TRANSMITTING DEVICE/METHOD AND RECEIVING DEVICE/METHOD IN PASSIVE OPTICAL COMMUNICATION NETWORK

PROBLEM TO BE SOLVED: To perform switching to a modulation scheme with higher frequency utilization efficiency per generation economically and easily when a multi-value modulation technique by digital signal processing is introduced into an optical access system.SOLUTION: In a PON, an OLT 1 comprises a modulation scheme execution unit corresponding to a modulation scheme of a switching target regardless of a current modulation scheme and the necessary number of input ports. In addition, at a stage where the modulation scheme of the switching target is not adopted, particular bits are copied and inserted so that the shortness of symbol length is eliminated relative to each symbol actually input to an input port. In the PON, an ONU 2 comprises a demodulation scheme execution unit corresponding to a demodulation scheme of a switching target regardless of a current demodulation scheme and the necessary number of output ports. In addition, at a stage where the demodulation scheme of the switching target is not adopted, the particular bits that are copied and inserted are discarded so that the length of symbol length is eliminated relative to each symbol generated by de-mapping.