A method of reducing transmission power. The method according to one embodiment includes calculating a maximum power reduction (MPR) on a maximum output power for transmission with non-contiguous resource allocation in a single component carrier; and transmitting a signal. The MPR is calculated differently depending on a ratio A which is a ratio of a number of simultaneously transmitted resource blocks in a channel bandwidth (NRB_alloc) to a number of aggregated resource blocks in a fully allocated aggregated channel bandwidth (NRB_agg). The MPR is calculated using a first equation when the ratio A is greater than 0 and less than or equal to 0.33. The MPR is calculated using a second equation when the ratio A is greater than 0.33 and less than or equal to 0.77. The MPR is calculated using a third equation when the ratio A is greater than 0.77 and less than or equal to 1.