Base station, radio communication system, and handover method

A communication method implemented by a first radio communication terminal in a radio communication network, the network including a macrocell that is a first type cell and a Closed Subscriber Group (CSG) cell that is a second type cell, wherein the first radio communication terminal has an inbound mobility control function to move to the second type cell, the method comprising the steps of:

• receiving a first cell list that is used by both a second radio communication terminal, which does not have the inbound mobility control function to move to the second type cell, and the first radio communication terminal;
• receiving a second cell list that includes information about the second type cell and that is used by the first radio communication terminal but is ignored by the second radio communication terminal;
• judging a neighboring cell to be a measurement target of reception quality measurement on the basis of the first cell list and the second cell list;
• and
• repeatedly receiving a signal containing a handover command from a target base station in the second type cell at an interval shorter than a period defined for the first radio communication terminal to monitor signals from the target base station in the second type cell.

A source base station in a radio communication network, the network including a macrocell that is a first type cell and a Closed Subscriber Group (CSG) cell that is a second type cell, the source base station being of the first type cell and comprising:

• a communication interface which, in operation, transmits a first cell list that is used by both a first radio communication terminal, which has an inbound mobility control function to move to the second type cell, and a second radio communication terminal, which does not have the inbound mobility control function to move to the second type cell, and a second cell list that includes information about the second type cell and that is used by the first radio communication terminal but is ignored by the second radio communication terminal;
• and
• a receiver, which is coupled to the communication interface and which, in operation, receives a measurement result of a neighboring cell from the first radio communication terminal, wherein the first radio communication terminal repeatedly receives a signal containing a handover command from a target base station in the second type cell at an interval shorter than a gap period defined for the first radio communication terminal to monitor signals from the target base station in the second type cell, the gap period being between two periods defined for the first radio communication terminal to monitor signals from the source base station in the first type cell.

A communication method implemented by a source base station in a radio communication network, the network including a macrocell that is a first type cell and a Closed Subscriber Group (CSG) cell that is a second type cell and the source base station is of the first type cell, the method comprising the steps of:

• transmitting a first cell list that is used by both a first radio communication terminal, which has an inbound mobility control function to move to the second type cell, and a second radio communication terminal, which does not have the inbound mobility control function to move to the second type cell;
• transmitting a second cell list that includes information about the second type cell and that is used by the first radio communication terminal but is ignored by the second radio communication terminal;
• and
• receiving a measurement result of a neighboring cell from the first radio communication terminal, wherein the first radio communication terminal repeatedly receives a signal containing a handover command from a target base station in the second type cell at an interval shorter than a gap period defined for the first radio communication terminal to monitor signals from the target base station in the second type cell, the gap period being between two periods defined for the first radio communication terminal to monitor signals from the source base station in the first type cell.