A Class of Ultra Wideband (UWB) Systems with Simple Receivers

Abstract

Ultra-wideband (UWB) communication systems are of interest in many applications, including those that require accurate positioning and low data rate communications (e.g. IEEE 802.15.4a). However, UWB systems have been dogged by implementation concerns, particularly that of building the receiver in a small integrated fashion for extremely low-power devices. Thus, UWB systems with simple receivers are of interest. Candidate modulations for such include the burst-mode pulse-position modulation (PPM) being standardized in IEEE 802.15.4a, and the recently-introduced frequency-shifted reference (FSR) UWB scheme. Here, we show that, in the single-user case, the FSR-UWB system can be modified in a very simple way to yield other systems that are also easy to implement. In particular, rather than employing a cosine for separating the data and reference signals (as we originally proposed in the FSR-UWB system), one can employ any waveform from a very large class for such. The resulting class is general enough to encompass FSR-UWB, PPM, and on-off keying (OOK), thus capturing all three of the commonly-considered UWB schemes that provide very simple receivers. We provide a performance characterization of systems in the class on both additive white Gaussian noise (AWGN) and multipath fading channels as a function of the waveform employed, thus allowing a unified performance comparison of not only the commonly considered systems listed above but also numerous other heretofore unconsidered systems. Optimization across this class can then be considered for various operating scenarios.