ments for data rate (both high and low), operating range (long and short) and power consumption (low and very low), as shown in Figure 1-1. The Diversity of Wireless Networking Technologies Wireless networks now operate over four orders of magnitude in data rate (from ZigBee at 20 kbps to wireless USB at over 500 Mbps), and six orders of magnitude in range (from NFC at 5 cm to WiMAX, and also Wi-Fi, at over 50 km). To deliver this breadth of capabilities, the many companies, research institutions and individual engineers who have contributed to these developments have called into service a remarkable range of technologies; from Frequency Hopping Spread Spectrum, the inspired World War II invention of a film actress and a screen composer that is the basis of the Bluetooth radio, to Low Density Parity Check Codes, a breakthrough in high efficiency data transmission that lay gathering dust for forty years Introducing Wireless Networking after its development in 1963 and has proved to be an enabling technology in the most recent advances towards gigabit wireless networks. Technologies that started from humble origins, such as OFDM - used in the 1980s for digital broadcasting, have been stretched to new limits and combined with other concepts, SO that Ultra Wideband (UWB) radio now uses multi-band OFDM over 7 GHz of radio spectrum with a transmitted power below the FCC noise limit, while OFDM combined with Multi- Carrier Code Division Multiple Access is another gigabit wireless network enabler. Techniques to satisfy the every growing demand for higher data rates have gone beyond the relatively simple approaches of shortening the time to transmit each bit, using both the phase and amplitude of the carrier to convey data or just using more radio bandwidth, as in UWB radio, and arrived at the remarkable concept of spatial diversity - of using the same space several times over for concurrent transmissions over multiple paths - as applied in MIMO radio. This fascinating breadth and variety of technologies is the first moti