Simulation Of The Non-Orthogonal Multi-modulation With Frequency, Time And Phase Shift

The modulator as a basic link plays a decisive role in the digital communication system.However,the development of the modulation technology is slower than other technologies.The Non-Orthogonal Multi-modulation Technology(NMT) developed by Professor Liang Dequn is a novel modulation technology which breaks through the limitation of orthogonality in traditional modulation methods.To verify the feasibility of NMT,PhD.student Cao Qi-Sheng and the graduate students have made a lot of investigations on the theory and computer simulation and proved the feasibility and advantage of NMT.But previous researches were generally been limited to the NMT of FTS.Since most of the channels are frequency selective channels,a bad decline of signal amplitude will be caused,meanwhile,the method of FTPS is not sensitive to frequency decline.Therefore,this research is mainly focused on the simulational application of NMT/FTPS.The simulational researchs of NMT/FTPS on wired and wireless channels have been made in this project,based on the platform of MATLAB.The wired channels mentioned above are ADSL channels of both 12kft and 15kft and category 5 cables with a length of 300 meter.And the wireless channels are Metropolitan Area Network WiMax channels.Simulation of system capability has been made with the technology of NMT/FTS using above-mentioned channels in the initial stage of the project,and then, the same simulation has been made based on the same model but with the technology of NMT/FTPS,consequently,the transmission performances between the two types of modulation under the same condition and with the same channel model have been compared.We introduced in the method of spectrum move in the simulation of 300-meter category 5 cables,and made the simulations with both the ordinary NMT technology and the NMT technology with the method of spectrum move under the same condition,and then compared their sampling rates.And the simulation results indicate that as far as the frequency selective channel is concerned,the transmission performance of the technology of FTPS is better than the technology of FTS;and the method of spectrum move could reduce the sampling rate.