Provided are methods and apparatus for transmitting an uplink data channel in a next-generation/5G radio access network. The method of a UE may include receiving first resource assignment information on a first UL data channel and second assignment information on a second UL data channel from a base station, and preferentially assigning transmission power to one of the first and second UL data channels and adjusting the transmission power for the other when the first and second UL data channels are need to e transmitted by at least partially overlapping with each other in a time domain based on the first and second resource assignment information.