Patent ID: 8397145

Claim:
An encoder that creates a low-density parity-check convolutional code of a time varying period of g (where g is a natural number) using a parity check polynomial of equation 1 of a coding rate of (q−1)/q (where q is an integer equal to or greater than 3), the encoder comprising: a coding rate setting section that sets a coding rate of (s−1)/s (s≦q); an r-th computing section that receives as input information X r,i (where r=1, 2, . . . , q−1) at point in time i and outputs a computation result of A Xr,k (D)X i (D) of equation 1; a parity computing section that receives as input parity P i-1 at point in time i−1 and outputs a computation result of B k (D)P(D) of equation 1; an adding section that acquires an exclusive OR of computation results of the first to (q−1)-th computation sections and the computation result of the parity computing section, as parity P i at point in time i; and an information generating section that sets zero between information X s,i and information X q-1,i , ⁢ [ 1 ] B k ⁡ ( D ) ⁢ P ⁡ ( D ) + ∑ r = 1 s - 1 ⁢ A Xr , k ⁡ ( D ) ⁢ X r ⁡ ( D ) + ∑ r = s q - 1 ⁢ A Xr , k ⁡ ( D ) ⁢ X r ⁡ ( D ) = 0 ⁢ ⁢ ⁢ ⁢ ( k = i ⁢ ⁢ mod ⁢ ⁢ g ) ( Equation ⁢ ⁢ 1 ) where D is a delay operator and k is an integer.