Signal multiplexing device and signal multiplexing method using layered division multiplexing
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, and a time interleaver configured to perform interleaving applied to both the core layer signal and the enhanced layer signal.
1. A signal multiplexing apparatus, comprising:
an injection level controller configured to generate a power-reduced enhanced layer signal by reducing power of an enhanced layer signal;
a combiner configured to generate a multiplexed signal by combining a core layer signal and the power-reduced enhanced layer signal;
a time interleaver configured to perform interleaving applied to both a core layer corresponding to the core layer signal and an enhanced layer corresponding to the enhanced layer signal; and
a power normalizer configured to reduce power of the multiplexed signal to power corresponding to the core layer signal,
wherein the injection level controller corresponds to a scaling factor and the power normalizer corresponds to a normalizing factor, and the scaling factor decreases as a reduction in power corresponding to the injection level controller becomes larger, and the normalizing factor increases as a reduction in power corresponding to the injection level controller becomes larger.
2. The signal multiplexing apparatus of claim 1 , wherein the injection level controller changes an injection level with predetermined step sizes, the predetermined step sizes including 0.5 dB.
3. A signal multiplexing method, comprising:
generating a power-reduced enhanced layer signal by reducing power of an enhanced layer signal;
combining a core layer signal and the power-reduced enhanced layer signal for generating a multiplexed signal;
performing interleaving applied to both a core layer corresponding to the core layer signal and an enhanced layer corresponding to the enhanced layer signal; and
reducing power of the multiplexed signal to power corresponding to the core layer signal,
wherein the reducing power of the enhanced layer signal corresponds to a scaling factor and the reducing power of the multiplexed signal corresponds to a normalizing factor, and the scaling factor decreases as a reduction in power corresponding to the reducing power of the enhanced layer signal becomes larger, and the normalizing factor increases as a reduction in power corresponding to the reducing power of the enhanced layer signal becomes larger.