Backscatter communication system, such as RFID, usually establishes bilateral communication link with time-wise half-duplex. Emerging data streaming using backscatter communication with low power or even batteryless sensors demands full duplex to stop streaming while a group of sensors backscatter. This paper introduces a full duplex method in backscatter communication using a simple decimation in backscatter sensors referred to as subcarrier synchronized decimation (SSD). Numerical simulations reveal that SSD can reconstruct the original reader-to-sensor link waveform subjected to backscatter modulation sensor-to-reader link, although the proposed method inevitably produces artificial noise because of the unequal time interval decimation. The contribution of artificial noise is investigated by using a sampling jitter model. This paper also reports a prototype implementation of SSD with USRP and LabVIEW NXG combined with a commodity DPDT switch to prove the feasibility of the proposal.