A New Technique for Frame Synchronization of OFDM Systems

Orthogonal frequency-division multiplexing (OFDM) is a well known multi-carrier digital modulation scheme in which a transmitted data is split into multiple streams that are modulated at different frequencies. The OFDM system is very sensitive to frame and frequency synchronization errors. In this paper, we propose a new OFDM preamble for accurate frame synchronization of OFDM systems. The preamble is generated by loading the second half of the subcarriers of the preamble with the complex conjugate of the PN (Pseudo random sequence) data loaded onto the first half of the subcarriers in frequency domain. By using the proposed preamble, a frame synchronization method for OFDM systems is described. And, it is shown that the proposed frame synchronization method yields sharp peak at the frame boundary and is independent of carrier frequency offset. Simulations are conducted for AWGN and frequency selective channels to demonstrate the performance of the proposed method. Finally, proposed method is compared with the existing methods and shown that it shows superior performance in severe fading channels.