A method for receiving, by a first device, data from a second device. The first device receives modulation and coding related information and resource related information for a transport block with a size for the data, and receives second cyclic redundancy check (CRC) attached code blocks to which a first CRC attached transport block corresponding to the transport block is mapped. The first device obtains the transport block with the size from the second CRC attached code blocks based on the modulation and coding related information and resource related information. The modulation and coding related information and the resource related information represent the size of the transport block. The size of the transport block is one of a plurality of predetermined transport block sizes. The plurality of predetermined transport block sizes are predetermined such that all the second CRC attached code blocks have a same size as each other.