Abstract: A communication device is provided in a wireless multi-hop network. The communication device receives a sequence number, a divided time acquired by dividing a time width allocated for transmitting detected usage data by a division number, and the division number. The communication device calculates a remainder by dividing the received sequence number by the division number and calculates a transmission offset time based on the remainder and the divided time. The communication device transmits the usage data based on the calculated transmission offset time.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A communication device is provided in a wireless multi-hop network. The communication device includes a receiving unit, a transmission-offset calculating unit, and a transmitting unit. The receiving unit receives a sequence number, a divided time acquired by dividing a time width allocated for transmitting detected usage data by a division number, and the division number. The transmission-offset calculating unit calculates a remainder by dividing the sequence number received by the receiving unit by the division number and calculates a transmission offset time based on the remainder and the divided time. The transmitting unit transmits the usage data based on the transmission offset time calculated by the transmission-offset calculating unit.

Abstract: 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.

Abstract: A terminal used in a network that constructs a communication route with ad hoc communications is connected to a server via a gateway. The terminal generates downstream route information from the server to a specific terminal based on information relating to occurrence of downstream communication from the server to the specific terminal, the information being included in a header of upstream communication from the specific terminal to the server, and preferentially retains the downstream route information.

Abstract: A mobile terminal being a searching source that searches for a communication device transmits a searching request addressed to a communication device being a searching destination using a plurality of channels without waiting for a reply to the searching request. A communication device adjacent to the mobile terminal being the searching source, upon receiving a reply to the searching request transmitted by the transmitting from the searching destination, holds the received reply. The mobile terminal being the searching source transmits an inquiry to the adjacent communication device using a plurality of channels about whether a reply to the transmitted searching request has been received from the searching destination. With this configuration, in an ad hoc network with a reactive scheme, the time taken for searching related to a partner device can be shortened.

Abstract: 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.

Abstract: 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.

Abstract: A downlink data frame addressed to a terminal is copied and obtained downlink data frames are transmitted through different APs, respectively. When a plurality of same uplink data frames are received through the different APs, any one uplink data frame selected out of the uplink data frames is transmitted to its destination. An uplink data frame received from the terminal is copied and obtained uplink data frames are transmitted through different STAs, respectively. When a plurality of same downlink data frames are received through different STAs, any one downlink data frame selected out of the downlink data frames is transmitted to the terminal.

Abstract: A wireless LAN system includes at least one LAN terminal wirelessly connected to a plurality of base stations, at least one IP terminal connected to an IP network, and a diversity device connected to the IP network and that relays packet transmission between the LAN terminal and the IP terminal via the IP network. The LAN terminal sequentially establishes association with a predetermined number of the base stations, and a plurality of data is transmitted parallelly via the predetermined number of the base stations, between the LAN terminal and the diversity device. At the receiving end, one of the plurality of data is selected and output.

Abstract: A timing master device transmits a timing packet for synchronizing time of base stations at each cycle of preset time synchronization adjustment timing. The base stations adjust a local-station standard timer based on the timing packet. The base stations measure a delay time of a network form the timing master device to a local station, and adjust the local-station standard timer based on the measured delay time.

Abstract: A wireless LAB system includes at least one LAN terminal wirelessly connected to a plurality of base stations, at least one IP terminal connected to an IP network, and a diversity device connected to the IP network and that relays packet transmission between the LAN terminal and the IP terminal via the IP network. The LAN terminal sequentially establishes association with a predetermined number of the base stations, and a plurality of data is transmitted parallelly via the predetermined number of the base stations, between the LAN terminal and the diversity device. At the receiving end, one of the plurality of data is selected and output.

Abstract: A control unit (100) sets up a path in a protocol conversion apparatus (30) based on call setting information from the calling side terminal. A signal monitor unit (300) monitors main data 220a transmitted in the path and sent/received between the terminals. When a specific connectivity confirmation sequence is detected by the signal monitor unit (300), the result is forwarded to the control unit (100). Based on the forwarded result, the control unit (100) specifies a protocol of the calling side terminal and a protocol of the called side terminal. A protocol conversion unit (310) performs the most suitable protocol conversion based on the specified protocols.

Abstract: In establishing an audio one link connection wherein an audio signal is not encoded/decoded in a relay station, loud noises may be produced if the states of two audio tandem relay devices which make a pair during relay are changed from a normal connection state to a relay connection state at different times. In order to solve this problem, comfort noise generators are provided. In detail, when a first pattern signal is detected while a relay call is connected via a relay exchange, switches are switched to be connected at a contact point 1, and a switch is at a contact point 2. Upon detection of a second pattern signal, the switches are connected at the contact points 2, while the switches are connected at the contact points 2. With this arrangement, outputs from the comfort noise generators are selected and outputted during a period from first pattern signal detection to second pattern signal detection, during which the states of the two devices of a pair are different.

Abstract: When a signal is transmitted from an STM line to an ATM relay channel, the signal is compressed to be cell assembled into a cell. To the contrary, a signal from the ATM relay channel is cell disassembled into separate data and then expanded. In cases where signals are exchanged between ATM relay channels, a multistage relay device does not repeatedly execute signal compression/expansion to the signal. Switching for the above operations is achieved, utilizing a signal pattern inserted into audio data. With this arrangement, an audio one-link operation is established in the environment where an STM and an ATM coexist. Because compression/expansion processes are not repeatedly conducted, delay in relaying is avoided.