Operator placement for efficient distributed complex event processing in MANETs

Complex Event Processing (CEP) and Mobile Adhoc networks (MANETs) are two technologies that can be used to enable monitoring applications for Emergency and Rescue missions (ER). MANETs are characterized by energy limitations, and in-network processing or distributed CEP is one possible solution. Operator placement mechanism for distributed CEP has a direct impact on energy consumption. Existing operator placement mechanisms focus on static network topologies and are therefore inappropriate for MANETs scenarios. We propose a novel energy efficient decentralized distributed placement mechanism, designed to achieve fast convergence with minimal data transmission cost while achieving a near optimal placement assignment. We compare our decentralized placement mechanism with a centralized approach under different mobility scenarios. Furthermore, we evaluate the distributed CEP under different workload scenarios in order to gain additional insight into different performance characteristics of the system. Finally, we measure the impact of a simple placement replication scheme on the overall system performance in terms of delay and message overhead. Our decentralized placement mechanism achieves up to almost 50% lower message overhead compared to the centralized approach, and it has lower message overhead across different mobility scenarios compared to the centralized approach. The placement replication scheme achieves up to 51% lower delay compared to the decentralized placement mechanism with no replication.