An optical line terminal, comprising: a common public radio interface,CPRI, interface, configured to receive first data from a baseband unit,BBU; a wireless compatibility module, configured to sequentially perform operations of decoding and CPRI control word extraction on the first data, to obtain second data and a CPRI control word; a data compression module, configured to perform data compression processing on the second data, to obtain third data; a framing module, configured to form a control frame by using the CPRI control word and an access network control word; a frequency aggregation module; a digital-to-analog conversion module, configured to perform digital-to-analog conversion on data obtained from the frequency aggregation module, to obtain an analog signal; and an optical transmitter, configured to modulate the analog signal into an optical signal, and send the optical signal to an optical distribution network,ODN; wherein the frequency aggregation module comprises: a fast Fourier transformation FFT unit, configured to separately perform FFT transformation on the third data and the control frame; an inverse fast Fourier transformation IFFT unit, configured to perform IFFT transformation on third data and a control frame that are obtained by means of FFT transformation; and a parallel-to-serial conversion unit, configured to perform parallel-to-serial conversion on third data and a control frame that are obtained by means of IFFT transformation. a common public radio interface,CPRI, interface, configured to receive first data from a baseband unit,BBU; a wireless compatibility module, configured to sequentially perform operations of decoding and CPRI control word extraction on the first data, to obtain second data and a CPRI control word; a data compression module, configured to perform data compression processing on the second data, to obtain third data; a framing module, configured to form a control frame by using the CPRI control word and an access network control word; a frequency aggregation module; a digital-to-analog conversion module, configured to perform digital-to-analog conversion on data obtained from the frequency aggregation module, to obtain an analog signal; and an optical transmitter, configured to modulate the analog signal into an optical signal, and send the optical signal to an optical distribution network,ODN; wherein the frequency aggregation module comprises: a fast Fourier transformation FFT unit, configured to separately perform FFT transformation on the third data and the control frame; an inverse fast Fourier transformation IFFT unit, configured to perform IFFT transformation on third data and a control frame that are obtained by means of FFT transformation; and a parallel-to-serial conversion unit, configured to perform parallel-to-serial conversion on third data and a control frame that are obtained by means of IFFT transformation. a fast Fourier transformation FFT unit, configured to separately perform FFT transformation on the third data and the control frame; an inverse fast Fourier transformation IFFT unit, configured to perform IFFT transformation on third data and a control frame that are obtained by means of FFT transformation; and a parallel-to-serial conversion unit, configured to perform parallel-to-serial conversion on third data and a control frame that are obtained by means of IFFT transformation.