一种改进的OFDM系统CFO的盲估计方法

OFDM系统的载波频偏导致相邻OFDM符号相同子载波上的信号功率产生了差异。基于这个思想,利用OFDM信号的4阶矩与频偏满足余弦函数关系的特点,提出一种载波频偏估计的改进方法,即子载波功率差分估计方法。该方法具有简单的闭式解,避免了迭代搜索过程,降低了计算量,同时也适用于慢时变的频率选择性衰落信道。仿真实验表明,与现有方法相比,改进后的方法在降低计算复杂度的同时也具有良好的估计性能。

An Improved Method for Blind Estimation of CFO in OFDM Systems

Carrier Frequency Offset （CFO） of OFDM system leads to the difference between signal powers of the same sub-carrier in neighboring OFDM symbols. Thus, an improved CFO estimation method, named the Difference of Sub-carrier Power （DSP）, is proposed on the basis of the characteristic that the 4th-order moment of OFDM signal is a cosine function of CFO. The proposed method has a simple closeform solution, which avoids the process of iterative searching and has less computational complexity, and it is suitable for slow time-varying frequency selective fading channels. The simulation results show that, compared with the existing methods, the proposed method provides a good trade-off between computational complexity and estimation performance.