原始名称记载: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

An objective of the present disclosure is to provide an optical coupler and an optical switch capable of achieving stable optical characteristics with low power consumption and more economical efficiency with respect to external factors. In order to achieve the aforementioned object, an optical coupler according to the present disclosure is an optical coupler which couples an optical fiber of a single core disposed in two ferrules using a sleeve, in which a first ferrule of the two ferrules has a plurality of optical fibers disposed in a bundle shape in a fiber hole on the same circumference around a ferrule center axis, at least one of the two ferrules is rotatable about the ferrule center axis, and butted end parts of the two ferrules have a convex spherical shape having a center point on the ferrule center axis.

A transfer function estimation device includes a composite transfer function calculation unit that calculates a composite transfer function which is obtained by combining a transmission transfer function that affects a signal transmitted by an optical transmitter and a reception transfer function that affects a signal received by an optical receiver in each of frequency offsets that are differences between a frequency of a carrier wave input to an optical modulation unit in the optical transmitter and a frequency of a carrier wave input to an optical demodulation unit in the optical receiver based on a signal transmitted by the optical transmitter and a signal received by the optical receiver, and a transfer function separation unit that calculates the transmission transfer function and the reception transfer function from the composite transfer function based on dependency of the composite transfer function on the frequency offset.

A control device in a communication system in which one-way communication and round-trip communication coexist, the control device includes: a request delay acquisition unit that, based on cooperation information obtained from traffic transmitted from a plurality of wireless terminals and indicating a communication state between the plurality of wireless terminals and a base station that performs wireless communication, acquires information regarding a request delay and information regarding a priority in the traffic for each piece of the traffic; a traffic-based congestion calculation unit that calculates a congestion delay in a wired section on the basis of the information regarding the request delay and the information regarding the priority acquired for each piece of the traffic by the request delay acquisition unit; and a priority change control unit that, in a case where congestion occurs or a total delay requirement is not satisfied on the basis of the congestion delay in the wired section calculated by the traffic-based congestion calculation unit, transmits, to a relay device that relays the traffic, a control signal including an instruction to change at least a priority of traffic of the round-trip communication such that the traffic of the one-way communication is preferentially transmitted.

A wireless communication system including a relay station apparatus capable of relaying wireless communication between one or more base station apparatuses and a terminal apparatus using a plurality of systems, and a control apparatus, the relay station apparatus acquires the quality between the terminal apparatus and each base station apparatus for which the relay station apparatus performs relaying, and the relay station apparatus for each system, and notifies the control apparatus of the acquired quality, and the control apparatus determines a data transmission method for each of a communication path between each base station apparatus and the relay station apparatus and a communication path between the relay station apparatus and the terminal apparatus on the basis of the quality and the priority of the terminal apparatus, and notifies the relay station apparatus of the determined data transmission method.