由于载波频偏会给多用户正交频分复用(Orthogonal Frequency—Division Multiplexing,OFDM)系统带来子载波之间干扰,从而造成多用户之间的干扰,导致系统性能下降.本文研究了多用户OFDM上行链路的频偏估计问题,通过使用多用户检测中的干扰抵消方法提出一种迭代参数估计算法用于估计多用户OFDM上行链路的频偏,该算法解决了使用似然估计(Maximum Likelihood,ML)进行多维搜索的问题,降低了ML估计器的复杂度,同时解决了多个频偏估计的问题。
Carder Frequency offsets in multiuser Orthogonal Frequency-Division Multiplexing (OFDM)system will introduce Inter-Cairier Interference (ICI)and Multiple-Access Interference (MAI), and consequently degrade the system performance. The problem of frequency offsets estimation in the uplink of multiuser OFDM is addressed. A novel iterative parameter estimation method with interference cancellation of multiuser detection is proposed. The new estimator decreases the complexity of the multi-dimensional search with ML method, and efficiently solves the problem of multi-frequency offsets estimation.