Group sweep coverage with guaranteed approximation ratio

Wireless Sensor Networks (WSNs) are often deployed to monitor a region of interest. With sweep coverage, mobile sensor nodes are scheduled to move along a planned route (i.e. sweep route) in order to collect the data from a series of Point of Interests (POIs) sequentially. In this paper, we generalize the sweep coverage problem by proposing a new coverage paradigm, group sweep coverage. With group sweep coverage, the POIs are divided into several groups. A group is said to be covered when one of the POIs in the group is covered. The goal in group sweep coverage is to construct a sweep route that mobile sensor nodes should follow in order to cover all groups during each predefined period. In our research, we devised two algorithms for group sweep coverage: AGSC and DSRM. AGSC is a centralized scheme whose approximation ratio is 5Δ. Namely, the length of the sweep route generated by AGSC is at most 5Δ times that of the optimal sweep route. DSRM is a distributed scheme for large-scale networks with dynamic POIs. Compared with AGSC, DSRM leads to the same approximation ratio and better scalability. Our experimental results indicate that both AGSC and DSRM outperform the state-of-the-art schemes in terms of average and maximal sweep route length.