A new frame synchronization algorithm for OFDM WiMAX system in Simulink

PHY(physical Layer) of WiMAX(Worldwide Interoperability for Microwave Access) which is one of 4G core technique adopts OFDM(Orthogonal Frequency Division Multiplexing)/OFDMA(Orthogonal Frequency Division Multiplexing Access), and the frame synchronization is key factor of the OFDM implementation. In this paper, a WiMAX system simulation model is achieved by Simulink firstly, and then a new frame synchronization algorithm based on IEEE802.16d downlink frame structure is proposed. The proposed algorithm first makes coarse synchronization with the first OFDM symbol in long preamble to identify the probable start point of OFDM symbol, and then makes fine synchronization with the second OFDM symbol in long preamble to identify the true start of OFDM symbol. In the end, the new algorithm is embedded into the WiMAX PHY model with the embedded MATLAB function block. The results of the simulation show that the proposed algorithm can produce impulse-shaped timing metric under the low SNR (signal-to-noise ratio) or over multiple fading channel, and timing estimation is more accurate than conventional algorithms.