Abstract: Before software for a routing protocol in a second wireless terminal receives a routing packet between a first wireless terminal and the second wireless terminal that are both included in an ad hoc network, stability determining software determines whether or not a link between the first wireless terminal, which is the source of the routing packet, and the second wireless terminal is stable. When the link is determined to be stable, the software for the routing protocol in the second wireless terminal processes the routing packet. This allows building of a route using only a stable link between adjacent nodes.

Abstract: In a network system including a first relay connected to a wire network and a radio network, a second relay for relaying data in the radio network, a first terminal connected by wireless to the first relay, and a second terminal connected by wireless to the second relay, the first relay keeps first information indicating a correspondence between an address of the second terminal, an identifier of a group to which the second terminal belongs, and an identifier of the second relay and second information indicating a correspondence between identifiers of groups formed by virtually subdividing the wire network and an identifier of a group to which the second terminal belongs, and the first relay transmits a packet according to the first or second information.

Abstract: A first and a second terminal carry out radio communications, the first terminal selects, based on an expectation saved in the concerned first terminal, a relay terminal relaying data to be transmitted to the second terminal and transmits the data, with a first information item indicating the address of the first terminal and a second information item indicating the address of the second terminal, to the relay terminal; and the relay terminal transmits the received first and second information items, and the data, to the second terminal; and if the second terminal receives the first and second information items, and the data, it transmits a completion report to the first terminal, based on expectation values saved by the second terminal concerned, making it capable of checking whether it has been possible to surely send and deliver the data.

Abstract: To make is possible to perform communication adapted to changes in a communication environment, a wireless communication device comprises a wireless communication unit for performing communication with another communication device through a wireless communication network, a communication quality evaluation unit for generating an evaluation value with regards to a communication quality of the communication, a communication mode switch unit for switching communication modes for use in the communication according to the evaluation value.

Abstract: In a mobile IP network system including a plurality of radio access networks for connecting with mobile stations via radio links and an IP network connected with a plurality of packet nodes for transferring IP packets, each of the radio access networks has at least one base station controller and at least one radio base station connected to the base station controller. Each of the base station controllers in the radio access network is connected to the plurality of packet nodes to each other via a network and selects one of the plurality of packet nodes in accordance with a state of each mobile station to establish a logical connection to be used in IP packet communication of the mobile station.

Abstract: In a mobile IP network system containing a plurality of radio access networks 2 for connecting with mobile stations 1 via radio links and an IP network 102 connected with a plurality of packet nodes for transferring IP packets, each of the radio access networks has at least one base station controller 7 and at least one radio base station 6 connected to the base station controller. Each of the base station controllers 7 in the radio access network is connected to the plurality of packet nodes to each other via a network 104 and selects one of the plurality of packet nodes in accordance with a state of each mobile station to establish a logical connection to be used in IP packet communication of the mobile station.

Abstract: A mobile IP data communication system is provided, which is capable of preventing dropouts of packet addressed to the mobile station at the time of switching the packet control station as a result of movement of the mobile station. A packet on an IP data connection that is used by the above-stated mobile station is forwarded to a next packet control station from a previous packet control station of the mobile station. The order of packets is correctly maintained by executing a process that a packet delivered to the next packet control station from the access router while the forwarding is in progress is buffered and a forwarding packet is put through ahead of such buffered packet or is forwarded only up to a time point when a packet from the access router is delivered.

Abstract: A mobile communication system that can obtain mobile station location information repeatedly at short intervals, without depending on whether base stations are synchronous or asynchronous, with lower loads and suppressed use of radio resources. For obtaining location information, a mobile station receives a paging channel periodically sent from a base station (Step 100), obtains the contents and the reception timing of this paging channel. Further, if it is necessary to obtain the transmission timing of the paging channel, that transmission timing is obtained (Steps 105, 106). The propagation delay of the paging channel or propagation delay differences between a plurality of periodic paging channels are calculated from the transmission timing and the reception timing of the paging channel (Step 107). The mobile station location information is calculated from the propagation delay or propagation delay difference, and outputted (Steps 108, 109, 110).