Date Added: Jul 2010
To address energy constraint problem in sensor networks, node reclamation and replacement strategy has been proposed for networks accessible to human beings and robots. The major challenge in realizing the strategy is how to minimize the system maintenance cost, especially the frequency in replacing sensor nodes with limited number of backup nodes. New duty cycle scheduling schemes are required in order to address the challenge. Tong et al. have proposed a staircase-based scheme to address the problem based on ideal assumptions of sensor nodes that are free of failure and have regular energy consumption rate. Since sensor nodes are often deployed in outdoor unattended environment, node failures are inevitable.