Fujitsu Corporation

Nippon Telegraph and Telephone Corporation

Masahiro Shioda

Toru Katagiri

Atsuki Taniguchi

Osamu Takeuchi

Yasuhiko Aoki

Takashi Kuwabara

Hideki Matsui

Hiroyuki Honma

Yukio Suda

Satoshi Nemoto

Mitsuhiro Kawaguchi

Tsutomu Chikazawa

Ryuji Kayama

Takashi Kaiga

Chiyoko Yamamoto

Daisuke Maruhashi

Hisao Nakashima

Tetsuya Takahashi

Masahito Tomizawa

Kosuke Komaki

Masahiro Suzuki

Takuya Ohara

Takashi Honda

Koji Takeguchi

Koji Matsunaga

Satoru Saitoh

Hideo Abe

Yohei Koganei

Kiyonori Kusuda

Katsuhiro Shirai

Junichi Moriyama

Junichi Ishiwatari

Shigeki Aisawa

Katsumi Fukumitsu

Hirofumi Imabayashi

Yukio Yamazaki

Tatsuya Toyozumi

Hideaki Arao

Shozo Shimada

Yasuhiro Murakami

Katsuya Fujii

Mitsumasa Matsuike

Junji Yamamoto

Koichi Sugama

Yumiko Ogata

Yukio Katayanagi

Hayato Furukawa

Yoshihisa Ikeda

Kenichi Yajima

Takanori Yasui

Nobuhiko Usui

Masayuki Maehira

A frame generating apparatus accommodating a client signal in an optical data transfer unit frame with a higher bit rate than the client signal includes a deserializer, a plurality of generic mapping procedure circuits, and a serializer. The deserializer deserializes the client signal into parallel signals, the number of parallel signals corresponding to the number of tributary slots used in the optical data transfer unit frame. The plurality of generic mapping procedure circuits inserts data and stuff into a frame accommodating portion of the optical data transfer unit frame based on a difference in the bit rate between the client signal and the optical data transfer unit frame. The serializer serializes the parallel signals output from the plurality of generic mapping procedure circuits.

Frame generating apparatus and frame generating method

In an apparatus for accommodating and multiplexing asynchronous client signals in which an idle signal is defined, the transmission side transmits client signals after synchronizing the client signals by inserting or removing, with reference to a specific client signal, an idle signal to/from the same type of another client signal, and in the receiving side, a PLL part is shared by recovering a clock from a client signal and distributing the clock for another client signal.

Client signal accommodating multiplexing apparatus and method

A node device in an optical transport ring network including plural node devices connected in a ring form using plural optical transmission paths so that optical transport frames of a working line and a protection line are transmitted using the plural optical transmission paths, includes a control information transmitter, when a failure occurs in the optical transmission paths, transmitting the optical transport frame to an opposing node device as a transmission destination node in the optical transmission paths, the optical transport frame including switching control information; and a switcher receiving the optical transport frame including switching control information, the optical transport frame being transmitted to the node device as the transmission destination node, forming a loop back to fold a transmission path between the plural optical transmission paths, and switching the optical transmission path from the work line to the protection line.

Method of switching optical transport network and node device

A transmitting apparatus includes a frame dividing circuit that maps frame data of each of a plurality of frames whose period is different from each other into one or a plurality of internal frames having a fixed frame period and a fixed transmission rate, based on a predetermined internal clock; a cross-connect circuit that cross-connects the frame data of each in a time division multiplexing system based on the internal clock in units of the internal frames; and a frame combining circuit that demaps, into any of the plurality of frames, or multiplexes, data of one or a plurality of internal frames cross-connected by the cross-connect circuit.

Transmitting apparatus and signal transmitting method

An optical transmission system transmits an optical signal of multi-level modulation. In a transmitter module, a data string in a specified frame is rearranged into a plurality of logical lanes. A lane ID, which specifies in what logical lane out of the plurality of logical lanes a start of the data string is arranged, is assigned to a non-scrambled area in an overhead portion of the frame. The lane ID corresponding to one of the plurality of logical lanes is different from the lane IDs corresponding to the other remaining logical lanes. The optical signal is generated using the data string rearranged into the plurality of logical lanes. In a receiver, the lane ID is detected according to a majority method. The inversion of bits and the swapping of lanes are detected using the lane ID and compensated.

Optical transmission system and optical transmission method

A signal demultiplexer includes a conversion unit that converts a format of a high speed signal transfer frame output from a terminating unit into a format of a converted frame; a parallelization unit that parallelizes the converted frame and outputs a predetermined number of data columns; and a separating unit that separates plural low speed signal transfer frames from the predetermined number of the data columns. The conversion unit converts the format of the high speed signal transfer frame into the format of the converted frame by delaying a signal storing area using first and second overhead areas, to include an 'i' th tributary slot among the predetermined number of the tributary slots assigned to the signal storing area into an arbitrary 'i' th data column among the predetermined number of the data columns, and to align front positions of the predetermined number of the data columns.

Signal demultiplexer, signal multiplexer, and signal multiplexer/demultiplexer

An optical receiver includes: a waveform distortion compensator to perform an operation on digital signal representing an optical signal generated by an A/D converter to compensate for waveform distortion of the optical signal; a phase detector to generate phase information representing sampling phase of the A/D converter; a phase adjuster to generate digital signal representing an optical signal in which the sampling phase of the A/D converter is adjusted from an output signal of the waveform distortion compensator using the phase information; a demodulator to generate a demodulated signal from the output signal of the phase adjuster; a phase controller to control the sampling phase of the A/D converter; a peak detector to detect a peak value of the phase information while the sampling phase of the A/D converter is controlled by the phase controller; and a compensation controller to control the waveform distortion compensator using the peak value.

Optical receiver

An optical transmission apparatus including a transmitting OTL processor to rearrange a data string stored in a frame into a plurality of logical lanes, and set a lane ID used to identify in which logical lane a beginning of the data string is arranged among the plurality of logical lanes in a non-scramble area in an overhead of the frame, and a receiving OTL processor to respectively identify the lane IDs included in the data string in the respective physical lanes rearranged, determine a generation state of a bit inversion and a lane replacement for each physical lane, compensate the bit inversion and the lane replacement so that the data string in the respective physical lanes becomes same state as the data string in the respective logical lanes, based on the identified result, and rearrange the compensated data string in the respective logical lanes so as to regenerate the frame.

Optical transmission apparatus and method

A read address from a memory and a write address to the memory are transmitted from a VT pointer circuit on an active side to a VT pointer circuit on a standby side in order to eliminate a difference between pointer values of the VT pointer circuits on the active and the standby sides, which is caused by a difference between the phases of the read address from the memory and the write address to the memory of the VT pointer circuits on the active and the standby sides, and the read and the write addresses on the standby side are overwritten with the transmitted address values. As a result, the address values can be made to match both on the active and the standby sides, and also the pointer values can be made to match.

Momentary-disconnection-free switching device

A transmission device in which a bus of a central processing unit is used to synchronize timing signals between units, thereby restraining enlargement in scale of wiring. A reference signal generator generates a reference signal. A reference signal receiver is mounted on a unit set as an active or standby unit and receives the reference signal. A timing signal generator divides the frequency of the received reference signal by means of a frequency divider/counter to generate a timing signal. A count holder holds the count value of the frequency divider/counter. The bus connects the units and the central processing unit. A count receiver receives, via the bus, the count value from the count holder of the active unit. A count updater updates the count value of the frequency divider/counter to the count value received by the count receiver.

Device for synchronizing between an active unit and a standby unit

A plug-in card for an optical transmission apparatus includes a J1generating unit. The J1 generating unit sends information on on-use side J1 data to a plug-in card at a spare side in a redundant structure when the plug-in card operates as an on-use side plug-in card. The J1 generating unit receives information on on-use side J1 data from a plug-in card at the on-use side when the plug-in card operates as a spare side plug-in card. Based on the information, the J1 generating unit matches spare side J1 data to the on-use side J1 data. The plug-in card also includes a B3 byte calculating unit that operates in a similar way as the J1 generating unit does in processing B3 byte data.

Plug-in card for optical transmission apparatus

An object of the invention is to provide a diagnosis method for standby systems in an optical ring network having a redundant configuration, which can confirm normal states of standby systems in all optical transmission apparatuses on the network, even during operations of active systems. To this end, in the present diagnosis method for standby systems, when a diagnosis start command is given to an arbitrary optical transmission apparatus on the network, the optical transmission apparatus provides a false signal to a standby system unit to diagnoses an operation state thereof, and transmits the result to the optical transmission apparatus on the downstream side by utilizing overhead information in the active system optical channel. The optical transmission apparatus on the downstream side confirms a normal operation on the upstream side, thereafter, diagnoses the operation state of the standby system by utilizing the false signal, and updates the overhead information of the active system optical channel corresponding to the diagnosis result, to transmit the updated information to the optical transmission apparatus on the further downstream side. According to the overhead information of the active system optical channel, which has made a round of the ring network, normal operations of the standby system units in all optical transmission apparatuses on the network are confirmed, to thereby finish the standby system diagnosis.

Diagnosis method for standby system of optical ring network

A transport systems is equipped with a burst error detecting unit that monitors a predetermined byte, which is specified in advance in a frame to be monitored, in a transmission signal having header information and data information multiplexed into the frame in bytes. The burst error detecting unit detects a burst error based on a change in a state of occurrence of a bit error in the predetermined byte in a predetermined time window.

Transport systems and method of monitoring burst error

Growing community of inventors

Kawasaki, Japan

Masahiro Shioda