BASE STATION, RADIO COMMUNICATION SYSTEM, AND HANDOVER METHOD

• US 20100330994A1
• Filed: 12/09/2008
• Published: 12/30/2010
• Est. Priority Date: 02/01/2008
• Status: Active Grant

• Current Assignee: Panasonic Intellectual Property Corporation of America (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Matsuo, Hidenori, Suzuki, Hidetoshi, Toh, Hong Tat, Aoyama, Takahisa
• Granted Patent: US 8,626,173 B2
• Time in Patent Office: Days
• US Class Current: 455/436
• CPC Class Codes: H04J 11/0069 Cell search, i.e. determining cell identity [cell-ID] design of multiplexing codes H04J13/00; processing access restriction or access information H04W48/16; discovery of network devices for network data management H04W8/005; sounding signals for channel estimation H04L25/0226; structure of reference signals in multicarrier modulation systems H04L27/2613; frame, time or carrier synchronisation in multicarrier modulation systems H04L27/2655
• CPC Class Codes: H04W 36/0058 Transmission of hand-off measurement information, e.g. measurement reports
• CPC Class Codes: H04W 36/0061 of neighbour cell information
• CPC Class Codes: H04W 36/0083 Determination of parameters used for hand-off, e.g. generation or modification of neighbour cell lists
• CPC Class Codes: H04W 36/00835 Determination of neighbour cell lists
• CPC Class Codes: H04W 36/00837 Determination of triggering parameters for hand-off
• CPC Class Codes: H04W 36/04 Reselecting a cell layer in multi-layered cells
• CPC Class Codes: H04W 36/30 by measured or perceived connection quality data
• CPC Class Codes: H04W 36/302 due to low signal strength
• CPC Class Codes: H04W 36/38 by fixed network equipment
• CPC Class Codes: H04W 4/08 User group management
• CPC Class Codes: H04W 48/02 Access restriction performed under specific conditions
• CPC Class Codes: H04W 84/045 using private Base Stations, e.g. femto Base Stations, home Node B
• CPC Class Codes: H04W 84/105 PBS [Private Base Station] network H04W84/12 - H04W84/16 take precedence

Abstract

When a handover request for performing a handover of a terminal (70) from a macro cell C1 to a CSG cell C2 is received from an SeNB 10 (S8), a base station (TeNB) (40) of the CSG cell C2 transmits a handover response in accordance with a handover enabled/disabled state (S12). The handover response includes an identifier of the terminal (70) in the CSG cell C2. Upon receiving the response, the SeNB (10) notifies the identifier to the terminal (70) (S14). The TeNB (40) repeatedly transmits a dedicated signal containing a handover command via a dedicated channel set using the identifier at an interval shorter than a gap period (S18). Accordingly, whether or not access is permitted can be judged promptly and a smooth handover can be realized.

Claims

1. A base station that controls, in a network including a first cell and a second cell contained in the first cell, communication with a terminal in the second cell, the base station comprising:

a handover request receiver that receives a handover request for performing a handover of the terminal from the first cell to the second cell from a base station of the first cell;

a handover response transmitter that transmits a handover response that is a response to the handover request and which includes an identifier of the terminal in the second cell to the base station of the first cell, and causes the base station of the first cell, to notify the identifier to the terminal; and

a dedicated signal transmitter that repeatedly transmits a dedicated signal containing a handover command to the terminal via a dedicated channel set using the identifier at an interval shorter than a period during which the terminal is able to receive data from the base station of the second cell.

2. The base station according to claim 1, further comprising a RACH preamble command receiver that receives a RACH preamble command transmitted from the terminal in accordance with the dedicated signal, wherein

the dedicated signal transmitter stops transmission of the dedicated signal when the RACH preamble command is received or when a predetermined period of time has lapsed from the start of transmission of the dedicated signal.

3. A base station that controls, in a network including a first cell and a second cell contained in the first cell, communication with a terminal in the second cell, the base station comprising:

a handover request receiver that receives a handover request for performing a handover of the terminal from the first cell to the second cell from a base station of the first cell;

a handover response transmitter that transmits a response to the handover request to the base station of the first cell; and

a system information transmitter that transmits a system information containing access information through a common channel, wherein

the system information transmitter shortens a transmission interval of the system information as compared to before receiving the handover request when performing a handover in accordance with the handover request.

4. The base station according to claim 3, further comprising

a RACH preamble command receiver that receives a RACH preamble command transmitted from the terminal in accordance with the dedicated signal, wherein

the system information transmitter restores the transmission interval of the system information to an original transmission interval when the RACH preamble command is received or when a predetermined period of time has lapsed after shortening the transmission interval of the system information.

5. A base station that controls, in a network including a first cell and a second cell contained in the first cell, communication with a terminal in the first cell, the base station comprising:

a measurement report receiver that receives, from the terminal, a measurement report including a cell identifier of the second cell whose radio wave has been detected by the terminal and quality information of the radio wave;

a handover request transmitter that transmits a handover request to a base station to which access from the terminal is permitted among base stations of the second cell having a cell identifier judged to be a handover destination when it is judged, based on the measurement report, that a handover of the terminal from the first cell to the second cell should be performed;

a handover response receiver that receives a handover response that is a response to the handover request and which includes an identifier of the terminal in the second cell from the second cell; and

an identifier transmitter that notifies the identifier contained in the handover response to the terminal.

6. A base station that controls, in a network including a first cell and a second cell contained in the first cell, communication with a terminal in the first cell, the base station comprising:

a measurement report receiver that receives, from the terminal, a measurement report including a cell identifier of the second cell whose radio wave has been detected by the terminal and quality information of the radio wave;

a handover request transmitter that transmits a handover request to a base station of the second cell having a cell identifier judged to be a handover destination when it is judged, based on the measurement report, that a handover of the terminal from the first cell to the second cell should be performed;

a handover response receiver that receives a handover response to the handover request from the second cell;

an access permission state notification receiver that receives information on an access permission state of the second cell from the terminal; and

a handover command transmitter that transmits a handover command to the terminal when access to the base station of the second cell is permitted.

7. The base station according to claim 6, wherein the handover request transmitter transmits the handover request to a base station to which access from the terminal is permitted among base stations of the second cell having a cell identifier to which it is judged that a handover should be performed based on the measurement report.

8. A base station comprising:

a receiver that receives a measurement report from a terminal;

a judging unit that judges whether a handover of the terminal should be performed or not based on the received measurement report; and

a transmitter that transmits, when it is judged that a handover of the terminal should be performed, an instruction for changing a transmission frequency of a system information to a base station device that is a handover destination.

9. The base station according to claim 8, further comprising

a handover command transmitter that transmits a handover command including a reception instruction of a system information to be transmitted from a base station that is a handover destination to the terminal when a handover-permitted response is received from the base station that is the handover destination.

10. A radio communication system comprising a first base station that controls communication with a terminal in a first cell and a second base station that controls communication with a terminal in a second cell contained in the first cell, wherein:

the first base station transmits a handover request for performing a handover of the terminal from the first cell to the second cell to the second base station;

the second base station transmits a handover response that is a response to the handover request and which includes an identifier of the terminal in the second cell to the base station of the first cell;

the first base station notifies the identifier contained in the handover response to the terminal; and

the second base station repeatedly transmits a dedicated signal containing a handover command to the terminal via a dedicated channel set using the identifier at an interval shorter than a period during which the terminal is able to receive data from the base station of the second cell.

11. A radio communication system comprising a first base station that controls communication with a terminal in a first cell and a second base station that controls communication with a terminal in a second cell contained in the first cell, wherein:

the first base station transmits a handover request for performing a handover of the terminal from the first cell to the second cell to the second base station;

the second base station transmits a handover response that is a response to the handover request to the base station of the first cell; and

the second base station shortens a transmission interval of a system information containing access information to be transmitted through a common channel in comparison to before receiving the handover request when performing a handover in response to the handover request.

12. A handover method to be performed by a base station that controls, in a network including a first cell and a second cell contained in the first cell, communication with a terminal in the second cell, the handover method comprising the steps of:

receiving a handover request for performing a handover of the terminal from the first cell to the second cell from a base station of the first cell;

transmitting a handover response that is a response to the handover request and which includes an identifier of the terminal in the second cell to the base station of the first cell, and causing the base station of the first cell to notify the identifier to the terminal; and

repeatedly transmitting a dedicated signal containing a handover command to the terminal via a dedicated channel set using the identifier at an interval shorter than a period during which the terminal is able to receive data from the base station of the second cell.

13. A handover method to be performed by a base station that controls, in a network including a first cell and a second cell contained in the first cell, communication with a terminal in the second cell, the handover method comprising the steps of:

receiving a handover request for performing a handover of the terminal from the first cell to the second cell from a base station of the first cell;

transmitting a handover response to the handover request to the base station of the first cell; and

shortening a transmission interval of a system information containing access information to be transmitted through a common channel in comparison to before receiving the handover request when performing a handover in response to the handover request.