Error Control Coding Schemes for Ultra-wideband Impulse Radio Systems

Abstract

Ultra-wideband (UWB) is a promising technology that offers a potential solution for the data rate, cost, power consumption and physical size requirements of the next generation wireless devices. UWB may also play an important role in the realization of future heterogeneous networking. This technology has recently gained significant interest from both academia and industry. The strength of the UWB lies in the very large instantaneous bandwidth that is used and the potential for simple transceiver architectures. This thesis deals with several important aspects of the UWB technology, including modeling of feasible ultra-wideband impulse radio (UWB-IR) systems, their performance characterizations, and suitable methods for protection against errors. The main goal of this thesis is to propose and evaluate novel error control techniques particularly suitable for UWB-IR systems operating in severe multipath interference prone environments. The proposed methods exploit the temporal diversity brought by the UWB channels through multipaths and as a result allow for the alleviation of destructive effects of inter-symbol (ISI), inter-frame (IFI), and inter-pulse (IPI) interference. We found that rearranging the order of UWB chips or UWB frames results in a bit error rate (BER) performance improvement. This improvement is particularly apparent in case of UWB-IR systems with frame repetition as the method of protection against errors. The novelty of the presented analysis is that it considers ISI, IFI, and IPI effects, RF front-end issues and real antenna characteristics that are often neglected by the researchers. Moreover, they are presented, for the first time, for the given type of the simple incoherent receiver architecture (differential autocorrelation receiver), channel coding scheme (superorthogonal convolutional coding), and channel model (IEEE 802.15.3a multipath fading channel).