Abstract: A communication system of a passive optical communication network includes an optical line terminal (OLT) system including a first OLT, a second OLT, and an OLT control device that controls the first OLT and the second OLT, a plurality of splitters that connect the first OLT and the second OLT with an optical communication path, and an ONU that is connected to each of the splitters with an optical communication path. The splitter distributes and outputs an optical signal transmitted from the OLT system to the ONU connected to the splitter and a succeeding device that is another splitter or the OLT system, and the OLT control device determines a distribution ratio at the splitter, the distribution ratio indicating a ratio between the intensity of the optical signal distributed to the succeeding device and the intensity of the optical signal distributed to the ONU.

Abstract: A buffer unit including a plurality of buffers, a sorting unit configured to sort an input signal to any of the plurality of buffers based on header information, a rate calculation unit configured to calculate a rate at which the input signal is read from each of the plurality of buffers based on burst information of the input signal, an adjustment unit configured to adjust a rate at which the input signal is read from each of the plurality of buffers based on the rate calculated by the rate calculation unit, and a transfer unit configured to transfer the signal read from each of the plurality of buffers are provided.

Abstract: A signal forwarding system includes: a plurality of signal forwarding devices forming a plurality of communication routes between a slave station and a master station; and a route control device that determines a communication route, wherein the route control device includes at least: a communication route calculation unit that calculates a communication route in response to a route switching request; and a forward destination setting instruction unit that outputs forward destination setting information based on the communication route, the signal forwarding devices include at least: a forward destination setting instruction acquisition unit that acquires the forward destination setting information; a forward destination set unit that changes a forward destination based on the forward destination setting information; and a forward unit that outputs input traffic based on the forward destination, and any of the route control device and the signal forwarding devices includes: a traffic monitor unit; a non-signa

Abstract: A relay device that relays between a plurality of radio devices that perform radio communication with terminals, and at least one radio control device that controls the radio devices, the relay device including: a replication necessity determination unit that determines whether or not to replicate a downlink signal received from the radio control device; a signal replicating unit that makes the same number of copies of a downlink signal as the number of destination radio devices only when the replication necessity determination unit determines that the downlink signal is to be replicated; and a downlink signal assignment unit that transfers a downlink signal that has been determined by the replication necessity determination unit as a signal that is not to be replicated, and downlink signals replicated by the signal replicating unit, to the radio devices respectively corresponding thereto.

Abstract: A path control device controls a plurality of paths for transmitting signals through a network including a plurality of signal transfer devices that transfer signals while switching a first transmission period during which high-priority traffic can be transmitted and a second transmission period during which low-priority traffic can be transmitted.

Abstract: An optical transmitter (3) tracks a moving body (1) and irradiates the moving body (1) with a laser beam (4). An optical receiver (5) is mounted on the moving body (1), receives the laser beam (4), and performs optical space communication with the optical transmitter (3). The optical transmitter (3) extends an irradiation range (6) of the laser beam (4) into an elliptical shape.

Abstract: A path control method of controlling a communication path in a network including a plurality of wireless devices communicating with a terminal in a wireless manner and a plurality of wireless control devices communicating with any one of the plurality of wireless devices through a plurality of signal transfer devices includes searching for available communication paths and listing the available communication paths for individual combinations of a wireless device of the plurality of wireless devices and a wireless control device of the plurality of wireless control devices, and selecting a combination of communication paths in which a maximum value of the number of communications passing through the same output port of a signal transfer device of the plurality of signal transfer devices is minimized from among the listed available communication paths.

Abstract: An uplink transmission band and a downlink transmission band that are allocated to each of a plurality of users are determined based on allocation information indicating allocation of a frequency bandwidth available to each of the plurality of users, and are output as uplink transmission band allocation information and downlink transmission band allocation information, respectively. Based on the downlink transmission band allocation information, downlink signals output from a plurality of wireless control devices toward a plurality of wireless devices for each of the plurality of users, and the uplink transmission band allocation information are multiplexed, and the multiplexed signal is demultiplexed into downlink signals for each of the plurality of users and the uplink transmission band allocation information.

Abstract: A signal transfer management apparatus manages operations of a plurality of signal transfer devices. The signal transfer management apparatus includes a gate calculation unit configured to calculate a gate start time of each of uplink time gates and a gate start time of each of downlink time gates of a plurality of signal transfer devices and open each of the time gates, a comparison unit configured to compare uplink time synchronization messages from the plurality of slave devices to a master device and detect a conflict between the uplink time synchronization messages, and an offset unit configured to, when the comparison unit detects a conflict, adjusts the gate start time of each of the uplink time gates and the gate start time of each of the downlink time gates of the signal transfer devices and set the adjusted gate start times in the signal transfer devices.

Abstract: A spatial optical communication system in which a plurality of transmitters and a plurality of receivers opposite to each of the plurality of transmitters perform an optical communication in parallel, in which the plurality of transmitters transmit optical signals of same or adjacent wavelengths to the receivers of each opposite location, and has an interference blocking unit which is disposed between the transmitter and the receiver and spatially blocks an optical signal that interferes with the receiver of a non-opposite location among optical signals transmitted from the transmitter to the receiver of an opposite location. As a result, it is possible to avoid interference with other optical communications with a reduced space and at low cost, without need to supply power.

Abstract: Provided is a multiplex transmission system capable of preventing occurrence of a mistake on connection of a client device to a multiplex transmission device. The multiplex transmission system includes: an extraction means configured to extract identification information from a signal inputted to a client port of each of a first multiplex transmission device 100 and a second multiplex transmission device 200; and a switch control unit 340 configured to control a switch unit 330 to connect the client port of the first multiplex transmission device 100 with the client port of the second multiplex transmission device 200 on the basis of a result of collation between identification information extracted from a signal inputted to the client port of the first multiplex transmission device 100 and identification information extracted from a signal inputted to the client port of the second multiplex transmission device 200.

Abstract: In a signal transfer system including a signal transfer management apparatus and a plurality of signal transfer apparatuses connected in multiple stages and forming a network between a distribution station apparatus and a central station apparatus, a signal transfer apparatus on an upper side among the plurality of signal transfer apparatuses transmits a timing adjustment request to at least one of a plurality of signal transfer apparatuses on a lower side among the plurality of signal transfer apparatuses upon determining that there is a possibility that a microburst occurs according to mobile scheduling information received from the plurality of signal transfer apparatuses on the lower side, and the signal transfer apparatus on the lower side that has received the timing adjustment request from the signal transfer apparatus on the upper side adjusts opening and closing timings of a gate based on the timing adjustment request. This can prevent the occurrence of a microburst.

Abstract: Provided is a multiplex transmission system capable of preventing occurrence of a mistake on connection of a client device to a multiplex transmission device.

Abstract: A signal transfer control apparatus that performs a control operation to switch a plurality of communication paths constituted by a plurality of signal transfer apparatuses transferring a signal includes: a fixed delay information acquisition unit that acquires fixed delay information for each of the plurality of communication paths; a traffic information acquisition unit that acquires traffic information indicating a traffic volume or each of the plurality of communication paths; a probability density function estimation unit that estimates a probability density function of a traffic volume of each of the plurality of communication paths based on the traffic information; an occurrence probability estimation unit that estimates an occurrence probability of variable delay in each of the plurality of communication paths based on the probability density function of each of the plurality of communication paths; a communication path calculation unit that performs a calculation for specifying a communication path w

Abstract: A communication control system includes a plurality of layer 2 switches (SWs); and a communication control device that controls communication of the SWs. Each SW includes one or more queues that each have a variable queue length for accumulating input frames, and a transmission unit that has a shaping function of transmitting the frames accumulated in the queues to a desired destination at a desired rate.

Abstract: Provided is a path control method of controlling a path of communication in a network including a high priority device dealing with high priority traffic, a high priority control device communicating with the high priority device through a plurality of signal transfer devices transferring signals by periodically repeating a high priority signal transmissible period in which high priority traffic is transmissible and a low priority signal transmissible period in which low priority traffic is transmissible, a low priority device dealing with the low priority traffic, and a low priority control device communicating with the low priority device through the plurality of signal transfer devices, the path control method including calculating a low priority signal transmissible period in each of paths between the low priority device and the low priority control device, and performing setting for switching the path between the low priority device and the low priority control device so that the low priority traffic is

Abstract: A relay device relaying, to a reception device, a signal stream transmitted by a transmission device through MIMO transmission, the relay device including a lattice base reduction processing unit transforming bases of the signal stream transmitted by the transmission device through MIMO transmission, to increase orthogonality of a lattice of the signal stream, a MIMO equalization unit detecting, by equalization, reception symbols in the signal stream with the bases transformed by the lattice base reduction processing unit, a symbol quantization unit performing quantization by mapping the reception symbols detected by the MIMO equalization unit, to a region on a complex plane delimited by quantization threshold values, and a transmission unit transmitting, to the reception device, at least a signal quantized by the symbol quantization unit.

Abstract: A communication system of a passive optical communication network includes an optical line terminal (OLT) system including a first OLT, a second OLT, and an OLT control device that controls the first OLT and the second OLT, a plurality of splitters that connect the first OLT and the second OLT with an optical communication path, and an ONU that is connected to each of the splitters with an optical communication path. The splitter distributes and outputs an optical signal transmitted from the OLT system to the ONU connected to the splitter and a succeeding device that is another splitter or the OLT system, and the OLT control device determines a distribution ratio at the splitter, the distribution ratio indicating a ratio between the intensity of the optical signal distributed to the succeeding device and the intensity of the optical signal distributed to the ONU.

Abstract: A monitoring device that monitors a network to which a plurality of terminal devices establishing a connection based on TCP are connected, includes: a request detection unit that detects a connection establishment request that a terminal device becoming a client sends to another terminal device becoming a server; an available bandwidth calculation unit that calculates an available bandwidth by subtracting a current amount of traffic from an allowable communication capacity, for each communication path identified by the connection establishment request detected by the request detection unit; and a setting command unit that, when the available bandwidth calculated by the available bandwidth calculation unit is smaller than a congestion window, transmits a command that sets the client to lower a slow start threshold to a predetermined value, or a command that sets the server to lower a window size to a predetermined value, regardless of whether or not a timeout occurs.

Abstract: In a signal transfer system including a signal transfer management apparatus and a plurality of signal transfer apparatuses connected in multiple stages and forming a network between a distribution station apparatus and a central station apparatus, a signal transfer apparatus on an upper side among the plurality of signal transfer apparatuses transmits a timing adjustment request to at least one of a plurality of signal transfer apparatuses on a lower side when discard of a signal received from the plurality of signal transfer apparatuses on the lower side has been detected or when an amount of traffic of a plurality of signals received from the plurality of signal transfer apparatuses on the lower side exceeds a predetermined threshold value, and the signal transfer apparatus on the lower side that has received the timing adjustment request from the signal transfer apparatus on the upper side adjusts opening and closing timings of a gate based on the timing adjustment request.