Fujitsu Corporation

Takao Ito

Taiji Kondo

Yoshihiko Shirokura

Takahiro Koharagi

Shigemasa Matsubara

Katsumi Kobayashi

Satoshi Kurosawa

Hiroaki Kawasumi

Yukio Hayashi

Kobun Nakajima

Satoshi Ikeda

Koichi Ishibashi

Yasuaki Kamimura

Yosuke Nishikata

Mitsuaki Yasuoka

Shinichi Hirata

Masashi Kuwahara

Naoto Miyauchi

Joji Maruyama

Masahiro Machida

Katsumi Okuda

Katsunori Hayashi

Hajimu Hirai

A node includes a time difference measurement unit and a time setting unit. The time difference measurement unit measures a time difference between a first time based on latest received time information and a second time based on second-latest received time information. The time setting unit calculates an adjustment time difference when the time difference exceeds an allowable range of error that is smaller than an allowable range of maintainable communication, sets a time obtained by adding the adjustment time difference and the second time to the time of the node when the adjustment time difference is within the allowable range of maintainable communication, and sets a time obtained by adding a time difference corresponding to the allowable range of maintainable communication and the second time to the time of the node when the adjustment time difference exceeds the allowable range of maintainable communication.

Node and method for communication control

A data communication apparatus forms a mesh network together with at least one gateway includes a frame generating unit and a frame transferring unit. The frame generating unit generates a meter data frame to transmit to a gateway. The meter data frame is a frame including meter data. The frame transferring unit transfers the meter data frame received from another data communication apparatus. The meter data frame is addressed to the gateway. The frame generating unit transmits the meter data frame to which number of alternate routing that indicates number of allowable transmission attempts from a data communication apparatus adjacent to a destination gateway of the meter data frame to the gateway is added. The frame transferring unit changes the number of alternate routing added thereto to a value smaller by 1 than a value that has been set and transits the meter data frame to another data communication apparatus.

Data communication apparatus, data communication system, and data communication method

An ad hoc network system includes a plurality of nodes that communicate with a specific node. Each of the nodes includes a calculator and a selector. The calculator calculates a cumulative value of the number of communication nodes connected through the node by adding the numbers of communication nodes from an upstream side, which is a side closer to the specific node than the node, to the node. The selector selects a node serving as a connection destination out of the nodes located on the upstream side on the basis of the cumulative value of the number of communication nodes calculated by the calculator.

Ad hoc network system and route selection method

A communication system includes: a specific node; and a plurality of nodes that are installed at fixed positions and perform ad hoc wireless communication with the specific node. The nodes each include a link quality evaluating unit, an upstream route constructing unit, a communicating unit, and a downstream route constructing unit. The link quality evaluating unit performs route evaluation using a hello frame based only on a track record of reception of the hello frame in order to perform upstream communication toward the specific node to form a network. The upstream route constructing unit constructs an upstream route based on the route evaluation. The communicating unit performs upstream communication toward the specific node on a regular basis with a predetermined frequency. The downstream route constructing unit constructs a downstream route from the specific node based on a route in the upstream communication toward the specific node.

Communication system and communication method

A communication device is included in an ad hoc network in a reactive routing scheme. The communication device includes a receiving unit, a selecting unit, and a transfer control unit. The receiving unit receives a route request frame including overall quality information on routes through which the route request frame has passed. The selecting unit selects a route request frame to be transferred to another communication device based on the quality information, from the route request frames received by the receiving unit through a plurality of routes. The transfer control unit transfers the route request frame selected by the selecting unit to the another communication device, and discards the route request frame when a quality value indicated by the quality information of the route request frame is smaller than a predetermined reference value.

Communication device and communication control method

A software update system includes an administration server, a wireless communication terminal, and a wireless-communication key station. The wireless communication terminal is configured to be connected to the administration server through a communication network. The a wireless-communication key station is configured to be positioned between the administration server and the wireless communication terminal, and to perform processing of distributing software of an update object transmitted from the administration server to the wireless communication terminal.

Wireless communication terminal, software update system, and software update method

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Kawasaki, Japan

Takao Ito