A method for transmitting channel quality information for a downlink channel; a user equipment (UE) therefore; a method for receiving channel quality information for a downlink channel; and a base station therefore are discussed. The method for transmitting channel quality information for a downlink channel includes according to one embodiment receiving, by a user equipment (UE), configuration information on periodic channel state information (CSI) reporting by higher layer signaling; determining, by the UE, a channel quality information index at least based on a number of a specific resource element; and transmitting the determined channel quality information index to a base station. The number of the specific resource element is determined based on a UE-specific reference signal overhead. A resource element allocated for a Channel Status Information-Reference Signal (CSI-RS) is regarded as the specific resource element regardless of transmitting the CSI-RS.