Multi-gateway precoding method in multi-beam satellite system

The invention discloses a multi-gateway precoding method in a multi-beam satellite system. The method comprises the following steps: constructing a user side receiving signal model; establishing an optimization problem which takes the total transmitting power as a constraint and takes weighting and rate maximization as a target; establishing an optimization problem which takes the total transmitting power as a constraint and takes MSE minimization as a target; establishing equivalence between a weighting and rate maximization problem and a matrix weighting and MSE minimization problem on the basis of the same global optimal solution, and integrating a constraint condition into an MSE minimization target to convert into an unconstrained weighting and MSE minimization problem; and solving the problems of unconstrained weighting and MSE minimization, minimizing an MSE cost function by fixedly solving a pre-coding matrix and a weight matrix and updating the pre-coding matrix, updating the three matrixes in a loop