Aggregator Modeling with Multiple Active/Sleep Modes for Wireless Sensor Networks

Data aggregation and active/sleep scheme are frequently used methods in energy efficient wireless sensor networks. However, little research has been done on the optimal active/sleep scheme design for an aggregator node. In our previous work, we developed a stochastic model of an aggregator node with active/sleep scheme for performance analysis and optimization. That model simulates the direct mode transfer from active to sleep and vice versa. In this paper, we propose a new stochastic analytical model for an aggregator with multiple modes in the active period which reflect the wireless sensor's multiple energy saving modes. We derive the Complete Aggregation Packet (CAP) rate, the Total Aggregation Packet (TAP) rate, the Success Ratio which is defined as CAP rate divided by TAP rate, and the Average Packet Delay (APD) to evaluate the aggregator performance. By the Lagrangian Optimization method, we optimize APD under the constraint of the TAP rate. The extensive numerical simulations validate the accuracy of the analytical results.