OFDM——第四代移动通信的主流技术

OFDM—Main Technology of 4G Mobile Communication System

正交频分复用(OFDM)是一种特殊的多载波数字调制技术。不像常规的单载波技术,如AM/FM(调幅/调频)在某一时刻只用单一频率发送单一信号,OFDM在经过特别计算的正交频率上同时发送多路高速信号。OFDM技术的最大优点是对抗频率选择性衰落或窄带干扰,同时又提高了频谱利用率。OFDM已经吸引了许多世界级电信设备制造商包括Alcatel-Lucent,Nortel(北电网络),Cisco,Nokia等公司的极大兴趣和认可,纷纷开始对其关键技术和标准进行研究和开发,希望能够在无线通信领域新的潜在市场中首先占领制高点,一些公司希望OFDM能推动更高速的第四代移动通信系统(4G)的形成。人们开始集中越来越多的精力开发OFDM技术在移动通信领域的应用,在无线宽带接入及未来4G领域中,OFDM技术都将成为继CDMA技术之后的又一核心技术。介绍了OFDM的原理和技术优势,分析了现存几种类型OFDM技术的特点,展望了OFDM标准化和在第四代移动通信系统的应用。

OFDM（orthugorml frequency division multiplexing）is a special digital modulation technology of multi-carriers. Unlike normal siugle carrier technology, such as AM/FM,OFDM can tranmit a number of data streams simultaneously through its sub - carriers which are orthogonal. The orthogonality also allows high spectral efficiency, and frequency （subcarrier） interleaving increases resistance to frequency- selective channel conditions such as fading. OFDM has attracted many suppliers worldwide, such as Alcatel - Lucent,Nortel,Cisco, Nokia etc. into the R＆D of its key techniques and standards. All of them want to have a share of the potential wireless communication marketing and try to make 4G come into being based on OFDM. Nowadays,more and more people are involved into OFDM technology, undoubtedly it will be the core technology of wireless wideband access system and 4G after CDMA technology. In this article, the principle,advantages and applications of OFDM in ccanmunications are briefly introduced. In the end,highlighted the standardization of OFDM and its applications in 4G mobile communication system.