FOMA: Flexible Overlay Multipath Data Aggregation for Wireless Sensor Networks

In wireless sensor networks source data must be routed by intermediate nodes to reach the sink. Data aggregation is an efficient method to decrease energy consumption in these networks. However, providing end to end data reliability is a major challenge when the network uses data aggregation, in this case, a packet loss can greatly affect final results. End to end reliability can be increased by data transmission in multiple paths; but energy consumption and computational error are major constraints. In this paper we propose FOMA (Flexible Overlay Multipath Data Aggregation) and FOMA-G (FOMA with gossiping) protocols for aggregation of sensor’s data with high reliability and low energy consumption in networks with large number of sensors. The proposed protocol aggregates data in two layers, routing and data aggregation, and eliminates computational error by using signature based structure. FOMA-G is extended version of FOMA that is introduced to reduce energy consumption. We implement two version of FOMA in TinyOs 2.x and test them by TOSSIM simulator. Finally, in order to evaluate FOMA, we compare it with previous works. The results show that our protocols consumes much less energy and FOMA has lower RMS (Root Mean Square) error in all cases. Keywords; Wireless Sensor Network, Data Aggregation, Reliability, Multipath, Overlay Network