在無線感測網路中最小化路徑長度及最大化覆蓋之充電技術

Recharging Mechanisms for Minimizing Path Length and Maximizing Coverage in Wireless Sensor Networks

秦御庭(Yu-Ting Chin)

指導教授 ： 張志勇

淡江大學/工學院/資訊工程學系博士班/博士(2020年)

https://doi.org/10.6846/TKU.2020.00405

摘要

近年來，隨著無線感測網路技術的快速發展和物聯網應用的普及，無線感測裝置的充電技術也愈來愈受到重視。如何設計合適的充電機制來提供感測器運作之電量，以延長無線感測網路的生命週期已成為現今最熱門研究主題之一。然而，現存大多數的充電機制，其基本概念是由一台具移動力的充電車，分別移動至每個感測器的可充電範圍內，再逐一地對各個感測器進行充電，導致充電車在執行充電任務時所需移動的充電路徑長度，將隨著感測器數量增多而有顯著的增加，進而造成充電車需要花費大量的時間與電量在充電的移動過程中。另一方面，現存的充電機制大多設計讓充電車移動至感測器充電範圍內的某定點後，停留在該定點並執行充電任務，待感測器充電完成後，充電車才繼續移動前往下一個目標感測器之充電範圍內的定點停留，並執行充電任務，換句話說，充電車的移動過程會是走走停停的狀態，無法維持等速移動，導致充電車必須花費更多的電量來執行充電任務，因此也降低了充電效率。有鑑於此，本論文提出兩種不同的充電技術，分別為Recharging Path Construction (RPC) 技術與Coverage Aware Energy Replenish Mechanism (CAERM) 技術，用以改善現存充電機制的效能。首先，本論文所提出之 RPC 技術，其探討充電車在等速移動下，同步進行充電工作時，如何規劃最佳的充電路徑，進而讓充電車的移動方式更有效率。接著，本論文所提出之 CAERM 技術，其將感測器之充電優先權納入考量，針對不同位置之感測器，分析其覆蓋面積對於整體感測的貢獻度，並協助充電車動態規劃其充電路徑，以進一步改善充電效率。實驗結果顯示，本論文所提出的兩種充電技術，可有效的解決現存充電機制所產生的問題，大幅提昇充電車執行充電任務的效能。

關鍵字

無線感測網路 ； 行動充電車 ； 固定式感測器 ； 覆蓋貢獻度 ； 充電路徑規劃

並列摘要

Energy recharging has received much attention in recent years. Several recharging mechanisms were proposed for achieving perpetual lifetime of a given Wireless Sensor Network (WSN). However, most of them require a mobile recharger to visit each sensor and then perform the recharging task, which increases the length of the recharging path. Another common weakness of these works is the requirement for the mobile recharger to stop at the location of each sensor. As a result, it is impossible for recharger to move with a constant speed, leading to inefficient movement. To improve the recharging efficiency, this thesis proposes two energy recharging path planning schemes, including Recharging Path Construction (RPC) mechanism and Coverage Aware Energy Replenish Mechanism (CAERM). The RPG mechanism enables the mobile recharger to recharge all sensors using a constant speed, aiming to minimize the length of recharging path and improve the recharging efficiency while achieving the requirement of perpetual network lifetime of a given WSN. Finally, the CAERM dynamically adjusts the recharging path according to the recharging requests of sensors, aiming to minimize the coverage loss for a given WSN. Theoretical analyses and performance evaluations show that the proposed mechanisms can significantly improve the performance of existing energy recharging techniques.

並列關鍵字

Wireless Sensor Networks ； Mobile Recharger ； Sensors ； Coverage Contribution ； Energy Recharging Path Planning

參考文獻

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