Subchannel encoding device, subchannel decoding device, subchannel encoding method, subchannel decoding method, and subchannel multiplexing optical communication system

A subchannel decoding device, comprising:

• processing circuitry performing a process of:
• separating a subchannel multiplexed signal into M×N subchannel signals wherein M×N (M and N are an integer of two or more) subchannels are classified into the N groups;
• restoring shaped bit strings belonging to each group from the M×N subchannel signals separated;
• and
• providing the N probability distribution shaping-decoders to convert shaped bit strings belonging to each group, restored into information bit strings on a basis of signal to noise ratios of subchannels belonging to each group.

A subchannel multiplexing optical communication system, comprising:

• a subchannel encoding device comprising:
• processing circuitry performing a process of:
• separating one information bit string into an information bit string belonging to each of groups wherein M×N (M and N are an integer of two or more) subchannels are classified into N groups;
• providing N probability distribution shaping-encoding processors to shape a probability distribution of transmission modulation symbols corresponding to the information bit string belonging to each group separated on a basis of signal-to-noise ratios of the M×N subchannels, and to convert the information bit string belonging to each group into a shaped bit string corresponding to the probability distribution of the shaped transmission modulation symbols;
• generating each subchannel signal in the M×N subchannels from the N shaped bit strings;
• and
• multiplexing the M×N subchannel signals generated to generate a subchannel multiplexed signal;
• and
• a subchannel decoding device comprising:
• processing circuitry performing a process of:
• separating a subchannel multiplexed signal into M×N subchannel signals wherein M×N (M and N are an integer of two or more) subchannels are classified into the N groups;
• restoring shaped bit strings belonging to each group from the M×N subchannel signals separated;
• and
• providing the N probability distribution shaping-decoders to convert shaped bit strings belonging to each group, restored into information bit strings on a basis of signal to noise ratios of subchannels belonging to each group.