Abstract: In this paper, a reliable orthogonal frequency division multiplexing (OFDM) baseband system is designed, including convolution coding and decoding, interleaver and deinterleaver, OFDM modulation and demodulation. The system scheme and implementation methods of field programmable gate array (FPGA) are also provided. A frame synchronization scheme based on delay-correlation and cross-correlation is adopted, and the result of frame synchronization is used for both lost frame complement zero module and deinterleaver module in order to improve reliability. The performances of system implemented by FPGA are tested under the additive white Gaussian noise (AWGN) and the interference of single tone and partial band respectively. The results indicate that the system implemented can achieve reliable data transmission with large noise and interference.