Blind Estimation of OFDM Carrier Frequency Offset Using Shift-invariance Properties

We address the problem of carrier frequency offset (CFO) synchronization in Orthogonal Frequency Division Multiplexing (OFDM) communications systems in the context of frequency-selective fading channels. The mathematic model of OFDM systems with cyclic prefix (CP) and virtual subcarrier is derived. And we propose the shift-invariance CFO estimation algorithm based on DOA-MATRIX method. After the rough estimation, it can acquire the frequency offset and matrix including channel information simultaneously, which are favorable for offset compensation and demodulation of received signals. Simulation results illustrate performance of this algorithm.