Decoding apparatus, decoding method, and non-transitory computer readable medium

A decoding method comprising:

• calculating, by using a branch label corresponding to a path extending toward a state S (S is an integer no less than zero) at a time point N (N is an integer no less than zero) in a trellis diagram and a plurality of reception signal sequences, a branch metric in the state S;
• calculating a path metric in the state S at the time point N by adding the branch metric in the state S at the time point N to a path metric in each of states at a time point N−1, each of which forms a path with the state S at the time point N;
• storing path labels corresponding to L path metrics (L is an integer no less than one) among a plurality of calculated path metrics;
• generating a path label in the state S at the time point N by combining the branch label with a path label in each of the states at the time point N−1, each of which forms a path with the state S at the time point N;
• and
• outputting, as a transmission signal sequence, path labels corresponding to L path metrics selected at an end point in the trellis diagram, wherein
• the method further comprises:
• performing, using one or more hardware calculation unit each including L successive cancelation (SC) units, decoding processing of a Polar code having a length of N1 bits (N1 is an integer no less than one), each of the SC units having a list size of 1, and
• calculating the branch metric by using L reception signal sequences each having a length of N2 bits and the branch label, the L reception signal sequences being ones output from N2 hardware calculation units (N2 is an integer no less than one).

A non-transitory computer readable medium storing a program for causing a computer to:

• calculate, by using a branch label corresponding to a path extending toward a state S (S is an integer no less than zero) at a time point N (N is an integer no less than zero) in a trellis diagram and a plurality of reception signal sequences, a branch metric in the state S;
• calculate a path metric in the state S at the time point N by adding the branch metric in the state S at the time point N to a path metric in each of states at a time point N−1, each of which forms a path with the state S at the time point N;
• store path labels corresponding to L path metrics (L is an integer no less than one) among a plurality of calculated path metrics;
• generate a path label in the state S at the time point N by combining the branch label with a path label in each of the states at the time point N−1, each of which forms a path with the state S at the time point N;
• and
• output, as a transmission signal sequence, path labels corresponding to L path metrics selected at an end point in the trellis diagram, wherein
• the non-transitory computer readable medium is configure to further cause the computer to:
• perform, using one or more hardware calculation unit each including L successive cancelation (SC) units, decoding processing of a Polar code having a length of N1 bits (N1 is an integer no less than one), each of the SC units having a list size of 1, and
• calculate the branch metric by using L reception signal sequences each having a length of N2 bits and the branch label, the L reception signal sequences being ones output from N2 hardware calculation units (N2 is an integer no less than one).