OFDM Technology And The Application In CDMA

OFDM is multi-carrier modulation technology to confront multi-routing , which can divide high-speed data flow to be low and modulate different carriers respectively .Then the symbol pulse duration of each carrier is broadened , by which the system character is developed in confronting multi-routing . With difference from the traditional frequency division multiplexing style , OFDM is permissive to symbol frequence superposition .As appositional carrier precept , OFDM can support high frequence efficiency . But this requires carriers should be serious orthogonal.The title is mainly about OFDM, which is one of the key technologies in 4G. It introduces the origin and development of OFDM, and shows detailed the feature of wireless channel and the principle of OFDM. The emphases of the content is about the key technologies of OFDM, such as the reduce the PAPR , estimating of channel and synchronization technology .In the ago solutions, the synchronization realized by inserted exercitation sequence and guide frequency and etc, which certainly will affect the carry efficiency of communication system , so we come out the relativity estimating based on CP to realize the synchronization , and we also give the simulation platform and putout .At last, it's mentioned the main application of OFDM , which is combined with CDMA . The most important is MC-CDMA , which combines the both strongpoints and develops many characters of CDMA . MC-CDMA is granted as one of the key projects for the next general wireless telecommunication system .