適用於室內環境之強健型無線感測網路架構與可靠的通訊機制

A Robust Wireless Sensor Network Infrastructure and Reliable Communication Mechanisms for Indoor Environments

鐘振華(Chen-Hua Chung)

指導教授 ： 林信標

國立臺北科技大學/電資學院/電腦與通訊研究所/碩士(2013年)

摘要

無線感測網路具有低成本及容易佈署等優勢，已廣泛運用於收集環境資訊和大樓自動化等應用中。但室內環境複雜且多變，有許多因素影響電波訊號的傳遞，諸如多路徑效應(multipath effect)，遮蔽效應(shadowing effect)和其他無線電波干擾(radio interference)等，使無線通訊無法維持穩定。在許多研究中，首要關心的議題是如何在充滿不確定性的室內環境中，使網路維持可靠的通訊。
本論文著重於改善室內無線通訊不可靠的問題，主要是藉由一個適當地網路基礎架構(infrastructure)來提昇通訊的可靠度，其包括一個叢集式(clustering)的網路拓樸(topology)及一個強健型的節點佈建，並結合一個「可調適性網路品質監控演算法(adaptive network quality control algorithm, ANQC)」來解決變化的環境引起的網路品質問題。無線感測網路節點的佈建位置，對於提昇通訊可靠度非常關鍵，本論文藉由模擬與實證研究方法來決定節點之佈建位置，包括距離與數量等，使佈建的無線網路之通訊可達到一定的可靠度；而「可調適性網路品質監控演算法」主要係因應室內環境動態變化，動態地調整各層的參數，即傳輸功率、運作頻道及路由表，使無線通訊能維持穩定的可靠度。為了驗證系統架構改善的效能，本論文以ns-2網路模擬器進行模擬，以ZigBee通訊協定實作了可調適性網路品質監控演算法，節點放置位置及網路拓樸則根據選定之基礎架構，並以平均封包接收率作為網路效能評量標準。實驗結果顯示採用此網路架構的網路品質可獲得改善，在受到干擾時，可調適性網路品質監控演算法能夠維持一定的網路品質。

關鍵字

無線感測網路 ； 通訊可靠度 ； 基礎架構 ； 跨層級 ； ZigBee

並列摘要

Wireless sensor networks have the advantages of low cost and easy deployment. These make them excellent mechanisms for capturing environmental data and interacting with the physical environment for the application of building automation. However, radio propagation suffers from multi-path, shadowing and other radio interference problems in building environments. The quality of network communication is highly unpredictable. In many researches, a main concern is to provide network reliability in a dynamic in-building environment.
In this paper, we focus on improving the network reliability of wireless communication in indoor environments. We address this problem by means of an appropriate network infrastructure which includes a cluster network topology and a robust nodes deployment, then through our proposed Adaptive Network Quality Control algorithm (ANQC) to overcome the dynamic environment. The position of sensor nodes is critical to improving network performance. We study the radio channel characteristics in indoor environment through empirical measurement and theoretical-based simulation. Based on these results, we propose deployment guidelines including the distance between a pair of nodes and the number of nodes in a cluster. The purpose in the use of ANQC algorithm is maintaining satisfactory network quality while the factors which influence the network quality are changed. ANQC algorithm can dynamically adjust the transmission power, operating channel and routing table.
To verify the improved performance of the system architecture, the proposed algorithm was implemented based on ZigBee protocol and simulated by ns-2 network simulator. We also have used the ns-2 to measure the network performance with a specific network infrastructure. Finally, the simulation results show that the average packet reception rate is maintained.

並列關鍵字

wireless sensor networks ； network reliability ； infrastructure ； cross-layer ； ZigBee

參考文獻

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