Encoding method based on multi-rate protograph low density parity check code and encoder

The invention discloses an encoding method based on a multi-rate protograph low density parity check code and an encoder. The method comprises the following steps of obtaining an information code vector s=[S1, S2,etc., Sn-3], wherein the size of si (i is no less than 1 and no more than n-3) is 1*N; determining a check matrix H(n-3)/n, wherein n is no less than 5; and obtaining a check code vector p=[P1, P2, P3] by encoding the information code vector based on the check matrix. Based on the invention, the encoding calculation amount can be dramatically reduced, the realization of an encoding system is simplified, and the encoding complexity is lowered.