Fujitsu Corporation

Katsuhiko Hirashima

Kazuhiro Uchida

Toshinori Koyanagi

Setsuo Abiru

Kazuya Ryu

Shinichi Fujiyoshi

Toshiyuki Sakai

Tateo Shimaru

Tamotsu Matsuo

Kenji Miura

Yoshimi Toyoda

Takashi Monzawa

Mitsuharu Wakayoshi

Jun Asato

Hideki Shiono

Daisuke Kobayashi

Kenichi Abe

Kiyotaka Shikata

Naoyuki Takeshita

Masaharu Matsumoto

Susumu Tominaga

Hiroaki Shiraishi

Kanna Okamura

Takamitsu Shirai

Yoshinari Sugimoto

Masaru Nishida

Hisaya Urabe

Hirofumi Yagawa

Masashi Shibata

Shigeharu Murakami

Tsuneharu Suzuki

Miho Kawai

Toshinobu Tsunematsu

A transmission apparatus includes a first storage configured to store data received from external into a write enable area, a second storage configured to store the data in accordance with a write request and output a retry request in response to occurring an error of writing a first data included in the data, and a controller configured to read the data from the first storage and send the write request to the second storage, set an area of the first storage storing the first data to a write disable area in combination with stop sending the retry request to external when receiving the retry request from the second storage, and send the first data reading from the write disable area of the first storage to external in response to a read request from external.

Transmission apparatus and retry method

A method of communicating through a passive optical network (PON) that improves the efficiency of the network with low cost child apparatuses having only simple functions. A parent apparatus provides the child apparatuses with a multi-frame standard signal, and a child apparatus transfers asynchronous information as a frame of variable length, as it is, at a time delayed from the multi-frame standard signal by a time period designated by the parent apparatus. Since the asynchronous information does not need to be divided into pieces to which a frame header is attached, the efficiency of the uplink channel is increased.

Method of transferring frames of variable length for a passive optical network that improves network efficiency and simplifies child apparatus

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

A frame transmission device which does not require a separate supervisory line and enables supervisory frames to efficiently enter subscriber traffic for transmission without securing a fixed bandwidth. A supervisory token computing section gives supervisory frames supervisory tokens as permission to transmit within a minimum bandwidth. Subscriber token computing sections give subscriber frames subscriber tokens as permission to transmit within respective set transmission bandwidths. A best-effort token computing section gives the frames best-effort tokens as permission to transmit by using an extra bandwidth. The supervisory or subscriber tokens are given to read frames from a supervisory queue or subscriber queues, and if a frame queue length is smaller than or equal to the best-effort tokens remains in the queue, a queue read control section reads and outputs the remaining frames from the queue by using the extra bandwidth of best-effort tokens.

Frame transmission device

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

Katsuhiko Hirashima