Method for performing a PDCCH monitoring in a carrier aggregation with at least one SCell operating in an unlicensed spectrum and a device therefor

1. A method for a User Equipment (UE) operating in a wireless communication system, the method comprising:

configuring the UE with a first cell group including at least one first cell and a second cell group including at least one second cell served by an e-Node B (eNB);

receiving first information for configuring with a Discontinuous Reception (DRX) operation, wherein the first information includes information on subframes, which the UE monitors in first Physical Downlink Control Channel (PDCCH) signals for the first cell group and second PDCCH signals for the second cell group;

receiving second information for configuring with an additional monitoring period for the second cell group, wherein the second information includes information on subframes, which the UE monitors in the second PDCCH signals for the second cell group;

monitoring the first PDCCH signals on a first cell in subframes included in the first information; and

monitoring the second PDCCH signals on a second cell in subframes included in the first information and the second information,

when the UE receives a PDCCH for an uplink grant or a downlink assignment through one of the second PDCCH signals based on the second information, stopping the monitoring of the first PDCCH signals and maintaining the monitoring of the second PDCCH signals by restarting a DRX-inactivity timer.

2. The method according to claim 1 , wherein the second cell group operates in an unlicensed spectrum.

3. The method according to claim 1 , wherein when the UE receives the PDCCH for the uplink grant or the downlink assignment through one of the first PDCCH signals and the second PDCCH signals included in the first information, the UE maintains the monitoring of the first PDCCH signals and the second PDCCH signals by restarting a DRX-inactivity timer.

4. A method for a User Equipment (UE) operating in a wireless communication system, the method comprising:

configuring the UE with a first cell group including at least one first cell and a second cell group including at least one second cell served by an e-Node (eNB);

receiving first information for configuring with a Discontinuous Reception (DRX) operation, wherein the first information include information on subframes, which the UE monitors in a first Physical Downlink Control Channel (PDCCH) signal for the first cell group and a second PDCCH signal for the second cell group;

receiving second information for configuring with an on-duration skip for the first cell group, wherein the second information includes information subframes, which the UE doesn't monitor in the first PDCCH signal for the first cell group; and

monitoring the first PDCCH signal on a first cell in subframes included in the first information, except subframes included in the second information,

when the UE receives a PDCCH for an uplink grant or a downlink assignment through one of the second PDCCH signals included in the second information, stopping the monitoring of the first PDCCH signals and maintaining the monitoring of the second PDCCH signals by restarting a DRX-inactivity timer.

5. The method according to claim 4 , wherein the second cell group operates in a unlicensed spectrum.

6. The method according to claim 4 , wherein when the UE receives a PDCCH for the uplink grant or the downlink assignment through one of the first PDCCH signals and the second PDCCH signals included in the first information, the UE maintains the monitoring of the first PDCCH signals and the second PDCCH signals by restarting a DRX-inactivity timer.

7. A User Equipment (UE) operating in a wireless communication system, the UE comprising:

a receiver and transmitter; and

a processor, operatively coupled to the receiver and transmitter, wherein the processor is configured to:

configure the UE with a first cell group including at least one first cell and a second cell group including at least one second cell served by an e-NodeB (eNB),

control the receiver to receive first information for configuring with a Discontinuous Reception (DRX) operation, wherein the first information includes information on subframeswhich the UE monitors in first Physical Downlink Control Channel (PDCCH) signals for the first cell group and second PDCCH signals for the second cell group,

control the receiver to receive second information for configuring with an additional monitoring period for the second cell group, wherein the second information includes information on subframes, which the UE monitors in the PDCCH signals for the second cell group,

monitor the first PDCCH signals on a first cell in subframes included in the first information, and

monitor the second PDCCH signals on a second cell in subframes included in the first information and the second information,

when the UE receives a PDCCH for an uplink grant or a downlink assignment through one of the second PDCCH signals based on the second information, the processor is further configured to stop the monitoring of the first PDCCH signals and to maintain monitoring of the second PDCCH signals by restarting a DRX-inactivity timer.

8. The UE according to claim 7 , wherein the second cell group operates in a unlicensed spectrum.

9. The UE according to claim 7 , wherein when the UE receives the PDCCH for the uplink grant or the downlink assignment through one of the first PDCCH signals and the second PDCCH signals included in the first information, the UE maintains the monitoring of the first PDCCH signals and the second PDCCH signals by restarting a DRX-inactivity timer.