Abstract: The authors propose a pseudo-noise (PN) sequence-based carrier frequency offset (CFO) estimation algorithmfor multiuser OFDMuplink. In the proposed algorithm, a PN sequence and its circular-shifting versions are considered as training sequences for different users, and then channel parameters with CFO factors from each user to a central base station can be estimatedby virtue of autocorrelation characteristic of the PN sequence. Finally all users’CFO estimates can be acquired simultaneously by calculating channel phase-angle difference between two training periods. The simulation result shows that the proposed algorithm achieves better estimation performance.

Key words: multiuser OFDM, pseudo-noise (PN) sequence, carrier frequency offset (CFO) estimation

摘要： 针对多用户正交频分复用(OFDM) 系统上行链路中的载波频偏估计问题, 提出一种基于伪噪声(PN)序列的载波频偏(CFO)估计算法。该算法将不同相位的PN序列作为各个用户的训练序列, 利用训练序列良好的自相关性估计出存在CFO 情形下不同用户的信道参数, 再根据两个训练周期内信道参数的相位变化获得各用户的CFO估值。理论分析和仿真结果表明本算法具有优 良的估计性能。

关键词: 多用户OFDM系统, 伪噪声(PN)序列, 载波频偏(CFO)估计