Patent attributes
A multicarrier transmitter and a multicarrier receiver improve the reception characteristic of hierarchical modulation multiplex communication. A base station transmits a multicarrier superposition signal of a modulated signal addressed to a far user (a far-user addressed signal) and a modulated signal addressed to a near user (a near-user addressed signal) and modulated with a modulation multivalued number different from that of the far-user addressed signal. The base station separates the far-user addressed signal into frequency range signals, serial/parallel-transforms the near-user addressed signal to generate N1 parallel signals, and combines the generated N1 frequency components and the N1 parallel signals. Since the far-user receiver changes the near-user addressed signal into white noise by inverse discrete Fourier transform, the far-user receiver can demodulate the far-user addressed signal with high accuracy. The near-user receiver can acquire the signal addressed thereto with high accuracy by subtracting the far-user addressed signal from the received signal.
