针对认知无线电系统中正交频分复用( OFDM )信号参数估计这一重要问题, 利用OFDM 信号的循环谱实现了符号周期的盲估计。-For cognitive radio systems, orthogonal frequency division multiplexing (OFDM) signal parameter estimation of this important issue, the cyclic spectrum of the OFDM signal to achieve the blind estimation of symbol period.