Frequency-Domain MIMO-FIR Filtering for Selective Band Processing
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Solution Overview
Problem
Current frequency domain MIMO-FIR signal processing methods independently process signals at odd and even sampling timings, leading to a loss of information regarding signal power localization on the frequency axis, particularly in high-density wavelength multiplexed signals.
Innovation Solution
A signal processing apparatus and method that utilizes filter processors, a sum operator, IFFT processor, output signal selector, error signal output, and FFT processor to selectively process only predetermined frequency bands, updating filter weight coefficients based on specific signal components, thereby reducing the scale of signal processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If frequency domain MIMO-FIR signal processing independently processes signals at odd and even sampling timings, then signal processing can be performed, but information regarding signal power localization on the frequency axis is lost
Solution Approach 1:
The patent merges the processing of odd and even sampling timing signals by performing Fourier transforms on combined signals rather than independently processing them. This allows the system to retain signal power localization information on the frequency axis while reducing processing complexity through unified handling of the combined signal components.
2Productivity
If all frequency components are processed in frequency domain MIMO-FIR signal processing, then complete signal reconstruction is achieved, but calculation load increases
Solution Approach 1:
The patent extracts and processes only the necessary frequency components that contain signal power localization information, rather than processing all frequency components. This selective extraction approach maintains complete signal reconstruction capability while significantly reducing the calculation load by eliminating redundant processing of frequency components that do not contribute to the signal.
Data Source
AI summary
One aspect of the present invention provides a signal processing apparatus including: filter processors, the number of the filter processors depending on the number of spatial modes of a received optical signal; a sum operator that outputs a sum of outputs of a plurality of the filter processors; an IFFT processor that performs inverse Fourier transform on the sum; an output signal selector that outputs a signal including only a predetermined part of an output of the IFFT processor; an error signal output that outputs, as an error signal, a difference between an output of the output signal selector and a desired signal; and an FFT processor that performs Fourier transform on signals including the error signal, in which the filter processors update a filter weight coefficient by using a signal obtained by performing multiplication only on a predetermined part for an output of the FFT processor and a signal obtained by performing processing including Fourier transform on the received optical signal, and the filter processors output a signal obtained by performing multiplication only on a predetermined part for the filter weight coefficient and the received optical signal.