Study On Signal Design And Modulation Scheme In Ultra-wideband (UWB) Communication Systems

The technical background, present research status, characteristics, basic theory, propagation channel, key techniques and application foreground of ultra-wideband communication are introduced in this paper. Firstly, the Gaussian pulse and its various differential functions in UWB communication system are introduced. Later, we analyze performance of various conventional binary modulation UWB communication system including TH pulse position modulation(TH-PPM),TH binary phase shift keying(TH-BPSK)and direct-sequence binary phase shift keying (DS-BPSK). In order to increase the rate of transmission, simplifying the complexity, the paper proposes two new ways:(1)Deduction the formula of the TH-BPPM UWB system bit error rate on the AWGN and multi-path channel conditions, based on the overlap and orthogonal pulse. The results show that the AWGN channel conditions, based on the overlapped of the pulse signal TH-BPPM have a superior system performance to based on orthogonal TH-BPPM pulse signal. But it can be severely worse if the signals are not well designed. Conditions on multi-path of the orthogonal TH-BPPM system performance, superior AWGN channel under the conditions of system performance.(2)A hybrid direct-sequence time-hopping (DS/TH) impulse radio IR UWB multiple access system is proposed and a simple error analysis is presented for the system. The error analysis facilitates to obtain simple-to-evaluate and accurate error probabilities based on Holtzman's simplified improved Gaussian approximation (S1GA), a method that has previously mainly been used in DS-CDMA. The simulated results show that the method can also be used effectively for IR UWB multiple access systems.