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: During communication by a mobile device, when a communication feasibility determining unit of an SGSN determines, based on a remaining communication volume, that the communication by the mobile device cannot be continued, an access point information extracting unit extracts APN information regarding an APN with an unused remaining communication volume and reports the extracted APN information to the mobile device. An access point information acquiring unit of the mobile device acquires APN information regarding the APN with an unused remaining communication volume. When communication is next initiated, the APN information regarding the APN with an unused remaining communication volume is transmitted to the SGSN to perform communication.

Abstract: During communication by a mobile device, when a communication feasibility determining unit of an SGSN determines, based on a remaining communication volume, that the communication by the mobile device cannot be continued, an access point information extracting unit extracts APN information regarding an APN with an unused remaining communication volume and reports the extracted APN information to the mobile device. An access point information acquiring unit of the mobile device acquires APN information regarding the APN with an unused remaining communication volume. When communication is next initiated, the APN information regarding the APN with an unused remaining communication volume is transmitted to the SGSN to perform communication.

Abstract: A communication system includes a GGSN calculating a communication volume of a mobile terminal, and a service control device storing a charge remaining amount corresponding to a communication volume available to the mobile terminal. The service control device includes an inquiry acceptance unit accepting an inquiry for the charge remaining amount of the mobile terminal, a communication state determination unit determining whether the mobile terminal is in communication, an updated remaining amount reception unit acquiring the charge remaining amount updated in accordance with the communication volume calculated by the GGSN when the communication state determination unit determines that the mobile terminal is in communication, and a remaining amount notification unit notifying of the charge remaining amount of the mobile terminal in response to the inquiry that the inquiry acceptance unit has accepted.

Abstract: A mobile terminal measures the time from when the data communication connection was established up to the disconnection or the time from when the wireless connection was established up to the disconnection as a chargeable duration. The time in which the mobile terminal uses a network resource in a network or the time in which exchange of data was actually carried out is thus measured as the chargeable duration. Since the information relating to the chargeable duration measured in this manner is stored and displayed in the mobile terminal, it is possible for the mobile terminal to recognize the information relating to the chargeable duration without sending an inquiry to the network including a base station.

Abstract: During communication by a mobile device, when a communication feasibility determining unit of an SGSN determines, based on a remaining communication volume, that the communication by the mobile device cannot be continued, an access point information extracting unit extracts APN information regarding an APN with an unused remaining communication volume and reports the extracted APN information to the mobile device. An access point information acquiring unit of the mobile device acquires APN information regarding the APN with an unused remaining communication volume. When communication is next initiated, the APN information regarding the APN with an unused remaining communication volume is transmitted to the SGSN to perform communication.

Abstract: When a request to start or a request to terminate mobile communication by a mobile communication terminal 2 or another exchange is received, a remaining communication volume update module 43 starts or stops updating a remaining communication volume information based on data communication by the mobile communication terminal 2. When a request to set or a request to reset a preservation state in the mobile communication by the mobile communication terminal 2 or another exchange is received, the remaining communication volume update module 43 stops or starts updating the remaining communication volume information based on data communication by the mobile communication terminal 2.