# Enhancing Heterogeneous Communication for Foggy Highways Using Vehicular Platoons and SDN
## 4 Performance Evaluation  
We evaluated the proposed scheme by optimizing the routing path in foggy weather on a 10 km highway by introducing platoons that move according to controller instructions and adjust their speed based on current visibility conditions. Five distinct platoons of vehicles were deployed along the highway. The speed of five cars in a platoon was varied, ranging from 5 to 10 m/s, with vehicles maintaining a minimum distance of 20 m and a maximum intra-platoon distance of 200 m. Different speeds were assigned to each platoon in a range of 5 to 20 m/s. The platoons changed their lane when the inter-platoon distance was less than 20 m. These platoons and vehicles were assigned unique identifiers to distinguish them. As our objective was to find an optimal routing path from the source platoon to the destination platoon on a foggy highway, we considered \(CR_{max}\) = 200 m for V2V communication and 500 m for V2I (vehicle to LC) communication. There were one MC, 10 RSUs, and five LCs in this topology, and \(L_{s}\) = 16 bytes, \(R_{MC,i}\) = 10 Mbps, and \(\alpha\) = 2/3 [19]. For V2V and V2I communication, DSRC was used operating in a 5.9 GHz frequency band. Direct, low-latency communication between vehicles was made possible by DSRC, which supports critical messages and is immune to fog [8, 20]. The communication model between the LCs and MC used the LTE cellular model, providing wide coverage for efficient data exchange, thereby ensuring reliable coordination between them.  
In a highway scenario, both small-scale and large-scale fading can affect the radio channel for V2V and V2I communications. It is common for there to be no line of sight between a transmitter and a receiver. The network performance may be affected by faded signals as the receiver signal is made up of various multipath components [21]. The Nakagami distribution is used to describe the statistical characteristics of both small-scale and large-scale fading, which is why we chose the Nakagami model for radio channel characteristics. In MATLAB-22b, a real-world scenario of highway road and vehicles was created. The platoons followed a straight path on the highway. OpenFlow [22] was chosen as the underlying protocol because it is widely accepted and flexible in routing strategies. The message passing mechanisms in MATLAB have been modified to replicate OpenFlow message exchanges. The performance was evaluated to assess the effectiveness of the proposed scheme by considering the following parameters. In order to compare our proposed cases, we considered [10, 11] as reference schemes. The former considered the truck platooning system to instruct trucks about road conditions by providing beacon safety messages during clear weather, and the latter considered an intelligent driver model to handle visibility (minimum of 30 m) on a ring road. We simulated this scheme [11] to determine the following metrics to achieve a perfect match with our scheme. Furthermore, as mentioned in section I, there is no scheme in the literature that addresses SDVN in foggy weather, so we selected these two schemes that have a partial match to our proposed scheme.  
* Packet delivery ratio (PDR)
* Average end-to-end delay
* Average number of hops
* Routing overhead ratio (RoR)