US Patent 7599446 Modulation and demodulation based on hierarchical modulation

A modulation device comprises a modulation unit (2) that modulates data in a hierarchical manner using multiple types of modulation techniques, and a transmission unit (3) that transmits the hierarchically modulated data. A demodulation device comprises a receiving unit (4) that receives the hierarchical modulation data having been subjected to hierarchical modulation using multiple types of modulation techniques, and a demodulation unit (6) that demodulates the hierarchical modulation data using a demodulation technique corresponding to a specific hierarchy of the hierarchical modulation data.