Demodulation device and method in a transmission system

Layer demodulator estimates a reference symbol on the basis of symbols already known to the channel generating the channel estimation value of the reference symbols and, based on the channel estimation value of the reference symbol by channel estimation for a plurality of information symbols channel of the plurality of information symbols to generate an estimated value, on the basis of channel estimation values ​​of the plurality of information symbols by estimating a plurality of channel services symbols to produce a channel estimation value of the plurality of service symbol. And the channel estimation value of the reference symbol, a plurality of channel estimation values ​​of the information symbol, and then a plurality of service channel estimate value signal based on the channel of the symbol equalization by the channel to remove the equalized signal layer the first layer modulation signal and the 2 generates a hierarchical modulation signal. This does not affect the base layer, while maintaining compatibility with the existing system, it is possible to improve the receiving performance of the enhancement layer. OFDM, a pilot, a demodulation, channel estimation,