無線感測網路中使用虛擬網格之節能式地理路由法

由於微機電與無線通訊技術的快速成長，促成低功率、低成本與多功能之無線感測節點的發展。但是感測網路節點通常擁有受限的資料存儲空間、通訊頻寬、運算能力及電池電能等特性，如何減少節點有限的資源消耗，尤其是以電池作為電能來源的節點，近年來是無線感測網路研究的重點之一。在節能方面，地理路由為最普遍的節能路由法，多數的地理路由法僅計算傳送及接收封包之電能消耗，並未考量節點於閒置時，其電能仍持續損耗。故本研究將以GPSR(貪婪及無狀態邊界路由法)為基礎，針對如何有效節省節點電能並能維持網路的正常運作而提出ESGR (節能式地理路由協定)。ESGR藉由全球定位系統或其他定位裝置所獲得的地理位置資訊，將感測區域分割成數個虛擬網格。此外，ESGR以閘道節點做為網格間的資料傳遞，且在不減損路由保真性的條件下，令大部分的冗餘節點進入睡眠狀態，以減少節點電能的消耗，並避免網路擴充性與網路壅塞的問題，進而延長感測網路之存活時間。由於ESGR只需少數閘道節點就能維持網路的連通性，所以當節點密度愈高時，所節省的總體電能將愈顯著。本研究以節點存活率、網路電能消耗與封包傳達率作為路由效能量測標準，並以NS2為平台建置一模擬系統，來分析GPSR與ESGR之效能優劣。由模擬結果顯示，在模擬時間約130秒時，使用GPSR協定的感測節點已全數失效，但使用ESGR協定的節點仍有70%以上的存活率，尤其在節點密度高的模擬中，甚至可達90%以上之存活率。雖然ESGR之資料傳達率無法如同GPSR達至100%，但由於ESGR能大幅延長網路的存活時間，所以ESGR比GPSR可多3倍以上資料傳輸量。

關鍵字

無線感測網路；虛擬網格；地理路由；閘道節點；節能

並列摘要

As the progress of its technology grew up rapidly, the micro-electronic technology and the wireless communication helped promoting the development of low power, low cost and multi-function wireless sensor nodes. Since having limited characteristics of storage, network bandwidth, computing ability, battery power and mass disposition, the issues of sensor networks always focus on how to efficiently reduce the consumption of limited resource while the batteries are used for nodes power energy. Many relative geographic routings present outstanding and efficient performances of energy-saving on nodes, but they only consider and calculate the power consumption in transmitting and receiving packets. However, the power still be consumed while the nodes are in an idle mode and not to transmitter packets. We proposed an energy-saving geographic routing, called ESGR. ESGR based on GPSR (Greedy and Perimeter Stateless Routing), focuses on how to efficiently save node’s resources and maintain the normal operation of sensor networks. ESGR, using the geographic information from Global Positioning System or similar systems, focus virtual grids that divide the sensing areas. ESGR elect some gateway nodes to forward packets between grids and makes other equivalent nodes fall into sleeping state without losing the routing fidelity. This way could reduce the power consumption of nodes. Besides, it does not lead to the problems of network’s scalability and crowdedness of network. We consider ESGR could prolong the lifetime of sensor networks. Since ESGR needs only gateway nodes to forwards packets and make the networks workable. The more density of nodes will save more nodes’ power energy. Finally, the network lifetime, the power consumption of node and the transmission rate of packets are measured by using NS2. A simulation system is built to measure, analysis and compare the routing efficiency between GPSR and ESGR.

並列關鍵字

Wireless Sensor Networks ； Virtual Grid ； Geographic Routing ； Gateway Nodes ； Energy Saving

參考文獻

[1] D. B. Johnson and D. A. Maltz, “Dynamic Source Routing in Ad Hoc Wireless Networks,” Mobile Computing, Kluwer Academic Publishers, vol. 353, pp.153-181, 1996.

[5] D. Estrin Tutorial “Wireless Sensor Networks,” Part IV : Sensor Network Protocols, ACM MobiCom, 2002.

[8] W. B. Heinzelman, P. Chandrakasan, and H. Balakrishnan, “An Application-Specific Protocol Architecture for Wireless Microsensor Networks,” IEEE Transactions on Wireless Communications, vol. 1, no. 4, pp. 660-670, Oct. 2002.

[9] J. Kulik, W. Heinzelman, and H. Balakrishnan, “Negotiation-Based Protocols for Disseminating Information in Wireless Sensor Networks,” ACM Wireless Networks, vol. 8, no. 2-3, pp. 169-185, Mar. 2002.

[11] B. Karp and H.T. Kung, “GPSR: Greedy Perimeter Stateless Routing for Wireless Networks,” ACM MoBiCom, 2000.

國際替代計量

無線感測網路中使用虛擬網格之節能式地理路由法

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