This work was supported by the Army Research Office under a Multidisciplinary University Research Initiative (MURI) Award, Contract DAAD10-01-1-0477, and by a grant from M/A-COM, Inc.
Left: Justin Burkhart (BS, UMass-Amherst, May 2006) demonstrates his group's senior design project, a functioning FSR-UWB link, at the UWB Workshop, April 2006.
Right: Ian O'Donnell (UC-Berkeley) works on jamming the FSR-UWB link.
The extremely large bandwidth of ultra-wideband (UWB) radio systems provides the potential for a number of desirable properties: significant diversity against multipath fading, accurate positioning, support for a large number of users, etc. However, this large bandwidth also makes it difficult to design the receiver, and such problems have plagued the UWB field. Digital receivers require a low-power analog-to-digital (A/D) converter with capabilities far beyond what is currently available, and transmitted-reference (TR) ultra-wideband schemes require a large-bandwidth analog delay line that has been a "showstopper" for practical implementation. In this project, we have developed an attractive alternative: a reference that is (slightly) offset in frequency rather than in time [Goeckel/Zhang, MilCom 2005][Goeckel/Zhang, to appear IEEE T-COM]. This small but subtle change results in a system that outperforms TR-UWB and provides a very simple receiver for this traditionally very difficult design problem. In fact, rather than requiring a receiver that is impossible to implement in a small integrated fashion, the FSR-UWB system was implemented by four University of Massachusetts undergraduates as their senior design project [Zhang et al, IC-UWB 2006].