Clustering concept and QoS constraints in dense mobile ad hoc networks

In mobile ad hoc networks, many routing protocols use broadcast mechanism to find route whereas one of the wireless network challenges is the bandwidth optimisation. This mechanism increases the control overhead and consumes bandwidth and energy. The overhead penalty increases with the density and the network size. Thus is important to reduce the number of participants in that mechanism. One of the used solutions consists of determining clusterheads nodes. In this paper, we propose an algorithm for choosing clusterheads (SRCAC). Each node in the network broadcasts its ID, status and election index. The election index is a combination of potentiality index and stability index. The potentiality index is a linear combination of the mobile resources like processor speed, RAM and ROM memories. The stability index shows the cluster life time. Then, we use SRCAC to build clusters. We suggest a backup clusterheadwhich could become the principal clusterhead when the first breaks down. To improve the reliability of interclusters communications, we build a mesh between gateway and distributed gateway. Moreover, we introduce Quality of Service (QoS) constraints in the ODMRP (On DemandMulticast Routing Protocol) mobility prediction version. We compare our algorithm with the WCA (Weighted Clustering Algorithm for Mobile Ad hoc Networks) algorithm in terms of clusterheads. The results show that our algorithm performs better than the WCA and, finally, the deterioration of the performances imposed by the constraints on this ODMRP version is unimportant.