QoS-driven design and operation of adaptive, self-organizing wireless sensor systems

Wireless locating systems are often of a mission-oriented nature and therefore have stringent requirements on application-level service quality. Because of the energy constraints of the underlying sensor devices, energy management plays a key role for successful system solutions. However, common design approaches only try to maximize system lifetime in a best-effort manner that is insufficient for many systems driven by quality of service (QoS). In this paper, we analyze system- and implementation-level requirements of such systems, introducing the concepts of QoS levels and context-dependent operating points. We use two localization applications to discuss challenges in the design and operation of mission-oriented systems and evaluate possible improvements of these systems with respect to guaranteed average QoS levels. Our results show that the average QoS level can be increased considerably through adaptive, context-sensitive systems. Finally, we share lessons learned in the analysis of QoS-driven, adaptable wireless sensor systems.