A method for encoding bits according to a convolutional code. Bits to be encoded with the convolutional code are obtained for transmission over a communication channel. The bits are encoded according to the convolutional code with an encoder having an M-bit memory and a plurality of logic gates so as to separate trellis segments of the convolutional code into trellis sub-segments having a reduced number of branches per state than that of the trellis segments.

An embodiment encoder device for encoding an information word c=[c.sub.0, c.sub.1, . . . , c.sub.K1] having K information bits, c.sub.i, includes an encoder for a tail biting convolutional code having a constraint length, L, where K<L1; the encoder being configured to receive the K information bits; and encode the K information bits so as to provide an encoded code word. An embodiment decoder device for determining an information word c=[c.sub.0, c.sub.1, . . . , c.sub.K1], having K information bits, c.sub.i, includes a decoder for a tail biting convolutional code having a constraint length, L, where K<L1; the decoder being configured to: receive an input sequence; compute at least one reliability parameter based on the received input sequence; and determine an information word c based on the at least one reliability parameter.

A method for encoding bits according to a convolutional code. Bits to be encoded with the convolutional code are obtained for transmission over a communication channel. The bits are encoded according to the convolutional code with an encoder having an M-bit memory and a plurality of logic gates so as to separate trellis segments of the convolutional code into trellis sub-segments having a reduced number of branches per state than that of the trellis segments.

An encoding method of generating an encoded sequence by performing encoding of a given encoding rate based on a predetermined parity check matrix. The predetermined matrix is either a first parity check matrix or a second parity check matrix. The first parity check matrix corresponds to a low density parity check (LDPC) convolutional code that uses a plurality of parity check polynomials, and the second parity check matrix is generated by performing at least one of row permutation and column permutation on the first parity check matrix. A parity check polynomial satisfying zero of the LDPC convolutional code is expressible by using a specific mathematical expression.

An encoding method of generating an encoded sequence by performing encoding of a given encoding rate based on a predetermined parity check matrix. The predetermined matrix is either a first parity check matrix or a second parity check matrix. The first parity check matrix corresponds to a low density parity check (LDPC) convolutional code that uses a plurality of parity check polynomials, and the second parity check matrix is generated by performing at least one of row permutation and column permutation on the first parity check matrix. A parity check polynomial satisfying zero of the LDPC convolutional code is expressible by using a specific mathematical expression.