Fujitsu Corporation

Toshio Irie

Tatsuru Nakagaki

Tetsuo Tachibana

Toshiyuki Hijikata

Masayuki Yamanaka

Katsutoshi Inoko

Hiroyuki Suzuki

Takashi Hatano

Ryoichi Ishibashi

Kosuke Nobuyasu

Emi Hata

Yoshinori Matsunaga

The present invention aims at providing an ascending transmission speed controlling method and a communication system in an ATM-PON (asynchronous transfer mode-passive optical network), in which ascending transmission speeds on the PON are dynamically allocated corresponding to actual transmission states of communication channels of a best effort type, to thereby effectively utilize respective bands. To this end, according to the present invention, in an OLT (optical line termination) constituting the ATM-PON system, active/inactive states of communication channels are identified based on receiving states of ascending data cells transmitted from ONU's of subscriber side, respectively, and a congestion state of the ATM network is recognized by extracting B-RM (backward resource management) cells from descending data cells, respectively, transmitted from the ATM network, so that ascending transmission speeds on the PON are allocated to communication channels corresponding to service categories, based on such as the thus recognized information.

Ascending transmission speed controlling method and communication system in ATM-PON system

By transmitting an analog CATV signal output from a CATV-HE (CAble TeleVision-Head End) to an HDT (Host Digital Terminal), an analog transmission channel for transmitting the analog CATV signal to an ONU (Optical Network Unit) is included in a path housing a digital transmission channel for transmitting a digital service signal for individual distribution service to the ONU. Furthermore, a digital service signal for multicast service is modulated and converted into an analog service signal by a modulator in the HDT. Then, the converted signal is mixed with the analog CATV signal, and transmitted to the ONU. Accordingly, each of the ONUs is equipped with only a built-in modulator for modulating the digital service signal for individual distribution service.

Mixed analog-digital service distribution system and method

A media information distribution service system, such as a video-on-demand service system, is disclosed which, even if the capacity of a line is small and the number of lines connected to a media server, such as a video server, has to be increased accordingly, permits an uneconomical increase in the number of line circuits in the media server to be checked. In the system, a subscriber group that a distributor accommodates can be associated with a plurality of distributor-side paths on a distributor-side line. Each of the distributor-side paths is connected to a respective one of server-side paths on separate server-side lines connecting the media server and an exchange. In sending media information to a subscriber group, an in-server path control unit installed in the media server is permitted to select a free one out of server-side paths on server-side lines allocated for that subscriber group and activates a line interface corresponding to the free server-side path.

Media information distribution services system and method

A broadband integrated services digital network includes a network, first and second terminals, and first and second terminal adapters. Each of the first and second terminal adapters includes a buffer storing a predetermined number of bursts of data from either the first or second terminal and storing a predetermined number of bursts of data from the network, and a first part for sending ready notification information to the network and for receiving the ready notification information from the network. The ready notification information shows that the buffer has an available storage capacity equal to at least one burst. Each of the first and second terminal adapters further includes a second part for sending ready information to the corresponding one of the first and second terminals before the first part receives the ready notification information from the network. At least, one burst is written into the buffer each time the ready information is sent.

Adapter monitoring storage capacity of its buffer and sequentially

A packet data is formed of a plurality of ATM cells. When cells of the packet data are lost, especially if the packet data is an image or picture signal including synchronous signals, it becomes difficult to reproduce the image or picture on a receiving terminal. A data length compensating device compensates the lost cell. In order to deal with the lost cells lying over between two packets, a data length compensating device includes a lost cell detecting circuit which detects a lost cell to be included in the data according to the sequence number of the plurality of cells, compensation control circuit which outputs compensation information including the number of lost cells to be compensated, and inserting circuit inserts dummy data corresponding to the lost cells to be compensated based on the compensation information.

Data length compensating device for compensating lost cells in packet

A broadband integrated services digital network includes a network, first and second terminals, and first and second terminal adapters. Each of the first and second terminal adapters includes a buffer having a capacity for storing a predetermined number of bursts of data, as received thereby from the respective first and second terminals, and for storing a predetermined number of bursts of data, as received thereby from the network, and a first part for sending ready notification information to the network and for receiving the ready notification information from the network. The ready notification information shows that the buffer has an available storage capacity equal to at least one burst. Each of the first and second terminal adapters further includes a second part for sending ready information to the corresponding one of the first and second terminals before the first part receives the ready notification information from the network. At least one burst is written into the buffer each time the ready information is sent.

Method and apparatus for controlling the flow of data transmissions by

A logical channel setting system is applied to an asynchronous transfer mode (ATM) network which is coupled to terminal equipments which are in conformance with a high performance parallel interface (HIPPI) via respective terminal adapters which are in conformance with the HIPPI. The logical channel setting system includes a call part, provided in a transmitting terminal adapter, for setting a logical channel in the ATM network in response to a request signal which is ON and is received from a transmitting terminal equipment which is coupled to the transmitting terminal adapter, and a disconnect part, provided in the transmitting terminal adapter, for releasing the logical channel which is previously set in the ATM network in response to a request signal which is OFF and is received from the transmitting terminal equipment which is coupled to the transmitting terminal adapter.

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Kawasaki, Japan

Toshio Irie