In a method of transmitting broadcasting signals, a transmission frame has the same configuration as that of the existing terrestrial DMB signal. A transmission frame including a base layer service stream is modulated to a base layer, and a transmission frame including an enhancement layer service stream is modulated to an enhancement layer. The enhancement layer service stream is composed of additional data that is not included in the base layer service stream, in order to provide an enhancement layer service. In this way, the method can provide a high-quality service requiring high transmission efficiency while being compatible with the existing terrestrial DMB system. The high transmission efficiency means a higher data transfer rate than that of the existing terrestrial DMB system.