Evaluation and Comparative Study of Structure Free Aggregation Techniques for Duty Cycled Wireless Sensor Networks

For delay sensitive event based applications, structure free data aggregation approach has been found to be more suitable because of the reduced structure maintenance overhead. However, in the literature, it has been observed that increasing the delay at intermediate sensor node increases aggregation and the event notification time. The objective is to investigate various structure free aggregation schemes in terms of aggregation gain, event notification time and the overall energy consumption. To achieve this objective, a comparative study of various structure free aggregation techniques is presented. First, we investigate the potential of aggregation in different structure free aggregation techniques for duty cycled sensor networks. Then the performance of the aggregation techniques is demonstrated with the help of simulations on Cooja network simulator in Contiki operating system. From the results, it has been observed that Tuned delay based aggregation scheme reduces energy consumption (upto 13%) as compared to Collect protocol. Moreover, it reduces the worst event notification time (upto 20%) in comparison to random delay based aggregation scheme.