Encoding circuit, decoding circuit, encoding method, decoding method, and computer program

A decoding circuit used for coherent digital signal processing, comprising:

• a serial-parallel circuit configured to perform serial-parallel conversion on input data to divide the data into a plurality of pieces of divided data;
• a first likelihood calculation circuit configured to calculate a likelihood by soft decision on a basis of some pieces of divided data of the plurality of pieces of divided data and information of noise generated in a communication channel;
• a decoder configured to use the likelihood as an input and corrects an error of the divided data input to the first likelihood calculation circuit;
• one or more second likelihood calculation circuits configured to calculate a likelihood related to a conditional probability on a basis of a code word error-corrected by the decoder, some pieces of divided data of the plurality of pieces of divided data, and information of noise generated in the communication channel, and makes a hard decision;
• a combiner configured to combine an obtained bit sequence and a decoded information bit;
• an outer code decoder configured to decode an outer code;
• a serial-parallel circuit configured to perform serial-parallel conversion on input data to divide the data into divided data of a uniform sequence and divided data of a non-uniform sequence;
• a sequence converter configured to decode the divided data of the non-uniform sequence and converts the divided data into divided data of a uniform sequence;
• and
• a parallel-serial circuit configured to perform parallel-serial conversion on the divided data of the uniform sequence output from the sequence converter and the divided data of the uniform sequence divided to restore the data of the uniform sequence,
• the decoding circuit further comprising:
• an inverse preprocessing circuit configured to output a bit sequence corresponding to amplitude as it is when a number of bits per symbol is larger than a number of divisions by the serial-parallel circuit.

A non-transitory computer readable storage medium that stores a computer program to be executed by the computer;

• performing serial-parallel conversion on input data to divide the data into a plurality of pieces of divided data;
• calculating a likelihood by soft decision on a basis of some pieces of divided data of the plurality of pieces of divided data and information of noise generated in a communication channel;
• using the likelihood as an input and correcting an error of the divided data;
• calculating a likelihood related to a conditional probability on a basis of a code word error-corrected, some pieces of divided data of the plurality of pieces of divided data, and information of noise generated in the communication channel, and making a hard decision;
• combining an obtained bit sequence and a decoded information bit;
• decoding an outer code;
• performing serial-parallel conversion on input data to divide the data into divided data of a uniform sequence and divided data of a non-uniform sequence;
• decoding the divided data of the non-uniform sequence and converting the divided data into divided data of a uniform sequence;
• and
• performing parallel-serial conversion on the divided data of the uniform sequence converted and the divided data of the uniform sequence divided to restore the data of the uniform sequence,
• outputting a bit sequence corresponding to amplitude as it is when a number of bits per symbol is larger than a number of divisions by the serial-parallel conversion.

An encoding method used for coherent digital signal processing, comprising:

• performing serial-parallel conversion on input data of a uniform sequence to divide the data into a plurality of pieces of divided data;
• encoding the divided data and converting the encoded divided data into divided data of a non-uniform sequence;
• converting the divided data and the divided data of the non-uniform sequence into serial data by performing parallel-serial conversion;
• adding an error correction code to the serial data and encoding the serial data;
• dividing the serial data to which the error correction code is added into a plurality of pieces of divided data;
• regarding the plurality of pieces of divided data divided as data to be transmitted in different subchannels and converting a bit sequence to make a communication channel capacity of each subchannel non-uniform;
• and
• allocating data of a uniform sequence to a least significant bit and allocating data of a non-uniform sequence to a most significant bit by performing Gray labeling on the plurality of pieces of divided data.

A decoding method used for coherent digital signal processing, comprising:

• performing serial-parallel conversion on input data to divide the data into a plurality of pieces of divided data;
• calculating a likelihood by soft decision on a basis of some pieces of divided data of the plurality of pieces of divided data and information of noise generated in a communication channel;
• using the likelihood as an input and correcting an error of the divided data;
• calculating a likelihood related to a conditional probability on a basis of a code word error-corrected, some pieces of divided data of the plurality of pieces of divided data, and information of noise generated in the communication channel, and making a hard decision;
• combining an obtained bit sequence and a decoded information bit;
• decoding an outer code;
• performing serial-parallel conversion on input data to divide the data into divided data of a uniform sequence and divided data of a non-uniform sequence;
• decoding the divided data of the non-uniform sequence and converting the divided data into divided data of a uniform sequence;
• and
• performing parallel-serial conversion on the divided data of the uniform sequence converted and the divided data of the uniform sequence divided to restore the data of the uniform sequence,
• the decoding method further comprising:
• outputting a bit sequence corresponding to amplitude as it is when a number of bits per symbol is larger than a number of divisions by the serial-parallel conversion.

A non-transitory computer readable storage medium that stores a computer program to be executed by the computer;

• performing serial-parallel conversion on input data of a uniform sequence to divide the data into a plurality of pieces of divided data;
• encoding the divided data and converting the encoded divided data into divided data of a non-uniform sequence;
• converting the divided data and the divided data of the non-uniform sequence into serial data by performing parallel-serial conversion;
• adding an error correction code to the serial data and encoding the serial data;
• dividing the serial data to which the error correction code is added into a plurality of pieces of divided data;
• regarding the plurality of pieces of divided data divided as data to be transmitted in different subchannels and converting a bit sequence to make a communication channel capacity of each subchannel non-uniform;
• and
• allocating data of a uniform sequence to a least significant bit and allocating data of a non-uniform sequence to a most significant bit by performing Gray labeling on among the plurality of pieces of divided data.