Multi-carrier Modulation Techniques To Achieve

The multi-carrier modulation technology has been put much importance since 1990s with the development of high-speed DSP and communication technology,and becomes an applicable digital modulation technology. The discrete multi-tone is an important type of MCM,it is mainly used in wire-line communication system such as ADSL/VDSL.Equalization is an important area of MCM technology.In DMT system, equalization contains two parts:the time-domain equalization and the frequency-domain equalization. Frequency-domain equalization adjusts the gain of every subchannel. Inter-symbol Interference is cancelled by the time-domain equalizer.The TEQ is used to reduce the duration of shortened channel so that the ISI can be absorbed by cyclic prefix. Because the TEQ influence the performance of the DMT system, the research on TEQ is an important area. This paper analyzes several kind of TEQ algorithms and the performance of DMT system with the optimal shortening algorithm of the channel impulse.The dissertation analyzes the key technology of DMT system. In the static circumstance , The whole DMT system is realized through simulation. Besides,the effect of cyclic prefix and TEQ in DMT system is tested. Finally , compared with the performance of Quadrature Amplitude Modulation system , the conclusion of the performance of the DMT system is drawn.