## 4 Modeling and Implementations of Software-Defined Vehicular Networks for V2X
### Modeling and Implementations of SDN for Vehicular Networks
\begin{table}
\begin{tabular}{p{113.8 pt} p{113.8 pt} p{113.8 pt} p{113.8 pt}} \hline \hline
**Description of the Problem** & **System** & **System Analysis** & **Model of the Proposed Architecture** \\ \hline Connectivity loss between vehicles and SDN controller [39] & SDVN & Local SDN controller domains through clustering & Hierarchical placement of SDN controllers decrease connectivity latency between them \\ \hline Routing in mobile cloud [12] & SDN-based routing & Track message overhead between vehicles and controller & Control the overhead of the SDN controller and packet delivery ratio \\ \hline Amount of data transfered for multimedia applications [1] & SDVN & Analyze throughput, end-to-end delay & RSU micro-datacenter, stochastic switching for reconfiguration overhead \\ \hline Heterogeneity of wireless infrastructures and inalterable in protocol [38] & SDVANETs & Abstract heterogeneous multihop switches enabled OpenFlow & Deploy adaptive protocol for heterogeneous multihop routing; mitigate SDN management overhead via status of SDN switches; SDN enabled V2V, V2I and V2N. \\ \hline Efficient resource utilization [11] & Software-defined Cloud/Fog network & SDN supports hybrid mode, Control plane is distributed between SDN controller, BS and RSU & Fog computing concept is adding to provide FSDN \\ \hline Latency control [10] & Software-defined Mobile Edge computing & Software-defined cloud/edge vehicular networking & Latency control mechanisms: radio access steering at the base stations (BS6) \\ \hline Latency control [40] on Multiple core network for autonomous driving vehicle & Software-defined VANET with 5G & Local knowledge of surroundings nodes, SDN controller, Broadcast beacon message & Cellular network integrated with network Model, SDN control eNB infrastructure, RSU controller controls RSU \\ \hline Latency control and cost on cellular network [32] & Software-defined VANET with 5G & Control communication: VANET based, cellular network-based, hybrid-based & Optimize continuous virtual routing mechanism, game equilibrium, two-stage leader-follower game for best decision between vehicle and controller \\ \hline Dynamic resource management [14] & Software-Defined VANETs & Topology of SDN controller, Model of Node in Mininet-WiFi & Extend modeling of node car in mininet-WiFi \\ \hline Control latency communication [13] & Vehicular networking heterogeneity of radio access technologies & Vehicle network architecture for resource management, SDN controller, redesign of existing vehicular networks & Model SDHVNet architecture \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Summary of related works on SDN based vehicular networks grouped according to the modeling and implementation scheme. the edge vehicular network architecture which in turns provide a modeling solution on how to control the communication latency through radio access steering at the base station. The advancement of 5G in the automotive field brings the integration of VANETS and 5G technology to construct 5G software-defined vehicular network with SDN technology as a primary key enabler. The authors in [32; 40] investigated the challenge of communication latency and the cost on multiple core network for the autonomous driving vehicle. The modeling and implementation of [32] provide a systematic analysis based on the control of latency at VANET position, the cellular network- or hybrid-based (VANET and cellular position). The outputs of the system analysis prompt the authors in [32] to model their solution for decreasing communication latency by optimizing southbound communication via both rebating mechanism and the use of game equilibrium associated with the two-stage leader-follower game in order to select best routing paths between vehicle and controller. In [40], the modeling concepts centers on the system analysis based on broadcasting V2V beaconing messages so that the local knowledge of surroundings nodes and their topology are available at the SDN controller.