Energy Efficient Circuits and Systems for Impulse Ultra-Wideband Communication

Ultra-wideband radio (UWB) is a rapidly developing wireless technology that promises unprecedented data rates for short-range commercial radios, combined with precise locationing and high energy efficiency. These benefits stem from the use of wide bandwidths and impulse signaling, implying high channel capacity and precise time resolution. UWB has been used for military radar and imaging since the 1950's, however in 2002 the Federal Communications Commission approved the use of the 3.1-10.6GHz band for unlicensed UWB applications. The restriction on transmitted power spectral density is equal to the noise emission limit of household digital electronics. This band is also shared with several existing services, therefore in-band interference is expected and presents a challenge to UWB system design.

This talk will present two impulse UWB chipsets recently developed at MIT that use techniques to gracefully scale power consumption with performance, and exploit the nature of pulsed-UWB signals to reduce energy/bit. The first system utilizes the entire UWB band by dividing it equally into 14 channels and communicating at 100Mb/s in one channel at a time. This system highlights how to automatically adapt complexity and power consumption in response to changing channel conditions. The second system utilizes the 3.1-5GHz portion of the UWB band by dividing it into 3 channels and communicating in each channel with a variable data rate of 10kb/s to 16.7Mb/s. This system exploits the pulsed nature of UWB signals by using an all-digital transmitter and an energy-detection receiver to achieve a low energy/bit that is constant over three orders of magnitude.
David Wentzloff is a Ph.D. candidate at the Massachusetts Institute of Technology, majoring in electrical engineering, with a minor in real estate/finance. David received his B.S. in E.E. from the University of Michigan in December, 1999, and his S.M. from MIT in August, 2002. He's expecting to graduate with a Ph.D. in June, 2007.

In the summer of 2004, David worked at Intel Corporation where he performed RF measurements in the 2.4-GHz and 5-GHz ISM bands using a wafer-probing station. In the summers of 1999 and 2000, he worked in the Powertrain Department at Ford Motor Company developing an automated electrical load box and fault testing system that operates with a Ford PCM (the mini-computer that operates the vehicle).

David's research interests are in RF and mixed signal circuit design. The focus of his Ph.D. thesis is on pulse-based transmitters for UWB applications.