A Relay System (RS)-based cellular network transmission method for MT having a function of single input and single output is provided. The method includes transmitting broadcast information to all RSs and Mobile Terminals (MTs); transmitting required data to each RS in an Orthogonal Frequency Division Multiplexing (OFDM) mode; performing the operations of selection of modulation scheme, addition of CP, addition of symbols for channel estimation and selection of OFDM symbols; feeding feedback information to the Base Station (BS); transmitting a synchronization request to the BS; transmitting a synchronization acknowledgement to the RS; transmitting information to each MT belonging to the BS; transmitting information to each MT belonging to the RS; the MT belonging to the BS transmitting ACK/NACK information to the BS; the MT belonging to the RS transmitting ACK/NACK information to the BS; and the BS informing the RS of the received ACK/NACK information.