Adaptive QoS-Based Real-Time Communication Framework for WSANs

As wireless sensor network deployments continue to expand there is a growing trend to not only monitor the environment but to control it as well. Traditionally, the monitoring capability (sensing) and the controlling capability (actuation) were tightly coupled integrated on the same hardware device. However, in order to provide for a higher degree of mobile control the sensing and control elements are becoming de-coupled and spread across distributed architectures. While this new approach provides for a new generation of control systems it also presents some considerable challenges related to quality-of-service (QoS) provisioning. These new challenges make it difficult to meet some of the requirements such as timeliness, reliability or stability of a cyber-physical control system. Therefore, in order to address some of these challenges we present a novel real-time communications framework for wireless sensor and actuator networks (WSANs). Our technique provides for a QoS based approach that utilizes feedback control to dynamically adapt to environmental changes and a prioritized medium access control protocol for deterministic network behavior. A significant benefit of our approach is that it is an application layer solution that does not require routing changes or modifications to the medium access layer (MAC) of the network stack. Simulations results indicate that our approach provides for deterministic behavior and improved QoS flows that can adapt to unpredictable network traffic patterns while still providing required levels of service to critical control applications.