Research On Energy Management And Task Scheduling In Passive Sensing System

With the rapid development of science and technology,human beings enter the Internet of Things era of the Internet of Everything,the latest emerging technology development report points out that there will be more than 100 billion IoT devices in 2045.Powering 100 billions of devices is a fundamental challenge of realizing the vision of the Internet of Things.Therefore,the Wireless Identification and Sensing Platform that harvest energy from the environment has received widespread attention.Firstly,WISP has limited efficiency in acquiring environmental energy.Secondly,WISP uses a 10?F capacitor with limited capacity to store energy.Therefore,the WISP is also subject to energy constraints.If the energy is insufficient,the task cannot be completed in one cycle,causing the task execution to be interrupted and affecting the entire system operation.Therefore,how to manage energy more efficiently becomes critical.In response to this problem,the main work of this paper is as follows.(1)RF energy transmission in an ideal environment cannot be applied to short-distance transmission of WISP tag and reader.According to the actual environment,two related parameters are introduced to correct and analyze and model the WISP charging process.At the same time,this paper analyzes the tag power consumption process and quantifies the energy consumption of the task,so that the remaining energy in different states of the tag can be obtained.Through algebraic operation,the energy available in the next working cycle was predicted,and the task scheduling algorithm PE-EDF which is proposed by this paper is more suitable for WISP.This algorithm avoids task execution failure caused by insufficient energy and greatly reduces the probability of data transmission failure and improves the reliability of task execution by 55%.(2)Multiple WISP tags cooperate with the task assigned by the reader.If the task execution is completed and communicates with the reader at the same time,a large number of communication collisions will occur.The transmitted data is difficult to be correctly decoded by the reader.Without changing the communication protocol,the collision-free communication algorithm CFC is proposed by optimizing the reader's residence position.And solve the NP-hard problem caused by the position of the reader,so as to minimize the collision of multi-tag communication,the total communication time is reduced by 27%.The experimental results show that the proposed algorithm in this paper can improve energy utilization and optimize multi-tag communication performance.