Connectivity, Energy and Mobility Driven Clustering Algorithm for Mobile Ad Hoc Networks Fatiha Djemili Tolba University of Haute Alsace – GRTC Colmar, France fatiha.tolba@uha.fr Damien Magoni University Louis Pasteur – LSIIT Strasbourg, France magoni@ieee.org Pascal Lorenz University of Haute Alsace – GRTC Colmar, France lorenz@ieee.org Abstract—In the context of mobile ad hoc networks (MANETs) routing, we propose a clustering algorithm called Connectivity, Energy and Mobility driven Clustering Algorithm (CEMCA). The aim of CEMCA consists in appropriately choosing the cluster head to reduce routing overhead. In order to reduce traffic and energy consumption, the control messages are sent only when needed, according to the speed of the node. Each node has a quality that indicates its suitability as a cluster head. This quality takes into account the node connectivity, battery energy and mobility. These parameters are very important for the stability of the cluster. Simulation experiments are carried out to validate our algorithm in terms of stability of the clusters and their members and the quality of the connectivity. The results are compared to a previous approach called Weight Clustering Algorithm (WCA) and they show that CEMCA is performing better. I. I NTRODUCTION Routing algorithms for ad hoc networks are responsible to establish low-cost and high quality route in rather dynamic environments. Indeed, the clustering algorithm can cooperate with routing algorithm in order to find a better route. This algorithm consists in dividing the network into a set of inter- connected nodes covering the total node population, this set of nodes is called cluster. The clustering algorithm is focused on the reduction of the route discovery overhead and the resources optimization such as battery power, network capacity and bandwidth. Some nodes in the cluster are named cluster heads and are responsible for several tasks among others: formation of cluster and its members and maintenance of the topology of the network. Due to the movement of mobile nodes, the network topology changes frequently. Consequently, the cluster stability will be perturbed and the reconfiguration of cluster head will be necessary. For these reasons, a good clustering algorithm should be stable to the radio motions, that is, should not change cluster configuration drastically and often when a few nodes are moving [1]. The remainder of this paper is organized as follows. Section 2 outlines the previous work proposed for cluster formation and its limitations. Section 3 presents our contribution and de- tails the proposed algorithm. The performance and evaluation of our algorithm are presented in section 4 with simulation results. We conclude the article and we present some future research directions. II. RELATED WORK The concept of clustering in ad hoc networks was treated in several research works. These works can be divided in three major trends of development. The First area of research fo- cused on high connectivity degree [2] [3]. The second focused on Low node identifier (ID) heuristic [4] [5], the possibility to combine these two algorithms was also developed. The last and recent area is the weight of node that takes into account the characteristics of node in the election of cluster head [6] [7] [8] [9] and [10]. In this paper, we propose a new clustering algorithm CEMCA that adapts to the needs of the network and the dynamic nature of nodes. Indeed, CEMCA has the aim to implement a platform usable by the routing algorithms of MANETs in order to facilitate the dynamic setup of the routes. The dissimilarities between CEMCA and other existing work consist in the importance and the equality between the parameters of choice (energy, connectivity and mobility) and in the conservation of both the energy and the connectivity by exploiting the SEMC algorithm [11]. Otherwise, the node with a high mobility or a low reserve of energy are not qualified to contribute to the election of cluster head. In this way, we avoid more cluster head re-elections. III. OUR CONTRIBUTION A. Principle of CEMCA Our aim is the design of an algorithm that selects appropri- ate nodes as cluster heads and creates clusters in a large ad hoc network. The idea of CEMCA is to find a number of cluster heads that ensures the stability of the network topology. The election of the cluster head is based on the combination of several significant metrics such as: the lowest node mobility, the highest node degree, the highest battery energy and the best transmission range. This algorithm is completely distributed and all nodes have the same chance to act as a cluster head. In the following, we explain the main objectives for the choice of each parameter. • Mobility: as we mentioned above, the main characteristic of the ad hoc network is the dynamic topology, so we must adapt the algorithm to support this topology. It is necessary that the cluster head changes as less as possible when it moves. So, we choose as a cluster head the