To provide the method/system for radio communication that overcome defects of a conventional technology.

This method consists of a step 100 that receives a radio frequency signal, a step 50 where a local signal with a fixed frequency ωRF corresponding to a carrier frequency of a desired modulated signal and a phase SS that changes with time depending on a prescribed phase function is oscillated, steps 110, 115 where a received signal and the local oscillation signal are mixed, a step 120 where the mixed signal is A/D-converted, a step where a low frequency local oscillator signal is generated, which has a zero fixed frequency and a phase SS changing with time depending on a prescribed phase function when a signal is delayed by a prescribed delay corresponding to a time when the signal propagates between the 1st mix step and the 2nd mix step, and a step where recovered signal including both a desired base band signal whose phase is independent of a prescribed phase function and a noise signal whose phase depends on a prescribed phase function are recovered by mixing the mixed signal with the low frequency local oscillator signal.