Distributed Coding In A Multiple Access Environment

With the fast expansion of communication networks and the increasing dynamic of wireless communication activities, a significant proportion of messages in wireless networks are being transmitted using distributed protocols that feature opportunistic channel access without full user coordination. This challenges the basic assumption of long message transmissions among coordinated users in classical channel coding theory. In this monograph, we introduce channel coding theorems for the distributed communication model where users choose their channel codes individually. We show that, although reliable message recovery is not always guaranteed in distributed communication systems, the notion of fundamental limit still exists, and can indeed be viewed as an extension to its classical correspondence. Due to historical priority of developing wireline networks, network architectures tend to achieve system modularity by compromising communication and energy efficiency. Such a choice is reasonable for wireline systems but can be disastrous for wireless radio networks. Therefore, to reduce efficiency loss, large scale communication networks often adopt wireless communication only at the last hop. Because of such a special structure, architectural inefficiency in wireless part of the network can be mitigated by enhancing the interface between the physical and the data link layers. The enhanced interface, to be proposed, provides each link layer user with multiple transmission options, and supports efficient distributed networking by enabling advanced communication adaptation at the data link layer. In this monograph, we focus on the introduction of distributed channel coding theory, which serves as the physical layer foundation for the enhanced physical-link layer interface. Nevertheless, early research results at the data link layer for the enhanced interface are also presented and discussed.

Mobile users are demanding fast and efficient ubiquitous connectivity supporting data applications. This connectivity has to be provided by various different networks and protocols which guarantee that mobile networks function efficiently, performing routing and handoff for mobile users. Hac proposes a comprehensive design for mobile communications including mobile agents, access networks, application protocols, ubiquitous connectivity, routing, and handoff. It covers the entire spectrum of lower and upper layer protocols to evaluate and design modern mobile telecommunications systems. Furthermore, the aspects of modern mobile telecommunications for applications, networking, and transmission are described. For mobile users and data applications these are new networking and communications solutions, particularly for the local area network environment. * Describes the recent advances in mobile telecommunications, their protocols and management * Covers hot topics such as mobile agents, access networks, wireless applications protocols, wireless LANs, architecture, routing and handoff * Introduces and analyses architecture and design issues in mobile communications and networks * Includes a section of questions/problems/answers after each chapter The book is written as a practical, easily accessible tutorial with many figures and examples of existing protocols and architectures making it essential reading for engineers, system engineers, researchers, managers, senior & graduate students.

It is our great pleasure to present the proceedings of the Third International Workshop on Multiple Access Communications (MACOM) that was held in Barcelona during September 13–14, 2010. In 1961, Claude Shannon established the foundation for the discipline now known as “multi-user information theory” in his pioneering paper “Two-way Communication Channels,” and later Norman Abramson published his paper “The Aloha System—Another Alternative for Computer Communications” in 1970 which introduced the concept of multiple access using a shared common channel. Thereafter, for more than 40 years of study, numerous elegant theories and algorithms have been developed for multiple-access communications. During the 1980s and 1990s the evolution of multiple-access techniques p- ceeded in conjunction with the evolution of wireless networks. Novel multiple access techniques like code division multiple access (CDMA) and orthogonal frequency division multiple access (OFDMA) provided increased spectral - ?ciency, dynamicity and ?exibility in radio resource allocation with intrinsic anti-multipath and anti-interference features. In this ?rst decade of the 21st century,multiple-accesstechniques,derivedfromadvancedwirelesstransmission methodologiesbasedonthediversityconcept(e. g. ,MC-CDMA,MIMO-OFDMA and SC-FDMA), opened the road to a renewed idea of multiple access. Today multiple-access communications involve many challenging aspects not only l- ited (like in the past) to physical layer design. Medium access control (MAC) techniques play a crucial role in managing the radio resources that users will exploit to transmit their data streams. Recent developments in software radios and cognitive radios have led to a signi?cant impact also on spectrum m- agement and access paradigms.

Network coding, a relatively new area of research, has evolved from the theoretical level to become a tool used to optimize the performance of communication networks – wired, cellular, ad hoc, etc. The idea consists of mixing “packets” of data together when routing them from source to destination. Since network coding increases the network performance, it becomes a tool to enhance the existing protocols and algorithms in a network or for applications such as peer-to-peer and TCP. This book delivers an understanding of network coding and provides a set of studies showing the improvements in security, capacity and performance of fixed and mobile networks. This is increasingly topical as industry is increasingly becoming more reliant upon and applying network coding in multiple applications. Many cases where network coding is used in routing, physical layer, security, flooding, error correction, optimization and relaying are given – all of which are key areas of interest. Network Coding is the ideal resource for university students studying coding, and researchers and practitioners in sectors of all industries where digital communication and its application needs to be correctly understood and implemented. Contents 1. Network Coding: From Theory to Practice, Youghourta Benfattoum, Steven Martin and Khaldoun Al Agha. 2. Fountain Codes and Network Coding for WSNs, Anya Apavatjrut, Claire Goursaud, Katia Jaffrès-Runser and Jean-Marie Gorce. 3. Switched Code for Ad Hoc Networks: Optimizing the Diffusion by Using Network Coding, Nour Kadi and Khaldoun Al Agha. 4. Security by Network Coding, Katia Jaffrès-Runser and Cédric Lauradoux. 5. Security for Network Coding, Marine Minier, Yuanyuan Zhang and Wassim Znaïdi. 6. Random Network Coding and Matroids, Maximilien Gadouleau. 7. Joint Network-Channel Coding for the Semi-Orthogonal MARC: Theoretical Bounds and Practical Design, Atoosa Hatefi, Antoine O. Berthet and Raphael Visoz. 8. Robust Network Coding, Lana Iwaza, Marco Di Renzo and Michel Kieffer. 9. Flow Models and Optimization for Network Coding, Eric Gourdin and Jeremiah Edwards.

"This book serves as a vital resource for practitioners to learn about the latest research and methodology within the field of wireless technology, covering important aspects of emerging technologies in the heterogeneous next generation network environment with a focus on wireless communications and their quality"--Provided by publisher.

This book "Communications and Networking" focuses on the issues at the lowest two layers of communications and networking and provides recent research results on some of these issues. In particular, it first introduces recent research results on many important issues at the physical layer and data link layer of communications and networking and then briefly shows some results on some other important topics such as security and the application of wireless networks. In summary, this book covers a wide range of interesting topics of communications and networking. The introductions, data, and references in this book will help the readers know more abut this topic and help them explore this exciting and fast-evolving field.

Climate change has been the subject of thousands of books and magazines, scientific journals, and newspaper articles daily. It’s a subject that can be very political and emotional, often blurring the lines between fact and fiction. The vast majority of research, studies, projections and recommendations tend to focus on the human influence on climate change and global warming as the result of CO2 emissions, often to the exclusion of other threats that include population growth and the stress placed on energy sources due to emerging global affluence. Climate Vulnerability, Five Volume Set seeks to strip away the politics and emotion that surround climate change and will assess the broad range of threats using the bottom up approach—including CO2 emissions, population growth, emerging affluence, and many others—to our five most critical resources: water, food, ecosystems, energy, and human health. Inclusively determining what these threats are while seeking preventive measures and adaptations is at the heart of this unique reference work. Takes a Bottom-Up approach, addressing climate change and the threat to our key resources at the local level first and globally second, providing a more accurate and inclusive approach. Includes extensive cross-referencing, which is key to readers as new connections between factors can be discovered. Cuts across a number of disciplines and will appeal to Biological Science, Earth & Environmental Science, Ecology, and Social Science, comprehensively addressing climate change and other threats to our key resources from multiple perspectives