An apparatus and method for multiplexing signals using layered division multiplexing are disclosed. A signal multiplexing apparatus according to an embodiment of the present invention includes a combiner configured to combine a core layer signal and an enhanced layer signal at different power levels to generate a multiplexed signal, a power normalizer configured to reduce power of the multiplexed signal to power corresponding to the core layer signal, and a time interleaver configured to perform interleaving applied to both the core layer signal and the enhanced layer signal.