A communication method that performs low density parity check (LDPC) coding to a data stream to be transmitted in a radio communication system by using a parity check matrix that has columns with uneven column degrees. The columns are arranged in a descending order of the column degrees. The communication method includes segmenting a code word into a plurality of data streams depending on number of data bits that are assignable to a radio resource block that is a unit of radio transmission, and assigning a segmented data stream having a higher column degree to a radio resource block with higher quality.