1. Field of the Invention
The present invention relates to a mobile communication system. More particularly, the present invention relates to a method for activating/deactivating secondary carrier(s) in addition to a primary carrier for the mobile communication system supporting carrier aggregation.
2. Description of the Related Art
With the rapid development of wireless communication technologies, Long Term Evolution (LTE) is taking a strong position in 4th Generation (4G) mobile communication technology. Various techniques have been introduced to meet the high capacity requirements of LTE. Carrier aggregation is a technique to increase the peak data rate and capacity, as compared to single carrier transmission, by aggregating one or more secondary carriers with a primary carrier between User Equipment (UE) and an evolved Node B (eNB). In LTE, the primary carrier is referred to as Primary Cell (PCell) and the secondary carrier as Secondary Cell (SCell).
The carrier aggregation technique causes additional control complexity for the PCell to control the SCells. This means that the PCell should be able to determine whether to use SCell and, if so, determine the SCell to be used. There is also a need for a method of activating and deactivating SCells. This means that the actual operations of the UE in receipt of SCell activation/deactivation command from the eNB should be specified in detail.