Fujitsu Corporation

Kazuya Ryu

Toshinori Koyanagi

Kazuhiro Uchida

Katsuhiko Hirashima

Setsuo Abiru

Shinichi Fujiyoshi

Toshiyuki Sakai

Tamotsu Matsuo

Kenji Miura

Yoshimi Toyoda

Mitsuharu Wakayoshi

Takashi Monzawa

Jun Asato

Hideki Shiono

Tateo Shimaru

Kanna Okamura

Masashi Shibata

A frame transmitting apparatus transmits a frame to a frame receiving apparatus. The frame transmitting apparatus includes the following units. An accumulated-capacity-value storage unit has stored therein an accumulated capacity value calculated. A cycle and capacity storage unit has stored therein a cycle and frame read capacity at every cycle. An adding unit adds the value indicative of the capacity of the frame to the accumulated capacity value. A subtracting unit subtracts the value indicative of the frame read capacity from the accumulated capacity value. A transmission controlling unit controls frame transmission by using the accumulated capacity value.

Frame transmitting apparatus and method utilizing a round-robin technique

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

Kazuya Ryu