運用公車收集無線感測網路資料達最大化傳輸量及網路生命期的分散式機制

Distributed Bus-based Data Collection Mechanisms for Maximizing Throughput and Lifetime in WSNs

林崇智(Chung-Chih Lin)

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.2020.00211

摘要

資料收集(Data collection)是無線感測網路(wireless sensor network)中最重要的研究主題之一。在文獻中，許多研究提出了集中式解決方案來處理資料收集問題。在過去的幾年中，使用行動收集器(mobile sink)進行資料收集受到很多關注。然而，其中多數都認為行動收集器是可控制行動收集器，並由演算法控制其速度、路徑、停止位置，以及執行的任務。實際上，不可控制行動收集器也可以用於資料收集應用。許多研究假設收集器(sink)是固定的，並且所有感測器(sensor)都將其感測資料傳輸到收集器。但是，這將導致工作負載不平衡和網路斷線的問題。其他一些研究則進行可控制行動收集器排程工作。然而，開發於採用可控制行動收集器的演算法並不能移轉至採用不可控制行動收集器的場景。主要原因是不可控制行動收集器的停止和到達時間未知。此外，仍有高硬體成本和可控制行動收集器能量限制等問題尚需克服。本文提出了2個分散式資料收集機制，分別為Distributed Bus-based Data Collection（DBDC）及Energy Balanced Multi-hop Data Collection (EBMDC)，其以公車(bus)為行動收集器，並以無線感測網路達最大化傳輸量(throughput)及網路生命期(network lifetime)為目的。
在DBDC演算法，每個感測器都基於bidding程序與其鄰居協商，使暫存較多資料的感測器可以獲得更多的共享時槽(time slots)，而不用增加其傳輸功率。另為了延長網路生命期，具較多剩餘電量的感測器可以增強其傳輸功率，以釋放更多共享時槽，進而協作幫助暫存較多資料但剩餘電量較少的鄰居節點。在EBMDC演算法，每個感測器依據父節點權重(weight)將其資料分別傳給樹上的多個父節點，以延長網路生命期。然後，每個anchor依據其及其鄰居節點的資料量和剩餘電量，自行排程其傳輸時槽，以便可以將所有資料轉發到公車而不會發生碰撞，並且可以平衡每個anchor的生命期。由實驗結果顯示，所提出的DBDC及EBMDC演算法在傳輸量、網路生命期、時槽使用率、資料遺失率及公平性方面均優於相關工作。

關鍵字

資料收集 ； 無線感測網路 ； 時槽排程 ； 傳輸電量調整 ； 資源公平性

並列摘要

Data collection is one of the most important research topics in WSNs. In literature, many studies have proposed centralized solutions to cope with the data collection problem. Data collection using mobile sink has received much attention in the past years. However, most of them considered controllable mobile sink which is controlled by an algorithm to determine its speed, path, stop locations as well as the performed task. In fact, the uncontrollable mobile sink can be also applied to collect data from a given set of deployed sensors. A number of studies assumed that the sink is fixed and all sensors transmit their data to the sink. However, it leads to the problems of unbalanced workload and network disconnection. Some other studies scheduled the controllable mobile sink. However, the algorithms developed by adopting the controllable mobile sink cannot be applied to the scenarios where the uncontrollable mobile sink is adopted. The main reason is that the stops and arrival time of the uncontrollable mobile sink are unknown. In addition, the problems including the high hardware cost and energy limitation of the controllable mobile sink are still needed to be overcome. This thesis proposes two distributed data collection mechanisms, called Distributed Bus-based Data Collection (DBDC) algorithm and Energy Balanced Multi-hop Data Collection (EBMDC) algorithm, which consider the bus as mobile sink aiming to maximize the amount of collected data and the network lifetime of wireless sensor networks.
Applying the proposed DBDC, each sensor negotiates with its neighbors based on a bidding procedure such that the sensor that buffers more data can obtain more sharing slots instead of increasing its power level. To prolong the network lifetime, the sensor with higher remaining energy can enlarge its transmission power, aiming to release more sharing slots to cooperatively help the neighbor that buffers more data. In the proposed EBMDC algorithm, each sensor node distributes its data to its multiple parents in trees according to their remaining energies for prolonging the network lifetime. Then each anchor node locally schedules its transmission slots based on its and its neighbors’ data volumes and remaining energies such that all data can be forwarded to the bus without collision and the lifetime of each anchor can be balanced. Experimental study reveals that the proposed DBDC algorithm and EBMDC algorithm outperform related works in terms of throughput, network lifetime, slot utilization, data loss ratio and fairness.

並列關鍵字

Data collection ； Wireless sensor network ； Slot scheduling ； Power adjusting ； Fairness

參考文獻

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