# VANET Clustering Based Routing Protocol Suitable for Deserts
## 2 Related Work
Due to continuous expansion of VANETs' structure, clustering is a popular means of organizing networks in MANETs and VANET. Consequently, clustering routing algorithms attracted many researchers, in favor of its convenience and useful features. Many clustering solutions, including topology-based clustering, mobility-based clustering, identifier neighbor-based clustering, energy-based clustering and weight-based clustering, have been proposed [7; 18; 19; 20; 21; 22]. In urban environments, the integration of VANET with 3G networks was investigated, where a VANET is divided into different clusters according to the movement direction of the vehicle, velocity, signal strength or VANET coverage range. The nearest vehicle to the center of the cluster is dynamically selected as a cluster head (CH). When a cluster member requires external communication, the selection of the gateway is based on the speed of the CH, signal strength and communication connectivity [4]. [PERSON] _et al._[17] presented an analytical design-based simulation of environmentally-aware clustering algorithms for wireless _ad hoc_ networks. The clustering algorithm establishes an adaptive dynamic arrangement that enables multi-mode routing scenarios needed to enhance scalability and robustness. In this method, clustering is based on a criterion that enforces an upper bound on the probability of path failure within the cluster over time. Moreover, [PERSON] _et al._[6] introduced a clustering technique suitable for a VANET environment on highways with the aim of enhancing the stability of the network topology. This technique takes the speed difference a parameter for creating a relatively stable cluster structure. It also developed a new multi-metric algorithm for CHE. One of the popular clustering algorithms is the affinity propagation (AP) algorithm, which has been recently proposed [23]. AP is a distance-based clustering algorithm, which results in the frequent changing of CHs when speed effectively changes. Moreover, AP requires a number of iterative loops that increase the delay time of cluster construction. To adapt the new features of VANET, a modified distributed mobility adaptive clustering algorithm has been presented in [24]. Since this modified algorithm is mobility adaptive, distributed and traffic direction dependent, re-clustering is avoided when the vehicles move in different directions. Some other literature works proposed a cluster-based directional routing protocol (CBDRP) suitable for highway scenarios in which the CH selects another one according to the direction of motion in order to forward packets [14]. In the cluster-based routing protocol (CBRP), VANETs are characterized by high vehicle mobility. Due to high mobility, the VANET topology changes rapidly, resulting in high communication overhead for exchanging new topological information. For more information, the readers are invited to review most of the well-known clustering solutions for VANETs in [15]. Most of the aforementioned algorithms are based on one-hop clustering, which only allows communication among one-hop neighbors. Consequently, the coverage rang is small, and many clusters are formed, which decreases cluster stability. Clustering algorithms are often designed to assure cluster stability, which is essential to reduce the maintenance cost and increase routing efficiency and throughput. In one-hop clustering algorithms, vehicles must identify the aggregate mobility of all \(M\) hops-distant neighbors. Consequently, various extra control messages are produced and broadcast within the network, which ultimately reduces the efficiency of cluster formation. Moreover, the majority of these research works only considered the location or the speed of the vehicles for constructing the clusters, while the direction or the equipment of the vehicles have not been thoroughly considered. These protocols also used various strategies having different limitations and drawbacks when selecting the CH.