第四代移动通信系统的调制技术

现有通信系统的调制技术限制了信号速率的进一步提高,即将推出的第四代(4G)移动通信系统需要更优良的调制技术。正交频分复用(OFDM)技术是很受欢迎的高速率无线通信技术,结合OFDM的调制技术将在4G系统中得到广泛应用。文中概要介绍了4G系统的特点及关键技术,然后系统介绍了OFDM多载波原理,最后重点介绍了多载波码分多址(MC-CDMA)和正交频分复用时分多址(OFDM-TDMA)两种多载波调制(MCM)技术。

Modulation Technologies for 4G Mobile Communication System

On account of the modulation technology used in current communication systems, the further increase of signal rate is limited. Thus, the impending 4G communication system provides us with a prefect opportunity to explore more eff ective and advanced modulation technology so as to adapt to the need of multimed ia communications. As orthogonal frequency division multiplexing (OFDM)is a popu lar method for high data rate wireless communication, this modulation technologi es combined with OFDM will be applied widely in 4G communication system. This pa per briefly describes the characteristics and key technologies in 4G mobile comm unication system, and then introduces OFDM multi-carrier theory systematically. Finally, it focuses on analyzing two kinds of multi-carrier modulation technolog ies, including multi-carrier CDMA and OFDM CDMA.