叢集化是一項能在車載隨意網路中減少廣播風暴的有效技術。在叢集化技術之下，由稱為叢集領導者的節點負責偵測惡意節點、廣播交通資訊。然而由於VANET高速移動的特性，叢集化也帶來穩定度(stability)議題，即叢集領導者與叢集成員移動模式相差太大，造成連線時間太短。
在這篇論文中，本研究提出一個車載隨意網路中以移動模式為基礎的權重叢集演算法，此方法稱為MPCA，內容包含叢集建立階段與叢集維護階段。在建立階段利用節的位置、速度、加速度計算節點之間相對移動模式，選出可以代表整個叢集移動模式的節點作為叢集領導者；在維護階段利用節點之間移動模式，避免無意義的叢集合併產生。
本研究使用SUMO、MOVE、NS2來做模擬實驗，本研究的方法將與AMACAD、NMCS比較，以節點不同最大速度和不同最大加速度進行實驗。實驗的結果顯示，與現有的AMACAD、NMCS叢集演算法相比，本研究所提出的方法能有效延長叢集領導者與叢集成員連線的時間。

Clustering of vehicles in a VANET can reduce the communication traffic information among vehicles. With an effective clustering algorithm, a cluster leader is responsible for detecting malicious nodes and broadcasting traffic information for the members of the same group. However, due to the high mobility of vehicles and the short linkage time between vehicles, forming stable clusters in a VANET remains a challenging problem. In this paper, we propose a Moving Pattern-based weighted Clustering Algorithm, termed MPCA, for VANETs. The MPCA algorithm consists of two phases: the cluster formation phase and the cluster maintenance phase. In the cluster formation phase, we characterize the relative mobility patterns of vehicles by using their positions, velocities and accelerations, and then select the vehicle whose mobility pattern matches most of those of vehicles in the same cluster as the leader of the cluster. In the cluster maintenance phase, we make use of the mobility between leaders to avoid meaningless coalescing of clusters. We compare the performance of MPCA with those of the AMACAD and NMCS by simulation using SUMO, MOVE and NS2. The experimental results show that MPCA offers longer lifetime for the clusters and extends the linkage time between the cluster members and their corresponding cluster leader.

[1]Y. L. Morgan, “Notes on DSRC & WAVE Standards Suite: Its Architecture, Design, and Characteristics,” IEEE COMMUNICATIONS SURVEYS & TUTORIALS, VOL. 12, NO. 4, FOURTH QUARTER 2010.
[2]Daniel Jiang, and Luca Delgrossi, “IEEE 802.11p: Towards an International Standard for Wireless Access in Vehicular Environments,” in Proc. IEEE Vehicular Technology Conference, pp. 2036-2040,2008 .
[3]Theodore L. Willke, Patcharinee Tientrakool, and Nicholas F. Maxemchuk, “A Survey of Inter-Vehicle Communication Protocols and Their Applications,” IEEE COMMUNICATIONS SURVEYS & TUTORIALS, VOL. 11, NO. 2, SECOND QUARTER 2009 .
[4]S. Panichpapiboon and W. Pattara-atikom, ” A Review of Information Dissemination Protocols for Vehicular Ad Hoc Networks,” IEEE COMMUNICATIONS SURVEYS & TUTORIALS, Nov. 2011.
[5]P. Fan, "Improving Broadcasting Performance by Clustering with Stability for Inter-Vehicle Communication," Proceedings of the 65th IEEE Vehicular Technology Conference (VTC 2007 Spring), Dublin, Ireland, April 2007.
[6]B. Ramakrishnan, R. S. Rajesh, and R. S. Shaji, “CBVANET: A Cluster Based Vehicular Adhoc Network Model for Simple Highway Communication,” Int.J.Advanced Networking and Application, accepted for publication, pp. 755-761, Dec, 2010.
[7]E. Souza, I. Nikolaidis, P. Gburzynski "A New Aggregate Local Mobility (ALM) Clustering Algorithm for VANETs," in Proc IEEE International Conference on Communications, 2010.
[8]Daxin Tian, Yunpeng Wang, Guangquan Lu, Guizhen Yu, “A VANETs Routing Algorithm Based on Euclidean Distance Clustering,” Future Computer and Communication (ICFCC), 2010 2nd International Conference, vol. 1, pp. V1-183 - V1-187, 2010.
[9]G. Wolny, "Modified dmac clustering algorithm for vanets," Systems and Networks Communication, International Conference on, vol. 0, pp. 268-273, 2008.
[10]K. Abboud and W. Zhuang, "Modeling and analysis for emergency messaging delay in vehicular ad hoc networks," in Global Telecommunications Conference, 2009. GLOBECOM 2009. IEEE, pp. 1-6, Nov. 2009
[11]O. Kayis and T. Acarman, "Clustering formation for inter-vehicle communication," Intelligent Transportation Systems Conference, 2007. ITSC 2007. IEEE, pp. 636-641, 30 2007-Oct. 3 2007.
[12]P. Fan, J. G. Haran, J. Dillenburg, and P. C. Nelson. Traffic model for clustering algorithm in vehicular ad-hoc network. In Proceedings of the Consumer Communications and Networking Conference, volume 1, pages 168–172, 2006.
[13]Fan Li and Yu Wang, “Routing in Vehicular Ad Hoc Networks: A Survey,” IEEE Vehicular Technology Magazine, Volume 2, Issue 2, pp.12-22, June 2007.
[14]Sadaf Momeni and M fathy,“Clustering in VANETs”, First IEEE international workshop on nonlinear dynamics and synchronization(INDS'08), KLAGENFURT, AUSTRIA, July 18-19, 2008.
[15]Tiecheng Wang, Gang Wang, “TIBCRPH: Traffic Infrastructure Based Cluster Routing Protocol with Handoff in VANET”, IEEE EXPLORER 2010.
[16]A. Daeinabi, A. G. P. Rahbar, A. Khademzadeh, "VWCA: An efficient clustering algorithm in vehicular ad hoc networks", Journal of Network and Computer Applications, 2010.
[17]W. Chen, R.K. Guha, T.J. Kwon, J. Lee, and Y.Y. Hsu. "A survey and challenges in routing and data dissemination in vehicular ad hoc networks". In IEEE Int. Conf. on Vehicular Electronics and Safety, Columbus, USA, Sept. 22-24, 2008.
[18]S. Yousefi, M. S. Mousavi, and M. Fathy, "Vehicular Ad Hoc Networks (VANETs): Challenges and Perspectives," Proceedings of the 6th IEEE ITS Telecom., China, pp. 761-766, Jun. 2006.
[19]N. Maslekar, M. Boussedjra, J. Mouzna, H. Labiod, “A stable clustering algorithm for efficiency applications in VANETs,” in: Wireless Communications and Mobile Computing Conference (IWCMC), IEEE 7th International, pp. 1188–1193, 2011.
[20]Mohammad S. Almalag and Michele C. Weigle. Using Traffic Flow for Cluster Formation in Vehicular Ad-hoc Networks. In Proceedings of the Workshop On User Mobility and VEhicular Networks (ON-MOVE), Denver, CO, October 2010.
[21]Slawomir Kuklinski and Grzegorz Wolny, “ Density Based Clustering algorithm for Vehicular Ad-Hoc Networks,” International Journal of Internet Protocol Technology, Volume 4 Issue 3, pp. 1-6, Sept. 2009..
[22]Z. Wang, L. Liu, M.C. Zhou, and N. Ansari, "A Position-Based Clustering Technique for Ad Hoc Intervehicle Communication," IEEE Transactions on Systems, Man, and Cybernetics, Part C: Applications and Reviews, Vol. 38, No. 2, pp. 201-208, March 2008.
[23]Mildred M. Caballeros Morales, Choong Seon Hong, Young-Cheol Bang: An Adaptable Mobility-Aware Clustering Algorithm in vehicular networks. , PP. 1-6, APNOMS 2011.
[24]P. Basu, N. Khan, and T. D. C. Little, “A Mobility Based Metric for Clustering in Mobile Ad Hoc Networks,” in Proc. IEEE ICDCSW’01, pp. 413–18, Apr. 2001.
[25]Zhenxia Zhang, Azzedine Boukerche, Richard W. Pazzi, “A novel multi-hop clustering scheme for vehicular ad-hoc networks,” in Proceedings of the ACM Workshop on MOBIWAC, New York, NY, USA, pp. 19-26, 2011.
[26]Sin, H.G., “Field Evaluation Methodology for quantifying Network-Wide Efficiency,Energy, Emission, and Safety Impacts of Operational-Level Transportation Projects,” Ph.D. Dissertation. School of Civil and Environmental Engineering, Virginia Polytechnic Institute and State University, Virginia, 2001.
[27]M. Chatterjee, S. K. Das, and D. Turgut, “WCA: A weighted clustering algorithm for mobile ad hoc networks,” Journal of Cluster Computing, No. 5, pp. 193-204, 2002.
[28]W. Su, S.J. Lee, and M. Gerla, “Mobility Prediction and Routing in Ad Hoc Wireless Networks, International Journal of Network Management, vol. 11, no. 1, pp. 3-30, 2001.
[29]MOVE (Mobility model generator for VEhicular networks). http://lens1.csie.ncku.edu.tw/MOVE/index.htm
[30]SUMO Simulation of Urban MObility. http://sumo.sourceforge.net
[31] The Network Simulator ns2. http://www.isi.edu/nsnam/ns
[32]B. Ramakrishnan, Dr. R. S. Rajesh and R. S. Shaji, "Performance Analysis of 802.11 and 802.11p in Cluster Based Simple Highway Model," International Journal of Computer Science and Information Technologies, Vol. 1 (5), PP. 420-426, 2010.