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標題: | 無線感測器網路的動態路由繞徑演算法與高準確度定位系統之研究 Study on optimal energy-efficient routing algorithm and high-precision localization system in wireless sensor networks |
作者: | Cheng-Long Chuang 莊欽龍 |
指導教授: | 江昭皚(Joe-Air Jiang) |
關鍵字: | 無線感測器網路,節能,路由繞徑演算法,無線電波節能控制,感測節點定位, Wireless sensor network,Energy-efficient,Routing protocol,Radio Power Control,Localization, |
出版年 : | 2010 |
學位: | 博士 |
摘要: | 無線感測器網路(WSNs)是由多個同時具有感測、計算與無線通訊功能之裝置(或稱感測節點)所構成。因為無線感測節點體積輕薄短小,無線感測器網路快速地衍生成可用於各種監控應用。然而,由於無線感測節點所搭載之電源珍貴且有限,如何使整體網路之運作時間延長則成為一個重要的課題。在本論文中,吾人將探討三個WSN相關領域的問題,包含:高能源效率之路由繞徑演算法、無線電強度動態調整,以及無線感測節點定位系統。前兩個主題之主要研究目的在延長整體網路運作時間,第三個主題則提出一套旋轉天線機構,並搭配以高準確度定位演算法進行感測節點之定位。因為無位址資訊之感測資料在分析上並不具任何意義,這更使定位系統在WSN應用中更顯得特別重要。
在第二章中,吾人提出一套可適性路由繞徑演算法,其包含兩大部分:自動網路拓墣生成法與感測資料封包之傳遞。每個在運作中的感測節點皆如路由器,可分散式決定傳遞感測資料之最有效率傳輸路徑,並且可平衡網路各感測節點之資料傳輸量與耗電量,以延長網路之可運作時間。另外,為了展現本可適性路由繞徑演算法在不同種網路平台之適用性,吾人亦將此演算法套用於以分封交換網路與WSN共同構成之混合式網路進行效能測試。 在第三章中,吾人提出一個動態電波強度控制法。WSN之主要耗電來源是無線通訊之電波傳輸所使用之能量,本章節中,吾人整合此動態電波強度控制法於第二章所提出之可適性路由繞徑演算法,以節省感測節點之耗電量,並且減少被孤立之感測節點的產生。但為了使這些演算法更有效地運用在實際的WSN應用,開發一套高精確性之感測節點定位系統是不可或缺的。 在第四章中,吾人提出一套以訊號強度指標(RSSI)為基礎之感測節點定位系統。此系統之主要創新之處,是利用無線電波訊號在空間中之不規則特徵來進行系統的設計。首先,吾人設計一套旋轉天線平台架設於參照節點上,並使一組全向性天線在水平軸上進行旋轉。透過吾人開發之可適性估測法來分析定位感測節點與參照節點間的RSSI模式,可直接算得其相對角度與距離。另外,吾人亦延伸此系統進行多重參照節點之協同定位工作,並且提供更高精準度之定位結果。 所有上述之演算法皆透過電腦模擬與實際測試來進行效果評估。實驗結果顯示本文提出之方法在效能與準確度上優於過去已知之演算法。 Wireless sensor networks (WSNs), which is formed by numerous sensing devices (or called sensor nodes) capable of computing and wireless communication. Due to the compact size of the sensor nodes, WSNs have soon becoming a revolutionary technology suitable with applications in wide areas of interest. However, limited energy supply in each sensor node brought new challenges and operational problems to the field of distributed and collaborative information processing in WSNs. In this dissertation, we concentrate on three essential problems within this extensive topic, including energy-efficient routing protocol, dynamic radio power control and two-dimensional sensor node localization. The first two topics emphasize on efficient use of limited energy in each sensor node. The primary goal is to prolong the network lifetime. The later part of this dissertation presents a rotational antenna configuration for accurate localization of sensor nodes. Localization is an essential function since it is meaningless to collect sensor data without knowing the position of the event. In Chapter 2, an adaptive routing protocol was presented to construct network topology and transmit sensor data to the sink. Each node acts as an independent router. Due to this key feature, the proposed routing algorithm determines the path to transmit data packets from its source nodes to the destination node (sink) with minimum delay time, and also balances the power consumption of all sensor nodes in the network. The routing protocol also applied to a hybrid network that consists of packet switching network and WSN to show its wide applicability in various types of networks. A dynamic radio power control method is proposed in Chapter 3. Radio transmissions are major sources of energy consumption in WSNs. In order to reduce redundant power consumptions and to prevent generating any orphan nodes in the WSN, a dynamic radio power management mechanism was developed to collaborate with the energy-efficient routing protocol proposed in Chapter 2. To maximize the merit of the radio power control, developing an accurate localization method for sensor nodes in a WSN is necessary. In Chapter 4, an RSSI-based collaborative localization method that makes use of the irregularity of the EM wave is proposed. First, we coupled external low-cost omnidirectional antennas with sensor nodes and reference nodes using specific antenna configurations. The omnidirectional antenna of the reference node rotates in the horizontal plane to measure the RSSI pattern between the sensor node and the reference node to estimate their relative angular direction and distance. A robust estimation technique is also presented to analyze the RSSI patterns obtained by the reference node. The proposed algorithm is thus able to provide the localization results with higher precision. In addition, a collaborative localization scheme is presented to integrate the information obtained by multiple reference nodes. All presented methods are evaluated via computer simulation and/or real-world field test. The experimental results show that the proposed algorithm outperforms existing algorithms with better performance in terms of energy efficiency and localization accuracy. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/44929 |
全文授權: | 有償授權 |
顯示於系所單位: | 生物機電工程學系 |
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