Fuji Xerox Co., Ltd.

Kouichi Yoshimura

Takeshi Ota

Kazunori Horikiri

Katsuya Mitsutake

Koh Kamizawa

Takanori Hisanaga

Yuji Kozawa

Yutaka Ogawa

A data transfer apparatus and method uses recovery-type congestion control and avoidance-type congestion control. A bandwidth determination unit determines a requested bandwidth for a congestion avoidance-type data transfer in accordance with control information communicated between applications prior to the congestion avoidance-type data transfer. A bandwidth estimation unit estimates a bandwidth having been used by a congestion recovery-type data transfer in accordance with the control information communicated between applications prior to the congestion recovery-type data transfer. A management information memory stores information data of all the congestion avoidance-type data transfers and congestion recovery-type data transfers that use the bandwidth at a particular moment (i.e., simultaneously). A bandwidth allocation unit determines whether a newly requested congestion avoidance-type data transfer can be performed in accordance with an unused bandwidth and a bandwidth requested by the new data transfer, and allocates a certain amount of bandwidth to the new congestion avoidance-type data transfer. A data transfer instruction unit instructs an application to perform new data transfer.

Data transfer apparatus and method using congestion recovery-type and

An overlay cellular communication network, which includes a first base station for providing a first cellular communication network having a first cell size, and a second base station for providing a second cellular communication network which covers the first cellular communication network and has a second cell size, is provided to determine a proper transmission route immediately and to cover a broad area communication network with certainty. A mobile station belonging to an overlay communication network, which includes a micro cell having a first cell size and a macro cell having a second cell size, has an mobile station identification address in the application layer defined by the OSI reference model, and also has a plurality of addresses, each of the plurality of addresses belonging to one of the data link layer through the presentation layer defined by the OSI reference model, which represent routes to reach the mobile station. A transmitting route is determined by combining properly the mobile station identification address and the address representing a route.

Cellular communication network and its communication method

The invention provides a light source for optical communication. The light source includes a spontaneous emission generator, an optical wavelength band narrower, an optical modulator, and an optical amplifier. The spontaneous emission generator generates non-coherent light which is band narrowed, modulated and amplified for a wireless optical communication in free space. The invention avoids a health hazard in respect of human eyes and remove a noise based on a spontaneous emission generated from an optical amplifier.

Light source for optical communication, optical transceiver and optical

A contention control system unitarily manages a plurality of data transmissions so as to avoid contention therebetween. Data transmission command sending equipment of a data receiver continuously sends data transmission commands to a data sender according to a data transmission request. Data transmission-command receive control equipment receives the first valid one of the continuously-delivered data transmission commands therein and delivers it to data transmission control equipment. Correspondingly, data sending equipment starts to transmit data. Data transmission monitoring equipment of the data receiver monitors the state of transmission of the data. When the data transmission corresponding to the data transmission commands is made, the data transmission monitoring equipment detects it and notifies the result of detection to data transmission-command transmit control equipment, which in turns terminates the notification of the data transmission commands in response to its notification delivered from the data transmission monitoring equipment. Thus, a reduction in the efficiency of bandwidth utilization at the time that transmission errors are produced in the notification of the above commands can be restrained.

Growing community of inventors

Nakai-machi, Japan

Kouichi Yoshimura