正交频分复用(OFDM) 是第四代移动通信的核心技术。该文首先简要介绍了OFDM的发展状况及基本原理, 文章对OFDM 系统调制与解调技术进行了解析，得到了OFDM 符号的一般表达式，给出了OFDM 系统参数设计公式和加窗技术的原理及基于IFFT/FFT 实现的OFDM 系统模型。-Orthogonal frequency division multiplexing (OFDM) is the fourth generation mobile communication core technology. The article briefly describes the development of OFDM and the basic principles, the article OFDM system modulation and demodulation techniques are parsed to obtain a general expression of OFDM symbols, OFDM system design parameters are given formula and windowing technology works and based on the IFFT/FFT OFDM system model implemented.