Study On The Waveform Design Of IR-UWB Communication Systems For Space Formation Flying Applications

The issue of outer space formation flying is an important developmentdirection of astronautics. Creating space formation flying communication system isan important direction of achieving space formation flying. The advantages ofultra-wideband (UWB) are suitable for outer space formation flying technology. Forthis reason, UWB is applied to this field increasingly. As a novel multi-usercommunication system, UWB multi-user communication system has the advantageof large communication capacity and excellent multiple access multiplexingcapability. However, the research is only at the stage of theoretical research due tohardware conditions. The system will disturb the existing measurement and controlsystem (mainly unified S-band control system) because of the widebandcharacteristic of ultra-wideband. This study discusses the issue of coexist spectrumfor the ultra-wideband communication system and other systems. It focuses on theproblems of designing ultra-wideband signal waveform. The research considersthree kinds of UWB waveform design methods and designs a new type ofultra-wideband communication system.Firstly, UWB waveform design methods based on Gaussian pulse are studiedfor the conditions of current limited load and simplified equipment. This method isvery suitable for wireless communication system inside satellite cabin, and it is anecessary means for the achieving of space formation flying communication systemearly days. The simulation shows the required waveform and the the shortcomingsof this approach.Secondly, UWB waveform design based on the soft spectrum adaptation (SSA)is researched. The main idea of this approach is that UWB waveform transmittingaccording to the independent designing and meeting specific functions. Thesimulation shows that this method has better notch characteristic. Simultaneously,we test the interference level of UWB signal to other common communicationsystems, and obtain the bit error rate performance curves. These studies can betterexplain and solve the compatibility issues of UWB communication system and othersystems. Finally, waveform division multiple access (WDMA) communication systembased on orthogonal wavelets is proposed for the demand of high-speedcommunications and good ability of anti-MAI. The properties of orthogonal waveletare used to design UWB waveform, and different users are separated by usingdifferent orthogonal wavelets. Therefore, it has a very good multi-site capability.Compared with pseudo-random sequence (DS-UWB) multiple access system, thesimulation shows the advantages of WDMA communication system based onorthogonal wavelets.