An object of the present disclosure is to provide a base station, a system, a method, and a program capable of improving DL MU-MIMO characteristics. A base station according to the present disclosure includes: a calculation unit that calculates a spatial multiplexing antenna weight VJL of each of a plurality of antennas owned by the base station based on information about at least one spatial multiplexing terminal and Down Link (DL) channel information of the at least one spatial multiplexing terminal; and an interference elimination unit that calculates an interference elimination antenna weight WJL that reduces interference power with respect to other terminals to a desired level or lower based on the spatial multiplexing antenna weight VJL, and calculates a desired signal power loss PLJL of the at least one spatial multiplexing terminal based on the spatial multiplexing antenna weight VJL and the interference elimination antenna weight WJL.