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Timing synchronization for MIMO-OFDM using orthogonal sequences in Rayleigh fading channel

MIMO-OFDM systems have the ability to maintain high performance even in sophisticated channel conditions. But to ensure that the system remains robust to multipath channel conditions proper timing and frequency synchronization is essential. The multipath fading channels and noise in the signal makes timing synchronization difficult to implement. In this paper, a timing synchronization technique using orthogonal sequences namely CAZAC sequence and Hadamard sequence is proposed. The timing ambiguity caused by the plateau problem owing to the repeated structure of short training sequence is removed by the use of a sliding window differentiator. The pseudo multipath problem caused by the cyclic delay diversity (CDD) scheme is also eliminated. The performances of both the sequences and the proposed design using CAZAC sequence are evaluated at different SNR values. The simulation results show that the newly designed CAZAC sequence has better performance.