# VANET Clustering Based Routing Protocol Suitable for Deserts
## 1 Introduction  
A vehicular _ad hoc_ network (VANET) primarily serves as a mesh network consisting of mobile and fixed nodes. It is a form of mobile _ad hoc_ network (MANET) used to provide communication among the adjacent vehicles and the nearby fixed equipment. It is defined as a network without infrastructure and centralized administration [1; 2; 3]. Intelligent vehicular ad hoc networking (IVANET) provides an intelligent way of using vehicular networking [4]. It targets supporting vehicular safety, traffic monitoring, accident prevention and many other applications. Although VANET is a subclass of MANET having different features from other types of _ad hoc_ networks, such as wireless sensor networks (WSNs) and delay-tolerant networks (DTNs), the nodes in VANETs can be equipped to serve as a host and router at the same time [5]. This special property and capability qualifies VANETs to form and set up a network connection in extraordinary environments, such as deserts, forests, mountains and in natural disaster situations, where ordinary communication infrastructure is lacking. Furthermore, the dynamic topological characteristics enable VANETs either to work as a standalone network or as a part of public networks, such as the Internet, using satellites and other communication links. Recently, economic development and the popularization of automobiles have brought high concern to VANETs. In 2003, the Federal Communications Commission (FCC) developed the Dedicated Short-Range Communications (DSRC) standard for dynamic organizing vehicular networking communication, which provides communications between the on board units (OBUs) of the vehicle and the roadside units (RSUs) in specific locations, as well as supporting particular ITS applications. DSRC operates on radio frequencies in the 5.85 GHz to 5.925 GHz range, which is the standard Industrial,Scientific and Medical (ISM) band. In 2009, the IEEE 802.11 standard was developed to launch a new standard for vehicle communication, named IEEE 802.11p [6; 7; 8; 9; 10; 11]. We noticed that previous researchers generally concentrated on VANETs located in cities or on highways. However, with economic development and from environmental perspectives, people's activities gradually have extended to rugged environments, such as deserts, forest and other unpopulated areas. Taking into account the irregular road conditions and lack of ordinary communication facilities in these environments, safe driving of a vehicle is quite challenging and even fatal. Although satellite and mobile communication can partially solve the problem of information exchange between vehicles, they are rather expensive and have limited bandwidth. Moreover, mobile communication systems covering such extraordinary regions are sometimes technically difficult. Therefore, a VANET is possibly a great alternative solution. In VANETs, topology-based routing protocols use link information that exists in the network to perform packet forwarding. They are divided into proactive and reactive protocols. The reactive one usually opens the route only when it is necessary for a node to communicate with another. It maintains only the routes that are currently in use. Therefore, it reduces the burden in the network. It consists of a route discovery phase in which the query packets are flooded into the network for the path search, and this phase completes when the route is found. The common sorts of reactive routing protocols in V2V communication are Ad hoc On-demand Distance Vector Routing (AODV), Temporally Ordered Routing Algorithm (TORA) and dedicated short-range (DSR) [12; 13]. Another type of V2V routing protocol is cluster-based routing protocols in which a group of nodes identifies themselves to be a part of a cluster, and a node designated as the CH will organize and broadcast the packet to the cluster. Reasonable scalability can be provided for large networks; however, network delays and overhead are incurred when forming clusters in highly mobile VANETs.