The Simulation Of NMT On ADSL Loop

The digital communication technology is developing rapidly, and many means of communication appear one after another. However, the modulation technique has not actually changed significantly. The traditional modulation techniques such as PAM, FSK and PSK are still in use. The Discrete Multi-tone Modulation Technology (DMT) which started to be used in DSL in 1990s and CDMA which is used in 3G are based on multiple carrier waves principal. And it has been founded since 1958. Professor Dequn Liang brought forward the Non-Orthogonal Multi-Modulation Technology, which breaks through the limitation of orthogonal character, brings higher spectrum usage efficiency, and may have significant influence to digital communication.In the past few years, wide band digital communication technique in backbone and many means of communication were developing rapidly; In comparison, user access network developed much more slowly and became the bottleneck of the entire communications network, especially the high speed Internet. Since the middle of 1990s, DSL has been one of the ways to solve the problem of the last kilometer. But there are limitations in distance and bit rate of xDSL. NMT can overcome this limitation.In order to promote NMT to practical application, the simulation research is necessary to validate the feasibility of NMT. Although many researches have been done by some graduate students before, with further studies of the project request, many technical barriers must be overcome and the simulation should be done according to project requirement. The aim is to do simulation of NMT on ADSL loop.The dissertation analyses the performance of NMT on ADSL loop, for instance, PAR, and makes the comparison between NMT and DMT of transmission rate under the same condition. The dissertation also simulates the system with the toolbox SIMULINK in MATLAB. The specific coding technology which is based on NMT is adding the additional wave, which solved the problem of distortion in loop and effectively enhances the transfer rate.