A blind timing and frequency synchronization method based on the correlation characteristics of an OFDM signal

Orthogonal Frequency Division Multiplexing (OFDM) systems are very sensitive to symbol timing and frequency offsets. Therefore, it is very important to achieve a high precision time and frequency synchronization. With the absence of pilot symbols, blind synchronization algorithms using different metric functions or statistics of the received signal can be used. In this paper, a new blind symbol timing and frequency offset estimation algorithm is proposed for OFDM systems in multipath fading channels. The method utilizes the redundant information contained in the cyclic prefix and does not necessitate any channel profile knowledge. In contrary to other works that propose a timing function, the proposed method extracts the timing offset and the channel length directly from the correlation characteristics between the received samples. Consequently, an interference-free region is specified and the frequency offset is jointly estimated. The performance of the proposed method is demonstrated using Monte Carlo simulations over Rayleigh multipath fading channels of different delay spreads. The results show that the proposed algorithm outperforms considerably other algorithms in related work and is robust to varying channel conditions.