Ola appratus for ofdm system and the method thereof

An OLA(Overlap and Add) apparatus and an OLA method are provided to improve interference of a symbol and a carrier due to the generation of an STO(Symbol Timing Offset) by selectively performing the OLA according to the STO bidirectionally, forward, or backward. An OLA apparatus for an OFDM system includes a reference symbol timing detection unit(310), and a D-OLA unit(320). The reference symbol timing detection unit detects an initial point of the receiving symbol vector y' consisting of Nzp 0 and the N transmission symbols which are digital-modulated. The D-OLA unit outputs the vector robust to interference between the symbol and the carrier by performing the forward OLA of the Ni y', the backward OLA of the Nb y', and the bidirectional OLA of the y'.