Patent ID: 8745471

Claim:
An encoding method comprising the steps of: supplying three different types of parity check polynomials for creating a Low-Density Parity-Check Convolutional Code of a coding rate of (n−1)/n (where n is an integer of 2 or more), the Low-Density Parity-Check Convolutional Code created by using a parity check matrix in which three check equations are arranged repeatedly, and switching the three different types of parity check polynomials by a period of 3 periodically and generating a low-density parity-check convolutional codeword using input data and the switched parity check polynomial of the three different types of parity check polynomials, wherein, the three different types of parity check polynomials are respectively represented by the following three Equations; ∑ j = 1 n - 1 ⁢ ⁢ [ ( D a ⁢ #1 , j , 1 + D a ⁢ #1 , j , 2 + D a ⁢ #1 , j , 3 ) ⁢ X j ⁡ ( D ) ] + ( D b ⁢ #1 , 1 + D b ⁢ #1 , 2 + D b ⁢ #1 , 3 ) ⁢ P ⁡ ( D ) = 0 ∑ j = 1 n - 1 ⁢ ⁢ [ ( D a ⁢ #2 , j , 1 + D a ⁢ #2 , j , 2 + D a ⁢ #2 , j , 3 ) ⁢ X j ⁡ ( D ) ] + ( D b ⁢ #2 , 1 + D b ⁢ #2 , 2 + D b ⁢ #2 , 3 ) ⁢ P ⁡ ( D ) = 0 ∑ j = 1 n - 1 ⁢ ⁢ [ ( D a ⁢ #3 , j , 1 + D a ⁢ #3 , j , 2 + D a ⁢ #3 , j , 3 ) ⁢ X j ⁡ ( D ) ] + ( D b ⁢ #3 , 1 + D b ⁢ #3 , 2 + D b ⁢ #3 , 3 ) ⁢ P ⁡ ( D ) = 0 wherein: said D is a delay operator; said X j (D) is a polynomial representation of a piece of information X j that is a target to be encoded where j is each integer of one or more, and n−1 or less; said P(D) is a polynomial representation of a parity; said a #k,j,1 , a #k,j,2 and a #k,j,3 are parameters, where k designates each of 1, 2 and 3, and j designates each integer of one or more, and n−1 or less, in which (a #k,j,1 , a #k,j,2 %3, a #k,j,3 %3) which is a combination of remainders obtained by dividing the parameters a #k,j,−1 , a #k,j,2 and a #k,j,3 by 3 respectively, where k designates each of 1, 2 and 3, and j designates each integer of one or more, and n−1 or less, is any one of (0, 1, 2), (0, 2, 1), (1, 0, 2), (1, 2, 0), (2, 0, 1), and (2, 1, 0); said b #k,1 , b #k,2 and b #k,3 are parameters, where k designates each of 1, 2 and 3, in which (b #k,1 %3, b #k,2 %3, b #k,3 %3) which is a combination of remainders obtained by dividing the parameters b #k,1 , b #k,2 and b #k,3 by 3 respectively, where k designates each of 1, 2 and 3, is any one of (0, 1, 2), (0, 2, 1), (1, 0, 2), (1, 2, 0), (2, 0, 1), and (2, 1, 0); and said n in the three Equations is the integer n used in the coding rate.