Ultra-wideband communications: an idea whose time has come

Summary form only given. Ultra-wideband (UWB) refers to bandwidths in excess of 2 GHz, whose utilization by radar systems dates back to the late ´60s. The renewed and rapidly growing interest for UWB was sparked by the spectral mask released by FCC in February 2002, and is well motivated by the attractive features UWB brings to commercial communications: low-power carrier-free transmissions, ample multipath diversity, enhanced penetration capability, low-complexity transceivers, ability to overlay existing systems, and a potential for increase in capacity. This article outlines features and challenges unique to UWB, with emphasis on timely signal processing issues that focus on synchronization, channel estimation, multiple access, and suppression of interference UWB systems cause to (and suffer from) co-existing narrowband systems. Application areas include shortrange indoor wireless links at home, and in the workplace for low-cost multimedia communications and storage, as well as secure connectivity for ranging, and covert communications.