To improve error tolerance of data.

For mapping of an LDPC code having a code length of 16,200 bits to 64 signal points, if an encoding rate is 4/15, 1/3 or 8/15, a demultiplexer permutes the LDPC code to assign b0, b1, b2, b3, b4, b5, b6, b7, b8, b9, b10 and b11 to y2, y8, y4, y6, y0, y11, y1, y9, y5, y7, y3 and y10, respectively, where bits b#i and y#i are #(i+1) bits from the most significant bits of 6×2 bits of code bits and 6×2 bits of symbol bits of two consecutive symbols, respectively. The present invention can be applied, for example, to a transmission system for transmitting LDPC codes.