The inadequate use of wireless spectrum resources has recently motivated researchers and practitioners to look for new ways to improve resource efficiency. As a result, new cognitive radio technologies have been proposed as an effective solution. Sensing Techniques for Next Generation Cognitive Radio Networks is a pivotal reference source that provides vital research on the application of spectrum sensing techniques. While highlighting topics such as radio identification, compressive sensing, and wavelet transform, this publication explores the standards and the methods of cognitive radio network architecture. This book is ideally designed for IT and network engineers, practitioners, and researchers seeking current research on radio scene analysis for cognitive radios and networks.

By the late nineteenth century, engineers and experimental scientists generally knew how radio waves behaved, and by 1901 scientists were able to manipulate them to transmit messages across long distances. What no one could understand, however, was why radio waves followed the curvature of the Earth. Theorists puzzled over this for nearly twenty years before physicists confirmed the zig-zag theory, a solution that led to the discovery of a layer in the Earth's upper atmosphere that bounces radio waves earthward-the ionosphere. In Probing the Sky with Radio Waves, Chen-Pang Yeang documents this monumental discovery and the advances in radio ionospheric propagation research that occurred in its aftermath. Yeang illustrates how the discovery of the ionosphere transformed atmospheric science from what had been primarily an observational endeavor into an experimental science. It also gave researchers a host of new theories, experiments, and instruments with which to better understand the atmosphere's constitution, the origin of atmospheric electricity, and how the sun and geomagnetism shape the Earth's atmosphere.