Method by which terminal reports channel status information to base station in wireless communication system, and apparatus therefor

A method of reporting CSI (channel status information), which is reported by a user equipment to a base station in a wireless access system, comprising the steps of:

• receiving information on a CSI process configured by a plurality of CSI-RS (channel status information-reference signal) resources from the base station;
• determining a CRI (CSI-RS resource indicator), the CRI indicating:
• one of the plurality of the CSI-RS resources, and
• a number of antenna ports of the CSI-RS;
• determining a precoding-related indicator based on the determined CRI;
• and
• reporting the CSI to the base station, the CSI containing the CRI and the precoding-related indicator,
• wherein when the number of antenna ports indicated by the CRI is equal to or less than a prescribed value, the precoding-related indicator has a value of 0, and
• wherein the reporting the CSI comprises reporting the precoding-related indicator according to a CSI reporting type that is maintained when the number of antenna ports of the CSI-RS indicated by the CRI changes from a first value equal to or less than the prescribed value to a second value equal to or less than the prescribed value.