Research: Interference Mitigation for Ultra-Wideband

The focus of this research is interference mitigation techniques for ultra-wideband (UWB) systems. UWB is designed to operate over a large band of frequencies, from 3.1GHz-10.6GHz. Within this band, there are many existing narrowband systems, such as WiMAX at 3.5GHz and the 5GHz ISM band. By operating within these frequencies, UWB systems may cause interference to these narrowband systems. To minimize the interference caused by UWB systems, spectral shaping coding techniques that minimize the power, and consequently the interference, in certain frequency bands have been developed. These coding techniques spectrally shape two UWB modulation techniques: impulse radio and MB-OFDM.

As a step towards testing the performance of possible UWB coding techniques, a 10Gsamples/sec 5-bit DAC is implemented in Jazz Semiconductor’s 0.18um SiGe BiCMOS process. A test circuit is integrated onto the chip, and the entire chip is probe tested to verify operation at conversion rates higher than 10Gsamples/sec.

This work is supported by the UCSD Center for Wireless Communications, and the UC Discovery grant.

Ph.D. Dissertation