Chapter 34 - Ultra-Wideband Wireless Technology

Summary

Ultra-Wideband (UWB) signaling technology is a modern wireless technique crafted to comply with recent regulations permitting UWB technology. Historically UWB, once called impulse radio, was defined by very short baseband signals that are transmitted and received without a radio frequency (RF) carrier in the usual sense. The technique reuses previously allocated RF bands by spreading the energy thinly in a wide spectrum, thus having a minimal impact on incumbent spectrum users. Regulations and Recommendations have been written in a way that restricted the permitted operating frequency ranges along with the emission levels, but remained silent on the modulation and signal characteristics. Hence in addition to pulse-based UWB technology, conventional technologies such as OFDM have been exploited under the rules. This chapter will expand on pulse-UWB, particularly at very high data rates, wherein the bandwidth of the signal is directly related to the inverse of the emitted pulse duration. Applications of UWB devices are presented, and potential use cases are described. It is shown that short-pulse low-power techniques have enabled practical through-wall radars, centimeter-precision 3-D positioning, and communications capabilities at the high data rates and with exceptional spatial capacities.

Introduction

Ultra-Wideband (UWB) wireless signaling is essentially the art of generating, modulating, emitting and detecting signals that inherently occupy large bandwidths. Wide band transmissions date back to the infancy of wireless technology. They include the wireless experiments of Heinrich Hertz in the 1880s, Alexander Popov in the 1890s, and later the 100 year old trans-Atlantic spark gap “impulse” transmissions of Guglielmo Marconi.