  The bistatic backscatter architecture, with its extended range, enables
flexible deployment opportunities for backscatter devices. In this paper, we
study the placement of power beacons (PBs) in bistatic backscatter networks to
maximize the guaranteed coverage distance (GCD), defined as the distance from
the reader within which backscatter devices are able to satisfy a given
quality-of-service constraint. This work departs from conventional energy
source placement problems by considering the performance of the additional
backscatter link on top of the energy transfer link. We adopt and optimize a
symmetric PB placement scheme to maximize the GCD. The optimal PB placement
under this scheme is obtained using either analytically tractable expressions
or an efficient algorithm. Numerical results provide useful insights into the
impacts of various system parameters on the PB placement and the resulting GCD,
plus the advantages of the adopted symmetric placement scheme over other
benchmark schemes.
