Multichannel-based signal transmission method and apparatus

This application provides a multichannel-based signal transmission method and apparatus. The method includes: combining N groups of lower-order modulation symbols into N groups of higher-order modulation symbols, where an ith higher-order modulation symbol in each group of higher-order modulation symbols is obtained by combining ith lower-order modulation symbols in all the N groups of lower-order modulation symbols, each group of lower-order modulation symbols includes M lower-order modulation symbols, i=1, 2, . . . , M, N is a positive integer greater than 1, and M is a positive integer greater than 1; determining N to-be-sent signals based on the N groups of higher-order modulation symbols; and sending a kth to-be-sent signal in the N to-be-sent signals by using a kth channel in N channels, where k=1, 2, . . . , N.