After channel coding, the input MPEG-TS code stream forms an IDFT data block with a length of 3780 in the frequency domain. Transform the IDFT data block into a time-domain discrete sample frame with a length of 3780 with a sample of 7.56 m/s by DFT; Inserting a PN sequence with a length of 378 into the guard interval of OFDM as the frame header; Combining the frame header and the frame body into a signal frame with a time length of 550; FIR low-pass filter with linear phase delay is used to shape the signal in frequency domain. Baseband signals are up-converted and modulated onto RF carriers.