Fujitsu Corporation

Shigemasa Matsubara

Takao Ito

Katsumi Kobayashi

Taiji Kondo

Hiroaki Kawasumi

Takahiro Koharagi

Mitsuaki Yasuoka

Satoshi Kurosawa

Yoshihiko Shirokura

Yasuaki Kamimura

Kobun Nakajima

Naoto Miyauchi

Satoshi Ikeda

Akira Okubo

Yukio Hayashi

Hiroaki Tamai

Masashi Kuwahara

Joji Maruyama

Yosuke Nishikata

Masahiro Machida

Takafumi Kawakami

Kazuya Takeuchi

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

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

The present invention increases accommodation efficiency in a wireless master station for wireless slave stations, and efficiently uses wireless resources while controlling traffic. In a communication system in which a plurality of wireless slave stations---, . . . , perform wireless communication with wireless master stations-and-directly or through another wireless slave station and which performs communication from the wireless master stations with a collection control deviceby means of wired communication or the like. The collection control devicestores first through fourth threshold values a, b, c, and d in memory, and makes efficient use while suppressing traffic by performing a 'connection suppression notification', a 'specific high-frequency communication stop notification', and an &#x201c;accommodation refusal notification&#x201d;, and performs functionality control through stages according to the number of accommodated wireless slave stations.

Communication system, congestion avoidance method thereof, and meter reading system using communication system

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

Growing community of inventors

Tokyo, Japan

Shigemasa Matsubara