Advanced Modulation Techniques Task A Space Application Of Frequency Hopping Multiple Access Techniques

This book provides a comprehensive overview of multiple access techniques used in the cellular industry. The usage of multiple access techniques in telecommunications enables many users to share the same spectrum in the frequency domain, time domain, code domain or phase domain. Licenses are given, by the FCC, to operate wireless communication systems over given bands of frequencies, with the smaller bands, (channels), reused to provide services to other users. Thus, bandwidth efficiency is vital, as the speed and size of digital data networks continue to expand. This brief also uses numerous illustrations to bring students up-to-date in the practical applications of multiple access techniques, which can then be put to work in the industry. Primarily, electrical engineering students who study telecommunications, as well as engineers and designers working in wireless communications, would find this book useful.

This lecture covers the fundamentals of spread spectrum modulation, which can be defined as any modulation technique that requires a transmission bandwidth much greater than the modulating signal bandwidth, independently of the bandwidth of the modulating signal. After reviewing basic digital modulation techniques, the principal forms of spread spectrum modulation are described. One of the most important components of a spread spectrum system is the spreading code, and several types and their characteristics are described. The most essential operation required at the receiver in a spread spectrum system is the code synchronization, which is usually broken down into the operations of acquisition and tracking. Means for performing these operations are discussed next. Finally, the performance of spread spectrum systems is of fundamental interest and the effect of jamming is considered, both without and with the use of forward error correction coding. The presentation ends with consideration of spread spectrum systems in the presence of other users. For more complete treatments of spread spectrum, the reader is referred to [1, 2, 3].

In response to a request from the Defense Advanced Research Projects Agency, the committee studied a range of issues to help identify what strategies the Department of Defense might follow to meet its need for flexible, rapidly deployable communications systems. Taking into account the military's particular requirements for security, interoperability, and other capabilities as well as the extent to which commercial technology development can be expected to support these and related needs, the book recommends systems and component research as well as organizational changes to help the DOD field state-of-the-art, cost-effective untethered communications systems. In addition to advising DARPA on where its investment in information technology for mobile wireless communications systems can have the greatest impact, the book explores the evolution of wireless technology, the often fruitful synergy between commercial and military research and development efforts, and the technical challenges still to be overcome in making the dream of "anytime, anywhere" communications a reality.

The superb organization of The Electronics Handbook means that it is not only a comprehensive and fascinating reference, but also a pleasure to use. Some of these organizational features include: