Wireless Local Area Networks (WLANs) have become increasingly popular due to the recent availability of affordable devices providing multiple and high rate capabilities. Optimizing the performance of WLANs for emerging new Internet applications that demand High Throughput (HT) is an important and a highly challenging issue. In this book, we present a new practical Rate Adaptation (RA) algorithm, termed L3S, which extends legacy schemes with new MIMO features suitable for the forthcoming 802.11n high-speed MIMO-based WLAN products. We implement our rate adaptation algorithm in real hardware devices and evaluate its performance and compare it to the existing rate control mechanisms. Our experiments demonstrate that our scheme allows the current 802.11n devices to have a greater adaptability to a variety of wireless channel conditions and performs better than state-of-the-art rate adaptation algorithms.

Multi-hop wireless networks offer promising applications for future communications and they differ from widespread single-hop networks. Throughput (node-to-node successfully transmitted bits per second) is an important performance metric in single-hop wireless net- works, whereas goodput (end-to-end successfully delivered bits per second) becomes an indication of the performance in multi-hop networks. Energy-efficiency is another impor- tant performance metric due to the limited battery life of mobile devices. Main factors that affect the network performances are packet collisions that occur due to the hidden terminal problem and blocking of packets at interface queues at intermediate nodes in multi-hop networks. In this dissertation, the effect of transmission rate on goodput, throughput and energy performances of IEEE 802.11g DCF based on multi-hop wireless networks are in- vestigated over a large range of traffic loads. The performances are observed under direct transmission and multi-hop transmission, considering MAC contention such as binary ex- ponential backoff, retransmissions, collisions and overhearing of nodes. IEEE 802.11g DCF is used because it supports high data rates and has interoperability with the older version of IEEE standards. Network Simulator 2 is modified to compute the goodput, throughput and energy per bit (EPB) performance metrics under perfect channel condi- tions. The results reveal that varying the data rate has no effect on goodput, throughput and energy under light traffic loads. Under moderate-to-heavy traffic loads, goodput and energy efficiency performances drop sharply whereas throughput remains constant. Hid- den terminals and interface queue blocking is observed to be the reason for performance reduction of increasing goodput and EPB which increase with traffic load under moderate- to-heavy traffic loads. This suggests that a rate adaptation algorithm, which discriminates the reason of packet drops and keeps the transmission rate at the maximum can improve goodput and energy performances significantly for multi-hop wireless networks.

Designing and Deploying 802.11 Wireless Networks Second Edition A Practical Guide to Implementing 802.11n and 802.11ac Wireless Networks For Enterprise-Based Applications Plan, deploy, and operate high-performance 802.11ac and 802.11n wireless networks The new 802.11ac standard enables WLANs to deliver significantly higher performance. Network equipment manufacturers have refocused on 802.11ac- and 802.11n-compliant solutions, rapidly moving older versions of 802.11 toward “legacy” status. Now, there’s a complete guide to planning, designing, installing, testing, and supporting 802.11ac and 802.11n wireless networks in any environment, for virtually any application. Jim Geier offers practical methods, tips, and recommendations that draw on his decades of experience deploying wireless solutions and shaping wireless standards. He carefully introduces 802.11ac’s fundamentally different design, site survey, implementation, and network configuration techniques, helping you maximize performance and avoid pitfalls. Geier organizes each phase of WLAN deployment into clearly defined steps, making the entire planning and deployment process easy to understand and execute. He illuminates key concepts and methods through realistic case studies based on current Cisco products, while offering tips and techniques you can use with any vendor’s equipment. To build your skills with key tasks, you’ll find several hands-on exercises relying on free or inexpensive tools. Whether you’re deploying an entirely new wireless network or migrating from older equipment, this guide contains all the expert knowledge you’ll need to succeed. Jim Geier has 30 years of experience planning, designing, analyzing and implementing communications, wireless, and mobile systems. Geier is founder and Principal Consultant of Wireless-Nets, Ltd., providing wireless analysis and design services to product manufacturers. He is also president, CEO, and co-founder of Health Grade Networks, providing wireless network solutions to hospitals, airports, and manufacturing facilities. His books include the first edition of Designing and Deploying 802.11n Wireless Networks (Cisco Press); as well as Implementing 802.1X Security Solutions and Wireless Networking Handbook. Geier has been active in the IEEE 802.11 Working Group and Wi-Fi Alliance; has chaired the IEEE Computer Society (Dayton Section) and various conferences; and served as expert witness in patent litigation related to wireless and cellular technologies. Review key 802.11 concepts, applications, markets, and technologies Compare ad hoc, mesh, and infrastructure WLANs and their components Consider the impact of radio signal interference, security vulnerabilities, multipath propagation, roaming, and battery limitations Thoroughly understand today’s 802.11 standards in the context of actual network deployment and support Plan your deployment: scoping, staffing, schedules, budgets, risks, feasibility analysis, and requirements Architect access networks and distribut

While there are countless books on wireless networks, few actually quantify the key performance-limiting factors of wireless local area networks (WLANs) and describe various methods for improving WLAN performance. Fulfilling these needs, Improving the Performance of Wireless LANs: A Practical Guide provides both theoretical background and empirical

Adaptive techniques play a key role in modern wireless communication systems. The concept of adaptation is emphasized in the Adaptation in Wireless Communications Series through a unified framework across all layers of the wireless protocol stack ranging from the physical layer to the application layer, and from cellular systems to next-generation wireless networks. Adaptation and Cross Layer Design in Wireless Networks is devoted to adaptation in the data link layer, network layer, and application layer. The book presents state-of-the-art adaptation techniques and methodologies, including cross-layer adaptation, joint signal processing, coding and networking, selfishness in mobile ad hoc networks, cooperative and opportunistic protocols, adaptation techniques for multimedia support, self –organizing routing, and tunable security services. It presents several new theoretical paradigms and analytical findings which are supported with various simulation and experimental results. Adaptation in wireless communications is needed in order to achieve high capacity and ubiquitous communications. The current trend in wireless communication systems is to make adaptation dependent upon the state of the relevant parameters in all layers of the system. Focusing on simplified cross layer design approaches, this volume describes advanced techniques such as adaptive resource management, adaptive modulation and coding, 4G communications, QoS, diversity combining, and energy and mobility aware MAC protocols. The first volume in the series, Adaptive Signal Processing in Wireless Communications (cat no.46012) covers adaptive signal processing at the physical layer.

This book presents revised versions of tutorial lectures given at the IEEE/CS Symposium on modeling, analysis, and simulation of computer and telecommunication systems held in Orlando, FL, USA in October 2003. The lectures are grouped into three parts on performance and QoS of modern wired and wireless networks, current advances in performance modeling and simulation, and other specific applications of these methodologies. This tutorial book is targeted to both practitioners and researchers. The practitioner will benefit from numerous pointers to performance and QoS issues; the pedagogical style and plenty of references will be of great use in solving practical problems. The researcher and advanced student are offered a representative set of topics not only for their research value but also for their novelty and use in identifying areas of active research.