  Indoor localization is a cornerstone of mobile services. Until now most of
the research effort has focused on achieving sub-meter localization accuracy
because many mobile applications depend on precise localization measurements.
In some scenarios, however, it is required to trade location accuracy for
system maintainability. For example, in large-scale deployments of indoor
networks, such as item-monitoring in smart buildings, attaining room-level
localization accuracy may be sufficient, but replacing the batteries of the
devices used for localization could lead to high operational costs. As indoor
localization systems grow in popularity it will be important to provide them
with full energy autonomy. To tackle this problem we propose WiPLoc: an indoor
localization system aimed at operating perpetually without batteries. Our
contributions are twofold. First, we propose a novel localization method that
exploits capture effect and orthogonal codes to operate at energy levels that
are low enough to operate within the energy budget provided by long-range
wireless power transmission. Second, we implement WiPLoc using off-the-shelf
components and test it extensively in a laboratory environment. Our test
results show that with WiPLoc one wireless charger per (16 m$^{\text{2}}$) room
can enable perpetual lifetime operation of mobile objects requiring
localization with an average accuracy of almost 90%.
