一個適用於無線感測網路的分散式排程媒體存取控制協定

A Distributed-Scheduling MAC Protocol for Wireless Sensor Networks

黃冠儒(Guan-Ru Huang)

指導教授 ： 郭耀文

國立暨南國際大學/科技學院/電機工程學系/碩士(2010年)

摘要

在這篇論文中，我們為減少無線感測網路中端對端的封包延遲以及能源損耗，提出了一個新的媒體存取控制協定，命名為分散式排程協定(DS-MAC)。感測節點常常會切換於動作與睡眠狀態以減少能源的損失，所以過程中當封包需要經歷較多跳點或是遇到壅塞的情況時，其端對端的延遲將會非常的高。類似於廣為人知的S-MAC，DS-MAC在每個循環中有兩個階段：監聽與睡眠週期。於第一個階段裡，每個節點藉著一般使用的RTS/CTS機制，對第二階段的通道使用作競爭。我們利用RTS/CTS封包中的“DURATION”欄位來記錄欲傳送的封包之排程，在這個RTS/CTS通訊範圍內的所有節點便可更新安排它們自己的傳輸行程。在第一個階段中，每個節點在送出或接收到RTS/CTS封包後會立即更新它們的封包排程，且所有節點的排程都是以分散的方式創建。在第二個階段中，每個節點只依照著各自的封包排程去發送或是接收封包。節點可以於一個循環中服務多個封包，即為DS-MAC其最主要的優點。我們將DS-MAC在封包延遲、平均網路傳輸流量、總耗能幾個項目中，與其它協定做了比較。從模擬的結果中顯示DS-MAC較它者有更好的效能表現，尤其在流量負載較大的情況下更為傑出。

關鍵字

無線感測網路 ； 媒體存取控制 ； 分散式排程

並列摘要

In this thesis, we propose a new medium access control protocol, named DS-MAC (Distributed-Scheduling MAC) for wireless sensor networks to reduce the end-to-end delay and consumed energy. Usually sensor nodes switch between sleep and active modes to reduce energy loss. As a result, the end-to-end delay of packets that travel many hops or pass a congested will be extremely high. Similar to the well-known S-MAC, DS-MAC has two phases in each cycle: listen and sleep periods. In the first phase, each node contends by the commonly used RTS/CTS mechanism for channel access at the second phase. We use the DURATION field in a RTS/CTS packet to record the packet schedule of the considered packet. All nodes in communication range of the RTS/CTS packet can update their packet schedule. During the first phase, each node updates its own packet schedule upon sending or receiving RTS/CTS packets and the packet schedules of all nodes are created in a distributed manner. In the second phase, each node just follows its packet schedule to send or receive a packet. The major advantage of DS-MAC is that a node can serve multiple packets in a cycle. We have compared the DS-MAC with others in terms of end-to-end delay, average throughput and energy consumption. The simulation results show that the DS-MAC has better performance, especially for high traffic loading.

並列關鍵字

wireless sensor network ； MAC ； Distributed-Scheduling

參考文獻

[1] Ian F. Akyildiz, Weilian Su, Yogesh Sankarasubramaniam, and Erdal Cayirci, “A Survey on Sensor Networks,”IEEE Communications Magazine, vol. 40, no. 8, pp. 102 – 114, Aug. 2002.

[2] M. Stemm and R. H. Katz, “Measuring and Reducing Energy Consumption of Network Interfaces in Hand-Held Devices, ” IEICE Transactions, vol. E80-B, no. 8, pp. 1125-1131, Aug. 1997.

[3] IEEE Std 802.11-2007, “IEEE Standard for Information Technology- Telecommunications and Information Exchange Between Systems-Local and Metropolitan Area Networks-Specific Requirements - Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications,” June 12 2007.

[4] IEEE Std 802.15.4-2006, “IEEE Standard for Information Technology- Telecommunications and Information Exchange Between Systems- Local and Metropolitan Area Networks- Specific Requirements Part 15.4: Wireless Medium Access Control (MAC) and Physical Layer (PHY) Specifications for Low-Rate Wireless Personal Area Networks (WPANs), ” 2006.

[5] Zigbee Standards Organization, “ZIGBEE SPECIFICATION V1.0 r13,”2006.