Multiple Wirelessly Powered Sensing Platform Scheduling Algorithm Based on Dynamic Priority Preemption

Abstract

The available energy of a wirelessly powered sensing platform is not enough, and there are constant real-time tasks to join the wirelessly powered sensing platform to run. So the wirelessly powered sensing system composed of many wirelessly powered sensing platforms is easy to enter the overloaded state, which may cause some tasks not to be executed on time. Therefore, to obtain as much task value as possible for the wirelessly powered sensing system when it is under the overloaded state, it is essential to design a reasonable task scheduling algorithm to arrange the task execution order. In this paper, we propose a policy named Wirelessly Dynamic Allocation Priority (WDAP) policy suitable for the wirelessly powered sensing system. The proposed WDAP is divided into a dynamic task priority allocation policy and a dynamic node priority allocation policy. Firstly, this paper analyzes the dynamic value density based on task value and execution time, studies the urgency of execution according to the execution time and the remaining idle time, and proposes the energy intensity through the task energy consumption and execution time. Based on the three impact factors of dynamic value density, urgency, and energy intensity, a policy for dynamic task priority allocation is proposed. Then, a policy for dynamic node priority allocation is proposed by combining the available energy and the energy acquisition speed of the nodes. Finally, the algorithm suitable for the wirelessly powered sensing system is proposed named Wirelessly Dynamic Real-time Task Scheduling (WDRTS) algorithm based on the WDAP. The algorithm clarifies the execution order of each task, responds to high-priority tasks first, and effectively guarantees task benefits. The experimental results show that compared with the main algorithms used in the literature among which is Generalized Earliest Deadline First, the WDRTS algorithm reduces the number of preemptive tasks by at least 36.49% and increases the successful scheduling rate of tasks by at least 15.17% and the overall system task income by at least 16.37% under high load.