Nec Communication Systems, Ltd.

Advanced Telecommunications Research Institute International

A School Corporation Kansai University

Advanced Telecommunications Research Institute Int

Advanced Telecommunications Reserach Institute International

Akio Hasegawa

Yukihiro Hara

Peter Davis

Sadao Obana

Masahito Iwai

Takatoshi Kimura

Naoto Kadowaki

Jun Hasegawa

Tetsuya Ito

Satoko Itaya

Hiroyuki Yomo

Akira Matsumoto

Hiroyuki Iizuka

Yuichiro Ezure

Suhua Tang

Shota Kakibuti

Ryou Nagase

Shohei Fukayama

Hironori Fukui

Yuma Asada

Noboru Miyamoto

Yuta Okamoto

A transmitter generates a header frame having a frame length indicating the beginning of data to be transmitted, data frames having frame lengths representing the data to be transmitted, and an end frame having a frame length indicating the end of the data to be transmitted. Then, for all of the header frame, data frames and end frame, the transmitter executes transmitting the kth frame when the wireless communication space is available, thereby transmitting the header frame, data frames and end frame, one after another, in accordance with the CSMA/CA scheme.

Program executed in transmitter, receiver and program executed in receiver

When a terminal device initiates a wireless communication when it has not established a wireless link between itself and another wireless device, it transmits, as a management frames in active scanning, a plurality of activation probe requests having frame lengths representing an identifier of a wireless base station to which connection is being made and which is intended to transition from sleep mode to operating mode. Then, the wireless base station receives the plurality of activation probe requests transmitted by the terminal device as management frames in active scanning in a wireless LAN, and, when a plurality of dummy network identifiers detected based on the received plurality of activation probe requests represent the identifier of its own, transitions from sleep mode to operating mode.

Terminal device, wireless device wirelessly communicating with the same, and wireless communication system including the terminal device and wireless device

A wireless device () searches a database that stores positional information of the wireless device (), a device (-) and control identifiers for controlling the devices (-) in an associated manner, acquires a device (-) located near the wireless device () and a control identifier for controlling the device (-) based on the positional information of the wireless device (), and, based on the device (-) and the control identifier for controlling the device (-) that have been acquired, determines a controlled device (at least one of the devices (-)) and generates a control identifier for the controlled device. The wireless device () transmits, by wireless communication, the generated controlled identifier to a receiver mounted on the controlled device to control the controlled device.

Wireless device, controlled device controlled by the same, control system including a wireless device and controlled device, and program for causing a computer in a wireless device to control a controlled device

Radio apparatuses each has a plurality of channels and, when data is to be transmitted, selects a specific channel having relatively low signal interference from the plurality of channels. Each radio apparatus spreads transmission data with a prescribed spread code arbitrarily selected from a plurality of spread codes, and modulates the spread spectrum signal with the frequency of the specific channel to transmit. As a result, delay in an autonomously established wireless network can be reduced.

Radio apparatus

Radio devices (to) receive a prescribed number of Hello packets from each of n radio devices existing within one hop from each radio device, detects six pairs of maximum and minimum values MAX[] and MIN[] to MAX[] and MIN[] based on the plurality of reception signal strengths of the plurality of received Hello packets, detects two adjacent maximum values having the largest difference among six pairs of maximum and minimum values D_MAX[] and D_MIN[] to D_MAX[] and D_MIN[] when the six maximum values MAX[] to MAX[] are in descending order, and determines the average of two minimum values corresponding to the detected two maximum values as a threshold. The radio devices (to) each produce a routing table including routes having reception signal strengths equal to or more than the threshold.

Radio device

A radio device is located far from other radio devices in a radio network system. The radio device determines a threshold WIth for detecting a strength equal to or more than the minimum strength of radio waves transmitted/received in a stable radio wave environment based on a plurality of reception signal strengths of Hello packets received from radio devices adjacent to the radio device. Then, if the number of radio devices adjacent to the radio device when the threshold WIth is introduced is less than a standard value (such as five), the radio device stores the adjacent radio devices in the neighbor list without introducing the threshold WIth, and then, maintains in the routing table the routing information of routes passing through the adjacent radio devices based on the neighbor list.

Radio device for preventing isolated radio devices in network

The route maintenance unit outputs a period setting request to the period setting unit when the communication unit normally receives a Hello packet for the first time. The period setting unit sets a link connection confirmation period in response to the period setting request and outputs the set period to the route maintenance unit. The route maintenance unit maintains a radio link between the radio device in which the route maintenance unit is provided and an adjacent device upon receiving a data packet other than a Hello packet from the adjacent radio device even if a Hello packet is not received in the link connection confirmation period. Consequently, route disconnection or switching occurs less often.

Radio device having fewer route disconnections and switchings by using control packets to maintain radio links

Growing community of inventors

Kyoto, Japan

Akio Hasegawa