Radio base station device, handover control system, and handover control method

A radio base station device capable of communicating with a radio terminal, comprising:

• a call connection control section for controlling a call connection of the radio terminal;
• and
• a position registration request section for requesting, to a management device through a communication network, a position registration that associates identification information on the radio terminal with identification information on the radio base station device,
• wherein when a radio terminal being communicating with the radio base station device conducts a handover to another radio base station device, the radio base station device returns a state acquisition reply to the another radio base station device in response to a state acquisition request from the another radio base station device;
• and
• wherein when receiving a position registration deletion request on the radio terminal from the another radio base station device, the position registration request section requests a cancel of the position registration to the management device.

A radio base station device that relays a call connection of a radio terminal to a management device,

• wherein in a state that the radio base station device relays a radio connection of the radio terminal, when the radio base station device conducts a handover to another radio base station device, the radio base station device transmits a signal for requesting a cancel of the radio connection to a communication network or the management device in response to a call end request of the radio terminal transmitted from the another radio base station device;
• wherein the radio base station device transmits a state notice to the another radio base station device when it is confirmed that the radio connection is cancelled;
• and
• wherein the radio base station device requests a cancel of the position registration of the radio terminal to the management device when receiving a position registration deletion request from the another radio base station device, and then transmits reply information indicating a position registration deletion completion to the another radio base station device.

A handover control system having a plurality of radio base station devices which are connected to a radio terminal and which relay a call connection of the radio terminal based on a control of a network side management device through a communication network, wherein a handover control is conducted if the radio terminal moves from a radio area of a first radio base station device to a radio area of a second radio base station device among the plurality of radio base station devices,

• wherein each of the radio base station devices includes a position registration request section for requesting, to the network side management device, a position registration that associates identification information on the radio terminal with identification information on the radio base station device;
• wherein in a state that the second base station device relays a radio connection of the radio terminal by a handover, the second radio base station device maintains a state in which call control data on the radio terminal is transmitted to or received from the radio terminal through the first radio base station device which has conducted the radio connection with the radio terminal before the radio terminal conducts the handover;
• and
• wherein the position registration request section of the second radio base station device does not request the position registration of the radio terminal to the network side management device until the state that the second radio base station device relays the radio connection of the radio terminal is ended;
• and
• wherein the position registration request section of the second radio base station device requests the position registration of the radio terminal to the network side management device when the state that the second radio base station device relays the radio connection of the radio terminal is ended.

A handover control system, wherein in a state that a radio terminal conducts a call with a second radio base station device by a handover, when the second radio base station device receives a call end request transmitted from the radio terminal which becomes on-hook, the second radio base station device transfers the call end request to a first radio base station device in which a position of the radio terminal is registered at a timing when the radio terminal becomes the on-hook;

• wherein the first radio base station device transmits a signal for requesting a cancel of the radio connection to a communication network or a management device;
• wherein the first radio base station device transmits a state notice to the second radio base station device when it is confirmed that the radio connection is cancelled;
• wherein the second radio base station device terminates a transmission of voice data to the radio terminal in accordance with the state notice from the first radio base station device;
• wherein the second radio base station device transmits a position registration deletion request to the first radio base station device;
• wherein the first radio base station device transmits a position registration deletion request to the management device when receiving the position registration deletion request from the second radio base station device, and then transmits reply information indicating a position registration deletion completion to the second radio base station device;
• and
• wherein in response to the reply information, the second radio base station device transmits a position registration request to the management device for registering a position of the radio terminal.