Method and apparatus for controlling and supporting a dynamic cell on/off in wireless access system

1. A method for supporting on or off of a second cell at a first cell neighboring to the second cell in a wireless access system, the method comprising:

receiving, by a device in the first cell from a device in the second cell, a cell on/off state indicator message indicating on or off of the device in the second cell;

adjusting, by the device in the first cell, a handover offset of the device in the second cell, taking into account interference within the first cell caused by the on or off of the device in the second cell;

transmitting, by the device in the first cell, handover offset information about the adjusted handover offset to the device in the second cell and a first User Equipment (UE),

wherein the first cell is a serving cell of the first UE and the second cell is a serving cell of a second UE,

if the cell on/off state indicator message indicates an on state of the device in the second cell:

receiving, by the device in the first cell, a first measurement report message from the first UE, the first measurement report message including first measurement result information measured by the first UE based on the adjusted handover offset; and

determining, by the device in the first cell, whether to perform handover of the first UE from the first cell to the second cell based on the first measurement result information; and

if the cell on/off state indicator message indicates an off state of the device in the second cell:

receiving, by the device in the first cell, a second measurement report message from the second UE, the second measurement report message including second measurement result information measured by the second UE based on the second adjusted handover offset; and

determining, by the device in the first cell, whether to perform handover of the second UE from the second cell to the first cell based on the second measurement result information.

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

when the second cell is off:

controlling, by the device in the first cell, transmission power of the device in the first cell based on the handover offset information; and

transmitting, by the device in the first cell, the controlled transmission power value to the second UE.

3. A method for controlling transmission power upon cell on/off in a wireless access system, the method comprising:

powering on with an initial transmission power by a device in a second cell,

wherein the initial transmission power is determined by the device in the second cell by taking into account interference with a device in a first cell neighboring to the second cell;

adjusting, by the device in the second cell, a handover offset to reduce the interference with the device in the first cell;

transmitting, by the device in the second cell, power information indicating the initial transmission power and handover offset information about the adjusted handover offset to the device in the first cell and a User Equipment (UE);

performing, by the device in the second cell, handover with the UE receiving the handover offset information;

adjusting, by the device in the second cell, a transmitting power from the initial transmission power based on the adjusted handover offset; and

transmitting, by the device in the second cell to the UE, a power level indicator message indicating the adjusted transmitting power,

wherein, if a coverage of the device in the second cell is expanded based on the adjusted handover offset, the power of the second cell is increased based on the extended coverage, and

wherein, if the coverage of the device in the second cell is reduced based on the adjusted handover offset, the power of the device in the second cell is decreased based on the extended coverage.

4. The method according to claim 3 , wherein the handover offset information is handover offset information about the second cell.

5. The method according to claim 3 , wherein the handover offset information is handover offset information about the first cell.

6. The method according to claim 3 , wherein the UE performs neighbor cell measurement to perform handover from the first cell to the second cell based on the handover offset information.

7. An apparatus for supporting on or off of a second cell in a wireless access system, the apparatus comprising:

a transmitter;

a receiver; and

a processor configured to support the on/off of the second cell,

wherein the processor is configured to:

control the receiver to receive from a device in a second cell a cell on/off state indicator message indicating on or off of the device in the second cell,

adjust a handover offset of the device in the second cell, taking into account interference experienced by the processor within a first cell neighboring to the second cell caused by the on or off of the device in the second cell, and

control the transmitter to transmit handover offset information about the adjusted handover offset to the device in the second cell and a first User Equipment (UE), and

wherein the first cell is a serving cell of the first UE and the second cell is a serving cell of a second UE,

wherein, if the cell on/off state indicator message indicates an on state of the device in the second cell, the processor is further configured to:

receive a first measurement report message from the first UE, the first measurement report message including first measurement result information measured by the first UE based on the adjusted handover offset; and

determine whether to perform handover of the first UE from the first cell to the second cell based on the first measurement result information; and

wherein, if the cell on/off state indicator message indicates an off state of the device in the second cell, the processor is configured to:

receive a second measurement report message from the second UE, the second measurement report message including second measurement result information measured by the second UE based on the second adjusted handover offset; and

determine whether to perform handover of the second UE from the second cell to the first cell based on the second measurement result information.

8. The apparatus according to claim 7 , wherein, when the second cell is off, the device in the first cell controls transmission power of the device in the first cell based on the handover offset information, and transmits the controlled transmission power value to the second UE.