A quasi cyclic low-density parity check, QC-LDPC, convolutional decoder comprising: an input configured to receive, each time instant n, n = 0, 1, 2,..., an encoded Z-grouped signal stream corresponding to kZ systematic bits in k groups of Z bits, I(Z nk),..., I(Z (n + 1)k-1), k ∈ [ 1, 2,...], and related Z-grouped (1-R b)N b parity bits P(Z n,i), i = 0, 1,..., ((1-R b)N b / Z)-1, wherein the received encoded signal stream is encoded by: generating a continuous H-matrix, from a regular QC-LDPC block code H-matrix of size N b x N b (1-R b) with lifting factor Z, block size Nb and code rate R b, comprising a data portion of size N b R b x N b (1-R b) with row weight j and a lower triangular parity check portion of size N b (1-R b) x N b (1-R b), by concatenating repeated instances of the data portion into successive, recurring systematic blocks, wherein the continuous H-matrix is a semi-infinite systematic flow corresponding to the Z-grouped stream of systematic bits I(Z 0, I(Z 1),...; and performing QC-LDPC convolutional encoding, with a syndrome former memory of m s = N b R b and a constraint length of j + 1, on the k groups of systematic bits of a time instant using the portion of the continuous H-matrix corresponding to (m s + 1)k groups of systematic bits and using the parity check portion to obtain (1-R b)N b parity bits related to the k groups of systematic bits of the time instant; and a plurality of N b (1-R b) / Z parallel working Z-grouped Soft-Output Viterbi Algorithm, Z-SOVA, decoders configured to: perform decoding of the received encoded signal stream, wherein each of the Z-SOVA decoders has the constraint length j + 1 and processes different Z-grouped rows of the continuous H-matrix independently by using the corresponding Z-grouped rows of the semi-infinite systematic flow and the parity check portion. an input configured to receive, each time instant n, n = 0, 1, 2,..., an encoded Z-grouped signal stream corresponding to kZ systematic bits in k groups of Z bits, I(Z nk),..., I(Z (n + 1)k-1), k ∈ [ 1, 2,...], and related Z-grouped (1-R b)N b parity bits P(Z n,i), i = 0, 1,..., ((1-R b)N b / Z)-1, wherein the received encoded signal stream is encoded by: generating a continuous H-matrix, from a regular QC-LDPC block code H-matrix of size N b x N b (1-R b) with lifting factor Z, block size Nb and code rate R b, comprising a data portion of size N b R b x N b (1-R b) with row weight j and a lower triangular parity check portion of size N b (1-R b) x N b (1-R b), by concatenating repeated instances of the data portion into successive, recurring systematic blocks, wherein the continuous H-matrix is a semi-infinite systematic flow corresponding to the Z-grouped stream of systematic bits I(Z 0, I(Z 1),...; and performing QC-LDPC convolutional encoding, with a syndrome former memory of m s = N b R b and a constraint length of j + 1, on the k groups of systematic bits of a time instant using the portion of the continuous H-matrix corresponding to (m s + 1)k groups of systematic bits and using the parity check portion to obtain (1-R b)N b parity bits related to the k groups of systematic bits of the time instant; and generating a continuous H-matrix, from a regular QC-LDPC block code H-matrix of size N b x N b (1-R b) with lifting factor Z, block size Nb and code rate R b, comprising a data portion of size N b R b x N b (1-R b) with row weight j and a lower triangular parity check portion of size N b (1-R b) x N b (1-R b), by concatenating repeated instances of the data portion into successive, recurring systematic blocks, wherein the continuous H-matrix is a semi-infinite systematic flow corresponding to the Z-grouped stream of systematic bits I(Z 0, I(Z 1),...; and performing QC-LDPC convolutional encoding, with a syndrome former memory of m s = N b R b and a constraint length of j + 1, on the k groups of systematic bits of a time instant using the portion of the continuous H-matrix corresponding to (m s + 1)k groups of systematic bits and using the parity check portion to obtain (1-R b)N b parity bits related to the k groups of systematic bits of the time instant; and a plurality of N b (1-R b) / Z parallel working Z-grouped Soft-Output Viterbi Algorithm, Z-SOVA, decoders configured to: perform decoding of the received encoded signal stream, wherein each of the Z-SOVA decoders has the constraint length j + 1 and processes different Z-grouped rows of the continuous H-matrix independently by using the corresponding Z-grouped rows of the semi-infinite systematic flow and the parity check portion.