SenCore: an Embedded Operating System for Wireless Sensor Networks

Abstract

Almost previous sensor network kernels can be roughly classified into two categories: event-driven and thread-driven. An event-based kernel is excellent in its tiny code size but fails to support time sensitive applications. In contrast, thread-driven is superior in its flexible programming construct but consumes more memory footprint. This motivates us to develop a new embedded kernel named SenCore. SenCore provides flexible programming construct by thread-driven architecture and achieves memory efficiency by preemptive three-queue FIFO scheduler. Owing to our scheduling scheme, no matter how many tasks exist, SenCore requires only three task stacks. In contrast, previous thread-driven networked sensor kernels require each task has its own stack. To be a functional operating system, SenCore also provides IPC, synchronization, timer and memory management. Furthermore, to enable portability, all hardwaredependent details are encapsulated in the Hardware Abstraction Layer. Finally, to address the energy constraints, SenCore scheduler sleeps the microcontroller when there is no ready task in the system. We have implement SenCore on the Mica2 mote and perform lots of performance evaluations. According to the performance results, SenCore is suitable for sensor network applications.