Simulating Real-Time Aspects of Wireless Sensor Networks

Wireless Sensor Networks (WSNs) technology has been mainly used in the applications with low-frequency sampling and little computational complexity. Recently, new classes of WSN-based applications with different characteristics are being considered, including process control, industrial automation and visual surveillance. Such new applications usually involve relatively heavy computations and also present real-time requirements as bounded end-to- end delay and guaranteed Quality of Service. It becomes then necessary to employ proper resource management policies, not only for communication resources but also jointly for computing resources, in the design and development of such WSN-based applications. In this context, simulation can play a critical role, together with analytical models, for validating a system design against the parameters of Quality of Service demanded for. In this paper, we present RTNS, a publicly available free simulation tool which includes Operating System aspects in wireless distributed applications. RTNS extends the well-known NS-2 simulator with models of the CPU, the Real-Time Operating System and the application tasks, to take into account delays due to the computation in addition to the communication. We demonstrate the benefits of RTNS by presenting our simulation study for a complex WSN-based multi-view vision system for real-time event detection

Simulating Real-Time Aspects of Wireless Sensor Networks

<p/> <p>Wireless Sensor Networks (WSNs) technology has been mainly used in the applications with low-frequency sampling and little computational complexity. Recently, new classes of WSN-based applications with different characteristics are being considered, including process control, industrial automation and visual surveillance. Such new applications usually involve relatively heavy computations and also present real-time requirements as bounded end-to- end delay and guaranteed Quality of Service. It becomes then necessary to employ proper resource management policies, not only for communication resources but also jointly for computing resources, in the design and development of such WSN-based applications. In this context, simulation can play a critical role, together with analytical models, for validating a system design against the parameters of Quality of Service demanded for. In this paper, we present RTNS, a publicly available free simulation tool which includes Operating System aspects in wireless distributed applications. RTNS extends the well-known NS-2 simulator with models of the CPU, the Real-Time Operating System and the application tasks, to take into account delays due to the computation in addition to the communication. We demonstrate the benefits of RTNS by presenting our simulation study for a complex WSN-based multi-view vision system for real-time event detection.</p

IMPACT OF THE OPERATING SYSTEM ON THE QOS OFFERED BY AN IEEE 802.15.4-COMPLIANT SENSOR NETWORK

Abstract: This paper ∗ presents a toolsuite for rapid prototyping and implementation of real-time applications on Wireless Sensor Networks. The work is motivated by the need to use WSNs in industrial control contexts, where the sampling rate, the workload and much higher than typical current applications of WSNs, and the real-time constraints are much tighter. We present a simulator for early evaluation of the real-time behavior of a WSN application; and a real-time operating system that implement appropriate real-time scheduling policies to allow timing analysis and guarantee timing constraints. After presenting the structure and the characteristics of both tools, we show that the results of the simulation are in line with experimental results of the implementation of a simple but realistic network scenario