[PDF] Development Of Resource Allocation Strategies Based On Cognitive Radio eBook

Author : Ku, Meng-Lin
Publisher : IGI Global
Page : 354 pages
File Size : 45,56 MB
Release : 2012-08-31
Category : Technology & Engineering
ISBN : 1466620064

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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.

Author : Lutfa Akter
Publisher :
Page : pages
File Size : 38,74 MB
Release : 2010
Category :
ISBN :

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With the explosive growth of wireless systems and services, bandwidth has become a treasured commodity. Traditionally, licensed frequency bands were exclusively reserved for use by the primary license holders (primary users), whereas, unlicensed frequency bands allow spectrum sharing. Recent spectrum measurements indicate that many licensed bands remain relatively unused for most of the time. Therefore, allowing secondary users (users without a license to operate in the band) to operate with minimal or no interference to primary users is one way of sharing spectrum to increase efficiency. Recently, Federal Communications Commission (FCC) has opened up licensed bands for opportunistic use by secondary users. A cognitive radio (CR) is one enabling technology for systems supporting opportunistic use. A cognitive radio adapts to the environment it operates in by sensing the spectrum and quickly decides on appropriate frequency bands and transmission parameters to use in order to achieve certain performance goals. A cognitive radio network (CRN) refers to a network of cognitive radios/secondary users. In this dissertation, we consider a competitive CRN with multiple channels available for opportunistic use by multiple secondary users. We also assume that multiple secondary users may coexist in a channel and each secondary user (SU) can use multiple channels to satisfy their rate requirements. In this context, firstly, we introduce an integrated modeling and forecasting tool that provides an upper bound estimate of the number of secondary users that may be demanding access to each of the channels at the next instant. Assuming a continuous time Markov chain model for both primary and secondary users activities, we propose a Kalman filter based approach for estimating the number of primary and secondary users. These estimates are in turn used to predict the number of primary and secondary users in a future time instant. We extend the modeling and forecasting framework to the case when SU traffic is governed by Erlangian process. Secondly, assuming that scheduling is complete and SUs have identified the channels to use, we propose two quality of service (QoS) constrained resource allocation frameworks. Our measures for QoS include signal to interference plus noise ratio (SINR) /bit error rate (BER) and total rate requirement. In the first framework, we determine the minimum transmit power that SUs should employ in order to maintain a certain SINR and use that result to calculate the optimal rate allocation strategy across channels. The rate allocation problem is formulated as a maximum flow problem in graph theory. We also propose a simple heuristic to determine the rate allocation. In the second framework, both transmit power and rate per channel are simultaneously optimized with the help of a bi-objective optimization problem formulation. Unlike prior efforts, we transform the BER requirement constraint into a convex constraint in order to guarantee optimality of resulting solutions. Thirdly, we borrow ideas from social behavioral models such as Homo Egualis (HE), Homo Parochius (HP) and Homo Reciprocan (HR) models and apply it to the resource management solutions to maintain fairness among SUs in a competitive CRN setting. Finally, we develop distributed user-based approaches based on ``Dual Decomposition Theory" and ``Game Theory" to solve the proposed resource allocation frameworks. In summary, our body of work represents significant ground breaking advances in the analysis of competitive CRNs.

Author : Samuel Cheng
Publisher : IntechOpen
Page : 312 pages
File Size : 15,4 MB
Release : 2012-03-16
Category : Technology & Engineering
ISBN : 9789535102687

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The fast user growth in wireless communications has created significant demands for new wireless services in both the licensed and unlicensed frequency spectra. Since many spectra are not fully utilized most of the time, cognitive radio, as a form of spectrum reuse, can be an effective means to significantly boost communications resources. Since its introduction in late last century, cognitive radio has attracted wide attention from academics to industry. Despite the efforts from the research community, there are still many issues of applying it in practice. This books is an attempt to cover some of the open issues across the area and introduce some insight to many of the problems. It contains thirteen chapters written by experts across the globe covering topics including spectrum sensing fundamental, cooperative sensing, spectrum management, and interaction among users.

Author : Chen Chen
Publisher : Springer
Page : 132 pages
File Size : 20,59 MB
Release : 2019-06-29
Category : Technology & Engineering
ISBN : 3030193926

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This book introduces the sources and historic collection campaigns of resource allocation in wireless communication systems. The unique characteristics of MIMO-OFDMA systems are thoroughly studied and summarized. Remarks on resource allocation and spectrum sharing are also presented, which demonstrate the great value of resource allocation techniques, but also introduce distinct challenges of resource allocation in MIMO-OFDMA systems. Novel resource allocation techniques for OFDMA Systems are surveyed from various applications (e.g., for unicast, or multicast with Guaranteed BER and Rate, subcarrier and power allocation with various detectors, low-complexity energyefficient resource allocation, etc.) in this book. Due to the high mobility and low latency requirements of 5G wireless communications, this book discusses how to deal with the imperfect CSI. It also discusses how to deal with e.g., throughput maximization, outage probabilities maximization and guarantee, energy efficiency, physical-layer security issues with feedback channel capacity constraints, in order to characterize and understand the applications of practical scenes. This book will target professionals & researchers working in the fields of Wireless Communications and Networking, Resource Allocation and Transmissions. Advanced-level students in electrical engineering and computer science will also find this book useful as a secondary textbook.

Author : Hilary Mutsawashe Tsimba
Publisher :
Page : 222 pages
File Size : 46,24 MB
Release : 2017
Category : Cognitive radio networks
ISBN :

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With the increase in wireless technology devices and mobile users, wireless radio spectrum is coming under strain. Networks are becoming more and more congested and free usable spectrum is running out. This creates a resource allocation problem. The resource, wireless spectrum, needs to be allocated to users in a manner such that it is utilised efficiently and fairly. The objective of this research is to find a solution to the resource allocation problem in radio networks, i.e to increase the efficiency of spectrum utilisation by making maximum use of the spectrum that is currently available through taking advantage of co-existence and exploiting interference limits. The solution proposed entails adding more secondary users (SU) on a cognitive radio network (CRN) and having them transmit simultaneously with the primary user. A typical network layout was defined for the scenario. The interference temperature limit (ITL) was exploited to allow multiple SUs to share capacity. Weighting was applied to the SUs and was based on allowable transmission power under the ITL. Thus a more highly weighted SU will be allowed to transmit at more power. The weighting can be determined by some network-defined rule. Specific models that define the behaviour of the network were then developed using queuing theory, specifically weighted processor sharing techniques. Optimisation was finally applied to the models to maximize system performance. Convex optimization was deployed to minimize the length of the queue through the power allocation ratio. The system was simulated and results for the system performance obtained. Firstly, the performance of the proposed models under the processor-sharing techniques was determined and discussed, with explanations given. Then optimisation was applied to the processor-sharing results and the performance was measured. In addition, the system performance was compared to other existing solutions that were deemed closest to the proposed models.

Author : Qilian Liang
Publisher : Springer
Page : 1125 pages
File Size : 32,33 MB
Release : 2019-05-04
Category : Technology & Engineering
ISBN : 9811362645

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This book brings together papers from the 2018 International Conference on Communications, Signal Processing, and Systems, which was held in Dalian, China on July 14–16, 2018. Presenting the latest developments and discussing the interactions and links between these multidisciplinary fields, the book spans topics ranging from communications, signal processing and systems. It is aimed at undergraduate and graduate electrical engineering, computer science and mathematics students, researchers and engineers from academia and industry as well as government employees.

Author : Shi Wang
Publisher :
Page : pages
File Size : 41,57 MB
Release : 2018
Category :
ISBN :

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Cognitive radio (CR) technology has been considered one of the most promising solutions to make the best potential use of the scarce spectrum resources in next generation wireless communication. Because of the stringent limitations on the utilization of the radio resources in a cognitive radio network (CRN), the available resources are usually scarce and dynamic. Developing appropriate mechanism to construct allocation protocols for CRN that can assign the resources in a fair and efficient manner to diverse users with different features is essential to achieve the promise of the CR technology in reality and worth studying. aÌ22́Ơ¿3The mechanism for resource allocation protocol design in CRNaÌ22́Ơ℗+ describes the topic of this research work and the contents of this thesis are organized around it. Before investigating how to design appropriate mechanism for CR resource allocation (RA) protocols, the model of the radio resource and the model of how a CR system utilizes the resource have to be clarified. In this thesis, by a comprehensive study of the relevant literatures, the modeling of critical components of a CR system and the theory behind it are identified and investigated. The existing protocols are also analyzed to address the limitations and gaps in the design of allocation protocols. An important feature, if not the most, that the allocation protocol for the CRN should possess is the ability to adjust the strategy of RA when the circumstances that affect the data transmission of the CR system varies, such as the activity of the license users or the variety of CR usersaÌ22́Ơ4́Ø demands. According to such considerations, the mechanism, namely distribution probability matrix (DPM), is designed to guide and describe the channel allocation protocol quantitatively. To testify how this mechanism works, the protocols based on the DPM, together with reference protocols in a multichannel CRN, are analyzed by a queuing model. The numerical results shows the flexibility and adaptability that the protocols based on the DPM can achieve. Another important function of the DPM mechanism is the potential to describe complex protocols with specific principles and to help design protocols aimed at specific objectives. To demonstrate this, a maximum throughput (MT) protocol that is aimed at maximizing the overall throughput of the CR system in a multi-user multi-channel scenario is structured using the DPM mechanism. The existing reference protocols, including maximum rate and random allocation, are described under the DPM mechanism as well as the MT protocol. All the protocols are implemented in a multiuser multichannel CRN and analyzed by a queueing analytical framework proposed by the author that is capable of acquiring the performance metrics of each CR user independently with efficiency. Numerical results show that the MT protocol is able to outperform the existing protocol in terms of the overall throughput of the CRN. The last problem identified and addressed in this thesis is to investigate the potential of specific performance metrics that a CR system can achieve under certain conditions with the help of the DPM mechanism. An optimization problem that is aimed at maximizing the overall weighted throughput of a multi-user multi-channel CRN under the delay constraint is formulated and solved using the DPM mechanism. The key factors that affect the optimal weighted throughput and the optimal allocations are investigated through the numerical results obtained by the proposed queueing analytical framework. The advantages of the DPM mechanism in optimizing the performance of CRN is also revealed by the formulation and solution of the optimization problem. The RA protocol is the essential kernel to address the RA problem in the CRN context. This thesis, by providing an objective and effective mechanism that works as a universal tool to describe and evaluate the RA protocols, succeeds in making effective contribution to addressing the RA problem in the CRN and further, helping the CR technology realize its meaningful promises.