On Sweep Coverage with Minimum Mobile Sensors

For some sensor network applications, the problem of sweep coverage, which periodically covers POIs (Points of Interest) to sense events, is of importance. How to schedule minimum number of mobile sensors to achieve the sweep coverage within specified sweep period is a challenging problem, especially when the POIs to be scanned exceeds certain scale and the speed of mobile sensor is limited. Therefore, multiple mobile sensors are required to collaboratively complete the scanning task. When the mobile sensor is restricted to follow the same trajectory in different sweep periods, we design a centralized algorithm, MinExpand, to schedule the scan path. When the scan path of the existing mobile sensors has been exceeds the length constraint, MinExpand gradually deploys more mobile sensors and eventually achieves sweep coverage to all POIs. When the mobile sensors are not restricted to follow the same trajectory in different sweep periods, we design OSweep algorithm, where all the mobile sensors are scheduled to move along a TSP (Traveling Salesman Problem) ring consists of POIs. We conduct comprehensive simulations to study the performance of the proposed algorithms. The simulation results show that MinExpand and OSweep outperform CSWEEP in both effectiveness and efficiency.