One disclosure of the present specification provides a method for receiving downlink data in a wireless communication system supporting 256 QAM. The method for receiving downlink data in a wireless communication system supporting 256 QAM comprises the steps of: receiving configuration information about power back-off; receiving downlink data transmitted on the basis of the configuration information about power back-off; and demodulating the received downlink data on the basis of the configuration information about power back-off, wherein the configuration information about power back-off may comprise information related to at least one of the following: whether to apply power back-off, the reduced amount of power of downlink data by power back-off, a frame index to which power back-off is applied, a subframe index and a resource to which power back-off is applied.