1. A reception apparatus comprising:a receiver, which, in operation, receives low-density parity-check (LDPC) encoded data which is encoded by a transmission apparatus and transmitted through a power line communication; and
a decoder, which, in operation, decodes the LDPC encoded data based on a parity check matrix in which n number of (where n is an integer equal to or greater than 1) parity check equation groups including a plurality of parity check polynomials are arranged, wherein each of the plurality of parity check polynomials satisfies zero, wherein
the LDPC encoded data includes a parity sequence and an information sequence, the parity sequence comprises low-density parity-check (LDPC) encoded data which is generated by LDPC-encoding the information sequence using the parity check matrix, and the parity sequence is generated by using a first column to a determined column of the parity check matrix for the information sequence having a sequence length that corresponds to a length from the first column to the determined column among one or more column(s) of the parity check matrix, wherein the determined column varies depending on a coding rate; and
the parity check equation groups support coding rates of (r?1)/r (where r equals to or more than 2 and equals to or less than q, where q is a natural number equal to or more than 3), support a time varying period of g (where g is an integer equal to or more 2), and are arranged repeatedly at every gth row of the parity check matrix, the parity check polynomial being represented as:
AX1,k(D)X1(D)+AX2,k(D)X2(D)+?+AXq?1,k(D)Xq?1(D)+Bk(D)P(D)=0(k=i mod g) (Equation 1)where, in Equation 1, X1(D), X2(D), Xq?1(D) are polynomial representations of data X1, X2, . . . , Xq?1 respectively, P(D) is a polynomial representation of parity P, AXr,k(D) is a term of Xr(D) in the parity check polynomial for k=i mod g at time i where the coding rate is (r?1)/r, Bk(D) is a term of P(D) in the parity check polynomial for k=i mod g at time i, where i mod g is a remainder after dividing i by g, and the highest order of D included in Bk(D) is equal to or higher than half of the highest order of D included in the AXr,k(D).