This application provides a signal generation method and an apparatus. In the method, a first communication apparatus generates a first signal, and sends the first signal to a second communication apparatus, who receives the first signal, and then demodulates the first signal. A symbol included in the first signal is carried on K+2(M−1) subcarriers. Middle K subcarriers are valid subcarriers, start M−1 subcarriers and last M−1 subcarriers are redundant subcarriers, and a subcarrier spacing between adjacent subcarriers is related to a feature of a time domain pulse used to shape the subcarrier, wherein a width of each of some or all side lobes of a spectrum of the time domain pulse is equal to 1/M of a main lobe width of the time domain pulse, the subcarrier spacing is 1/M of the main lobe width. K is a positive integer, and M is a positive integer greater than 1.