中文摘要：

文中结合OFDM信号二阶循环特性的自身特点，提出一种基于循环统计量的OFDM信号CFAR检测算法。通过采用改进的白相关算法确定特定时延，将协方差估计矩阵由2N维降至2维，避免多维运算的复杂度。并在此基础上，实现了对OFDM符号长度、有用符号时间、循环前缀长度、子载波间隔的盲估计。仿真实验表明，该算法具有较强的抑制加性干扰和乘性干扰的能力；并能在缺乏先验知识的条件下。实现低信噪比下OFDM信号的可靠检测及其参数的有效估计。

英文摘要：

Combining with the special characters of 2-th cyclic cumulants for orthogonal frequency division multiplexing （OFDM） signals, constant false alarm rate（CFAR） test for OFDM presence is proposed particularly. Covariance matrix dimension is descended from 2N to 2, which avoids the complexity of multi-dimensional computation. On the base of this, blind estimations of the symbol period, useful symbol duration, and the length of cyclic prefix and the carrier frequency offset of OFDM can be obtained. Experimental results demonstrate the detection algorithm has strong ability to counteract the add interference and multiply interference; It also can detect OFDM signals and achieve the parameters estimation effectively at a lower SNR.