Method and apparatus for performing carrier management in carrier aggregation system

1. A method performed by a base station for carrier configuration and activation in a carrier aggregation system, comprising:

transmitting a first signaling to configure at least one additional carrier to a user equipment (UE) at which the additional carriers are deactivated, and to configure a timer to each additional carrier for the UE by which the carrier is deactivated after the corresponding timer expiry;

transmitting a second signaling that carries an activation indication to the UE to indicate the UE to activate at least one deactivated additional carrier in the configured carriers for the UE;

activating the at least one deactivated additional carrier, starting the corresponding timer and controlling the UE to start Physical Downlink Control Channel (PDCCH) monitoring and Physical Downlink Shared Channel (PDSCH) receiving on the activated additional carrier;

transmitting PDCCH on the activated additional carrier for the UE, by which the corresponding timer being restarted; and

deactivating the activated additional carrier after the corresponding timer expiry and controlling the UE to stop the PDCCH monitoring and the PDSCH receiving on the deactivated additional carrier.

2. A method performed by a user equipment (UE) for carrier configuration and activation in a carrier aggregation system, the method comprising:

receiving a first signaling to configure at least one additional carrier transmitted from a base station, and to configure a timer to each additional carrier for the UE by which the carrier is deactivated after the corresponding timer expiry;

receiving a second signaling that carries an activation indication to indicate the UE to activate at least one deactivated additional carrier in the configured carriers for the UE; and

activating at least one deactivated additional carrier in the configured carriers for the UE according to the second signaling, starting the corresponding timer and starting the PDCCH monitoring and PDSCH receiving on the activated additional carrier; and

restarting the corresponding timer by PDCCH on the activated additional carrier for the UE; and

deactivating the activated additional carrier after the corresponding timer expiry and stopping the PDCCH monitoring and the PDSCH receiving on the deactivated additional carrier.

3. A base station that performs carrier configuration and activation in a carrier aggregation system, comprising:

a transmitter that transmits a first signaling to configure at least one additional carrier to a user equipment (UE) at which the additional carriers are deactivated, and to configure a timer to each additional carrier for the UE by which the carrier is deactivated after the corresponding timer expiry, and transmits a second signaling that carries an activation indication to the UE to indicate the UE to activate at least one deactivated additional carrier in the configured carriers for the UE;

a processor that activates the at least one deactivated additional carrier, starts the corresponding timer and controls the UE to start PDCCH monitoring and PDSCH receiving on the activated additional carrier, wherein the transmitter transmits PDCCH on the activated additional carrier for the UE, by which the corresponding timer being restarted, and

the processor deactivates the activated additional carrier after the corresponding timer expiry and controls the UE to stop the PDCCH monitoring and the PDSCH receiving on the deactivated additional carrier.

4. A user equipment (UE) that performs carrier configuration and activation in a carrier aggregation system, comprising:

a receiver that receives a first signaling to configure at least one additional carrier transmitted from a base station, and to configure a timer to each additional carrier for the UE by which the carrier is deactivated after the corresponding timer expiry, and receives a second signaling that carries an activation indication to indicate the UE to activate at least one deactivated additional carrier in the configured carriers for the UE;

a processor that activates at least one deactivated additional carrier in a configured carriers for the UE according to the second signaling, starts the corresponding timer and starts the PDCCH monitoring and PDSCH receiving on the activated additional carrier, wherein the corresponding timer is restarted when PDCCH on the activated additional carrier is received, and

the processor deactivates at least one activated additional carrier after the corresponding timer expiry and stops the PDCCH monitoring and PDSCH receiving on the deactivated additional carrier.

5. A communication system in which a communication is performed using carrier aggregation, the communication system comprising:

a base station; and

a user equipment;

wherein the base station includes,

a transmitter that transmits a first signaling to configure at least one additional carrier to a user equipment (UE) at which the additional carriers are deactivated, and to configure a timer to each additional carrier for the UE by which the carrier is deactivated after the corresponding timer expiry, and transmits a second signaling that carries an activation indication to the UE to indicate the UE to activate at least one deactivated additional carrier in the configured carriers for the UE;

a first processor that activates the at least one deactivated additional carrier, starts the corresponding timer and controls the UE to start PDCCH monitoring and PDSCH receiving on the activated additional carrier, wherein the transmitter transmits PDCCH on the activated additional carrier for the UE, by which the corresponding timer being restarted, and

the first processor deactivates the activated additional carrier after the corresponding timer expiry and controls the UE to stop PDCCH monitoring and PDSCH receiving on the deactivated additional carrier; and

wherein the UE includes,

a receiver that receives the first signaling, and to configure the timer to each additional carrier for the UE by which the carrier is deactivated after the corresponding timer expiry, and receives the second signaling;

a second processor that activates at least one deactivated additional carrier in the configured carriers for the UE according to the second signaling, starts the corresponding timer and starts the PDCCH monitoring and PDSCH receiving on the activated additional carrier, wherein the corresponding timer is restarted when PDCCH on the activated additional carrier is received, and

the second processor deactivates at least one activated additional carrier after the corresponding timer expiry and stops the PDCCH monitoring and PDSCH receiving on the deactivated additional carrier.