正交频分复用技术及其在4G移动通信中的应用

正交频分复用（ OFDM）技术是一种特殊的多载波数字调制技术。由于OFDM的各个子载波存在正交性，极大地利用了频谱资源，所以在一定程度上缓解了未来频谱资源紧缺的问题；OFDM有良好的抗码间干扰能力和对抗频率选择性衰落，能够适应未来无线通信无失真高速数据传播的要求；各个子信道的调制和解调能用FFT和IFFT实现，因而能够满足无线通信系统中的业务要求。文中首先介绍了OFDM技术的基本原理，接着阐述了它的优势以及需要克服的缺陷，再分析了4G移动通信技术的特点，最后讨论了OFDM技术在4G移动通信系统中的应用。

Orthogonal Frequency Division Multiplexing Technology and Its Application in 4 G Mobile Communication

OFDM （Orthogonal Frequency Division Multiplexing） is a special kind of multi-carrier digital modulation technique. Each OFDM subcarrier orthogonality exists,great using of spectrum resources,to a certain extent,ease the problem of shortage of spectrum re-sources in the future. OFDM has a good ability to resist intersymbol interference and fight against frequency selective fading,able to adapt to the future wireless high-speed data transmission without distortion. Each channel modulation and demodulation with FFT and IFFT is easy to implement,and thus can satisfy the requirements for the business in the wireless communication system. In this paper,introduce the key techniques of OFDM,describe the advantages of OFDM and the need to overcome the defects,and then analyze the characteristics of 4G mobile communication technology,finally discuss the application of OFDM in 4G mobile communication system.