# Performance Evaluation of VANET Routing Protocols in Madinah City
## 2 Related Works
The performance of DSDV, AODV, Greedy Perimeter Stateless Routing (GPSR) [46], OLSR, and Greedy Perimeter Coordinator Routing (GPCR) [47] routing protocols are evaluated in terms of PDR, end-to-end delay, throughput, and routing overhead by varying the node density. The authors observe that the OLSR protocol outperforms other protocols in terms of PDR and throughput. GPSR and GPCR protocols perform better concerning the routing overhead and end-to-end delay. Additionally, the authors propose a new greedy forwarding technique based on the angle direction, speed variation, density, and distance to the next-hop node to improve the GPSR and GPCR protocols. However, no simulation was conducted based on the proposed technique. Furthermore, the authors did not consider autonomous traffic distribution in their traffic scenarios. [PERSON] et al. [48] evaluate the performance of two communication technologies, including 802.11p and LTE-V, in the V2X scenario. The authors consider a scenario where the vehicles communicate an accident at an intersection. To perform the experiments, the authors deploy two vehicles in a real-world test field, which communicate with each other using 802.11p and LTE-V technologies. The Packet Delivery Ratio (PDR) and latency are selected as two performance metrics. From the results, the authors conclude that 802.11p provides much lower latency compared to LTE-V; however, the PDR of LTE-V is much better. Nevertheless, the study only provides a small-scale deployment and does not provide an extensive comparison between the two technologies. Furthermore, the implementation scenario is oversimplified in this study. The authors of [49] conduct a performance evaluation of routing protocols for VANETs using a simulation system called Cellular Automaton-based VEhicular NETwork (CAVENET). CAVENET generates mobility behavior in one-dimensional cellular automata, and the network is simulated on NS-2. They implemented two reactive routing protocols, AODV and DYMO, and one proactive routing protocol, OSLR. Packet delivery ratio is used as the primary evaluation metric between the protocols. They claim that DYMO is the best routing protocol because of its route maintenance ability. Their simulation is limited as it only considers 30 nodes from a 10 to 90 s simulation time. Further, only two nodes can deliver the majority of the packets, while some cannot deliver any packet at all because of disappearing routes over multi-hop communication, and the PDR is dependent on the number of hops in this simulation, not the routing protocol. [PERSON] et al. [50] perform a comparison study of ad hoc reactive routing protocols for VANETs in urban settings. The routing protocols studied were AODV, DSR, DYMO, and Location-Aided Routing (LAR) [51], and the MAC protocol used was IEEE 802.11p. The performance evaluation was conducted on the ns-2 simulator for the network simulation and BonnMotion for the mobility generator. The number of nodes in the VANET ranged up to a maximum of 175 with increments of 25 vehicles. Performance metrics captured were throughput, end-to-end delay, max. route activity time, number of hops, jitter, and more. Their results show that Dymo and AODV perform best for the jitter metric, Dymo for route activity time, and LAR for the remaining metrics. Their study is limited in that only one distribution of vehicles are used, and they only scale the traffic to 175 nodes.