The present invention discloses a signal processing method, apparatus, and system. In M user equipments, an active set Ki and an interference set K′i of a user equipment i are determined according to power measurement values from the user equipment i to N sites; for the active set Ki of the user equipment i, superposition of sent signals of all other user equipments j of all active sites ki are cancelled out with each other, to obtain one constraint condition of a weight, and for the M user equipments, M constraint conditions are obtained, and a weight subspace T is determined; and one weight is determined in the weight subspace according to an interfering signal of another user equipment j for the user equipment i in the interference set K′i of the user equipment i and a wanted signal of the user equipment i in the active set Ki of the user equipment i.