無線感測網路近年來廣泛應用於生態環境監控，提供一個密集的時間與空間上的監測，此為傳統監控生態方式所不及的。因為感測節點能量上的限制，如何有效節能的將感測資料傳送到基地台，延長感測網路的網路生存期間是相關研究努力的目標。

　　本研究提出一個新的叢集演算法，基於兩階段遠近叢集首的選擇方式，將感測區域劃分成遠近區域，並配合協調者來統一叢集資訊以解決叢集首碰撞問題，並搭配遠近區域調整，以求整體網路消耗能量上的均衡，達到延長有效網路生存時間。並在給予叢集首排除範圍的架構下，使單一回合中叢集首得以空間上均勻分佈，如此必定能達到更佳的節能效果。

使用NS2網路模擬器實驗證明，我們提出來的演算法不論在增加網路生存時間以及使用網路剩餘能量上都能達到一個很好的效果。此外，我們提出的遠近區域調整演算法，經過實驗證明也能確實達到平衡兩邊區域消耗能量的目的。

We propose a new clustering algorithm based on far and near cluster-heads selection mechanism which partition the sensing area into far and near regions.

The selected coordinator can unify the cluster –heads in each round to solve the cluster-head collision problem. Furthermore, the selected coordinator can adaptively adjust the far and near regions to balance the energy consumption of the far and near regions, resulting in extending the life time of the sensor networks significantly. With the exclude distance of cluster-heads, cluster-heads can be distributed evenly in spatial respects for each round, resulting in reducing the energy consumption.

NS2 network simulator is employed to verify the proposed algorithm, The simulation results show that the proposed algorithm can extend network life time significantly, because of limited residual energy. Furthermore, the experiments show that the far and near regions can stay in balanced states convergent, with adaptively adjusting far and near regions.

Keywords: wireless sensor networks, cluster, coordinator, energy-efficient, balanced distribution, exclude distance.

[1] I. F. Akyildiz, W. Su, Y. Sankarasubramaniam, and E. Cayirci, “Wireless sensor networks: a survey,” Computer Networks, Elsevier Science, vol. 38, no. 4, 15 Mar. 2002, pp. 393-422.
[2] H. Viswanathan, C. Baozhi, and D. Pompili, “Research Challenges in Computation, Communication, and Context Awareness for Ubiquitous Healthcare,” IEEE Communications Magazine, vol. 50, no. 5, May. 2012, pp. 92-99.
[3] J. Polastre, R. Szewczyk, D. Culler, and J. Anderson, “Wireless sensor networks for habitat monitoring,” Proc. of the 1st ACM international workshop on Wireless sensor networks and applications, 28 Sept. 2002, pp. 88-97.
[4] W. Heinzelman, A. Chandrakasan, and H. Balakrishnan. “Energy-efficient communication protocols for wireless microsensor networks (LEACH),” Proc. of the 33rd Hawaii International Conference on Systems Science, vol. 8, 4-7 Jan. 2000, pp. 3005-3014.
[5] 鍾惠如，「在無線感測網路中基於時間與空間的叢集首選擇機制節能通訊協定」，碩士論文，國立台灣科技大學，台北 (2009)。
[6] 詹育儒，「在無線感測網路中能量均衡的通訊協定之研究」，碩士論文，國立台灣科技大學，台北 (2011)。
[7] J. Hu, Y. Jin, and L. Dou, “A Time-based Cluster-Head Selection Algorithm for LEACH,” Proc. of IEEE Symposium on Computers and Communications, 6-9 July 2008, pp. 1172 – 1176.
[8] T. Mu, and M. Tang, “An Improved LEACH Protocol for Wireless Sensor Network,” 2010 6th International Conference on Wireless Communications Networking and Mobile Computing (WiCOM), 23-25 Sept. 2010, pp. 1-4.
[9] R. Mehta, A. Pandey, and P. Kapadia, “Reforming clusters using C-LEACH in Wireless Sensor Networks,” International Conference on Computer Communication and Informatics (ICCCI), 10-12 Jan. 2012, pp. 1-4.
[10] R. K. Tripathi, Y. N. Singh, and N. K. Verma, “N-LEACH, a balanced cost cluster-heads selection algorithm for Wireless Sensor Network,” National Conference on Communications (NCC), 3-5 Feb. 2012, pp. 1-5.
[11] H. Xinghua, L. Jian, X. Zhen, and H. Maomao, “Adaptive algorithm of cluster head in wireless sensor network based on LEACH,” IEEE 3rd International Conference on Communication Software and Networks (ICCSN), 27-29 May. 2011, pp. 14-18.
[12] R. Hou, W. Ren, and Y. Zhang, “A Wireless Sensor Network Clustering Algorithm Based on Energy and Distance,” 2009 Second International Workshop on Computer Science and Engineering, 28-30 Oct. 2009, pp. 439-442.
[13] T. Zhong, S. Wang, S. Xu, H. Yu, and D. Xu, “Time Delay based Clustering in Wireless Sensor Networks,” Wireless Communications and Networking Conference, 11-15 Mar. 2007, pp. 3956–3960.
[14] P.-J. Chuang, S.-H. Yang, and C.-S. Lin, “Energy-Efficient Clustering in Wireless Sensor Networks,” Journal of the Chinese Institute of Engineers, vol. 32, no. 7, Oct. 2009, pp. 951-957.
[15] M. J. Handy, M. Haase, and D. Timmermann, “Low energy adaptive clustering hierarchy with deterministic cluster-head selection,” 2002. 4th International Workshop on Mobile and Wireless Communications Network, 2002, pp. 368-372.
[16] D.G. Melese, H. Xiong, and Q. Gao, “Consumed Energy as a Factor for Cluster Head Selection in Wireless Sensor Networks,” 2010 6th International Conference on Wireless Communications Networking and Mobile Computing (WiCOM), 23-25 Sept. 2010, pp. 1-4.
[17] H. Jingde, S. Gang and Y. Chao, “Wireless Sensor Network Optimal Hop Routing Algorithm Study,” ICINIS '08. First International Conference on Intelligent Networks and Intelligent Systems, 1-3 Nov. 2008, pp. 183-186.
[18] C. Wang, Design and Simulation of the Wireless Sensor Network. China excellent Dr. Degree dissertation, University of Electronic Science and Technology of China, 2004.
[19] The Network Simulator - ns-2 http://www.isi.edu/nsnam/ns/
[20] 柯志亨,程戎祥,謝錫堃編著. “計算機網路實驗” 學貫行銷股份有限公司