Apparatus and method for selecting user of sdma on mimo system

An apparatus and a method for selecting a user of SDMA(Spatial Division Multiple Access) on an MIMO(Multiple Input Multiple Output) system are provided to reduce the amount of operation for selecting the user by limiting the number of investigations of user combination by using a signal to noise ratio or the reduction amount of signal to noise ratio. In an apparatus for selecting user of SDMA on an MIMO system, a channel information storing unit stores channel information of the entire users. A selecting unit generates a combination for selecting U persons among the entire users by using the channel information stored at the channel information storing unit, outputs the number of limited investigations by using the capacity of generated combination, and selects the user accomplishing the SDMA by using the number of limited investigations.