The present application relates to a filtering scheme with low complexity. The method includes: dividing an orthogonal frequency division multiplexing (OFDM) signal into a first sideband signal, a first signal, and a second sideband signal; sampling the first sideband signal by using a first sampling rate; sampling the first signal by using a second sampling rate; sampling the second sideband signal by using a third sampling rate; and separately performing filtering processing of a third spectral mask, upsampling processing, and digital frequency conversion processing to generate a first filtered-OFDM (f-OFDM) signal, a second f-OFDM signal and a third f-OFDM signal; and superposing the first f-OFDM signal, the second f-OFDM signal, and the third f-OFDM signal to obtain an f-OFDM signal, where the first sampling rate and the third sampling rate are both less than the second sampling rate.