关键词: 循环谱, 认知无线电, 盲信号处理, 正交频分复用, 参数估计

Abstract: To explore the parameters estimation of OFDM (Orthogonal Frequency Division Multiplexing) signals in cognitive radio systems, the symbol duration blind estimation of OFDM signals was achieved through the cycle spectrum. Firstly, the cyclostationarity of the OFDM signals with cyclic prefix and rectangular pulse shape was demonstrated. Then based on the cycle spectrum of single-carrier signal and the orthogonality of OFDM subcarriers, the cycle spectrum expressions of OFDM signals were derived on the condition of no noise and low SNR. Finally, the computer simulation results of both the continuous signals and discrete signals are the same, which can estimate the symbol duration of OFDM signals blindly with low SNR through the cycle spectrum.

Key words: cyclic spectrum, cognitive radio, blind signal processing, OFDM(Orthogonal Frequency Division Multiplexing), parameters estimation