Abstract: In a case where another user's communication terminal (nTE113) departs from a group, user's communication terminal (TEb14) updates encryption information, using the terminal individual information of only the communication terminals (nTE213 and nTE313) which remain in the group (PNy). User's communication terminal (TEb14) encrypts the PN-shared key (KPNy), using the updated encryption information. User's communication terminal (TEb14) transmits the encrypted shared key information obtained from this encryption to a management device (PNSP11), and updates the encrypted shared key information stored in the management device (PNSP11).

Abstract: In a case where another user's communication terminal (nTE113) departs from a group, user's communication terminal (TEb14) updates encryption information, using the terminal individual information of only the communication terminals (nTE213 and nTE313) which remain in the group (PNy). User's communication terminal (TEb14) encrypts the PN-shared key (KPNy), using the updated encryption information. User's communication terminal (TEb14) transmits the encrypted shared key information obtained from this encryption to a management device (PNSP11), and updates the encrypted shared key information stored in the management device (PNSP11).

Abstract: A wireless network system relays a broadcast signal in multiple stages and distributes data to terminals there around, and relay terminals determine whether to relay broadcast packets according to the direction vector and the position information, specified by the information transmission source terminal, referring to their own position information and direction, and relay and accept the packets or ignore them.

Abstract: A content display system is disclosed for offering, excellent multimedia content browsing/viewing environments to handheld device users, from a server of a communication network, by the use of a handheld device and a cooperating computer device cooperated to the handheld device.

Abstract: A radio LAN master station system which provides long distance communication and suffers from small interference by another system located inside and/or outside of a service area comprises a transceiver, and a plurality of directional antennas each directed to a respective section with some angular spacing, through a power distributor which couples said transceiver with said antennas. Polarization plane of any antenna is orthogonal to polarization plane of an adjacent antenna.

Abstract: A communication system capable of avoiding congestion in transmission of moving image data, includes (1) at least one receiving terminal, (2) a moving image delivery device for delivering moving image data to the at least one receiving terminal, (3) a moving image conversion device which has at least one moving image conversion unit for converting, in accordance with conversion parameters, the moving image data sent from the moving image delivery device, a conversion parameter setting unit for determining the conversion parameters, and a monitored result receiving unit, and (4) at least one packet switching node which has at least one data storage unit for preliminarily storing the moving image data from the moving image conversion device to be sent to the at least one receiving terminal, a data amount monitor unit for monitoring an amount of the moving image data stored in the at least one data storage unit to judge that the monitored data amount reaches a first threshold, and a monitored result sending unit

Abstract: A wireless network system relays a broadcast signal in multiple stages and distributes data to terminals there around, and relay terminals determine whether to relay broadcast packets according to the direction vector and the position information, specified by the information transmission source terminal, referring to their own position information and direction, and relay and accept the packets or ignore them.

Abstract: A content display system is disclosed for offering, excellent multimedia content browsing/viewing environments to handheld device users, from a server of a communication network, by the use of a handheld device and a cooperating computer device cooperated to the handheld device.

Abstract: A radio LAN master station system which provides long distance communication and suffers from small interference by another system located inside and/or outside of a service area comprises a transceiver, and a plurality of directivity antennas each directed to respective section with some angular spacing, through a power distributor which couples said transceiver with said antennas. Polarization plane of any antenna is orthogonal to polarization plane of an adjacent antenna.

Abstract: A communication system capable of avoiding congestion in transmission of moving image data, includes (1) at least one receiving terminal, (2) a moving image delivery device for delivering moving image data to the at least one receiving terminal, (3) a moving image conversion device which has at least one moving image conversion unit for converting, in accordance with conversion parameters, the moving image data sent from the moving image delivery device, a conversion parameter setting unit for determining the conversion parameters, and a monitored result receiving unit, and (4) at least one packet switching node which has at least one data storage unit for preliminarily storing the moving image data from the moving image conversion device to be sent to the at least one receiving terminal, a data amount monitor unit for monitoring an amount of the moving image data stored in the at least one data storage unit to judge that the monitored data amount reaches a first threshold, and a monitored result sending unit