Disclosed is a signal transmitting and receiving method and system in a mobile communication system provided with a plurality of antennas. The signal transmitting method in the mobile communication system that transmits a signal through a plurality of antennas includes separating by layers and primarily encoding input data for an independent signal generation interleaving in space and time the primarily encoded data of the respective layers, receiving and secondarily encoding the interleaved data, and transmitting the secondarily encoded data through the plurality of antennas.