be taken into account. The impact of this area is learnt by simulation and presented in Chapter 4. As a consequence, potential interference is envisaged. Along with observation, we investigate a proper mechanism to better prevent perturbation on PR devices using the Grey model and Kalman filter as a prediction model for predicting the density of primary receivers. In addition, we provide a strategy to combine the obtained observations into a metric that can be used in routing design in the context of coexistence between Cognitive Radio Networks (CRNs) and primary networks. The proposed strategy, using fuzzy logic, is presented in Chapter 5. In this chapter, we investigate how the routing layer reacts and makes the right decisions to maximise the spectrum resources, while avoiding interference with the primary receivers. For instance, a CR node can operate in an overlap region if primary receivers are inactive within this area. Also, we propose a routing mechanism based on the DYMO routing protocol that takes into account the observed relative impact. In the same chapter, we provide some practical scenarios illustrating the usefulness of our proposal. Interconnecting the CR nodes in CRNs is also a critical problem for the establishment of the network. We therefore present a beacon-based dissemination process in Chapter 6. In this chapter, we also describe a practical device designed for cognitive radio experiments. Even though our work affects different protocol layers, the designed framework is cross-layered. Indeed, the different components of the proposed framework access the various layers to retrieve information, process it, and react accordingly. Thus, our work constitutes a cross-layer framework for a local cognitive radio that aims to minimise the interference and maximise the network resources in cognitive radio networks.
Download or read book Cognitive Radio and Interference Management Technology and Strategy written by Ku, Meng-Lin and published by IGI Global. This book was released on 2012-08-31 with total page 354 pages. Available in PDF, EPUB and Kindle. Book excerpt: Broadcast spectrum is scarce, both in terms of our ability to access existing spectrum and as a result of access rules created by governments. An emerging paradigm called cognitive radio, however, has the potential to allow different systems to dynamically access and opportunistically exploit the same frequency band in an efficient way, thereby allowing broadcasters to use spectrum more efficiently. Cognitive Radio and Interference Management: Technology and Strategy brings together state-of-the-art research results on cognitive radio and interference management from both theoretical and practical perspectives. It serves as a bridge between people who are working to develop theoretical and practical research in cognitive radio and interference management, and therefore facilitate the future development of cognitive radio and its applications.
Download or read book Cognitive Networks written by Jaime Lloret Mauri and published by CRC Press. This book was released on 2014-12-09 with total page 518 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Practical Interference Avoidance Protocols for Cognitive Radio Networks written by Robert Murawski and published by . This book was released on 2011 with total page 153 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Cognitive radios are devices which have the ability to adjust their communication parameters based on observations of the surrounding environment. Cognitive Radio Networks (CRNs) are envisioned for use in licensed communication channels, operating on 'borrowed' spectrum in a non-interference manner. This technology has the potential to revolutionize wireless communication and alleviate the overuse of certain unlicensed communication bands. Research in this area is relatively new, and significant effort must be placed into researching how cognitive radio devices can operate with a reasonably low effect on the licensed spectrum users. In this dissertation, three areas are researched, focusing on practical mechanisms which can provide service to CRNs while minimizing the impact on licensed users. First, a cross-layer routing selection algorithm is proposed which utilizes fuzzy-logic modeling to gracefully map network quality of service (QoS) requirements and CRN-aware requirements to a route cost function. The second method looks into utilizing cooperation between licensed users and cognitive radios to facilitate CRN communication while improving the throughput of licensed users. Finally, the use of directional transmissions is researched. Directional transmissions have the potential to significantly reduce the impact of cognitive radios on licensed users, however, directional transmissions introduce many complexities to the realm of wireless communication. Some of these complexities will be explored, along with practical and implementable solutions.
Download or read book Spectrum Coordination Protocols and Algorithms for Cognitive Radio Networks written by and published by . This book was released on 2008 with total page 107 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis focuses on the problem of efficiently sharing spectrum resources in wireless networks through the use of appropriate spectrum etiquette protocols and related coordination algorithms. The performance of the proposed class of spectrum etiquette protocols is evaluated in various wireless network scenarios and compared with simpler reactive interference avoidance schemes. After validating its utility for coordination between existing wireless standards (such as IEEE 802.11/WiFi, Bluetooth, and 802.16/WiMax), the spectrum etiquette protocol is extended to serve as the foundation for a more complete adaptive wireless network where radio nodes may cooperate by forming or joining autonomous ad hoc clusters with multi-hop routing. A cognitive radio protocol stack is proposed for this scenario and validated using a combination of ns-2 simulations and experiments on the ORBIT radio grid testbed. The spectrum etiquette protocol proposed here is based on the Common Spectrum Coordination Channel (CSCC) approach which allows explicit coordination for spectrum usage among heterogeneous wireless radio nodes by announcement of their operation parameters such as frequency, power, rate, interference, etiquette policies, etc. An experimental proof-of-concept protocol evaluation is conducted to examine interoperability between WiFi and Bluetooth networks, demonstrating significant performance gains with CSCC as compared to the case with no coordination. Simpler reactive interference avoidance schemes in which radio nodes adjust their transmit parameters such as frequency, power and transmission time based on local observations are also examined in more detail for comparison with CSCC. In particular, we present a detailed comparison between reactive algorithms and proactive CSCC-based etiquette for a co-existence scenario in which both 802.11b and 802.16a operate in the same shared spectrum. With a higher level of spectrum coordination complexity, we examine the ad hoc collaboration scenario in which radio nodes may cooperate with each other to form so-called adaptive wireless networks with multi-hop routing. The CSCC protocol provides a reasonable foundation for this scenario as well by serving as a bootstrapping and resource coordination protocol for radios involved in ad hoc collaboration. Using the CSCC as a base, we propose a complete cognitive radio protocol stack which includes bootstrapping, network/service discovery, cross-layer routing and name/address translation. Each protocol component is validated using a combination of ORBIT experiments and ns-2 simulations.
Download or read book Cognitive Radio Mobile Ad Hoc Networks written by F. Richard Yu and published by Springer Science & Business Media. This book was released on 2011-09-28 with total page 491 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cognitive radios (CR) technology is capable of sensing its surrounding environment and adapting its internal states by making corresponding changes in certain operating parameters. CR is envisaged to solve the problems of the limited available spectrum and the inefficiency in the spectrum usage. CR has been considered in mobile ad hoc networks (MANETs), which enable wireless devices to dynamically establish networks without necessarily using a fixed infrastructure. The changing spectrum environment and the importance of protecting the transmission of the licensed users of the spectrum mainly differentiate classical MANETs from CR-MANETs. The cognitive capability and re-configurability of CR-MANETs have opened up several areas of research which have been explored extensively and continue to attract research and development. The book will describe CR-MANETs concepts, intrinsic properties and research challenges of CR-MANETs. Distributed spectrum management functionalities, such as spectrum sensing and sharing, will be presented. The design, optimization and performance evaluation of security issues and upper layers in CR-MANETs, such as transport and application layers, will be investigated.
Download or read book Cross layer Design and Optimization of OFDMA based Cognitive Radio Networks written by Hadi Saki and published by . This book was released on 2014 with total page 312 pages. Available in PDF, EPUB and Kindle. Book excerpt: In order to protect the primary service operation from harmful intervention, stochastic transmit and interference power constrains are imposed on the cognitive users. The performance of the proposed stochas¬tic algorithms and their advantages over the conventional hard-decision-based approaches are assessed and demonstrated through simulation results. Finally a specific cross-layer design for multi scalable video application transmis¬sion in an interference-limited spectrum sharing system is proposed. The proposed design jointly considers the parameters from the PHY and the application layers in order to maximize the overall peak signal-to-noise ratio (PSNR). Results indicate that significant improvement in secondary receivers (SRxs) average video quality is achieved through our proposed algorithm over other state-of-the-art non-quality-aware (NQA) designs in the literature. The enhanced performance was obtained whilst guaranteeing SRx minimum quality and primary receiver (PRx) prescribed quality of service (QoS) constraints.
Download or read book Cross Layer Resource Allocation in Cognitive Radio Networks Models Algorithms and Applications written by Hang Qin and published by Scientific Research Publishing, Inc. USA. This book was released on 2017-04-30 with total page 194 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is about cognitive radio (CR), a revolution in radio technology and an enabling technology for dynamic spectrum access. Due to the unique characteristics of the wireless networks, it is essential to address the approach of multiple layers (e.g., physical, link, and network) to maximize the network performance. The formulation of this cross-layer problem is usually complicated and challenging, while wireless resource allocation is a vital way to handle the race condition of the limited wireless resources. However, given the intrinsic characteristics of cognitive radio networks (CRN), none of the existing analytical approach could be a direct fit. Therefore, innovative theoretical results, along with the corresponding mathematical techniques, are necessary. In this book, we aim to develop some novel algorithmic design and optimization techniques that provide optimal or near-optimal solutions. Although cross-layer design has been introduced to CRN for many years, there are rarely any books for researchers, engineers, and students, from the engineering perspective. From one hand, most of the existing books primarily focus on the mathematical and economic aspects, which are considerably different from the engineering. On the other hand, all of the books mainly aim to system optimization or control techniques, while the cross-layer algorithm design in the distributed environment is usually ignored. As the result, there is an urgent demand for a reference source, which can provide complete information on how to fully adopt cross-layer resource allocation to the CRN. In this regard, this book not only focuses on the description of the main aspects of cross-layer resource allocation over CRN, but also provides a review of the application solutions. In a nutshell, it provides a specific treatment of cross-layer design in CRN. The topics range from the basic concepts of cross-layer resource allocation, to the state-of-the-art analyses, modelings, and optimizations for CRN.
Download or read book A Cross Layer Approach to Multi Hop Networking with Cognitive Radios written by and published by . This book was released on 2008 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cognitive radio (CR) is an enabling technology for efficient use of available spectrum and promises unprecedented flexibility in multi-hop wireless networking. This paper explores networking related issues associated with CRs. Specifically, we consider how to maximize the rates of a set of user communication sessions in a multi-hop CR-based wireless network. Due to potential interference at the physical layer, we find that it is essential to follow a cross-layer approach, with joint optimization at physical (power control), link (frequency band scheduling) and network (flow routing) layers. We give a mathematical characterization of this cross-layer optimization problem. We develop a centralized solution procedure based on the branchand- bound framework. Using numerical results, we demonstrate the efficacy of the solution procedure and offer quantitative understanding on the joint optimization at different layers.
Download or read book Some Cross layer Design and Performance Issues in Cognitive Radio Networks written by S. M. Shahrear Tanzil and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Interference Avoidance in Cognitive Radio Networks written by Karama Hamdi and published by . This book was released on 2007 with total page 164 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Cross Layer Routing Protocol for Cognitive Radio Networks Using Channel Activity Tracking written by Sandeep Gogineni and published by . This book was released on 2012 with total page 37 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Cognitive Radio Networks written by Yan Zhang and published by CRC Press. This book was released on 2019-08-30 with total page 484 pages. Available in PDF, EPUB and Kindle. Book excerpt: While still in the early stages of research and development, cognitive radio is a highly promising communications paradigm with the ability to effectively address the spectrum insufficiency problem. Written by those pioneering the field, Cognitive Radio Networks: Architectures, Protocols, and Standards offers a complete view of cognitive radio--including introductory concepts, fundamental techniques, regulations, standards, system implementations, and recent developments. From the physical layer to protocol layer, world-class editors provide comprehensive technical and regulatory guidance across cognitive radio, dynamic spectrum access, and cognitive wireless networks. The book examines routing, Medium Access Control (MAC), cooperation schemes, resource management, mobility, and game theory approach. Organized into three sections for ease of reference: Introduces and addresses the issues in the physical layer, including sensing, capacity, and power control Examines issues in the protocol layers and supplies practical solutions Explores applications, including cognitive radio systems Complete with illustrative figures that allow for complete cross-referencing, this authoritative reference provides readers with the understanding of the fundamental concepts, principles, and framework of cognitive wireless systems needed to initiate the development of future-generation wireless systems and networks.
Download or read book Cross Layer Routing in Cognitive Radio Network Using Deep Reinforcement Learning written by Snehal Sudhir Chitnavis and published by . This book was released on 2018 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Development of 5G technology and Internet of Things (IoT) devices has resulted in higher bandwidth requirements leading to increased scarcity of wireless spectrum. Cognitive Radio Networks (CRNs) provide an efficient solution to this problem. In CRNs, multiple secondary users share the spectrum band that is allocated to a primary network. This spectrum sharing of the primary spectrum band is achieved in this work by using an underlay scheme. In this scheme, the Signal to Interference plus Noise Ratio (SINR) caused to the primary due to communication between secondary users is kept below a threshold level. In this work, the CRNs perform cross-layer optimization by learning the parameters from the physical and the network layer so as to improve the end-to-end quality of experience for video traffic. The developed system meets the design goal by using a Deep Q-Network (DQN) to choose the next hop for transmitting based on the delay seen at each router, while maintaining SINR below the threshold set by primary channel. A fully connected feed-forward Multilayer Perceptron (MLP) is used by secondary users to approximate the action value function. The action value comprises of SINR to the primary user (at the physical layer) and next hop to the routers for each packet (at the network layer). The reward to this neural network is Mean Opinion Score (MOS) for video traffic which depends on the packet loss rate and the bitrate used for transmission. As compared to the implementation of DQN learning at the physical layer only, this system provides 30\% increase in the video quality for routers with small queue lengths and also achieves a balanced load on a network with routers with unequal service rates."--Abstract.
Download or read book Cognitive Radio Ad Hoc Networks written by Peng Hu and published by . This book was released on 2013 with total page 280 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Design and Analysis of Common Control Channels in Cognitive Radio Ad Hoc Networks written by Brandon Fang-Hsuan Lo and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Common control channels in cognitive radio (CR) ad hoc networks are spectrum resources temporarily allocated and commonly available to CR users for control message exchange. With no presumably available network infrastructure, CR users rely on cooperation to perform spectrum management functions. One the one hand, CR users need to cooperate to establish common control channels, but on the other hand, they need to have common control channels to facilitate such cooperation. This control channel problem is further complicated by primary user (PU) activities, channel impairments, and intelligent attackers. Therefore, how to reliably and securely establish control links in CR ad hoc networks is a challenging problem. In this work, a framework for control channel design and analysis is proposed to address control channel reliability and security challenges for seamless communication and spectral efficiency in CR ad hoc networks. The framework tackles the problem from three perspectives: (i) responsiveness to PU activities: an efficient recovery control channel method is devised to efficiently establish control links and extend control channel coverage upon PU's return while mitigating the interference with PUs, (ii) robustness to channel impairments: a reinforcement learning-based cooperative sensing method is introduced to improve cooperative gain and mitigate cooperation overhead, and (iii) resilience to jamming attacks: a jamming-resilient control channel method is developed to combat jamming under the impacts of PU activities and spectrum sensing errors by leveraging intrusion defense strategies. This research is particularly attractive to emergency relief, public safety, military, and commercial applications where CR users are highly likely to operate in spectrum-scarce or hostile environment.
Download or read book Cross layer Design in Cognitive Radio Systems written by Krishna Nehra and published by . This book was released on 2011 with total page 286 pages. Available in PDF, EPUB and Kindle. Book excerpt: Increasing demand and sophistication of wireless applications require intelligent systems which, along with performing efficient and reliable adaptive operations, should be simple to implement. CR is one such intelligent system which has the capability of adapting to its surroundings. In this thesis, the role of different layers of network in carrying out the functionalities of CR systems is investigated and cross-layer design strategies involving the PHY, the DLL, and the TCP are proposed. Prior to that OFDM, the PHY transmission technique used in CR systems, is dealt with some detail. -- This thesis makes several contributions. Firstly, one of the challenges associated with OFDM systems, CFO, is considered in relation to the link adaptation. In particular, the impact of CFO is analysed on the performance of continuous adaptive MQAM/OFDM systems with both the assumptions of availability of perfect and imperfect channel state information at the transmitter. Towards this, an upper bound for the maximum spectral efficiency of the considered system is derived in closed form. -- Secondly, an exhaustive study of main cognitive radio functionalities is presented from the perspective of different layers involved in performing these functions. Based on this study an identification of the parameters from different layers (which affect the CR functionalities) as well as of the CR functions' outputs required back by the protocol layers is provided, which clearly shows the need of cross-layer design in CR systems. Some new as well already proposed cross-layer design research ideas are then presented to optimize the performance of CR systems. -- A specific cross-layer design proposed for interference-limited spectrum sharing systems is then dealt with more detail. The proposed design jointly considers the parameters from the PHY and the DLL in order to maximize the overall spectral efficiency of the SU.
