  Long Term Evolution (LTE) systems provide ubiquitous coverage for mobile
communications, which makes it a promising candidate to be used as a signal
source in the ambient backscatter communications. In this paper, we propose a
system in which a backscatter device modulates the ambient LTE signal by
changing its reflection coefficient and the receiver uses the LTE Cell Specific
Reference Signals (CRS) to estimate the channel and demodulates the
backscattered signal from the obtained channel impulse response estimates. We
first outline the overall system, discuss the receiver operation, and then
provide experimental evidence on the practicality of the proposed system.
