Communication method and device under mode of frequency division duplexing

1st frequency band of the down-going signal sent by the base station and the 2nd frequency band of the up-going signal sent by the mobile station are setup in advance. The wireless channel carrying the mentioned down going and up going signals includes several wireless frames. Each wireless frame contains the normal slot and the special slot. The base station sends the down going signal via the 1st frequency band within the normal slot. The mobile station sends the up going signal via the 2nd frequency band within the normal slot. When applies this invention to the semi-duplex frequency division duplex mode, the normal slot is split into the 1st time section and the 2nd time section. The mobile station sends the up going signal via the 2nd frequency band within the 1st time section of the normal slot and receives the down-going signal within the 2nd time section. The invention realizes that the TDD system is extended to apply under the FDD mode.