A method for determining an uplink transmission power, the method performed by a user equipment, UE, and comprising: determining a maximum power reduction, MPR, value based on whether 64 Quadrature Amplitude Modulation, QAM, is used for uplink data transmission, whether multi-clustered transmission is used for the uplink data transmission, and whether a plurality of carriers, which are aggregated by a carrier aggregation, CA, are used for the uplink data transmission; determining the uplink transmission power based on the MPR value; and transmitting uplink data based on the determined uplink transmission power, wherein when the 64 QAM, the multi-clustered transmission and a single carrier are used for uplink data transmission, a first MPR value is determined as the MPR value to be applied to the uplink data transmission; wherein when the 64 QAM, the multi-clustered transmission, and the plurality of carriers are used for uplink data transmission, a second MPR value is determined as the MPR value to be applied to the uplink data transmission, wherein the first MPR value is determined based on CEIL {MA, 0.5}, wherein, M A = 10.0 ; 0 < A ≤ 0.1 11.75 - 17.5A ; 0.1 < A ≤ 0.5 3.6 - 1.2A ; 0.5 < A ≤ 1.0 wherein the second MPR value is determined based on CEIL {MA, 0.5}, wherein, M A =10.0 ; 0 < A ≤ 0.16 12.3 - 23.3A ; 0.16 < A ≤ 0.4 3.67 - 1.67A ; 0.4 < A ≤ 1.0 wherein A = N RB _ alloc / N RB _ agg , wherein N RB_agg is a number of RBs in a channel band, N RB_alloc is a total number of RBs transmitted simultaneously, and CEIL {M A , 0.5} is a function that rounds off M A on a per-0.5 dB basis, and wherein when the 64 QAM and a single-clustered transmission are used for the uplink data transmission, a MPR value to be applied for transmission of the uplink data using 16 QAM is determined as the MPR value to be applied to the uplink data transmission using the 64 QAM. determining a maximum power reduction, MPR, value based on whether 64 Quadrature Amplitude Modulation, QAM, is used for uplink data transmission, whether multi-clustered transmission is used for the uplink data transmission, and whether a plurality of carriers, which are aggregated by a carrier aggregation, CA, are used for the uplink data transmission; determining the uplink transmission power based on the MPR value; and transmitting uplink data based on the determined uplink transmission power, wherein when the 64 QAM, the multi-clustered transmission and a single carrier are used for uplink data transmission, a first MPR value is determined as the MPR value to be applied to the uplink data transmission; wherein when the 64 QAM, the multi-clustered transmission, and the plurality of carriers are used for uplink data transmission, a second MPR value is determined as the MPR value to be applied to the uplink data transmission, wherein the first MPR value is determined based on CEIL {MA, 0.5}, wherein, M A = 10.0 ; 0 < A ≤ 0.1 11.75 - 17.5A ; 0.1 < A ≤ 0.5 3.6 - 1.2A ; 0.5 < A ≤ 1.0 wherein the second MPR value is determined based on CEIL {MA, 0.5}, wherein, M A =10.0 ; 0 < A ≤ 0.16 12.3 - 23.3A ; 0.16 < A ≤ 0.4 3.67 - 1.67A ; 0.4 < A ≤ 1.0 wherein A = N RB _ alloc / N RB _ agg , wherein N RB_agg is a number of RBs in a channel band, N RB_alloc is a total number of RBs transmitted simultaneously, and CEIL {M A , 0.5} is a function that rounds off M A on a per-0.5 dB basis, and wherein when the 64 QAM and a single-clustered transmission are used for the uplink data transmission, a MPR value to be applied for transmission of the uplink data using 16 QAM is determined as the MPR value to be applied to the uplink data transmission using the 64 QAM. <EOS>