A first radio network node (110) and a method therein for measuring interference as well as a second radio network node (120) and a method therein for enabling the first radio network node to measure interference are disclosed. The first radio network node (110) obtains (201) configuration information for indicating a designated subframe in which a reference signal for measurement of the interference is to be transmitted by the second radio network node (120). The second radio network node (120) obtains (202) configuration information for configuring a designed subframe for transmission of a reference signal. The first radio network node (110) receives (205), in the designated subframe indicated by the configuration information, the reference signal transmitted by the second radio network node (120). The first radio network node (110) determines (206) a value of the interference based on the reference signal.