Although the nodes in the wireless ad hoc network are designed to have similar function and equal status, there still exist some critical nodes that may cause the partition of network topology due to the mobility of nodes and the harsh environment. In this paper, we propose that such critical nodes can be detected by neighbor degree and loop degree. Using this method, the critical nodes can be identified quickly from paths without multihop paths by clustering coefficient. Finally, this paper uses weighted coupling method of node degree and clustering coefficient to analyze the importance of critical nodes, which is helpful to sort and protect the critical nodes.
Wireless ad hoc network, Critical nodes, Node degree, Clustering coefficient
 X. Liu, Z. Li, P. Yang, Information-centric mobile ad hoc networks and content routing: A survey, 2016, Ad Hoc Networks, vol. 58, pp. 255-268.
 D.S. Zhang, J.P.G. Sterbenz, Analysis of critical node attacks in mobile ad hoc networks, 2015, International Workshop on Reliable Networks Design and Modeling, Barcelona, Munich, Germany, pp. 171-178.
 D. STÉPHANE, A silent self-stabilizing algorithm for finding cut-nodes and bridges, 2005, Parallel Processing Letters, vol. 15, no. 01-02, pp. 183-198.
 T.H. Kim, D. Tipper, P. Krishnamurthy, Improving the topological resilience of mobile ad hoc networks, 2009, International Workshop on Design of Reliable Communication Networks, Washington, DC, USA, pp. 191-197.
 H. Noureddine, Q. Ni, G. Min, A new link lifetime estimation method for greedy and contention-based routing in mobile ad hoc networks, 2014, Telecommunication Systems, vol. 55, no. 3, pp. 421-433.
 Y. Sha, N. Li, B. Wu, Research on critical nodes detection algorithm based on node stability prediction in ad hoc network, 2012, Computer Science, vol. 39, no. 7, pp. 87-91.
 J.D. Li, Y. Tian, M. Sheng, Partition detection for large scale ad hoc networks, 2008, Journal on Communications, vol. 29, no. 9, pp. 54-61.
 J.G. Liu, Z.M. Ren, Q. Guo, Node importance ranking of complex networks, 2013, Acta Physica Sinica, vol. 62, no. 17, p. 178901.
 X.L. Ren, L.Y. Lv, Review of ranking nodes in complex networks, 2014, Chinese Science Bulletin, vol. 59, no. 13, p. 1175.
 D.S. Zhang, J.P.G. Sterbenz, Measuring the resilience of mobile ad hoc networks with human walk patterns, 2015, International Workshop on Reliable Networks Design and Modeling, Barcelona, Munich, Germany, pp. 161-168.