Abstract: A communication apparatus includes a receiver, a memory, a processor, and a transmitter. The receiver receives a route information frame and a first frame that is not the route information frame. The memory holds a route information table. The route information table records route information included in the route information frame. When the route information table does not include the source address of the first frame, the processor associates the source address with the address of a transfer-source apparatus that has transferred the first frame to the receiver, and registers these addresses in a registration table. In order to transmit a second frame addressed to a destination apparatus that is not recorded in the route information table, the processor obtains the address of a transfer-source apparatus registered in association with the address of the destination apparatus. The transmitter transmits the second frame to the address obtained by the processor.

Abstract: A wireless communication apparatus stores therein, in an associated manner, each piece of path information on a plurality of destinations and a use frequency of data communication that is performed by using the path information. When the wireless communication apparatus receives data whose send source is a first destination, the wireless communication apparatus specifies, on the basis of the use frequency, path information that is less frequently used from among the pieces of the stored path information. The wireless communication apparatus updates the specified path information to path information whose destination is the first destination.

Abstract: A method and a device perform time-synchronization with an ad hoc network configured by a plurality of nodes. The method includes: transmitting a time-synchronization request frame including an address of one of the plurality of nodes which belong to the ad hoc network to one of the plurality of nodes having a function of receiving the time-synchronization request frame and transmitting a time-synchronization reply frame including time-synchronization information; receiving the time-synchronization reply frame including the time-synchronization information from one of the plurality of nodes which receive the time-synchronization request frame; and performing time-synchronization with one of the plurality of nodes using the time-synchronization information included in the time-synchronization reply frame.

Abstract: A network includes node devices each storing a table that manages paths to plural gateway devices for connecting to another network. A node device generates a hello frame for specifying a main gateway device of the node device at a predetermined timing, and transmits the hello frame to adjacent node devices. The node device, upon receiving a hello frame from an adjacent node device operating as a first hop destination of a data frame destined for the main gateway device, determines whether quality of a path to the main gateway device is lowest among paths to the plural gateway devices, based on path quality information included in the hello frame. When the quality of a path to the main gateway device is lowest, the node device changes the main gateway device to a gateway device that is registered in the table and specified by information included in the hello frame.

Abstract: A wireless communication apparatus on the receiving side receives communication data that is a transmitted to the wireless communication apparatus using one of the plurality of channels. Subsequently, the wireless communication apparatus on the receiving side obtains channel information contained in the communication data received by the receiving unit and judges whether the obtained channel information is target information indicating a channel of a processing target. The wireless communication apparatus on the receiving side performs a receiving process on the received communication data, when the judging unit determines that the obtained channel information is the target information, performs a receiving process on the communication data received by the receiving unit and that, when the judging unit determines that the obtained channel information is not the target information, discards the received communication data.

Abstract: A wireless communication system is provided. A control device includes: a receiver configured to be able to receive information from radio frequency channels; a processor that judges whether a first channel is congested, and generates switchover instruction information when the first channel is judged to be congested; and a transmitter that transmits the switchover instruction information. Each node device includes: a receiver that receives information through the first channel; a transmitter that transmits information through a transmission channel; and a processor that recognizes whether a hop count from the control device is one, selects a second channel and specifies it as the transmission channel in a first case in which the receiver receives the switchover instruction information from the control device and the hop count is recognized as one, and specifies the first channel as the transmission channel in a second case in which the first case does not hold.

Abstract: If destination information on a packet is not present in a routing table, a network device broadcasts, to adjacent nodes, a path request packet in which destination information on a packet is set. When the network device receives a path response packet associated with the path request packet from another node, the network device sends the packet after setting a send source node of the path response packet to the transfer destination. Furthermore, if the network device does not receive the path response packet, the network device sends, by using flooding, a packet in which the destination information on the packet is set.

Abstract: A network includes node devices each storing a table that manages paths to plural gateway devices for connecting to another network. A node device generates a hello frame for specifying a main gateway device of the node device at a predetermined timing, and transmits the hello frame to adjacent node devices. The node device, upon receiving a hello frame from an adjacent node device operating as a first hop destination of a data frame destined for the main gateway device, determines whether quality of a path to the main gateway device is lowest among paths to the plural gateway devices, based on path quality information included in the hello frame. When the quality of a path to the main gateway device is lowest, the node device changes the main gateway device to a gateway device that is registered in the table and specified by information included in the hello frame.

Abstract: A wireless communication apparatus stores therein, in an associated manner, each piece of path information on a plurality of destinations and a use frequency of data communication that is performed by using the path information. When the wireless communication apparatus receives data whose send source is a first destination, the wireless communication apparatus specifies, on the basis of the use frequency, path information that is less frequently used from among the pieces of the stored path information. The wireless communication apparatus updates the specified path information to path information whose destination is the first destination.

Abstract: Anode device includes a transmitter and a processor. The transmitter transmits an inspection frame used in inspecting a status of a route from a source node device to a destination node device. The processor generates a first inspection frame and selects a first node device to which the transmitter transmits the first inspection frame from among candidates for a node device to which a frame addressed to the destination node device is to be forwarded. The processor judges whether a transmission of the first inspection frame has been successfully performed. When the transmission of the first inspection frame has failed, the processor generates a second inspection frame which records a failure in a communication with the first node device. The processor selects a second node device to which the transmitter transmits the second inspection frame from among the candidates.

Abstract: Anode device includes a transmitter and a processor. The transmitter transmits an inspection frame used in inspecting a status of a route from a source node device to a destination node device. The processor generates a first inspection frame and selects a first node device to which the transmitter transmits the first inspection frame from among candidates for a node device to which a frame addressed to the destination node device is to be forwarded. The processor judges whether a transmission of the first inspection frame has been successfully performed. When the transmission of the first inspection frame has failed, the processor generates a second inspection frame which records a failure in a communication with the first node device. The processor selects a second node device to which the transmitter transmits the second inspection frame from among the candidates.

Abstract: A method and a device perform time-synchronization with an ad hoc network configured by a plurality of nodes. The method includes: transmitting a time-synchronization request frame including an address of one of the plurality of nodes which belong to the ad hoc network to one of the plurality of nodes having a function of receiving the time-synchronization request frame and transmitting a time-synchronization reply frame including time-synchronization information; receiving the time-synchronization reply frame including the time-synchronization information from one of the plurality of nodes which receive the time-synchronization request frame; and performing time-synchronization with one of the plurality of nodes using the time-synchronization information included in the time-synchronization reply frame.

Abstract: A communication apparatus includes a receiver, a memory, a processor, and a transmitter. The receiver receives a route information frame and a first frame that is not the route information frame. The memory holds a route information table. The route information table records route information included in the route information frame. When the route information table does not include the source address of the first frame, the processor associates the source address with the address of a transfer-source apparatus that has transferred the first frame to the receiver, and registers these addresses in a registration table. In order to transmit a second frame addressed to a destination apparatus that is not recorded in the route information table, the processor obtains the address of a transfer-source apparatus registered in association with the address of the destination apparatus. The transmitter transmits the second frame to the address obtained by the processor.

Abstract: A wireless communication apparatus on the receiving side receives communication data that is a transmitted to the wireless communication apparatus using one of the plurality of channels. Subsequently, the wireless communication apparatus on the receiving side obtains channel information contained in the communication data received by the receiving unit and judges whether the obtained channel information is target information indicating a channel of a processing target. The wireless communication apparatus on the receiving side performs a receiving process on the received communication data, when the judging unit determines that the obtained channel information is the target information, performs a receiving process on the communication data received by the receiving unit and that, when the judging unit determines that the obtained channel information is not the target information, discards the received communication data.

Abstract: In a location identification/management system, a portable medium reader reads a moving object identifier stored in a portable medium and relays the moving object identifier. A radio frequency identification (RFID) reader receives relayed moving object identifier and transmits a notification containing the moving object identifier and a unique RFID-reader identifier assigned thereto. A management server receives the notification and identifies a location of the moving object from the moving object identifier and the unique RFID-reader identifier contained in the notification.