Method by which base station transmits signal for coverage coordination in wireless communication system and device for same

1. A method for transmitting a signal for coverage coordination by a base station in a wireless communication system, the method comprising:

transmitting, by a coordinating base station, information notifying the coordinating base station to each of a first base station and a second base station;

receiving, by the coordinating base station, coverage related information from each of the first base station and the second base station, the coverage related information of the first base station including an idle mode switching request of the first base station, the coverage related information of the second base station including information on a coverage area compensated for by the second base station, the coverage related information of the first base station being received from the first base station when a cell load of the first base station maintains a predetermined threshold value or less for a predetermined time;

performing a coverage coordination procedure by using the coverage related information of the first and second base stations; and

transmitting a coverage coordinating signal determined in accordance with the result of the coverage coordinating procedure to each of the first and second base stations, the coverage coordination procedure including determining whether the second base station compensates for a coverage of the first base station when the first base station is switched to an idle mode.

2. The method according to claim 1 , further comprising:

configuring an X2 interface between the coordinating base station and each of the first and second base stations,

wherein, when the X2 interface is configured, it is notified that the coordinating base station determines whether to perform coverage coordination or not.

3. The method according to claim 1 , further comprising:

receiving an idle mode switching request cancellation message indicating that switching to an idle mode will not be performed from the first base station if the cell load of the first base station exceeds a predetermined threshold value after receiving the coverage related information of the first base station,

wherein the idle mode switching request and the idle mode switching request cancellation message of the first base station are identified from each other as a value of 0 or 1.

4. The method according to claim 1 , wherein, if it is determined that the second base station compensates for the coverage of the first base station as a result of the coverage coordination procedure:

the coverage coordinating signal transmitted to the first base station includes an idle mode switching indication message; and

the coverage coordinating signal transmitted to the second base station includes a coverage compensation indication message indicating coverage compensation of the first base station.

5. The method according to claim 4 , wherein the idle mode switching indication message indicates that the first base station performs handover for one or more user equipments located within a service area of the first base station to the second base station and then is switched to an idle mode.

6. The method according to claim 4 , wherein:

the coverage compensation indication message indicates that the second base station compensates for the coverage of the first base station; and

the coverage is compensated in such a manner that the second base station continuously provides one or more user equipments receiving a service from the first base station, with the service.

7. The method according to claim 1 , wherein the coverage coordinating signal transmitted to the first base station includes an idle mode switching unavailable message if coverage compensation of the first base station is not possible.

8. A device for transmitting a signal for coverage coordination in a wireless communication system, the device comprising:

a radio frequency (RF) unit that includes a transmitter and a receiver; and

a processor operably connected with the transmitter and the receiver, supporting communication of the device, the processor being configured to:

transmit information notifying the coordinating base station to each of a first base station and a second base station;

receive coverage related information from each of the first base station and the second base station, the coverage related information of the first base station including an idle mode switching request of the first base station, the coverage related information of the second base station including information on a coverage area compensated for by the second base station, the coverage related information of the first base station being received from the first base station when a cell load of the first base station maintains a predetermined threshold value or less for a predetermined time;

perform a coverage coordination procedure by using the coverage related information of the first and second base stations; and

transmit a coverage coordinating signal determined in accordance with the result of the coverage coordination procedure to each of the first and second base stations, the coverage coordination procedure including determining whether the second base station compensates for a coverage of the first base station when the first base station is switched to an idle mode.