Abstract: A wireless LAN communication device is provided for making it possible to set beacons including DTIM information elements not to be synchronous in the case that the timing for generating the beacons including DTIM information elements is the same among access points, so that it is avoidable that only a terminal device under a specific access point among access points using the same channel is subjected to a delay and jitters, while anxiety about mutual interference of the terminal devices is removed in the case of broadcast and multicast service, so that a fair broadcast and multicast service can be received. In the device, a wireless LAN control unit (202) detects beacons of other stations received in a prescribed period of time before the transmission of its own station (200). A beacon analyzing unit (203) analyzes the beacons of the other stations and adjusts transmission intervals of its own DTIM beacon.

Abstract: A communication terminal apparatus wherein even if there occurs a dropout or overtaking of call control messages, the current service can be continued without increasing the load of an apparatus such as a server in the network. In this apparatus, a VoIP call control part (103) performs call controls including both a call establishment of a VoIP telephone conversation using a wireless LAN system and a call disconnection thereof. A line switching call control part (104) performs call controls including both a call establishment of a line switching telephone conversation using a mobile communication (cellular) system and a call disconnection thereof. A handover part (105) determines the reception quality of the wireless LAN system and that of the mobile communication (cellular) system and controls, based on the determination results, the handover between the wireless LAN system and the mobile communication (cellular) system.

Abstract: A wireless LAN communication device is provided for making it possible to set beacons including DTIM information elements not to be synchronous in the case that the timing for generating the beacons including DTIM information elements is the same among access points, so that it is avoidable that only a terminal device under a specific access point among access points using the same channel is subjected to a delay and jitters, while anxiety about mutual interference of the terminal devices is removed in the case of broadcast and multicast service, so that a fair broadcast and multicast service can be received. In the device, a wireless LAN control unit (202) detects beacons of other stations received in a prescribed period of time before the transmission of its own station (200). A beacon analyzing unit (203) analyzes the beacons of the other stations and adjusts transmission intervals of its own DTIM beacon.

Abstract: A communication terminal apparatus wherein even if there occurs a dropout or overtaking of call control messages, the current service can be continued without increasing the load of an apparatus such as a server in the network. In this apparatus, a VoIP call control part (103) performs call controls including both a call establishment of a VoIP telephone conversation using a wireless LAN system and a call disconnection thereof. A line switching call control part (104) performs call controls including both a call establishment of a line switching telephone conversation using a mobile communication (cellular) system and a call disconnection thereof. A handover part (105) determines the reception quality of the wireless LAN system and that of the mobile communication (cellular) system and controls, based on the determination results, the handover between the wireless LAN system and the mobile communication (cellular) system.

Abstract: The throughput of a network system as a whole is improved in the case where there is a wireless terminal not good in radio wave condition. An AP control device 12 includes a communication portion 27 serving as a unit for transmitting/receiving Ethernet frames, a packet storage portion 25 serving as a unit for storing packets, and a transmission control portion 26 serving as a unit for selecting packets stored in the packet storage portion 25 to transmit the selected packets to the communication portion 27, for deciding whether to store received packets in the packet storage portion 25 or not and for controlling the transmission/reception volume in accordance with the radio wave condition of each of terminals 15, 16 and 19 notified by the APs 13, 17 and 20.

Abstract: An ATM header conversion circuit for realizing bidirectional header conversion through the use of a simple arrangement using only one entry data storage device. The entry data storage device stores bidirectional header data in a state associated with each of a plurality of addresses. The ATM header conversion circuit partially collates inputted header data with one of entry data groups placed in the entry data storage device on the basis of mask bits which designate the collation bit positions of the inputted header data, and outputs, as new header data, the header data of the other entry data group at the addresses where the partial collation shows coincidence.