TRANSACT: A Transactional Framework for Programming Wireless Sensor/Actor Networks

Effectively managing concurrent execution is one of the biggest challenges for future distributed cyber physical systems (DCPSs), and especially for wireless sensor/actor networks (WSANs) as a realization of DCPSs. For safety reasons concurrency needs to be tamed to prevent unintentional nondeterministic executions, on the other hand, for real-time guarantees concurrency needs to be boosted to achieve timeliness. We propose a transactional, optimistic concurrency control framework for WSANs that enables understanding of a system execution as a single thread of control, while permitting the deployment of actual execution over multiple threads distributed on several nodes. By exploiting the atomicity and broadcast properties of singlehop wireless communication, we provide a lightweight implementation of our transactional framework on the motes platform. We analyze the framework through a parametric probabilistic model. This model allows calculation of theoretical bounds on consistency under various conditions. Our model identifies effects of parameters on consistency and facilitates parameter tuning for application needs and environment constraints. We support our theoretical results by discrete event simulations as well as an actual implementation on tmote invent motes.