Abstract: A call control device including: a memory, and a processor coupled to the memory and configured to: receive a call request from a communication device, a source of the call request being a terminal, the call request being transferred by the communication device when the terminal is registered in a management device, and request the management device to deregister the terminal when the call control device is determined that the call control device is attacked from the terminal based on the call request.

Abstract: A first call control server transmits line information of a line to be used by a terminal device calls of which are controlled by the first call control server to a second call control server when congestion is detected. The first call control server receives the line information to be used in call control from the second call control server, and establishes a connection with the terminal device using the received line information. The second call control server receives the line information from the first call control server, and receives a call control request for the terminal device, the call control request being addressed to the first call control server. The second call control server responds to the first call control server with the received line information, when the call control request is received.

Abstract: A call control device including: a memory, and a processor coupled to the memory and configured to: receive a call request from a communication device, a source of the call request being a terminal, the call request being transferred by the communication device when the terminal is registered in a management device, and request the management device to deregister the terminal when the call control device is determined that the call control device is attacked from the terminal based on the call request.

Abstract: A first call control server transmits line information of a line to be used by a terminal device calls of which are controlled by the first call control server to a second call control server when congestion is detected. The first call control server receives the line information to be used in call control from the second call control server, and establishes a connection with the terminal device using the received line information. The second call control server receives the line information from the first call control server, and receives a call control request for the terminal device, the call control request being addressed to the first call control server. The second call control server responds to the first call control server with the received line information, when the call control request is received.

Abstract: A mobile radio communication system is provided for keeping high-quality communications and preventing disconnection of a radio link in fast movement. The system includes the radio network controller provided with a storage unit and a control unit. The storage unit stores grouped-user-equipments management information to be used for identifying and managing a plurality of user equipments as one group. The control unit controls the user equipments belonging to the same group so that they may be connected with their respective ones of the cells formed by the node bases. This allows the plurality of user equipments belonging to the same group to execute multiplex communications, thereby preventing simultaneous disconnection of the radio links of the user equipments belonging to the same group even when those user equipments are moving fast.

Abstract: In a method and a device, and a mobile communication system by which a connection switchover between wireless network control devices can be performed with a connected base station being maintained in order to avoid a congestion when the congestion occurs in one of the wireless network control devices within a mobile communication network, network management information indicating congestion states of all wireless network control devices is acquired from a core network within the mobile communication network, a wireless network control device list is prepared in which a higher priority is assigned to the wireless network control devices in ascending order of congestion degree based on the network management information when a call request is received from one mobile terminal through a base station, the wireless network control device list is notified to the mobile terminal through the base station, and the mobile terminal is enabled to select one of the wireless network control devices as a connecting destina

Abstract: A mobile radio communication system is provided for keeping high-quality communications and preventing disconnection of a radio link in fast movement. The system includes the radio network controller provided with a storage unit and a control unit. The storage unit stores grouped-user-equipments management information to be used for identifying and managing a plurality of user equipments as one group. The control unit controls the user equipments belonging to the same group so that they may be connected with their respective ones of the cells formed by the node bases. This allows the plurality of user equipments belonging to the same group to execute multiplex communications, thereby preventing simultaneous disconnection of the radio links of the user equipments belonging to the same group even when those user equipments are moving fast.