Download or read book Stochastic Control of Time varying Wireless Networks written by and published by . This book was released on 2002 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: PhD.

Download or read book Stochastic Control of Time varying Wireless Networks written by Mahdi Lotfinezhad and published by . This book was released on 2009 with total page 396 pages. Available in PDF, EPUB and Kindle. Book excerpt: One critical step to successfully integrate wireless data networks to the high-speed wired backbone is the design of network control policies that efficiently utilize resources to provide Quality of Service (QoS) to the users in the integrated networks. Such a design has remained a challenge since wireless networks are time-varying in nature, not only in terms of user/packet arrivals but also in terms of physical channel conditions and access opportunities. In this thesis, we study the stochastic control of time-varying networks to design efficient scheduling and resource allocation policies.Finally, motivated by the current under-utilization of wireless spectrum, in Chapter 5, we investigate the control of cognitive radio networks as a special example of networks that provide time-varying access opportunities. We assume that users dynamically join and leave the network and may have different utility functions, or could collaborate for a common purpose. We develop a policy that performs joint admission and resource control and works for any user load, either inside or outside the capacity region. Through Lyapunov Optimization techniques, we show that the developed policy can achieve a utility performance arbitrarily close to the optimality with a tradeoff in the average service delay of admitted users.In particular, in Chapter 3, we focus on a broad class of control policies that work based on a pick-and-compare principle for networks with time-varying channels. By trading the throughput for complexity and memory requirement, these policies require less complexity compared to the well-investigated throughput-optimal Generalized Maximum Weight Matching (GMWM) policy and also require only linear-memory storage with the number of dataflows. Through Lyapunov analysis tools, we characterize the stability region and delay performance of the studied policies and show how they vary in response to the channel variations.In Chapter 4, we go into further detail and consider the problem of network control from a new perspective through which we carefully incorporate the time-efficiency of underlying scheduling algorithms. Specifically, we develop a policy that dynamically adjusts the time given to the available scheduling algorithms according to queue-backlog and channel correlations. We study the resulting stability region of developed policy and show that the region is at least as large as the one for any static policy.

Download or read book Stochastic Control written by Chris Myers and published by BoD – Books on Demand. This book was released on 2010-08-17 with total page 663 pages. Available in PDF, EPUB and Kindle. Book excerpt: Uncertainty presents significant challenges in the reasoning about and controlling of complex dynamical systems. To address this challenge, numerous researchers are developing improved methods for stochastic analysis. This book presents a diverse collection of some of the latest research in this important area. In particular, this book gives an overview of some of the theoretical methods and tools for stochastic analysis, and it presents the applications of these methods to problems in systems theory, science, and economics.

Download or read book Stochastic Control and Filtering over Constrained Communication Networks written by Qinyuan Liu and published by Springer. This book was released on 2018-10-24 with total page 233 pages. Available in PDF, EPUB and Kindle. Book excerpt: ​Stochastic Control and Filtering over Constrained Communication Networks presents up-to-date research developments and novel methodologies on stochastic control and filtering for networked systems under constrained communication networks. It provides a framework of optimal controller/filter design, resilient filter design, stability and performance analysis for the systems considered, subject to various kinds of communication constraints, including signal-to-noise constraints, bandwidth constraints, and packet drops. Several techniques are employed to develop the controllers and filters desired, including: recursive Riccati equations; matrix decomposition; optimal estimation theory; and mathematical optimization methods. Readers will benefit from the book’s new concepts, models and methodologies that have practical significance in control engineering and signal processing. Stochastic Control and Filtering over Constrained Communication Networks is a practical research reference for engineers dealing with networked control and filtering problems. It is also of interest to academics and students working in control and communication networks.

Download or read book Stochastic Optimization and Its Applications in Time varying Wireless Systems written by Yih-Hao Lin and published by . This book was released on 2007 with total page 159 pages. Available in PDF, EPUB and Kindle. Book excerpt: With the advent of third generation wireless cellular systems, new functionalities are deployed to support dynamic adjustments of system parameters and operating points. How to effectively manage the resources using these functions with system state information, such like queue dynamics, packet delay and channel fluctuation, is very critical to the system performance. greatly increase the chance of encountering better channel states, and helps in achieving better average resource utilization. In this dissertation, we investigate the optimal channel-aware scheduling policy for applications concerned with the long-term average performance (such as average power consumption and throughput, etc.), and the realization of the policy in various contexts. A broad class of scheduler design problems can be expressed as optimal stochastic control problems concerned with the time and ensemble average of controlled processes. In light of this, we devise a framework for stochastic dynamic control utilizing a mathematical tool, referred to as Stochastic Optimization. Leveraging the duality approach developed for convex optimization, we simplify the constrained Stochastic Optimization problem into an unconstraint one. Furthermore, we develop an online algorithm for solving the stochastic optimization problem. For a broad class of stationary stochastic processes which satisfy a set of mixing conditions, the behavior of the algorithm can be approximately characterized by a projected differential inclusion. Exploring the trajectory of the projected differential inclusion, it is proved that the long-term average of the control variables generated by the proposed algorithm along its recursive steps converges asymptotically to the optimal one. To demonstrate the use cases of the established framework, we study the power-optimized routing problem in multi-hop wireless networks. A distributed implementation of the algorithm is devised. Applying the same framework, we also look into the problem of joint source distortion management and wireless downlink scheduling, in which we aim to minimize the maximum average distortion of the data requested by each user. The proposed algorithm comes with the properties of finite receiver buffer occupation as well as the negligible packet-drop ratio.

Download or read book Energy Efficient Scheduling under Delay Constraints for Wireless Networks written by Randal Berry and published by Springer Nature. This book was released on 2022-05-31 with total page 84 pages. Available in PDF, EPUB and Kindle. Book excerpt: Packet delay and energy consumption are important considerations in wireless and sensor networks as these metrics directly affect the quality of service of the application and the resource consumption of the network; especially, for a rapidly growing class of real-time applications that impose strict restrictions on packet delays. Dynamic rate control is a novel technique for adapting the transmission rate of wireless devices, almost in real-time, to opportunistically exploit time-varying channel conditions as well as changing traffic patterns. Since power consumption is not a linear function of the rate and varies significantly with the channel conditions, adapting the rate has significant benefits in minimizing energy consumption. These benefits have prompted significant research in developing algorithms for achieving optimal rate adaptation while satisfying quality of service requirements. In this book, we provide a comprehensive study of dynamic rate control for energy minimization under packet delay constraints. We present several formulations and approaches adopted in the literature ranging from discrete-time formulations and dynamic programming based solutions to continuous-time approaches utilizing ideas from network calculus and stochastic optimal control theory. The goal of this book is to expose the reader to the important problem of wireless data transmission with delay constraints and to the rich set of tools developed in recent years to address it. Table of Contents: Introduction / Transmission Rate Adaptation under Deadline Constraints / Average Delay Constraints

Download or read book Stochastic Network Optimization with Application to Communication and Queueing Systems written by Michael J. Neely and published by Morgan & Claypool Publishers. This book was released on 2010 with total page 212 pages. Available in PDF, EPUB and Kindle. Book excerpt: This text presents a modern theory of analysis, control, and optimization for dynamic networks. Mathematical techniques of Lyapunov drift and Lyapunov optimization are developed and shown to enable constrained optimization of time averages in general stochastic systems. The focus is on communication and queueing systems, including wireless networks with time-varying channels, mobility, and randomly arriving traffic. A simple drift-plus-penalty framework is used to optimize time averages such as throughput, throughput-utility, power, and distortion. Explicit performance-delay tradeoffs are provided to illustrate the cost of approaching optimality. This theory is also applicable to problems in operations research and economics, where energy-efficient and profit-maximizing decisions must be made without knowing the future. Topics in the text include the following: - Queue stability theory - Backpressure, max-weight, and virtual queue methods - Primal-dual methods for non-convex stochastic utility maximization - Universal scheduling theory for arbitrary sample paths - Approximate and randomized scheduling theory - Optimization of renewal systems and Markov decision systems Detailed examples and numerous problem set questions are provided to reinforce the main concepts. Table of Contents: Introduction / Introduction to Queues / Dynamic Scheduling Example / Optimizing Time Averages / Optimizing Functions of Time Averages / Approximate Scheduling / Optimization of Renewal Systems / Conclusions

Download or read book Stochastic Network Optimization with Application to Communication and Queueing Systems written by Michael Neely and published by Springer Nature. This book was released on 2022-05-31 with total page 199 pages. Available in PDF, EPUB and Kindle. Book excerpt: This text presents a modern theory of analysis, control, and optimization for dynamic networks. Mathematical techniques of Lyapunov drift and Lyapunov optimization are developed and shown to enable constrained optimization of time averages in general stochastic systems. The focus is on communication and queueing systems, including wireless networks with time-varying channels, mobility, and randomly arriving traffic. A simple drift-plus-penalty framework is used to optimize time averages such as throughput, throughput-utility, power, and distortion. Explicit performance-delay tradeoffs are provided to illustrate the cost of approaching optimality. This theory is also applicable to problems in operations research and economics, where energy-efficient and profit-maximizing decisions must be made without knowing the future. Topics in the text include the following: - Queue stability theory - Backpressure, max-weight, and virtual queue methods - Primal-dual methods for non-convex stochastic utility maximization - Universal scheduling theory for arbitrary sample paths - Approximate and randomized scheduling theory - Optimization of renewal systems and Markov decision systems Detailed examples and numerous problem set questions are provided to reinforce the main concepts. Table of Contents: Introduction / Introduction to Queues / Dynamic Scheduling Example / Optimizing Time Averages / Optimizing Functions of Time Averages / Approximate Scheduling / Optimization of Renewal Systems / Conclusions

Download or read book Stochastic Power Control for Wireless Networks written by Shili Lu and published by . This book was released on 2005 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Dynamic Wireless Network Control Via Stochastic Approximation written by Sina Firouzabadi and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis investigates different stochastic approximation-based algorithms for performance optimization of wireless networks. Stochastic approximation is used to learn the randomly-varying characteristics of the network conditions and adapt the transmission strategies accordingly. The basic premise of wireless network optimization based on stochastic approximation will be presented, followed by several applications of this technique. The first application optimizes secondary user transmission strategies in cognitive networks with imperfect network state observations. In this setting the secondary user maximizes its revenue while generating a bounded performance loss to the primary users' network. The state of the primary users' network, defined as a collection of variables describing features of the network (e.g., buffer state, packet service state) evolves over time according to a homogeneous Markov process. The statistics of the Markov process are dependent on the strategy of the secondary user and, thus, the instantaneous idleness/transmission action of the secondary user has a long term impact on the temporal evolution of the network. The Markov process generates a sequence of states in the state space of the network that projects onto a sequence of observations in the observation space, that is, the collection of all the observations of the secondary user. Based on the sequence of observations from secondary users, an iterative stochastic approximation based algorithm is proposed that optimizes the strategy of the secondary users with no a priori knowledge of the statistics of the Markov process and of the state-observation probability map. The second application of stochastic approximation theory presented is around the design of green cellular networks through the use of distributed antennas. After presenting an information theoretic analysis of the ergodic capacity of distributed antenna systems in a cellular setting, optimized antenna placement in such systems is investigated. A general framework for this optimization based on stochastic approximation theory, with no constraint on the location of the antennas, will be presented. It will be shown that optimal placement of antennas inside the coverage region can significantly improve the power efficiency of wireless networks. As we will see, our stochastic optimization framework is sufficiently general to incorporate interference as well as general performance metrics. We will also present different numerical studies for illustrating the power efficiency and area spectral efficiency of distributed antenna systems, under different assumptions about availability of channel side information at the transmitter. Finally in the last part of the thesis, we present a distributed algorithm for optimizing the rate-reliability tradeoff in wireless networks with randomly time-varying channels. The stochastic optimization is based on wireless network utility maximization, extended to incorporate dynamics at the physical layer. The proposed algorithm enables a distributed implementation. We also verify the convergence of the proposed algorithm using Stochastic Approximation. The performance of the proposed algorithm and its convergence is illustrated via simulations.

Download or read book Stochastic Control of Ad Hoc Communication Networks written by and published by . This book was released on 2002 with total page 3 pages. Available in PDF, EPUB and Kindle. Book excerpt: The proposed research had two main purposes. The first was to develop simple, adaptive, and distributed energy control (transmission power and transmission rate control) algorithms that (i) control the topology of wireless ad hoc communication networks, subject to traffic with diverse bandwidth and end-to-end quality of service requirements, in a spectrally and energy efficient manner; (ii) control multiple access interference and adapt to time-varying propagation losses; and (iii) combine with transmission scheduling, media access control, and multi-hop routing. The second is to design simple, efficient, and robust mechanisms to improve the performance of Transmission Control Protocol (TCP) in mixed wired/wireless communication and ad-hoc networks. The basic approach is to study how the soon-to-be-standardized Selective Acknowledgement feature of TCP, together with knowledge of the statistical behavior of wireless links, can be used to decouple the error recovery and flow control functions of TCP by distinguishing between congestion and non-congestion related packet loss.

Download or read book Advanced Wireless Networks written by Savo Glisic and published by John Wiley & Sons. This book was released on 2009-04-27 with total page 892 pages. Available in PDF, EPUB and Kindle. Book excerpt: With 40% new material the new edition of Advanced Wireless Networks provides a comprehensive representation of the key issues in 4G wireless networks. Focussing on cognitive, cooperative and opportunistic paradigms to provide further increase in network efficiency, the book explores and addresses issues in wireless internet, mobile cellular and WLAN, as well as sensor, ad hoc, bio-inspired, active and cognitive networks. It examines the problem of cross-layer optimisation and network information theory as well as adaptability and reconfigurability in wireless networks. This book is an integral description of future wireless networks and the interconnection between their elements. The information is presented in a logical order within each chapter making it ideal for all levels of reader including researchers involved in modelling and analysis of future networks as well as engineers working in the area. Each chapter starts with introductory material and gradually includes more sophisticated models and mathematical tools concluding with a comprehensive list of references. Fully updated throughout with five new chapters on Opportunistic Communications; Relaying and Mesh Networks; Topology Control; Network Optimization; and Cognitive Radio Resource Management Unifies the latest research on cognitive, cooperative and opportunistic paradigms in wireless communications Provides efficient analytical tools for network analysis Discusses security issues, an essential element of working with wireless networks Supports advanced university and training courses in the field Companion website containing extra appendix on Queuing theory

Download or read book Drift Fields a Method for Resource Allocation in Wireless Networks written by Vinay Rudramuni Majjigi and published by Stanford University. This book was released on 2011 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation recommends system engineering designs that implement the latest technologies in OFDMA cellular and femtocellular networks, specifically in the area of resource allocation and interference coordination. These recommended designs guarantee good user experience for time-sensitive applications such as streaming video. While throughput is often the metric used to benchmark a system, field performance requires the system also guarantees a maximum service latency to satisfy users. This dissertation provides both intuitive and low-overhead schemes that are robust and practical for implementation. The novelty of this work is the application of stochastic control techniques that guarantee the Quality of Service (QoS) through proper buffer management. Guarantee of a non-empty user buffer for streaming applications prevents service interruption. The thesis considers both centralized and distributed topologies that result from either a single base-station serving many users, or many femtocell base-stations each serving a single user, respectively. This dissertation provides insight and solutions to the following question: Under the constraints of buffer management, how does a system engineer determine the transmission scheme, resource allocation algorithms, transmitter coordination, user feedback, and achievable QoS guarantees that maximize efficiency. A combination of theory, heuristics motivated in theory, and numerical simulations will justify the presented methods.

Download or read book Power Control in Wireless Cellular Networks written by Mung Chiang and published by Now Publishers Inc. This book was released on 2008 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt: Transmit power in wireless cellular networks is a key degree of freedom in the management of interference, energy, and connectivity. Power control in both the uplink and downlink of a cellular network has been extensively studied, especially over the last 15 years, and some of the results have enabled the continuous evolution and significant impact of the digital cellular technology. This survey provides a comprehensive discussion of the models, algorithms, analysis, and methodologies in this vast and growing literature. It starts with a taxonomy of the wide range of power control problem formulations, and progresses from the basic formulation to more sophisticated ones. When transmit power is the only set of optimization variables, algorithms for fixed SIR are presented first, before turning to their robust versions and joint SIR and power optimization. This is followed by opportunistic and non-cooperative power control. Then joint control of power together with beamforming pattern, base station assignment, spectrum allocation, and transmit schedule is surveyed one-by-one. Throughout the survey, we highlight the use of mathematical language and tools in the study of power control, including optimization theory, control theory, game theory, and linear algebra. Practical implementations of some of the algorithms in operational networks are discussed in the concluding section. As illustrated by the open problems presented at the end of most chapters, in the area of power control in cellular networks, there are still many under-explored directions and unresolved issues that remain theoretically challenging and practically important.

Download or read book Stochastic Signal Processing and Power Control for Wireless Communication Systems written by and published by . This book was released on 2007 with total page 145 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation is concerned with dynamical modeling, estimation and identification of wireless channels from received signal measurements. Optimal power control algorithms, mobile location and velocity estimation methods are developed based on the proposed models. The ultimate performance limits of any communication system are determined by the channel it operates in. In this dissertation, we propose new stochastic wireless channel models which capture both the space and time variations of wireless systems. The proposed channel models are based on stochastic differential equations (SDEs) driven by Brownian motions. These models are more realistic than the time invariant models encountered in the literature which do not capture and track the time varying characteristics of the propagation environment. The statistics of the proposed models are shown to be time varying, and converge in steady state to their static counterparts. Cellular and ad hoc wireless channel models are developed. In urban propagation environment, the parameters of the channel models can be determined from approximating the band-limited Doppler power spectral density (DPSD) by rational transfer functions. However, since the DPSD is not available on-line, a filterbased expectation maximization algorithm and Kalman filter to estimate the channel parameters and states, respectively, are proposed. The algorithm is recursive allowing the inphase and quadrature components and parameters to be estimated on-line from received signal measurements. The algorithms are tested using experimental data, and the results demonstrate the method's viability for both cellular and ad hoc networks. Power control increases system capacity and quality of communications, and reduces battery power consumption. A stochastic power control algorithm is developed using the so-called predictable power control strategies. An iterative distributed algorithm is then deduced using stochastic approximations. The latter only requires each mobile to know its received signal to interference ratio at the receiver. Several methods for tracking a user based on wave scattering models and particle filtering are presented. These algorithms cope with nonlinearities in order to estimate the mobile location and velocity. They take into account non-line-of-sight and multipath propagation environments. To show that the algorithms are robust numerical results are presented to evaluate their performance of the algorithms in the presence of parametric uncertainties.

Download or read book The Control Handbook written by William S. Levine and published by CRC Press. This book was released on 2018-10-08 with total page 944 pages. Available in PDF, EPUB and Kindle. Book excerpt: At publication, The Control Handbook immediately became the definitive resource that engineers working with modern control systems required. Among its many accolades, that first edition was cited by the AAP as the Best Engineering Handbook of 1996. Now, 15 years later, William Levine has once again compiled the most comprehensive and authoritative resource on control engineering. He has fully reorganized the text to reflect the technical advances achieved since the last edition and has expanded its contents to include the multidisciplinary perspective that is making control engineering a critical component in so many fields. Now expanded from one to three volumes, The Control Handbook, Second Edition organizes cutting-edge contributions from more than 200 leading experts. The second volume, Control System Applications, includes 35 entirely new applications organized by subject area. Covering the design and use of control systems, this volume includes applications for: Automobiles, including PEM fuel cells Aerospace Industrial control of machines and processes Biomedical uses, including robotic surgery and drug discovery and development Electronics and communication networks Other applications are included in a section that reflects the multidisciplinary nature of control system work. These include applications for the construction of financial portfolios, earthquake response control for civil structures, quantum estimation and control, and the modeling and control of air conditioning and refrigeration systems. As with the first edition, the new edition not only stands as a record of accomplishment in control engineering but provides researchers with the means to make further advances. Progressively organized, the other two volumes in the set include: Control System Fundamentals Control System Advanced Methods

Download or read book The Control Handbook three volume set written by William S. Levine and published by CRC Press. This book was released on 2018-10-08 with total page 3379 pages. Available in PDF, EPUB and Kindle. Book excerpt: At publication, The Control Handbook immediately became the definitive resource that engineers working with modern control systems required. Among its many accolades, that first edition was cited by the AAP as the Best Engineering Handbook of 1996. Now, 15 years later, William Levine has once again compiled the most comprehensive and authoritative resource on control engineering. He has fully reorganized the text to reflect the technical advances achieved since the last edition and has expanded its contents to include the multidisciplinary perspective that is making control engineering a critical component in so many fields. Now expanded from one to three volumes, The Control Handbook, Second Edition brilliantly organizes cutting-edge contributions from more than 200 leading experts representing every corner of the globe. They cover everything from basic closed-loop systems to multi-agent adaptive systems and from the control of electric motors to the control of complex networks. Progressively organized, the three volume set includes: Control System Fundamentals Control System Applications Control System Advanced Methods Any practicing engineer, student, or researcher working in fields as diverse as electronics, aeronautics, or biomedicine will find this handbook to be a time-saving resource filled with invaluable formulas, models, methods, and innovative thinking. In fact, any physicist, biologist, mathematician, or researcher in any number of fields developing or improving products and systems will find the answers and ideas they need. As with the first edition, the new edition not only stands as a record of accomplishment in control engineering but provides researchers with the means to make further advances.