Hereinafter, the structures, operations, and other features of the present invention will be understood readily from the embodiments of the present invention, examples of which are described with reference to the accompanying drawings. The embodiments which will be described below are examples in which the technical features of the present invention are applied to a 3GPP system.
Although the embodiments of the present invention will be described based on an LTE system and an LTE-Advanced (LTE-A) system, the LTE system and the LTE-A system are only exemplary and the embodiments of the present invention can be applied to all communication systems corresponding to the aforementioned definition. In addition, although the embodiments of the present invention will herein be described based on Frequency Division Duplex (FDD) mode, the FDD mode is only exemplary and the embodiments of the present invention can easily be modified and applied to Half-FDD (H-FDD) mode or Time Division Duplex (TDD) mode.