Master station device, slave station device, optical communication system, control device, and bandwidth allocation method

A slave station device connected to a master station device through an optical communication path, where a bandwidth for communication in an upload direction that is a direction toward the master station device is allocated to the slave station device per logical link by the master station device, wherein

• the slave station device transmits to the master station device a bandwidth request signal for each logical link and in which a requested bandwidth for transmitting upload data from the slave station device itself is stored, and
• the slave station device
• receives from the master station device a transmission-permitted time slot to which each logical link is set according to an allocation order for a bandwidth allocation request on the basis of the bandwidth request signal and for a bandwidth allocation request for transmitting the bandwidth request signal, which is determined on the basis of an allowable delay time for each logical link for communication in an upload direction, and
• transmits the bandwidth request signal and the upload data on the basis of the transmission-permitted time slot.

An optical communication system comprising:

• a master station device;
• and one or more slave station devices connected to the master station device through an optical communication path, where a bandwidth for communication in an upload direction that is a direction from the slave station devices toward the master station device is allocated to each of the slave station devices by the master station device, wherein
• the slave station device transmits to the master station device a bandwidth request signal for each logical link and in which a requested bandwidth for transmitting upload data from the slave station device itself is stored,
• the master station device includes
• an analysis unit that receives the bandwidth request signal from the slave station device and that extracts the requested bandwidth for each logical link from the bandwidth request signal,
• a bandwidth calculation unit that calculates, on the basis of the requested bandwidth, an upload bandwidth for transmitting the upload data,
• a residual-time calculation unit that holds an allowable delay time for each logical link for communication in an upload direction and that acquires a residual time of each logical link on the basis of the allowable delay time and an estimated value of a time for which the upload data stays in the slave station device,
• a priority calculation unit that acquires, on the basis of the residual time of each logical link, a priority of a bandwidth allocation request for transmitting the upload data, which is requested by the bandwidth request signal,
• a bandwidth-request generation unit that generates a bandwidth allocation request for each logical link and which requests allocation of an upload bandwidth for transmitting a bandwidth request signal and that determines a priority of a generated bandwidth allocation request,
• an allocation-order decision unit that decides, on the basis of the priority, an allocation order corresponding to the bandwidth allocation request, and
• a transmission-permission generation unit that decides a transmission-permitted time slot corresponding to the bandwidth allocation request on the basis of the allocation order and on the basis of the upload bandwidth in each of the bandwidth allocation requests and that notifies the slave station device of the transmission-permitted time slot, and
• the slave station device transmits the bandwidth request signal and the upload data on the basis of the transmission-permitted time slot notified from the master station device.

A control device in a master station device that is connected to one or more slave station devices through an optical communication path and that allocates a bandwidth for communication in an upload direction, which is a direction from the slave station devices toward the master station device itself, to each of the slave station devices per logical link, the control device comprising:

• an analysis unit that receives a bandwidth request signal, requesting a bandwidth for transmitting upload data, from the slave station device, and that extracts a requested bandwidth for each logical link from the bandwidth request signal;
• a bandwidth calculation unit that calculates, on the basis of the requested bandwidth, an upload bandwidth for transmitting the upload data;
• a residual-time calculation unit that holds an allowable delay time for each logical link for communication in an upload direction and that acquires, on the basis of the allowable delay time and an estimated value of a time for which the upload data stays in the slave station device, a residual time of each logical link;
• a priority calculation unit that acquires, on the basis of the residual time of each logical link, a priority of a bandwidth allocation request for transmitting the upload data, which is requested by the bandwidth request signal;
• a bandwidth-request generation unit that generates a bandwidth allocation request for each logical link, which requests allocation of an upload bandwidth for transmitting a bandwidth request signal, and that decides a priority of a generated bandwidth allocation request;
• an allocation-order decision unit that decides, on the basis of the priority, an allocation order corresponding to the bandwidth allocation request;
• and
• a transmission-permission generation unit that decides a transmission-permitted time slot corresponding to the bandwidth allocation request on the basis of the allocation order and on the basis of the upload bandwidth in each of the bandwidth allocation requests and that notifies the slave station device of the transmission-permitted time slot.

A control device in a slave station device connected to a master station device through an optical communication path, where a bandwidth for communication in an upload direction that is a direction toward the master station device is allocated to the slave station device per logical link by the master station device, wherein

• the control device transmits to the master station device a bandwidth request signal for each logical link, in which a requested bandwidth for transmitting upload data from the control device itself is stored, and
• the control device
• receives from the master station device a transmission-permitted time slot to which each logical link is set according to an allocation order for a bandwidth allocation request on the basis of the bandwidth request signal and for a bandwidth allocation request for transmitting the bandwidth request signal, which is decided in the master station device on the basis of an allowable delay time for each logical link for communication in an upload direction, and
• transmits the bandwidth request signal and the upload data on the basis of the transmission-permitted time slot.

A bandwidth allocation method in an optical communication system including a master station device and one or more slave station devices connected to the master station device through an optical communication path, where a bandwidth for communication in an upload direction that is a direction from the slave station devices toward the master station device is allocated to each of the slave station devices by the master station device, the bandwidth allocation method comprising:

• a request-signal transmitting step, performed by the slave station device, of transmitting to the master station device a bandwidth request signal for each logical link, in which a requested bandwidth for transmitting upload data from the slave station device itself is stored;
• an analyzing, performed by the master station device, of receiving the bandwidth request signal from the slave station device and extracting the requested bandwidth for each logical link from the bandwidth request signal;
• a bandwidth calculating, performed by the master station device, of calculating an upload bandwidth for transmitting the upload data on the basis of the requested bandwidth;
• a residual-time calculating, performed by the master station device, of holding an allowable delay time for each logical link for communication in an upload direction and acquiring a residual time of each logical link on the basis of the allowable delay time and an estimated value of a time for which the upload data stays in the slave station device;
• a priority calculating, performed by the master station device, of acquiring a priority of a bandwidth allocation request for transmitting the upload data, which is requested by the bandwidth request signal, on the basis of the residual time of each logical link;
• a bandwidth-request generating, performed by the master station device, of generating a bandwidth allocation request from each logical link, which requests allocation of an upload bandwidth for transmitting a bandwidth request signal, and deciding a priority of a generated bandwidth allocation request;
• an allocation-order deciding, performed by the master station device, of deciding an allocation order corresponding to the bandwidth allocation request on the basis of the priority;
• a transmission-permission generating, performed by the master station device, of deciding a transmission-permitted time slot corresponding to the bandwidth allocation request on the basis of the allocation order and on the basis of the upload bandwidth in each of the bandwidth allocation requests and notifying the slave station device of the transmission-permitted time slot;
• and
• a transmission controlling, performed by the slave station device, of transmitting the bandwidth request signal and the upload data on the basis of the transmission-permitted time slot notified from the master station device.