查看文章

In this paper, we investigate a unique phase cancellation problem that occurs in backscatter-based tag-to-tag (BBTT) communication systems. These are systems wherein two or more radio-less devices (tags) communicate with each other purely by reflecting (backscattering) an external signal (whether ambient or intentionally generated). A transmitting tag modulates baseband information onto the reflected signal using backscatter modulation. At the receiving tag, the backscattered signal is superimposed to the external excitation and the resulting signal is demodulated using envelope detection techniques. The relative phase difference between the backscatter signal and the external excitation signal at the receiving tag has a large impact on the envelope of the resulting signal. This often causes a complete cancellation of the baseband information contained in the envelope, and it results in a loss of …