Structure Free Aggregation in Duty Cycle Sensor Networks for Delay Sensitive Applications

Abstract

Duty cycling and data aggregation are widely used energy management techniques in sensor networks. In this paper, we investigate structure free aggregation in duty cycle sensor networks, which is used for reporting random events sensed by sensor nodes to a fixed sink. The objective is to optimize energy consumption as well as the event reporting time (ERT). To achieve the objective, first, an aggregation aware mixed integer linear formulation (named AMIP) is proposed. Later, three aggregation aware strategies have been proposed which are based on: distance of nodes to the sink node, link quality of nodes and both link quality and distance (hybrid). Finally, AMIP is used to optimize parameters for the proposed aggregation strategies. The techniques are implemented in Contiki operating system and are tested over Cooja network simulator as well as on a real test bed. It has been observed that the hybrid technique is more close to the optimal solution obtained from the AMIP. It minimizes the energy consumption and ERT and increases the aggregation gain as compared to the other approaches in simulation as well as in real experiments.