A new time delay estimation algorithm for mixed OFDM signal

In the paper, a new time-delay estimation algorithm, which is based on the cyclic auto-correlation function, is proposed for single-channel two mixed OFDM signals without data-aided. In the method, the linear equations on time delay parameters are constructed from different cyclic autocorrelation functions, and the closed-form solutions are obtained by solving the equations without any prior information of fading parameter and shaping filter. Besides, it also analyzes the Cramer-Rao bound of time-delay estimation of mixed OFDM signal, and verifies the effectiveness of the proposed method through computer simulation. The analysis and simulation results show that the proposed algorithms can achieve good blind estimation for the time delay of mixed OFDM signal in a single channel.