BASE STATION DEVICE, MOBILE TERMINAL, COMMUNICATION SYSTEM, AND RADIO COMMUNICATION METHOD

• US 20120225682A1
• Filed: 05/16/2012
• Published: 09/06/2012
• Est. Priority Date: 12/04/2009
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: KOJIMA, Yuji
• Granted Patent: US 9,294,968 B2
• Time in Patent Office: Days
• US Class Current: 455/507
• CPC Class Codes: H04W 36/0058 Transmission of hand-off measurement information, e.g. measurement reports
• CPC Class Codes: H04W 48/16 Discovering, processing access restriction or access information

Abstract

A base station device characterized by including: a transmission portion that broadcast-transmits identification information indicating a first cell to a mobile terminal in an idle mode under control of the base station device; and a reception portion that receives information indicating a destination cell that the mobile terminal in the idle mode transmits when moving between cells; wherein when the base station device is a base station device forming a second cell adjacent to the first cell, the reception unit receives information indicating the second cell from the mobile terminal in the idle mode which has received the identification information indicating the first cell transmitted from another base station device forming the first cell, and receives information indicating the first cell from the mobile terminal in the idle mode which has received the identification information indicating the first cell transmitted from the base station device.

Claims

1. A base station device comprising:

a transmission portion that broadcast-transmits identification information indicating a first cell to a mobile terminal in an idle mode under control of the base station device; and

a reception portion that receives information indicating a destination cell that the mobile terminal in the idle mode transmits when moving between cells;

wherein when the base station device is a base station device forming a second cell adjacent to the first cell, the reception unit receives information indicating the second cell from the mobile terminal in the idle mode which has received the identification information indicating the first cell transmitted from another base station device forming the first cell, and receives information indicating the first cell from the mobile terminal in the idle mode which has received the identification information indicating the first cell transmitted from the base station device.

2. The base station device as claimed in claim 1, wherein when the mobile terminal in the idle mode moves between the first cell and the second cell, the transmission portion transmits a flag indicating whether the base station device forming the second cell is notified of the information indicating the destination cell to the mobile terminal.

3. The base station device as claimed in claim 1, wherein the transmission portion transmits a given parameter used when the mobile terminal in the idle mode selects a cell, and the base station device further comprises a changing portion that changes a value of the given parameter based on a number of mobile terminals in the idle mode in the first cell, the number of mobile terminals being calculated with the information indicating the destination cell received from the mobile terminal in the idle mode.

4. The base station device as claimed in claim 3, wherein the changing portion sets a target number of mobile terminals in the idle mode which move between the first cell and the second cell based on a number of mobile terminals in an active mode which move between the first cell and the second cell, and changes the parameter based on the target number.

5. The base station device as claimed in claim 3, wherein the changing portion sets a target number of mobile terminals in the idle mode included in each of a plurality of cells based on a number of mobile terminals in an active mode included in each of the cells in a position registration range including the cells, and changes the parameter based on the target number.

6. The base station device as claimed in claim 4, wherein the transmission portion transmits parameters before and after the changing portion changes, to the mobile terminal, and the mobile terminal notifies information indicating the destination cell selected based on each of the parameters before and after the change.

7. A base station device that transmits a parameter to be used for selection of a cell for a mobile terminal in an idle mode, comprising:

a changing portion that changes the parameter based on at least any one of a number of mobile terminals in the idle mode that exist in a cell which the base station device forms, and a number of mobile terminals in the idle mode that exist in a neighboring cell.

8. The base station device as claimed in claim 7, wherein the changing portion changes the parameter based on at least any one of the number of mobile terminals in the idle mode that exist in the cell which the base station device forms, and the number of mobile terminals in the idle mode that exist in the neighboring cell, the at least any one of the numbers of mobile terminals being guessed based on a number of mobile terminals in the idle mode or an active mode which move between the cell which the base station device forms and the neighboring cell.

9. The base station device as claimed in claim 7, wherein the changing portion changes the parameter based on at least any one of the number of mobile terminals in the idle mode that exist in the cell which the base station device forms, and the number of mobile terminals in the idle mode that exist in the neighboring cell, the at least any one of the numbers of mobile terminals being guessed based on the number of mobile terminals in the active mode which exist in each of the cell which the base station device forms and the neighboring cell.

10. A mobile terminal comprising:

a reception portion that receives identification information indicating a first cell from a base station device when the mobile terminal is in an idle mode; and

a notification portion that notifies a base station device forming a second cell of information indicating a destination cell after the mobile terminal moves to the second cell when a serving cell to which the mobile terminal belongs is the first cell and the destination cell is the second cell adjacent to the first cell, and notifies the base station device forming the second cell of information indicating the destination cell before the mobile terminal moves to the first cell when the serving cell is the second cell and the destination cell is the first cell.

11. The mobile terminal as claimed in claim 10, wherein the reception portion receives from the base station device a flag indicating whether the base station device forming the second cell is notified of the information indicating the destination cell when the mobile terminal in the idle mode moves between the first cell and the second cell.

12. The mobile terminal as claimed in claim 11, wherein the notification portion notifies the base station device of the information indicating the destination cell after the mobile terminal moves to the second cell when identification information of the serving cell is included in the flag, and notifies the base station device of the information indicating the destination cell before the mobile terminal moves to the first cell when the identification information of the serving cell is not included in the flag and identification information of the destination cell is included in the flag.

13. The mobile terminal as claimed in claim 11, wherein the notification portion notifies the base station device of the information indicating the destination cell after the mobile terminal moves to the destination cell when identification information of the serving cell is included in the flag and identification information of the serving cell is included in a flag received from a base station device of the destination, and does not notify the base station device of the information indicating the destination cell when the identification information of the serving cell is included in the flag and the identification information of the serving cell is not included in the flag received from the base station device of the destination.

14. The mobile terminal as claimed in claim 11, wherein the notification portion does not notify the base station device of the information indicating the destination cell when the identification information of the serving cell is included in the flag and the identification information of the destination cell is included in the flag, and notifies the base station device of the information indicating the destination cell after the mobile terminal moves to the destination cell when the identification information of the serving cell is included in the flag and the identification information of the destination cell is not included in the flag.

15. A communication system including a mobile terminal and a base station device wirelessly communicated with the mobile terminal, comprising:

the base station device including;

a transmission portion that broadcast-transmits identification information indicating a first cell to a mobile terminal in an idle mode under control of the base station device; and

a reception portion that receives information indicating a destination cell that the mobile terminal in the idle mode transmits when moving between cells;

wherein when the base station device is a base station device forming a second cell adjacent to the first cell, the reception unit receives information indicating the second cell from the mobile terminal in the idle mode which has received the identification information indicating the first cell transmitted from another base station device forming the first cell, and receives information indicating the first cell from the mobile terminal in the idle mode which has received the identification information indicating the first cell transmitted from the base station device,

the mobile terminal including;

a reception portion that receives identification information indicating the first cell from the base station device when the mobile terminal is in the idle mode; and

a notification portion that notifies the base station device forming the second cell of information indicating the destination cell after the mobile terminal moves to the second cell when a serving cell to which the mobile terminal belongs is the first cell and the destination cell is the second cell, and notifies the base station device forming the second cell of information indicating the destination cell before the mobile terminal moves to the first cell when the serving cell is the second cell and the destination cell is the first cell.

16. A radio communication method of a base station device wirelessly communicated with a mobile terminal, comprising:

broadcast-transmitting identification information indicating a first cell to a mobile terminal in an idle mode under control of the base station device;

receiving, when the base station device is a base station device forming a second cell adjacent to the first cell, information indicating the second cell from the mobile terminal in the idle mode which has received the identification information indicating the first cell transmitted from another base station device forming the first cell; and

receiving, when the base station device is the base station device forming the second cell adjacent to the first cell, information indicating the first cell from the mobile terminal in the idle mode which has received the identification information indicating the first cell transmitted from the base station device.

17. A radio communication method of a mobile terminal wirelessly communicated with a base station device, comprising:

receiving identification information indicating a first cell from the base station device when the mobile terminal is in an idle mode;

notifying a base station device forming a second cell of information indicating a destination cell after the mobile terminal moves to the second cell when a serving cell to which the mobile terminal belongs is the first cell and the destination cell is the second cell adjacent to the first cell, and

notifying the base station device forming the second cell of information indicating the destination cell before the mobile terminal moves to the first cell when the serving cell is the second cell and the destination cell is the first cell.