System policies for gradual tuning of security and workload in wireless sensor networks

In wireless sensor networks (WSN) energy consumption is a key issue. Security of communications, with its demand of computational resources, as well as performances are other fundamental issues. Finding a trade-off between performance and energy consumption, yet providing an adequate level of security is very challenging. Traditional solutions for the aforementioned problem assume that the operative environment is well-known and static, thus limiting the flexibility of the system. In this paper, instead, we propose a self-adaptation mechanism for gradual adaption of security and system workload in WSNs. The adaptation process can be tuned by using specific policies both for controlling the running tasks and for customizing the behavior of the self-adaptation mechanism. The ultimate goal is to perform adaptations by maximizing system performances while satisfying power constraints. A case study, implemented on Sun SPOTs, is also presented to show how the self-adaptation mechanism works in a real sensor node.