A method is provided for performing, by a first device, channel coding of data to be transmitted to a second device. The first device determines a size of a transport block for the data, attaches a first cyclic redundancy check (CRC) code to the transport block having the determined size to produce a first CRC-attached transport block, and segments the first CRC-attached transport block into multiple code blocks when a size of the first CRC-attached transport block is larger than a predetermined size. The size of the transport block is determined from among a plurality of predetermined transport block sizes, and the plurality of predetermined transport block sizes are predetermined such that all the multiple code blocks have a same size as each other.