上行链路中的粗频偏及定时估计是多用户 OFDM系统的关键技术之一。如果粗频偏估计不准 ,将带来严重的子载波间干扰 ( ICI) ,而定时估计引入的符号间干扰 ( ISI)虽然可以通过加入保护间隔予以消除 ,但是如果定时估计不稳定将影响整频偏移的估计及均衡的效果。本文提出了一种基于 PN序列的粗频偏及定时估计 ,仿真结果表明该方法具有良好的性能 The coarse frequency offset and timing estimation in the uplink are one of the key technologies in multi-user OFDM systems. If the coarse frequency offset estimation is not accurate, it will bring serious inter-carrier interference (ICI), while the ISI introduced by the timing estimation can be eliminated by adding a guard interval. However, if the timing estimation is unstable, it will affect the whole Frequency Offset Estimation and Equilibrium Effects. This paper presents a coarse frequency offset and timing estimation based on PN sequence. The simulation results show that this method has good performance