Research On Clustering Algorithms For Crossroads In VANETs

In recent years, as the development of economy and the popularization of automobile, the urban traffic safety and congestion issues are growing day by day. For the purpose of providing a more comfortable and safe transportation experience, research on VANETs has caused a great attention all over the world. VANET is a typical application of MANET in terms of vehicle traffic. In VANETs, traffic information is acquired by the sensors equipped on vehicles and exchanged via V2V and V2I.Due to the fast movement of vehicles and the highly dynamic network topology in VANETs, traditional clustering schemes for MANETs can’t be directly applied in VANETs. It is very important to develop an efficient and stable clustering algorithm for VANETs. In this paper, we study the characteristics of VANETs and design two new clustering algorithms based on cluster stability, communication overhead, load balancing and network security.1. LOSC (Low Overhead and Stable Clustering scheme)We propose a novel Low Overhead and Stable Clustering scheme (LOSC) that considers both the stability of clusters and the communication overhead. In LOSC, a Cluster Head Electing in Advance Mechanism (CHEAM) is developed in order to select a new head for "isolated" vehicles that may not belong to a cluster. Based on CHEAM, a cluster maintenance scheme is proposed so as to reduce the number of isolated vehicles and the communication overhead. Numerical results indicate that the cluster stability and communication overhead can be significantly enhanced by our proposed clustering scheme.2. EnLOSC (Enhanced Low Overhead and Stable Clustering scheme)Considered load balancing of both whole network and each cluster based on the multiple metrics, an Enhanced Low Overhead and Stable Clustering scheme (EnLOSC) is presented to ensure the stability and security of clusters and to reduce the communication overhead in this case. Based on LOSC scheme, another metrics are related to the node density and cluster size, which are exploited in the Cluster Merging and Splitting Mechanisms to keep the system load balancing and to improve the communication quality. Furthermore, the proposed Discovery & Elimination Scheme (DES) is to designed to tackle the malicious nodes that may hurt the cluster communication. Accordingly, an enhanced cluster maintenance strategy with multi-metrics and secure scheme is proposed so as to reduce the number of isolated vehicles, keep appropriate loading for each cluster head, and protect the whole link over cluster communication. Numerical results and discussion indicate that the cluster stability, communication overhead, load balance and security can be significantly enhanced by our proposed scheme.Numerical simulation results show that, compared with traditional clustering schemes for VANETs and MANETs, LOSC scheme has great improvements on the performance of both the cluster stability and the network overhead. EnLOSC scheme can not only improve the cluster stability and the network overhead, but also perform well on the load balancing and the avoidance of malicious nodes.