Pulse Shaping And Waveform Optimization Algorithm For Ultra-wideband Communication Systems

Ultra-wideband(UWB)wireless communication system uses ultra-narrow pulses as transmitted signals to carry date symbols.It has large communication capacity,low power consumption,high positioning accuracy and immunity to multipath fading.In order to meet the U.S.Federal Communication Commission(FCC)regulations on radiation mask,pulse design has been one of the major issues of UWB communication systems.Moreover,the requirements of the large bandwidth and low power spectral density(PSD)make the basic pulse signal unable to meet the needs of UWB waveform design.Accordingly,pulse shaping and waveform optimization techniques are investigated in this dissertation,in which the main contributions are summarized as follows:(1)In order to overcome the drawback of the spectrum shifted Gaussian waveforms(SSGW)method in which the coefficient suffers from large computation complexity and excessive error,the random selection(RS)and Least Square Error(LSE)algorithms are introduced to the SSGW pulse design to get the weighting coefficients.Theoretical analysis and simulation results show that compared with the SSGW and the Gaussian derivative approaches,the improved SSGW(ISSGW)method can meet the requirements of FCC spectrum mask better.Meanwhile,it has higher spectral efficiency and better link transmission capacity.(2)To evaluate the effect of pulse waveform on system bit error rate(BER)performance,the transmitted reference(TR-)UWB system is investigated using the raised cosine pulse,Scholtz's pulse,and LSE-ISSGW pulse,respectively.Theoretical analysis and simulation results indicate that the BER performance with the LSE-ISSGW pulse is better than that with the other two pulse waveforms and therefore it can be considered as a promising pulse candidate for UWB communications.