@misc{oai:niigata-u.repo.nii.ac.jp:00004878,
 author = {Sum, Chin sean},
 month = {Mar},
 note = {In this research, the study of signaling design in ultra wideband (UWB) system is conducted. 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. Then the objectives are listed to provide a clear direction for the study. Finally the overview of the thesis is to define the areas in which the research has covered. Chapter 2 provides an overall introduction to UWB systems, with specific emphasis on direct sequence (DS) and DS multiband (MB). System models including signal model, received signal and receiver model are presented and discussed in detail. The UWB system is designed to propagate over multipath and multi-user channel. The considered multipath environment is defined by the IEEE 802.15.3a channel models (CM). The characteristics of the CM’s are also introduced and elaborated with suggested further references. Multi-user environment in this study assumes that asynchronous simultaneous users share the same propagation channel with similar transmitted power. Next, applying the system model developed, performance of UWB system corresponding to different parameters and propagation environments are presented and analyzed. Chapter 3 deals with signaling design in varying low chip duty factor (DF), a unique parameter in UWB system. Firstly, three methods of designing low DF UWB signal are introduced. Each method manipulates different parameters, requires different system resources and is capable of offering respective advantages. Then, the systems are simulated over multipath and multi-user environment in the presence of a coexisting narrowband signal. In multipath and multi-user environment, the interactions between low DF UWB signaling design to channel fading, self interference and multi-user interference are analyzed, and the related system performance are evaluated. Additionally, assuming the presence of a coexisting narrowband signal, the advantage of low DF UWB signaling over narrowband interference is also presented and discussed. System performance is evaluated from both the perspectives of energy capture and bit error rate., In this chapter, besides DS and DS-MB spreading techniques, time hopping (TH) and DS-TH spreading techniques are also coupled to low DF UWB signal to provide more thorough investigations. Chapter 4 proposes two interference mitigation techniques developed by manipulating signaling design in DS and DS-MB UWB system. UWB system occupies a wide bandwidth, thus easily receives interference from coexisting narrowband systems, and simultaneously generates UWB interference to these narrowband systems. Techniques which are able to mitigate this mutual interference by: (a) suppressing sub-band power in a multiband UWB system and (b) employing signaling design with low DF, are developed and presented. Firstly, DS-MB-UWB system with sub-band power suppression is proposed and the ability to mitigate mutual interference is discussed. Next, DS and DS-MB-UWB systems employing low DF signaling design are proposed with analysis of their interference mitigation capabilities. Then, by combining the mitigation techniques to respective UWB systems, performance in coexistence with a narrowband system over different propagation environments is investigated. Additionally, the effects of applying different parameters in system design are also presented and commented. Chapter 5 highlights and mitigates the impact of timing jitter in UWB signaling design. Timing jitter exists in all digital communication systems, and is particularly pronounced in UWB signal with nano-second order pulses. Firstly, the introduction on timing jitter existing in UWB receiver is presented. Then, the relationship between timing jitter and the degradation of correlator output in the receiver is discussed. Next, the statistical properties of timing jitter are characterized and modeled. Applying the system model and timing jitter model, the performance of UWB system over multipath and multi-user environment in the presence of timing jitter is evaluated. The compromised performance improvement achievable by adding different system resources are investigated and commented corresponding to varying timing jitter. Lastly, a mitigation technique to timing jitter is developed by employing DS-MB-UWB signaling design, and the results are shown. Chapter 6 sums up the study with concluding remarks. The prospects of signaling design in UWB performance improvement and interference mitigation are commented with potential future works., 新大院博（工）甲第247号},
 title = {Signaling  Design in Ultra-Wideband wireless communication system},
 year = {2007}
}