SensorOS: A New Operating System for Time Critical WSN Applications

This paper presents design and implementation of a multi-threading Operating System (OS), SensorOS, for resource constrained Wireless Sensor Network (WSN) nodes. Compared to event-handler kernels, such as TinyOS, SensorOS enables coexistence of multiple time critical application tasks. SensorOS supports preemptive priority-based scheduling, very fine-granularity timing, and message passing inter-process communication. SensorOS has been implemented for resource constrained Tampere University of Technology WSN (TUTWSN) nodes. In TUTWSN node platform with 2 MIPS PIC micro-controller unit, SensorOS kernel uses 6964 B code and 115 B data memory. The context swap time is 92 μs and the variance of timing accuracy for a high priority thread less than 5 μs. The results show that the realtime coordination of WSN applications and protocols can be managed by a versatile OS even on resource constrained nodes.