Abstract: A radio base station receives a handover message from a network related to a handover of a terminal and determines the number of handover failures based on a number of the handover failures based on the handover message. The radio base station releases the terminal when the number of failures reaches a predetermined number.

Abstract: An RNC includes: a first call request reception unit configured to receive from an exchange a first call request to only an already located wireless cell; a presumably located wireless cell derivation unit configured to derive a presumably located wireless cell in which a target communication terminal device is presumably located; a first call making unit configured to make a call to the already located wireless cell and the presumably located wireless cell; a call response signal transmission unit configured to transmit a response signal to the call, to the exchange; a second call request reception unit configured to receive from the exchange a second call request to a wireless cell different from the already located wireless cell, in a case where the response signal to the first call request has not been transmitted; and a second call making unit configured to make the call to the different wireless cell.

Abstract: An RNC includes: a first call request reception unit configured to receive from an exchange a first call request to only an already located wireless cell; a presumably located wireless cell derivation unit configured to derive a presumably located wireless cell in which a target communication terminal device is presumably located; a first call making unit configured to make a call to the already located wireless cell and the presumably located wireless cell; a call response signal transmission unit configured to transmit a response signal to the call, to the exchange; a second call request reception unit configured to receive from the exchange a second call request to a wireless cell different from the already located wireless cell, in a case where the response signal to the first call request has not been transmitted; and a second call making unit configured to make the call to the different wireless cell.

Abstract: A mobile communication system includes a first radio control device that manages a first cell, a second radio control device that manages a second cell, and a third radio control device. The second cell is set as a handover destination cell of the first cell. The third radio control device manages the second cell as a redundant configuration of the second radio control device. The third radio control device notifies the first radio control device of the third radio control device managing the second cell as the redundant configuration of the second radio control device. The first radio control device sets so that the third radio control device manages the second cell as the redundant configuration of the second radio control device.

Abstract: A mobile communication system includes a first radio control device that manages a first cell, a second radio control device that manages a second cell, and a third radio control device. The second cell is set as a handover destination cell of the first cell. The third radio control device manages the second cell as a redundant configuration of the second radio control device. The third radio control device notifies the first radio control device of the third radio control device managing the second cell as the redundant configuration of the second radio control device. The first radio control device sets so that the third radio control device manages the second cell as the redundant configuration of the second radio control device.

Abstract: A network apparatus having a plurality of call control cards, comprising: a selection unit configured to select at least one call control card from among the plurality of call control cards, when the number of connected calls controlled by the whole of the plurality of call control cards is less than a first threshold value; and a power saving control unit configured to cause the call control card selected by the selection unit to shift to a cutoff ready state in which allocation of a new call is restricted.