Download or read book Resource allocation for OFDMA Relay Systems written by Ryoulhee Kwak and published by . This book was released on 2009 with total page 244 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Resource Allocation in Uplink OFDMA Wireless Systems written by Elias Yaacoub and published by John Wiley & Sons. This book was released on 2012-02-10 with total page 298 pages. Available in PDF, EPUB and Kindle. Book excerpt: Tackling problems from the least complicated to the most, Resource Allocation in Uplink OFDMA Wireless Systems provides readers with a comprehensive look at resource allocation and scheduling techniques (for both single and multi-cell deployments) in uplink OFDMA wireless networks relying on convex optimization and game theory to thoroughly analyze performance. Inside, readers will find topics and discussions on: Formulating and solving the uplink ergodic sum-rate maximization problem Proposing suboptimal algorithms that achieve a close performance to the optimal case at a considerably reduced complexity and lead to fairness when the appropriate utility is used Investigating the performance and extensions of the proposed suboptimal algorithms in a distributed base station scenario Studying distributed resource allocation where users take part in the scheduling process, and considering scenarios with and without user collaboration Formulating the sum-rate maximization problem in a multi-cell scenario, and proposing efficient centralized and distributed algorithms for intercell interference mitigation Discussing the applicability of the proposed techniques to state-of-the-art wireless technologies, LTE and WiMAX, and proposing relevant extensions Along with schematics and figures featuring simulation results, Resource Allocation in Uplink OFDMA Wireless Systems is a valuable book for?wireless communications and cellular systems professionals and students.

Download or read book Distributed Resource Allocation in OFDMA based Relay Networks written by Ulrich Christian Müller and published by . This book was released on 2010 with total page 171 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Dynamic Resource Allocation for Relay based OFDMA Systems With Fairness Considerations written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Resource Allocation for OFDMA Systems written by Chen Chen and published by Springer. This book was released on 2019-06-29 with total page 132 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Resource Allocation in OFDM Based Wireless Relay Networks written by Guftaar Ahmad Sardar Sidhu and published by . This book was released on 2012 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt: The combination of relay transmission with orthogonal frequency division multiplexing (OFDM) technique is deemed as the candidate for the fourth generation (4G) wireless networks. This thesis addresses the resource allocation problem in OFDM based relay networks. Different scenarios of relay networks are considered, e.g., the multi-user relay networks, the multi-relay networks, and the cognitive radio (CR) relay networks. The resource management strategies are developed to analyse: how to optimally distribute available resources among different users, how resource optimization enhances the performance under cooperative communication, how to maximize the lifetime of multi-hop wireless sensor networks (WSNs), and how to improve CR transmission without degrading the performance of the primary network? For each relay transmission scenario, two or more resources are optimized to enhance the system performance under various constraints. The resources include: the power allocation at the source terminal, the power allocation at the relay nodes, the sub-carrier allocation among different users, and the sub-carrier matching over different hops. Multi-user transmission adopts orthogonal frequency division multiple access (OFDMA) technique and is subject to separate power constraint at each terminal. Initially, the resource management issue in multi-user uplink relay transmission is discussed. Then, the similar resource allocation problem is solved when OFDMA multi-user system operates under the bidirectional relay transmission. The multi-relay dual hop transmission is optimized under different transmission schemes, specifically, the non-orthogonal transmission where all the terminals transmit simultaneously in the second time slot and the time division multiple access (TDMA) based transmission where each relay transmits in the pre-defined time slot. The resource allocation in CR relay networks is considered which ensures that the interference caused by the secondary network is not harmful to the primary system. Convex optimization techniques are exploited to solve the problems for each relay transmission and the near optimal solutions are developed. Further, several suboptimal algorithms are also designed to reduce the computational complexity.

Download or read book Uplink OFDMA Resource Allocation Using Mobile Relays and Proportional Fairness written by Salma Hamda Harchay and published by . This book was released on 2016 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: In wireless systems, resource allocation is still an important challenge to satisfy user requirements and to ensure good system performances with always greedy data applications. Multicarrier techniques especially the Orthogonal Frequency Division Multiplexing (OFDM) techniques are generally used to carry data into orthogonal subcarriers. Furthermore, relaying strategies are used to enhance cell edge performances. Many types of relays can be investigated as fix relays being part of the network infrastructure or mobile relays without additional deployment cost.In this thesis, we mainly consider the resource allocation for an uplink Orthogonal Frequency Division Multiple Access (OFDMA) system for a cellular system model ensuring Quality of Service (QoS) requirements and fairness between users. The most used resource allocation algorithms are presented and a novel Weighted Proportional Fair (WPF) algorithm is proposed to approach upper bounds of both throughput and fairness. The WPF algorithm considers user weights to allocate more subcarriers in the cell center than in the cell edge keeping sufficient fairness between users. We establish a theoretical analysis to compare the behavior of the proposed WPF algorithm to the classical Proportional Fair (PF) algorithm. Then, we extend this WPF algorithm to a multi-cell system model where the Inter-Cell Interference (ICI) limits the system performance. Moreover, we study ICI mitigation strategies and propose a novel method to reduce the ICI based on Base Station (BS) cooperation and interference indicators. We propose the Enhanced Interference Indicator (EII) with integer values to be exchanged by the BSs indicating interference levels for the subcarriers. Function of these communicated EII values, each BS allocates dynamically subcarriers in order to reduce the ICI. Our contributions in the multi-cell system model are the WPF and the EII.Moreover, we investigate in this dissertation the cooperative communication using mobile relays and propose multiple contributions. For this, simple mobile users with advantageous positions can relay cell edge users to carry data to the BS in addition to their own data. A Decode and Forward (DF) relay multiplex then its own data and relayed data before transmitting to the BS. The resource allocation is formulated as an optimization problem aiming to minimize the system transmit power and respecting a required target data rate per user constraint. In a first time, we propose an initialization method for the paring step to associate source-relay pairs and propose an iterative heuristic to optimize both power and Resource Blocks (RB) allocations. In a second time, we consider the relay selection as an optimization variable in addition of power and RB allocations. For resolution, Lagrangian decomposition and Dual method are used and the global problem is divided into subproblems iterativelly resolved to approach the optimal solution. Finally, we extend this cooperative system model to a Multiple Input Multiple Output (MIMO) system model to study the influence of multiple antennas on the system transmit power. The features to optimize are relay selection, power and RBs allocation. Moreover, to allocate power in the different antennas for each user, both Equal Power Allocation (EPA) and beamforming are studied. Theoretical expressions are established and simulations results are presented to compare EPA, beamforming and non-cooperative system.

Download or read book Resource Allocation for Multi cell Orthogonal Frequency Multiplexing Access Based Cooperative Relay Network written by Nidhal Odeh and published by . This book was released on 2014 with total page 244 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Ofdm Based Relay Systems for Future Wireless Communications written by Milica Pejanovic-Djurisic and published by CRC Press. This book was released on 2022-09-01 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt: Relay systems have become a subject of intensive research interest over the recent years, as it is recognized that they can improve performances and extend the coverage area of wireless communication systems. Special attention has been dedicated to them since the proposal appeared for their implementation in mobile cellular systems. Numerous researches conducted after that proposal have enabled incorporation of OFDM based relay systems in both accepted standards for IMT-Advanced systems. Nowadays, researches are ongoing with the aim to define new solutions for performance improvement of the standardized OFDM relay systems for cellular networks and one of the interesting solutions is implementation of subcarrier permutation (SCP) at the relay (R) station.The book OFDM based relay systems for future wireless communications presents a comprehensive research results in analyzing behavior and performance of the OFDM based relay systems with SCP. Dual-hop relay scenario with three communication terminals, and no direct link between the source (S) and the destination (D) has been analyzed, as it is compliant with the accepted solutions for IMT-Advanced systems. The book includes performance analysis and performance comparison of OFDM based:• amplify-and-forward (AF) relay systems with fixed gain (FG),• amplify-and-forward (AF) relay systems with variable gain (VG),• decode-and-forward (DF) relay systems,each including two SCP schemes, known to maximize the system capacity and/or improve the bit error rate (BER) performances. Performance comparisons have enabled definition of optimal solutions for the future wireless communication systems in a given conditions, and for the given optimality criteria. OFDM based relay systems for future wireless communications contains recent research results in this area and is ideal for the academic staff and master/research students in area of mobile communication systems, as well as for the personnel in communication industry.

Download or read book Joint Resource and Relay Allocation in Multi cell Downlink OFDMA Systems written by Shiyang Tu and published by . This book was released on 2009 with total page 45 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Radio Resource Allocation in Relay Based OFDMA Cellular Networks written by Lin Xiao and published by . This book was released on 2010 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Resource Allocation in OFDMA based Relaying Networks written by Yuwen Pan and published by . This book was released on 2010 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Adaptive Frame Structure and OFDMA Resource Allocation in Mobile Multi hop Relay Networks written by Bongkyoung Kwon Kwon and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of this thesis research is to optimize network throughput and fairness, and enhance bandwidth utilization in wireless mobile multi-hop relay (MMR) networks. To enhance bandwidth utilization, we propose an adaptive OFDMA frame structure which is used by the base station and the non-transparent relay stations. To optimize throughput and fairness, we develop an adaptive OFDMA allocation algorithm by using the proposed adaptive OFDMA frame. The effectiveness of the proposed schemes has been verified by numeric simulations. Providing ubiquitous coverage with wireless metropolitan area networks (WMANs) can be costly, especially in sparsely populated areas. In this scenario, cheaper relay stations (RSs) can be used to provide coverage instead of expensive base stations (BSs). The RS extends the coverage area of traditional BSs. This sort of network is known as a wireless MMR network. This thesis focuses on MMR networks that use orthogonal frequency division multiple access (OFDMA) and time division duplex (TDD) as a multiple access scheme and a duplex communication technique (e.g., WiMAX). The use of OFDMA resources (e.g., OFDMA symbols and subcarriers) and how they are shared in current schemes can reduce system capacity and network throughput in certain scenarios. To increase the capacity of the MMR network, we propose a new protocol that uses an adaptive OFDMA frame structure for BSs and RSs. We also propose adaptive OFDMA resource allocation for subscriber stations (SSs) within a BS or RS. We derive the maximum OFDMA resources that RSs can be assigned and synchronize access zones and relay zones between a superior station and its subordinate RSs. This is bounded by three properties defined in this thesis: a data relay property, a maximum balance property, and a relay zone limitation property. Finally, we propose max-min and proportional fairness schemes that use the proposed adaptive frame structure. The proposed scheme is the first approach that incorporates the adaptive technique for wireless MMR networks. We evaluate our scheme using simulations and numerical analysis. Results show that our technique improves resource allocation in wireless MMR networks. Further, in asymmetric distributions of SSs between access zones and relay zones, the proposed OFDMA allocation scheme performs two times better than the non-adaptive allocation scheme in terms of average max-min fairness and 70% better in terms of average throughput.

Download or read book Modeling and Performance Analysis of Relay based Cooperative Orthogonal Frequency Division Multiple Access Networks written by Md Shamsul Alam and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Next generation wireless communication networks are expected to provide ubiquitous high data rate coverage and support heterogeneous wireless services with diverse quality-of-service (QoS) requirements. This translates into a heavy demand for the spectral resources. In order to meet these requirements, Orthogonal Frequency Division Multiple Access (OFDMA) has been regarded as a promising air-interface for the emerging fourth generation (4G) networks due to its capability to combat the channel impairments and support high data rate. In addition, OFDMA offers flexibility in radio resource allocation and provides multiuser diversity by allowing subcarriers to be shared among multiple users. One of the main challenges for the 4G networks is to achieve high throughput throughout the entire cell. Cooperative relaying is a very promising solution to tackle this problem as it provides throughput gains as well as coverage extension. The combination of OFDMA and cooperative relaying assures high throughput requirements, particularly for users at the cell edge. However, to fully exploit the benefits of relaying, efficient relay selection as well as resource allocation are critical in such kind of network when multiple users and multiple relays are considered. Moreover, the consideration of heterogeneous QoS requirements further complicate the optimal allocation of resources in a relay enhanced OFDMA network. Furthermore, the computational complexity and signalling overhead are also needed to be considered in the design of practical resource allocation schemes. In this dissertation, we conduct a comprehensive research study on the topic of radio resource management for relay-based cooperative OFDMA networks supporting heterogeneous QoS requirements. Specifically, this dissertation investigates how to effectively and efficiently allocate resources to satisfy QoS requirements of 4G users, improve spectrum utilization and reduce computational complexity at the base station. The problems and our research achievements are briefly outlined as follows. Firstly, a QoS aware optimal joint relay selection, power allocation and subcarrier assignment scheme for uplink OFDMA system considering heterogeneous services under a total power constraint is proposed. The relay selection, power allocation and subcarrier assignment problem is formulated as a joint optimization problem with the objective of maximizing the system throughput, which is solved by means of a two level dual decomposition and subgradient method. The computational complexity is finally reduced via the introduction of two suboptimal schemes. The performance of the proposed schemes is demonstrated through computer simulations based on OFDMA network. Numerical results show that our schemes support heterogeneous services while guaranteeing each user's QoS requirements with slight total system throughput degradation. Secondly, we investigate the resource allocation problem subject to the satisfaction of user QoS requirements and individual total power constraints of the users and relays. The throughput of each end-to-end link is modeled considering both the direct and relay links. Due to non-convex nature of the original resource allocation problem, the optimal solution is obtained by solving a relaxed problem via two level dual decomposition. Numerical results reveal that the proposed scheme is effective in provisioning QoS of each user's over the conventional resource allocation counterpart under individual total power constraints of the users and relays . Lastly, decentralized resource allocation schemes are proposed to reduce the computational complexity and CSI feedback overhead at the BS. A user centric distributed (UCD) scheme and a relay centric distributed (RCD) scheme are proposed, where the computation of the centralized scheme is distributed among the users and relays, respectively. We also proposed suboptimal schemes based on simplified relay selection. The suboptimal schemes can be combined with the distributed schemes to further reduce of signalling overhead and computational complexity. Numerical results show that our schemes guarantee user's satisfaction with low computational complexity and signalling overhead, leading to preferred candidates for practical implementation. The research results obtained in this dissertation can improve the resource utilization and QoS assurance of the emerging OFDMA networks.

Download or read book Radio Resource Management in Wireless Networks written by Ekram Hossain and published by Cambridge University Press. This book was released on 2017-04-27 with total page 433 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book allows readers to gain an in-depth understanding of resource allocation problems in wireless networks and the techniques used to solve them.

Download or read book Resource Allocation for Wireless Early Networks written by and published by . This book was released on 2014 with total page 650 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this thesis, we propose several resource allocation strategies for relay networks in the context of joint power and bandwidth allocation and relay selection, and joint power allocation and subchannel assignment for orthogonal frequency division multiplexing (OFDM) and orthogonal frequency division multiple access (OFDMA) systems. Sharing the two best ordered relays with equal power between the two users over Rayleigh flat fading channels is proposed to establish full diversity order for both users. Closed form expressions for the outage probability, and bit error probability (BEP) performance measures for both amplify and forward (AF) and decode and forward (DF) cooperative communication schemes are developed for different scenarios. To utilize the full potentials of relay-assisted transmission in multi user systems, we propose a mixed strategy of AF relaying and direct transmission, where the user transmits part of the data using the relay, and the other part is transmitted using the direct link. The resource allocation problem is formulated to maximize the sum rate. A recursive algorithm alternating between power allocation and bandwidth allocation steps is proposed to solve the formulated resource allocation problem. Due to the conflict between limited wireless resources and the fast growing wireless demands, Stackelberg game is proposed to allocate the relay resources (power and bandwidth) between competing users, aiming to maximize the relay benefits from selling its resources. We prove the uniqueness of Stackelberg Nash Equilibrium (SNE) for the proposed game. We develop a distributed algorithm to reach SNE, and investigate the conditions for the stability of the proposed algorithm. We propose low complexity algorithms for AF-OFDMA and DF-OFDMA systems to assign the subcarriers to the users based on high SNR approximation aiming to maximize the weighted sum rate. Auction framework is proposed to devise competition based solutions for the resource allocation of AF-OFDMA aiming tomaximize either vi the sum rate or the fairness index. Two auction algorithms are proposed; sequential and one-shot auctions. In sequential auction, the users evaluate the subcarrier based on the rate marginal contribution. In the one-shot auction, the users evaluate the subcarriers based on an estimate of the Shapley value and bids on all subcarriers at once. Acknowledgments All praise and thanks be to Allah, for blessing me with the strength and enthusiasm to seek knowledge and to complete this work. Foremost, I would like to express my sincere appreciation and gratitude to my advisor Dr. Imad Barhumi, for his academic guidance and enthusiastic encouragement throughout this PhD. His constant encouragement was vital in making this dissertation a reality. He spent endless hours proofreading my research papers and giving me excellent suggestions, which always resulted in improved versions of the documents. He also supportedme during the difficult times in my research. He believed in me when I doubted myself, and always preserved his confidence in my ability to complete my PhD. Doing a PhD is always challenging, and I will not forget how Dr. Imad assisted me. I cannot thank him enough for all the encouragement and advice, helping to make it an enjoyable experience. I owemy deepest gratitude to theUnitedArab EmiratesUniversity (UAEU) for its generosity in supporting me financially during my PhD study. I would like to thank Dr. Mohammad Hayajneh, Dr. Qurban Ali, and Prof. Noafal Al-Dahir for serving as my PhD Advisory Committee. I would like to thank Prof. K.J. Ray Liu, Dr. Mohammed Abdel-Hafez, Dr. Khaled Shuaib for serving as my PhD Examining Committee. Iwould like to thank all the faculty and staff in the Electrical Engineering Department in UAEU for their continuous encouragement. I would like to acknowledge the help of all the people who have contributed to my education, especially,my professors in Jordan University and colleagues in Amman Al-Ahliyyah University. I would like to thank friends at UAEU; Salam, Assha, Hanifa, Razan, Shumma, Taghreed, Sawsan, Nedaa, Reem, Maysara, Dr. Maysa, Hanan, Hana, and Swzen. Thank you for the true positive experience we had during my PhD research. I would like to thank my friends Rana, Ymna, Lubna, Lena, Lamiss, Abir, Huda, Maram, Ahlam, and Angham. Your friendship and prayers gave me strength to overcome difficulties throughout this endeavor. All thanks to Alah for blessing me with good friends. My heartiest thanks go to my parents, brothers and their families, thank you for everything, for your support, love, and care.

Download or read book Resource Allocation and Performance Optimization in Communication Networks and the Internet written by Liansheng Tan and published by CRC Press. This book was released on 2017-08-15 with total page 669 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a comprehensive introduction to the underlying theory, design techniques and analytical results of wireless communication networks, focusing on the core principles of wireless network design. It elaborates the network utility maximization (NUM) theory with applications in resource allocation of wireless networks, with a central aim of design and the QoS guarantee. It presents and discusses state-of-the-art developments in resource allocation and performance optimization in wireless communication networks. It provides an overview of the general background including the basic wireless communication networks and the relevant protocols, architectures, methods and algorithms.