Mitsubishi Electric Corporation

Daisuke Osagawa

Atsushi Kajino

Kazuya Inazuma

Kenichi Iwamatsu

Yuma Hayashi

A list distribution station of a communication station includes processing circuitry to record, in a memory, a grand master list containing a station code of a grand master and a station code of a communication station synchronized with the grand master, and receive a priority notification frame which contains, as a sender station code, a station code of a present grand master in the communication system. The processing circuitry is further included to decide, when notified of the station code of the present grand master, whether or not to update the grand master list based on the notified station code of the present grand master and the grand master list, and upon having decided to update the grand master list, to update the station code of the present grand master station on the grand master list with the notified station code of the present grand master station.

Communication system, list distribution station, communication method, and computer readable medium

A network system constituted by a communication device performing communication of a first communication protocol for periodically transmitting data requiring low-delay transmission, a communication device performing communication of a second communication protocol for non-periodically transmitting data requiring low-delay transmission, and a communication device performing communication of a third communication protocol for transmitting data that does not require low-delay transmission, wherein a period in which transmission with the first protocol is permitted, a period in which transmission with the second protocol is permitted, and a period in which transmission with the third protocol is permitted are allocated, and each communication device transmits data in a period in which transmission with the protocol supported by the communication device is permitted, and transfers data received from another communication device in a period in which transmission with a protocol supported by a data transmission source communication device is permitted.

Network system and communication method

A communication system includes a plurality of high-performance communication devices located in a first communication network and having a first communication processing performance, and a low-performance communication device located in a second communication network and having a second communication processing performance. A high-performance communication device, which is one of the high-performance communication devices and is located at a boundary of connection with the low-performance communication device, restricts relay of a broadcast frame transmitted and received in the first communication network to the second communication network.

Communication system and communication method

A communication system includes: a first communication device that transmits a plurality of frames at a transmission time interval shorter than a time required for transmitting a minimum frame; and a second communication device that performs timing synchronization with the first communication device on the basis of the plurality of frames when a reception time interval of the plurality of frames received is equal to the transmission time interval.

Communication system, communication device, and communication method

Even if the propagation time interval of a sync signal is not constant, an accurate correction parameter is calculated, so that a corrected time point synchronized with a main clock device is obtained. A main transmission time point storage part stores respective main transmission time points at which a main device has transmitted a plurality of main sync signals and which are measured using a main clock device. A subordinate reception time point storage part stores respective subordinate reception time points at which a subordinate device has received the plurality of main sync signals and which are measured using a subordinate clock device. A speed ratio calculation part calculates a speed ratio of a ticking time speed of the main clock device to a ticking time speed of the subordinate clock device, based on a main transmission mean time point being a mean of the main transmission time points and a subordinate reception mean time point being a mean of the subordinate reception time points.

Correction parameter calculation device, system, correction parameter calculation method, and computer program

A communication device which has a frame reception unit to separate a frame received from one device into a relay sub-payload that is not addressed to the device itself, and an own-device addressed sub-payload that is addressed to the device itself, an error detection unit to perform error detection based on the error-detection code within the own-device addressed sub-payload, a relay sub-payload storage unit to store the relay sub-payload, a communication-start notification unit to notify a communication-start timing to start communication simultaneously with other devices, and a frame transmission unit to start transmitting to another device the frame including a preamble and the relay sub-payload upon being notified of the communication-start timing, and to add the relay sub-payload to an end of the frame currently being transmitted, so as to continue transmission of the frame, when the relay sub-payload is stored in the relay sub-payload storage unit.

Communication device and communication method

Correction parameter calculation system and method

A synchronous frame reception unit receives a synchronous frame describing a reference value for time synchronization with a management apparatus which is transmitted repeatedly from the management apparatus. A propagation delay computation unit computes, each time when the synchronous frame is received, a propagation delay of the synchronous frame. A propagation delay time period computation unit computes, each time when the propagation delay is computed, a propagation delay time period by adding a target value of a synchronous accuracy to the propagation delay. A propagation delays computation unit operates a logical OR operation of M pieces of propagation delay time periods computed for M pieces of synchronous frames which precede a latest synchronous frame. A synchronous determination unit decides, based on the propagation delay of the latest synchronous frame and a logical OR operation result of the M pieces of propagation delay time periods of the M pieces of synchronous frames, whether or not to use the reference value described in the latest synchronous frame for time synchronization with the management apparatus.

Growing community of inventors

Tokyo, Japan

Daisuke Osagawa