Fujitsu Corporation

Shinichi Fujiyoshi

Toshinori Koyanagi

Kazuhiro Uchida

Setsuo Abiru

Katsuhiko Hirashima

Kazuya Ryu

Toshiyuki Sakai

Tamotsu Matsuo

Kenji Miura

Yoshimi Toyoda

Takashi Monzawa

Mitsuharu Wakayoshi

Jun Asato

Hideki Shiono

Tateo Shimaru

Kanna Okamura

Hidetoshi Kawamura

Michihiko Goto

Masashi Shibata

A communication system capable of communicating control information without decreasing the bandwidth available to users. A coder encodes a primary signal to generate encoded data such that the polarity of the encoded data alternates between positive and negative polarities. A polarity-reversed data generator reverses the polarity of part of the encoded data to generate polarity-reversed data. A transmitter transmits, as communication data, the encoded data including the polarity-reversed data. A receiver receives the communication data, and a polarity-reversed data detector determines whether or not the polarity of the received communication data alternates between positive and negative polarities, and detects, as the polarity-reversed data, data of which the polarity differs from an expected polarity. A polarity recognizer recognizes the polarity of the polarity-reversed data and treats the recognized polarity as control information.

Communication system

An optical network unit and an optical line terminal which efficiently control the data receiving and dechurning processes in a passive optical network. In a churning parameter memory subsystem, a first memory bank stores churning parameters that are currently used, while a second memory bank stores updates made to the churning parameters. Under the control of the churning parameter memory subsystem, those first and second memory banks change their roles with each other at a churning key updating time point. A data dechurning unit receives a data stream consisting of a plurality of frames and dechurns the information contained in the data stream, according to the stored churning parameters. When an update is done to the parameters in a certain frame, the data dechurning unit makes the update effective at the next frame, thus starting data dechurning operations from the next frame.

Optical network unit and optical line terminal

An optical line terminal which sends and receives messages or data to/from optical network units (ONUs) connected thereto. A cyclic message monitor produces a trigger signal, for use in a PLOAM grant generator, at certain intervals in harmonization with upstream messages that a specific optical network unit regularly transmits. A downstream message monitor watches outgoing downstream messages to detect a certain message requesting an ONU to return a response, and it triggers the PLOAM grant generator if such a message is detected. An upstream message monitor detects an upstream message whose identification code indicates that the sending ONU has no information to return. If such an upstream message is found, it limits the issuance of PLOAM grants to that optical network unit. The PLOAM grant generator produces PLOAM grants which permit ONUs to transmit their messages, and sends them out through a PLOAM cell transmitter.

Optical line terminal

In a homo-code continuity proof testing device for testing with test data including a predetermined homo-code continuity proof test pattern, a testing device on a transmitting side synchronizes the test data in the form of a frame, including a predetermined test pattern, a data synchronous pattern, an error detecting pattern, and preferably a frame synchronous pattern for testing a homo-code continuity proof strength, with a predetermined clock, to be transmitted. A tested device on a receiving side extracts a clock included in the test data, detects the data synchronous pattern, the error detecting pattern, and the frame synchronous pattern in synchronization with the extracted clock, and determines a homo-code continuity proof test by the detection/undetection of each pattern.

Homo-code continuity proof testing device

Growing community of inventors

Fukuoka, Japan

Shinichi Fujiyoshi