A method for acquiring channel status information, CSI, by a base station in a mobile communication system, the method comprising: identifying whether a single interference measurement resource, IMR, or a plurality of interference measurement resources, IMRs, are assigned to a terminal; generating interference measurement configuration information for measuring interference in a multi-user multiple-input multiple-output, MU-MIMO, mode based on the identification, the interference being caused by signals transmitted from a serving base station of the terminal to at least one other terminal, wherein the interference measurement configuration information is configured differently based on whether there is a single IMR or a plurality of IMRs assigned to the terminal; transmitting the generated interference measurement configuration information to the terminal; and receiving CSI, generated using the transmitted interference measurement configuration information from the terminal, wherein, in case that the plurality of IMRs are assigned to the terminal, the interference measurement configuration information comprises selection information for selecting at least two IMRs among the plurality of IMRs, and the at least two IMRs are used to measure the interference caused by the signals from the serving base station to the at least one other terminal, wherein the at least two IMRs and a CSI reference signal, CSI-RS, are configured for a CSI-process, and the CSI is determined based on the at least two IMRs and the CSI-RS, and wherein in case that the single IMR is assigned to the terminal, the interference measurement configuration comprises information which instructs the terminal to calculate the interference in the MU-MIMO mode by adding the signals addressed to the at least one other terminal and removing a signal addressed to the terminal. identifying whether a single interference measurement resource, IMR, or a plurality of interference measurement resources, IMRs, are assigned to a terminal; generating interference measurement configuration information for measuring interference in a multi-user multiple-input multiple-output, MU-MIMO, mode based on the identification, the interference being caused by signals transmitted from a serving base station of the terminal to at least one other terminal, wherein the interference measurement configuration information is configured differently based on whether there is a single IMR or a plurality of IMRs assigned to the terminal; transmitting the generated interference measurement configuration information to the terminal; and receiving CSI, generated using the transmitted interference measurement configuration information from the terminal, wherein, in case that the plurality of IMRs are assigned to the terminal, the interference measurement configuration information comprises selection information for selecting at least two IMRs among the plurality of IMRs, and the at least two IMRs are used to measure the interference caused by the signals from the serving base station to the at least one other terminal, wherein the at least two IMRs and a CSI reference signal, CSI-RS, are configured for a CSI-process, and the CSI is determined based on the at least two IMRs and the CSI-RS, and wherein in case that the single IMR is assigned to the terminal, the interference measurement configuration comprises information which instructs the terminal to calculate the interference in the MU-MIMO mode by adding the signals addressed to the at least one other terminal and removing a signal addressed to the terminal. <EOS>