Path Construction and Visit Scheduling for Targets using Data Mules

This paper considers the target patrolling problem which asks a set of mobile data collectors (or data mules) to efficiently patrol a set of given targets. Since the time interval (also referred to visiting interval) for consecutive visits to each target reflects the monitoring quality of this target, the goal of this research is to balance the visiting interval of each target. This paper firstly proposes a Basic Target Points Patrolling (B-TPP) algorithm which aims at constructing an efficient patrolling route for a number of given data mules such that the visiting intervals of all target points can be stable. For the scenario containing weighted target points, a Weighted TPP (W-TPP) algorithm is further proposed to satisfy the demand that targets with higher weights have higher data collection frequencies. By considering the energy constraint of each data mule, this paper additionally proposes a W-TPP with Recharge (RW-TPP) algorithm which treats energy recharge station as a weighted target and arranges the data mules visiting the recharge station before exhausting their energies. Performance study demonstrates that the proposed algorithms outperform existing approaches in terms of, average visiting frequency, movement distance of DM, average quality of monitoring satisfaction rate, and efficiency index. Keywords—WSNs; Mobile data collectors; Disconnected targets; Weighted target; Recharge station