Coverage aware sensor node scheduling algorithm with node reclamation and replacement strategy for wireless sensor networks

Scope and Method of Study: The Adaptive Rendezvous-bases Two-tier Scheduling (ARTS) scheme is a combination of sensor node scheduling and sensor node reclamation and replacement (NRR) schemes in wireless sensor networks. The ARTS consists of local-tier and global-tier scheduling algorithms. The local-tier scheduling algorithm is run independently by each sensor node within a group of sensors (the post) using a one-hop communication model while the global-tier scheduling algorithm calculates the routes for the mobile repairman that traverses the network visiting posts to reclaim and replace sensor nodes. Since the energy in the sensor nodes is replenished periodically, the ARTS scheme increases the longevity of the wireless sensor network. However, the ARTS scheme's local-tier scheduling algorithm does not take the sensory coverage into account during the scheduling. Therefore, we propose three coverage aware local-tier scheduling algorithms utilizing a multi-hop communication model to replace the ARTS' local-tier scheduling algorithm. Our CA-ARTS schemes individually employ one of three proven techniques (Cumulative Reduction of Coverage, Local Reduction of Coverage and Energy Increase) to assign weights for each failed or energy depleted sensor nodes to aid the scheduling in improving the sensory coverage of each post. We also propose an energy model that provides information on energy utilization of all schemes simulated. Finally, we simulate all schemes and compare their post coverage and energy usage using the simulation software we developed.;Findings and Conclusions: In the initial simulation results, we found that at least one of our schemes (CA-ARTS-CR) provided as much as 0.63% better coverage compared to the ARTS scheme. In addition to the coverage increase we found through our simulations that our CA-ARTS schemes were also on average 4 times more energy efficient than the ARTS scheme. Using the energy efficiency advantage, we modified our scheduling algorithms to schedule as many sensor nodes as can be scheduled with respect to the surveillance requirements. We were able to achieve on average 58% coverage increase over the ARTS scheme while still consuming on average 3 times less energy than the ARTS scheme. Our schemes also produced on average 5% less sensor nodes to be reclaimed during the simulations.