Optical transmission system, signal quality measurement apparatus and signal quality measurement method

Abstract

A transmission apparatus repeatedly inserts reference signal sequences into a transmission signal sequence at different timings, and converts the transmission signal sequence, into which the reference signal sequences are inserted, into an optical signal. The reception apparatus includes a detection unit, a waveform equalization unit, and a signal quality measurement unit. The detection unit receives the optical signal transmitted through an optical transmission line, and converts the received optical signal into a reception signal of an electrical signal. The waveform equalization unit performs waveform equalization on the reception signal converted into the electrical signal. The signal quality calculation unit extracts a reception signal sequence set in each section corresponding to the reference signal sequence from the received signal on which waveform equalization performed. For each combination of different sections, the signal quality calculation unit calculates a mean square error between the mean of the reception signal sequences set in the sections included in a combination and the reference signal sequence, and calculates a signal-to-noise ratio and a signal-to-distortion ratio of the reception signal using the mean square error calculated for each combination.