Abstract: A communication system that uses a wired transmission line and multi-carrier modulation includes a transmitting device and a receiving device that are connected through the wired transmission line, wherein the receiving device includes an estimator configured to estimate a first SINR (Signal-to-Interference-Plus-Noise Ratio) of a first sub-carrier and a second SINR of a second sub-carrier, the transmitting device includes a power adjustor configured to boost a transmission power for the first sub-carrier such that an SINR of the first sub-carrier reaches a first SINR threshold corresponding to a first MCS (Modulation and Coding Scheme) that is larger than the first SINR, and back off a transmission power for the second sub-carrier such that an SINR of the second sub-carrier is lowered to a second SINR threshold corresponding to a second MCS that is smaller than the second SINR, and the transmitting device allocates the first MCS to the first sub-carrier.

Abstract: A communication device includes a zero-forcing equalizer that receives a receipt signal and execute zero-forcing equalization on the receipt signal, a partial response equalizer that receives the receipt signal and execute partial response equalization on the receipt signal, a first weighted value calculator that calculates a first weighted value based on signal quality of the receipt signal output from the zero-forcing equalizer, a second weighted value calculator that calculates a second weighted value based on signal quality of the receipt signal output from the partial response equalizer, and an estimator that estimates a maximum likelihood sequence by supplying the first weighted value to state transition based on output by the zero-forcing equalizer and supplying the second weighted value to state transition based on output by the partial response equalizer.

Abstract: A communication device includes a zero-forcing equalizer that receives a receipt signal and execute zero-forcing equalization on the receipt signal, a partial response equalizer that receives the receipt signal and execute partial response equalization on the receipt signal, a first weighted value calculator that calculates a first weighted value based on signal quality of the receipt signal output from the zero-forcing equalizer, a second weighted value calculator that calculates a second weighted value based on signal quality of the receipt signal output from the partial response equalizer, and an estimator that estimates a maximum likelihood sequence by supplying the first weighted value to state transition based on output by the zero-forcing equalizer and supplying the second weighted value to state transition based on output by the partial response equalizer.

Abstract: A communication system that uses a wired transmission line and multi-carrier modulation includes a transmitting device and a receiving device that are connected through the wired transmission line, wherein the receiving device includes an estimator configured to estimate a first SINR (Signal-to-Interference-Plus-Noise Ratio) of a first sub-carrier and a second SINR of a second sub-carrier, the transmitting device includes a power adjustor configured to boost a transmission power for the first sub-carrier such that an SINR of the first sub-carrier reaches a first SINR threshold corresponding to a first MCS (Modulation and Coding Scheme) that is larger than the first SINR, and back off a transmission power for the second sub-carrier such that an SINR of the second sub-carrier is lowered to a second SINR threshold corresponding to a second MCS that is smaller than the second SINR, and the transmitting device allocates the first MCS to the first sub-carrier.

Abstract: A partition based slot assignment method and apparatus, applying to other nodes than a sink node in a multi-hop sensor network including: transmitting a detection request packet including subtree information of a subtree of the sink node, using a node one-hop away as a root node; determining whether other nodes and the sink node are in the same subtree according to received detection request packets transmitted by other nodes including subtree information of subtrees of the other nodes; and storing the subtree information of the subtrees of other nodes in a local collision table if the other nodes and sink node are not in a same subtree, and transmitting the table to a parent node of the sink node. By changing a slot assignment in a larger network into independent slot assignments in smaller networks, a slot assignment problem resulting from a large number of nodes may be solved.

Abstract: 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.

Abstract: A node apparatus calculates the arrival rate in a link, discretizes the calculated arrival rate according to thresholds that are set so that the intervals between thresholds in the range in which a large number of the arrival rates in the links with a high frequency of usage exist become narrower, and calculates the link cost according to the value after the discretization. The node apparatus then obtains, from adjacent node apparatuses, the route cost for each route to each final destination that may be reached, and integrates the obtained route cost by the calculated link cost to calculate the route cost to each final destination that can be reached from the local node apparatus via the adjacent node apparatus. The node apparatus then selects the adjacent node apparatus to be the transmission destination according to the route cost of the route to the final destination of a data frame.

Abstract: The present invention includes a liquid crystal panel, a light guide member, at least one laser diode (LD), and a heat sink. The light guide member is arranged on a back surface of the liquid crystal panel. The LD is arranged on at least one side surface of the light guide member. The heat sink is arranged to extend along a back surface of the light guide member and the side surface of the light guide member integrally and at least partially. The heat sink is arranged such that a part of the heat sink corresponding to the side surface of the light guide member houses at least a light-emitting surface of the LD.

Abstract: A stepwise slot allocation method and apparatus applicable to a node in a wireless network and includes: by the node, determining an initial boundary value of a slot for slot allocation at a current slot allocation stage; calculating a slot length needed by the node at the current slot allocation stage; and selecting a slot index needed by the current slot allocation stage starting from the initial boundary value. By using the method, the slot allocation is combined with an amount of traffic in the network, and slot index of each node is more proper. And it is ensured that one packet corresponds to a slot, and a case will not occur where a slot is reserved but not used.

Abstract: A node device includes: a communication unit to transmit a data frame containing frequency information and receive the data frame; a storage unit to store a table in which frame identification information and the frequency information are associated; and a control unit to: determine whether a destination of the received data frame is its own node device; determine whether the frame identification information of the received data frame is registered in the table; determine whether the number of transmission times is less than or equal to the number of transmission times corresponding to the frame identification information registered in the table; update the frequency information corresponding to the frame identification information registered in the table with the frequency information of the received data frame; and increase the number of transmission times, wherein the communication unit transmits the data frame for which the number of transmission times is increased.

Abstract: A system includes first and second apparatuses configured to communicate with a server apparatus; and a third apparatus configured to transmit data to the first apparatus and record number of transfer of the data in the system, the data including information on a destination of the data and the number of transfer, wherein the first apparatus is configured to set the destination to the second apparatus and update the number of transfer, when receiving the data and not being allowed to communicate with the server apparatus, and transmit an updated data including information on the set destination and the updated number of transfer, to the third apparatus, and the third apparatus is configured to transmit the updated data to the second apparatus based on the set destination when the updated number of transfer is equal to or smaller than the recorded number of transfer when receiving the updated data.

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: Node device calculates reception rate of frames of particular frame type transmitted from adjacent node device, calculates arrival rate of unicast frames on the basis of calculated reception rate and frame length, and calculates inverse number of calculated arrival rate as link cost. Node device obtains from adjacent node device route cost for each route from adjacent node device to each node device that is reachable final destination, calculates route cost of route from node device itself to each node device that is final destination reachable via adjacent node device by integrating calculated link cost and obtained route cost. Node device selects adjacent node device that is transmission destination of data frame on the basis of route cost of route from node device itself to node device that is final destination of data frame when data frame is transmitted.

Abstract: An apparatus includes a memory; and a processor coupled to the memory and configured to generate a first common key whose key value varies based on a first elapsed time when a notification of the first elapsed time after a start-up of another apparatus to which a data frame to be encrypted is to be transmitted has been made, generate a second common key whose key value varies based on a second elapsed time after a start-up of the apparatus when a notification of the first elapsed time has not been made, and encrypt the data frame by any one of the first common key and the second common key as a common key and transmit the encrypted data frame to the another apparatus.

Abstract: First node stores completion information on second node that is adjacent to the first node, the completion information indicating whether or not a route between a target destination and the second node has been constructed using an address with a specified size; acquire a first address with the specified size that specifies the first node, and transmits to adjacent nodes the completion information on the first node indicating that the route between the target destination and the first node has been constructed using an address with a specified size, when the completion information on the second node has indicated that the route between the target destination and the second node has been constructed using the address with the specified size and when the first address has been acquired; and transmits a data frame by using the first address, when the completion information on the first node is transmitted.

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: Embodiments of the present invention provide a method and apparatus for assigning slot. The method includes: constructing an HELLO packet, the HELLO packet including GTS request information of a local node or including GTS request information of the local node and GTS request information of at least one neighboring node within a collision domain of the local node; and broadcasting the HELLO packet, so that a node receiving the HELLO packet performs slot reservation according to information contained in the HELLO packet. With the method and apparatus for assigning slot provided by the embodiments of the present invention, no central controller is needed any longer in comparison with a centralized slot assignment method, complexity of calculation is lowered, and utilization of slot is improved.

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 method and apparatus for assigning a slot, including: constructing a HELLO packet, the packet including slot request information of a local node and/or slot request information of a neighbor node of the local node; and transmitting the packet, so that a node receiving the packet authenticates a reservation slot requested by a sender; wherein the slot request information of the local node includes an address of the local node and of a receiving node of a data packet to be transmitted and an index of the reservation slot requested by the local node; and the slot request information of the neighbor node includes an address of the neighbor node, an address of a receiving node of a data packet to be transmitted, an index of a reservation slot requested by the neighbor node, and confirmation information of the reservation slot requested by the neighbor node.