Preemption Threshold Scheduling for Energy Harvesting Based Cyber-Physical Systems

In energy harvesting based cyber-physical systems (EHCPS), energy management architecture is different from traditional battery powered embedded systems. The task scheduling of EHCPS should take account of the output power of energy harvesting unit, the energy level of battery and the energy consumption of computing tasks. A real-time task may meet time constraint only if its energy constraint is satisfied. Against this background, the schedulability analysis of conventional preemption threshold scheduling doesn’t consider the tasks energy consumption, thus the preemption threshold assignment algorithm is not suitable for EHCPS. An energy related preemption threshold scheduling (ERPT) for EHCPS is proposed in this paper. It integrates tasks energy consumption and energy supply ability into schedulability analysis, and the preemption threshold assignment algorithms are also presented. ERPT presents a solution for applying preemption threshold scheduling in EHCPS. The proposed scheduling strategy is validated compared with other two existing classical algorithms. The experimental results show that the proposed scheduling can reduce the tasks preemption effectively.