臺灣博碩士論文加值系統

在無線感測器網路中，由於感測器皆是獨立運作，所以搭載電力的有效運用便成為重要的研究議題。但是現今使用在無線傳輸上的路由方法大多是以hop-by-hop的方式傳輸封包，而在處於傳輸路徑上的感測器不僅僅要收集自己周圍的環境資訊並將之傳送給基地台，且還要額外負擔其他感測器的資料封包的轉送。如此便會造成無線感測器網路的能量不均衡消耗問，即是靠近基地台附近的感測器會因為不斷協助轉送封包而快速的消耗能量而導致失效，這也是所謂的能量黑洞問題。而這個問題是同時存在於訊息均衡產生及事件觸發式無線感測器網路當中。在這篇論文當中，我們提出一個利用可移動式無線感測器的局部移動路由輔助策略(RASLM)，來減輕事件觸發式無線感測網路中流量負載過高的節點的負擔，以避免因為感測器因為負載過大而過早失效造成感測環境資料的不可靠問題。而這個方法同時可以穩定路由且讓資料可以更順暢的傳遞。實驗結果證實局部移動路由輔助策略(RASLM)可以有效地改善事件觸發式無線感測器網路的系統壽命。

In wireless sensor networks (WSNs), energy is one of the most important resources that should be economically used. But most routing approaches deployed by WSNs are hop-by-hop relay schemes, causing that sensors along a routing path should not only collect its environmental data, and then sending the data to base station, but also relay data received from its neighbors toward the base station. This will result in an unbalance energy consumption problem for WSNs, i.e., nodes near the base station will exhaust their energy more quickly than those far away, which is so-called energy hole problem. This problem appears in both message-evenly generated environment and event-driven WSNs. In the paper, we propose a routing assistant scheme with localized movement (RASLM) by using mobile nodes to help nodes along an active routing path to prevent them from dying much earlier than others. This scheme can also stabilize the routing path to ensure that the sensed data can be sent to base station safely and smoothly. The experimented results show that the RASLM can effectively improve the system lifetime in event-driven wireless sensor networks.

摘要 i
Abstract ii
誌謝 iii
List of Contents iv
List of Figures vi
1. Introduction 1
2. Background and Related Work 3
2.1 Mobile Sink 3
2.2 Mobile Sensor Node 4
3. Preliminaries 5
3.1 Event-driven Environment 5
3.2 Energy Consumption 6
3.3 Energy Hole Problem and Non-Surveillant Zone 8
3.4 Mobility Models 9
4. Proposed Protocol 10
4.1 Effective Assistant Zone 10
4.2 Broadcasting RAPs 12
4.2.1. Call for Help 13
4.2.2. Handling a RAP Request 15
4.3 A Relaying Schedule and Handling Flow of Assistant Nodes 18
4.3.1. TTL Values 19
4.3.2. Timeline for Call-for-Help 20
5. Experiment and Discussion 24
5.1 Randomly Distributed Sensor Environment 24
5.2 Nodes’ Loading 28
5.3 System Lifetime 29
5.4 Sensor Nodes Distributed in RASLM System 34
5.5 System Lifetime on Different Ratios of Nodes Failure 38
6. Conclusion and Future Work 40
7. References 41

[1]I. F. Akyildiz, W. Su, Y. Sankarasubramaniam, and E. Cayirci, “ A survey on sensor networks,” IEEE Communications Magazine, vol. 40, issue 9, pp. 102-114, Aug. 2002.
[2]W. Heinzelman, A. Chandrakasan, and H. Balakrishnan, “An Application-Specific Protocol Architecture for Wireless Microsensor Networks,” IEEE Transactions on Wireless Communications, vol. 1, issue 4, pp. 660-670, Oct. 2002.
[3]C. Intanagonwiwat, R. Govindan, and D. Estrin, “Directed diffusion: A scalable and robust communication paradigm for sensor networks,” In Proc. of ACM/IEEE International Conference on Mobile Computing and Networking (MobiCOM’00), pp.56-67, Aug. 2000.
[4]X. Wu, G. Chen, and S.K. Das, “On the Energy Hole Problem of Nonuniform Node Distribution in Wireless Sensor Networks,” in Proc. of IEEE International Conference on Mobile Adhoc and Sensor Systems, pp. 180-187, Oct. 2006.
[5]J. Luo and J. P. Hubaux, “Joint mobility and routing for lifetime elongation in wireless sensor networks,” in Proc. of IEEE Conference on Computer Communications, vol. 3, pp. 1735-1746, Mar. 2005.
[6]H. Luo, F. Ye, J. Cheng, S. Lu, and L. Zhang, “TTDD: Two-Tier Data Dissemination in Large-Scale Wireless Sensor Networks,” ACM Wireless Networks, vol. 11, issue 1-2, pp. 161-175, Jan. 2005.
[7]X. Wu and G. Chen, “Dual-Sink: Using Mobile and Static Sinks for Lifetime Improvement in Wireless Sensor Networks,” in Proc. of International Conference on Computer Communications and Networks, pp. 1297-1302, Aug. 2007.
[8]M. Zhao, Z. G. Chen, X. H. Deng, L. M. Zhang, A. F. Liu, and G. S. Huang, “MAEC: A Movement-Assisted Energy Conserving Method in Event Driven Wireless Sensor Networks,” In Proc. of International Conference on Wireless Communications, Networking and Mobile Computing, vol. 2, pp. 915-920, Sept, 2005.
[9]B. Wang, D. Xie, C. Chen, C. Chen, J. Ma, S. Cheng, “Employing Mobile Sink in Event-Driven Wireless Sensor Networks,” in Proc. of IEEE International Conference on Vehicular Technology, pp. 188-192, May 2008.
[10]S. Yang, J. Wu and F. Dai, “Localized Movement-Assisted Sensor Deployment in Wireless Sensor Networks,” in Proc. of IEEE International Conference on Mobile Adhoc and Sensor Systems, pp. 753-758, Oct. 2006.
[11]S. Chellappan, Wenjun Gu, X. Bai, D. Xuan, B. Ma, and K. Zhang, “Deploying Wireless Sensor Networks under Limited Mobility Constraints,” IEEE Transactions on Mobile Computing, vol. 6, no. 10, pp. 1142-1157, Oct. 2007.
[12]Yang and M. Cardei, “Movement-Assisted Sensor Redeployment Scheme for Network Lifetime Increase,” in Proc. of the ACM Symposium on Modeling, analysis, and simulation of wireless and mobile systems, pp. 13-20, Oct. 2007.
[13]F.Y. Leu, and G.C. Li, “A Scalable Sensor Network Using a Polar Coordinate System,” Signal Processing, vol. 87, issue 12, pp. 2978-2990, Dec. 2007.
[14]Y. Bi, J. Niu, L. Sun, W. Huangfu, and Y. Sun, ”Moving Schemes for Mobile Sinks in Wireless Sensor Networks,” in Proc. of International Conference on Performance, Computing, and Communications (IPCCC 2007), pp. 101-108, Apr. 2007.
[15]Y.C. Wang, C.C. Hu, and Y.C. Tseng, “Efficient Placement and Dispatch of Sensors in a Wireless Sensor Network,” IEEE Transactions on Mobile Computing, vol. 7, issue 2, Feb. 2008.
[16]J. Li and P. Mohapatra, “An Analytical Model For The Energy Hole Problem In Many-To-One Sensor Networks,” in Proc. of the IEEE 62nd Vehicular Technology Conference (VTC-2005), Sept. 2005.
[17]F. Y. Leu, G. C. Li and W. C. Wu, “An Autonomous Energy-Aware Routing Scheme: a Supplementary Routing Approach for Path-Preserving Wireless Sensor Networks,” in Proc. of the IFIP Annual Mediterranean Ad Hoc Networking Workshop, pp. 49-60. June 2008.
[18]X. Wu and G. Chen, “Avoiding Energy Holes in Wireless Sensor Networks with Nonuniform Node Distribution,” IEEE Transaction on Parallel and Dirtributed Systems, vol. 19, no. 5, pp. 710-720, May 2008.
[19]R. Jurdak, P. Baldi, C.V. Lopes, “Adaptive Low Power Listening for Wireless Sensor Networks,” IEEE Transactions on Mobile Computing, vol. 6, issue 8, pp. 988-1004, Aug. 2008.
[20]M. Tacca, P. Monti, A. Fumagalli, “Cooperative and Reliable ARQ Protocols for Energy Harvesting Wireless Sensor Nodes,” IEEE Transactions on Wireless Communications, vol. 6, issue 7, pp. 2519-2529, July 2007.
[21]S. Chellappan, X. Bai, B. Ma, D. Xuan, and C. Xu, “Mobility limited flip-based sensor networks deployment,” IEEE Transactions on Parallel and Distributed Systems, vol. 18, issue 2, pp. 199-211, Feb. 2007.
[22]D. Lymberopoulos and A. Savvides, “XYZ: A Motion-Enabled, Power Aware Sensor Node Platform for Distributed Sensor Network Applications,” in Proc. of International Symposium on Information Processing in Sensor Networks, pp. 449-454, Apr. 2005.
[23]http://www.darpa.mil/sto/smallunitops/shm/index.htm
[24]http://www.isi.edu/nsnam/ns/