  We consider the problem of data collection from a continental-scale network
of energy harvesting sensors, applied to tracking mobile assets in rural
environments. Our application constraints favour a highly asymmetric solution,
with heavily duty-cycled sensor nodes communicating with powered base stations.
We study a novel scheduling optimisation problem for energy harvesting mobile
sensor network, that maximises the amount of collected data under the
constraints of radio link quality and energy harvesting efficiency, while
ensuring a fair data reception. We show that the problem is NP-complete and
propose a heuristic algorithm to approximate the optimal scheduling solution in
polynomial time. Moreover, our algorithm is flexible in handling progressive
energy harvesting events, such as with solar panels, or opportunistic and
bursty events, such as with Wireless Power Transfer. We use empirical link
quality data, solar energy, and WPT efficiency to evaluate the proposed
algorithm in extensive simulations and compare its performance to
state-of-the-art. We show that our algorithm achieves high data reception
rates, under different fairness and node lifetime constraints.
