Signal processing circuit, receiver, and signal processing method

A receiver comprising:

• a coherent receiver that coherently receives a plurality of signals corresponding to a plurality of modes;
• and
• a signal processing circuit, wherein
• the signal processing circuit includes:
• a MIMO demodulator that includes a first multi input multi output (MIMO) filter and performs MIMO demodulation processing on the plurality of signals;
• a signal extractor that extracts a signal of a predetermined time slot from an output signal output from the MIMO demodulator;
• a removal component generator that includes a second MIMO filter and generates a signal component to be removed including an interference component generated between the plurality of modes based on the signal output from the MIMO demodulator;
• an interference canceller that removes the signal component to be removed from the signal extracted by the signal extractor;
• at least one memory storing instructions;
• and
• at least one processor configured to execute the instructions to adaptively control coefficients of the first MIMO filter and coefficients of the second MIMO filter using an error back propagation method and a gradient descent method using a magnitude of a difference between a signal in which the signal component to be removed has been removed and a reference signal as a loss function.

A signal processing method comprising:

• performing, using a first multi input multi output (MIMO) filter, MIMO demodulation processing on a plurality of signals corresponding to a plurality of modes;
• extracting a signal of a predetermined time slot from an output signal of the MIMO demodulation processing;
• generating, using a second MIMO filter, a signal component to be removed including an interference component generated between the plurality of modes based on the output signal subjected to the MIMO demodulation processing;
• generating a signal in which the signal component to be removed has been removed from the extracted signal;
• and
• adaptively controlling coefficients of the first MIMO filter and coefficients of the second MIMO filter using an error back propagation method and a gradient descent method using a magnitude of a difference between the signal in which the signal component has been removed and a reference signal as a loss function.