## 3 Literature Review  
Recently, in the ad hoc networks community, many researchers have proposed a variety of geographic routing strategies in WANET with fixed and dynamic beaconing. Some of these studies are conducted using analytical models; others are built on intelligent approaches [38; 39; 40]. Table 2 shows some of the recent related works. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Routing Protocol** & **Categories** & **Description** & **Advantages** & & **Drawbacks** \\ \hline \multirow{4}{*}{Cluster based} & \multirow{4}{*}{GBDRP, PBSM, LEACH} & The protocol divides network nodes into a number of overlapping or disparate clusters and assigns cluster heads to keep track of cluster membership. & \multirow{4}{*}{Low energy consumption} & \multirow{4}{*}{\(\bullet\)} & Complexity. \\  & & The protocol divides network nodes into a number of overlapping or disparate clusters and assigns cluster heads to keep track of cluster membership. & \multirow{4}{*}{\(\bullet\)} & Low storage consumption & \multirow{4}{*}{\(\bullet\)} & \multirow{4}{*}{\(\bullet\)} \\  & & The protocol divides network nodes into a number of overlapping or disparate clusters and assigns cluster heads to keep track of cluster membership. & \multirow{4}{*}{\(\bullet\)} & Low storage consumption & \multirow{4}{*}{\(\bullet\)} & \multirow{4}{*}{\(\bullet\)} \\ Cluster based & \multirow{2}{*}{GBDRP, PBSM, LEACH} & The protocol divides network nodes into a number of overlapping or disparate clusters and assigns cluster heads to keep track of cluster membership. & \multirow{2}{*}{\(\bullet\)} & Low storage consumption & \multirow{2}{*}{\(\bullet\)} \\ Cluster based & \multirow{2}{*}{GBDRP, PBSM, LEACH} & The protocol divides network nodes into a number of overlapping or disparate clusters and assigns cluster heads to keep track of cluster membership. & \multirow{2}{*}{\(\bullet\)} & Low storage consumption & \multirow{2}{*}{\(\bullet\)} \\ Cluster based & \multirow{2}{*}{GBDRP, PBSM, LEACH} & The protocol divides network nodes into a number of overlapping or disparate clusters and assigns cluster heads to keep track of cluster membership. & \multirow{2}{*}{\(\bullet\)} & Low storage consumption & \multirow{2}{*}{\(\bullet\)} \\ Cluster based & \multirow{2}{*}{GBDRP, PBSM, or disparate LEACH} & The protocol divides network nodes into a number of overlapping or disparate clusters and  
In [38], the authors develop a contention-based adaptive position update (CAPU) scheme to improve the geographic routing performance for VANETs. Two mechanisms are suggested; the first is to update the node position, and the other is to manage the contention beacon. In this scheme, the next-hop selection depends on the difference between an estimated position and the actual position of the next hop; so if the value is greater than a specific threshold, the vehicle node can update its information and send a \"Beacon\" message including the vehicle ID, position, velocity, and direction. Otherwise, a \"Hello\", as a basic message, is sent with only the vehicle ID. However, this approach increases the communication overhead and the chances of collision in the network. On the other hand, in [39], the authors modeled a fuzzy logic dynamic beaconing (FLDB) method to optimize the beaconing transmission time. In the GPSR routing protocol, where the improvement is based on the correlation between neighbor nodes quantity, node mobility speed and beacon interval time using the fuzzy logic technique. [PERSON] et al. [40] introduced an analytical beaconing approach to improve the greedy forwarding strategy of geographic routing and predict the future movement of the nodes each time the nodes broadcast the beacons periodically. The resulting scheme is the GPSR + Predict protocol in VANET. In [41], a directional geographic routing based on a fuzzy logic system, namely FL-DGR, is proposed to improve the road safety and transportation capacity in V2V.