This book summarizes the study on signaling design in ultra-wideband (UWB) system wireless communication systems. UWB signaling design can be effectively manipulated for the purposes of performance improvement and interference mitigation. Timing jitter, as a critical issue in UWB signaling design, is also investigated to assess its impact to system performance. Chapter 1 describes the research background, and the motivation that becomes the catalyst to the completion of this study. Chapter 2 provides an overall introduction to UWB systems, with specific emphasis on direct sequence (DS) and DS multiband (MB) approaches. Chapter 3 deals with signaling design in varying low chip duty factor (DF), a unique parameter in UWB system. Chapter 4 proposes two interference mitigation techniques developed by manipulating signaling design in DS and DS-MB UWB system. Chapter 5 highlights and mitigates the impact of timing jitter in UWB signaling design.