Patent ID: 8811819
Filing Date: 2014-08-19
Classification: H04B,H04J,H04L,H04Q

Abstract:
1. An optical multiplexing terminal device in a wavelength multiplexing passive optical network system in which the optical multiplexing terminal device connected to an upper-level communication network and a plurality of optical network terminal devices for accommodating subscriber terminals are connected via an optical fiber network having an optical splitter and a plurality of optical fibers, communication in a direction from the optical multiplexing terminal device to the optical network terminal devices being made using a plurality of wavelengths fewer in number than a total number of the optical network terminal devices connected to the optical multiplexing terminal device, the optical multiplexing terminal device comprising: a transmission timing table for storing, for each optical network terminal device ID, a type of downlink wavelength, a start position of transmission timing, and an end position of transmission timing; an allocated byte length table for storing an allocated byte length indicating an amount of data allocated to each optical network terminal device for each optical network terminal device ID; and a control part configured to allocate the type of downlink wavelength and the transmission timing to each optical network terminal device by referring to the transmission timing table and the allocated byte length table; wherein the control part is configured to decide a quantity of signal permitted to transmit to each of the optical network terminal devices at every fixed period, with a total sum of transmission rates corresponding to the plurality of wavelengths for use in the communication in the direction from the optical multiplexing terminal device to the optical network terminal devices as an upper limit, to select the wavelength in which the corresponding transmission rate is the slowest from among the wavelengths of which bandwidth allocation is not completed and allocates the transmission timing to the optical network terminal devices in ascending order of the decided quantity of signal permitted to transmit, and to store, for the optical network terminal device ID, a start position of transmission timing and an end position of transmission timing along with a type of downlink wavelength for the selected wavelength in the transmission timing table; the control part is configured to create a downlink grant indication, successively including a data set having the type of downlink wavelength, the start position of transmission timing and the end position of transmission timing for the optical network terminal device ID of each entry by referring to the transmission timing table, and to create a frame payload including transmit data from the start position to the end position of transmission timing to the designated optical network terminal device for each data set of the downlink grant indication; and the control part is configured to transmit the downlink grant indication to each optical network terminal device with the wavelength selected by each optical network terminal device in accordance with a downlink grant indication transmitted at a previous transmission period, and to subsequently transmit a downlink signal including the frame payload at the wavelength with the type of downlink wavelength designated by the downlink grant indication by successively switching the wavelengths.