Abstract: Provided are a signal transmission method and signal reception method of heterogeneous systems sharing a frequency band. The signal transmission method performed by a transmitter of a target communication system sharing a frequency band of a general communication system in an underlay form includes mapping information symbols to be transmitted to a delay-Doppler (DD) domain and determining an information symbol mapping matrix, applying an inverse symplectic finite Fourier transform (ISFFT) to the information symbol mapping matrix and transforming the information symbol mapping matrix into a frequency-time (FT) matrix, and applying a Heisenberg transform to the FT matrix and generating a transmission signal of a time domain.

Abstract: When a disaster occurs, a disaster information transmitting apparatus generates disaster information, spreads the disaster information with a spreading code, modulates the spread disaster information, and transmits the modulated disaster information using a guard band of a broadcasting frequency band.