ons issues, and technical issues facing wireless communica- tions, including wireless impairments, antennas, bandwidth, signal modulation, and spectrum utilization. Chapter 14, "Wireless WANs," discusses the impressive range of standards and generations in the brief history of wireless wide area net- works (WWANs). Chapter 15, "WMANs, WLANs, and WPANs," explores the var- ious options in wireless metropolitan area networks (WMANs), wireless local area networks (WLANs), and wireless personal area networks (WPANs). Chapter 16, "Emerging Wireless Applications," delves into the emerging applications propel- ling the need for high-speed mobile communications. A Brief History of Wireless Telecommunications Radio is defined as the transmission and reception of electrical impulses or signals by means of electromagnetic waves without the use of wires. Basically, radio waves are electromagnetic radiation transmitted through the air to a receiver. The history of wireless technology goes back over 200 years. It began in 1747, when Benjamin Franklin illustrated that electricity can move through air and pro- posed a model of electricity that proved to be correct. In 1819, Hans Christian Oersted, a Danish physicist, observed that a compass needle would move in the presence of an electric field. This established the fundamental relationship between electricity and magnetism and gave rise to the field of study we know as electro- magnetics. Then, between 1865 and 1873, Scottish physicist James Maxwell identi- fied the mathematical relationships between electricity and magnetism, developing four equations that describe the movement of electromagnetic waves through space. He illustrated the basic principle of radio transmission by showing that an A Brief History of Wireless Telecommunications oscillating electric field would produce an oscillating magnetic field that would in turn produce an oscillating electric field. The next step in the development of wireless communications came in 1887, when German physicist Heinrich Rudolf Her