用於工廠無線感測網路的強健傳輸排程演算法的設計

近幾年來，無線感測網路 (Wireless Sensor Network, WSN) 應用廣泛。無線感測網路的應用包含工廠環境、工業自動化、居家保全等等。無線感測網路是由一個或數個的資料收集端 (Sink) 及許多的感測節點所組成的，感測節點可能以預先計畫的方式佈建在一個區域，再透過無線通訊傳輸裝置及網路的路由技術，將資料傳送至資訊收集端。由於大量佈建的考量，感測節點的體積、計算能力、電源皆有限制，使得多數感測網路應用在長時間且緩慢收集小量資料的情況。工廠無線感測網路的需求不同於一般感測網路，在工廠無線感測網路中，為了讓監控設備的感測節點其感測資料能盡快到達監控中心，以便針對出現問題的設備及時做處置，需保證網路時間延遲應在可接受的時間延遲上限 (Delay Bound) 內。本論文研究鏈狀結構的傳輸排程演算法，藉由令牌 (Token) 在鏈上的傳遞，安排每一節點傳輸的順序，避免碰撞的發生，也提供時間延遲的保證。每條子鏈上的節點順序即為節點傳送資料封包的順序，但是資料封包傳送的路徑則是依據Sink Tree 上的最短路徑，以降低時間延遲。我們探討排程演算法建立子鏈的成功率與節點數的關聯，節點數對吞吐量、時間延遲的影響，以及時間延遲的理論上限與實際值的比較等等。

關鍵字

傳輸排程；無線感測網路；受限的延遲

並列摘要

The wireless sensor network (WSN) has been widely used recently in many areas like factory environment monitoring, industrial automation and home security. WSN is usually composed of one or several Sink nodes and many sensor nodes. The sensor nodes can be deployed in advance, then use the wireless communication device and the network routing method to transmit data to the data-collection end. Due to the limitation in the size, computing ability, and the power capacity of senor nodes, the sensor network is typically used to collect data in a low rate mode so that it can last for a long period of time. The requirements of industrial WSN differ from those of the traditional WSN. In the industrial WSN, the sensed information should be sent to the monitoring center as soon as possible. The delay time should be within the pre-determined delay bound in order for the technician to replace the problem-prone device in time. In this thesis, we study the chain-based transmission scheduling algorithm. The token passing on the chain determines the order of data packet transmission of each nodes and therefore avoids packet collisions and provides a delay bound guarantee to each data packet. The order of nodes to send data packets follows the sequential positional order of the nodes in the chain, while the routing of data packets toward the Sink follows the Sink tree so that the packet delay can be further reduced. We study how the probability of building a sub-chain by the scheduling algorithm in affected by the number of nodes in the network. We show how the throughput and delay are affected by the node number. We also compare the actual delay with the theoretical delay bound.

並列關鍵字

limited bounded delay ； transmission scheduling ； WSN

參考文獻

G. Bianchi, “IEEE 802.11-Saturation Throughput Analysis,” IEEE Commun. Lett., vol2, pp. 318-320, Dec. 1998.

G. Bianchi, “Performance analysis of the IEEE 802.11 Distributed Coordination Function,” IEEE J. Sel. Areas Commun., pp. 535-547, Mar.

P. Ferre, A. Doufexi, A. Nix, D. Bull, “Throughput Analysis of IEEE 802.11 and IEEE 802.11e MAC,” Wireless Communications and Networking Conference (WCNC), 2004.

[4] V. C. Gungor and G. P. Hancke, “Industrial Wireless Sensor Networks Challenges Design Principles and Technical Approaches,” IEEE Transactions on Industrial Electronics, vol. 56, pp. 4258 – 4265, October 2009.

[5] N. Tabassum, Q. Ehsanul, K. Mamun, Y. Urano, “COSEN: A Chain Oriented Sensor Network for Efficient Data Collection,” Information Technology: New Generations, ITNG, 2006.

國際替代計量

用於工廠無線感測網路的強健傳輸排程演算法的設計

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