# An Intelligent Fuzzy-Based Routing Protocol for Vehicular Opportunistic Networks
## 4 Evaluation of FCRP
### Simulation in FuzzyC  
The FuzzyC simulation environment was used to model and evaluate the fuzzy-logic-based decision-making framework of the FCRP. It allows precise control over the input parameters--buffer occupancy, angle to destination, and the number of unique connections--enabling detailed testing of the fuzzy rule base and its corresponding outputs. Simulations in FuzzyC focus on validating the correctness of the fuzzy logic implementation, ensuring that the output routing decisions align with the intended design in various network scenarios.  
The simulations in FuzzyC were categorized into scenarios based on high, medium, and low buffer occupancy, as shown in Figure 4(a)-c, respectively. We show how buffer capacity impacts routing decisions in diverse network conditions.  
In the high buffer occupancy scenario (BO = 0.9), depicted in Figure 4(a), the RD values are consistently low, indicating a strong preference for not forwarding messages. This outcome arises because high buffer occupancy signifies that the node's storage is nearly full, leaving limited space for new messages. In such situations, the protocol prioritizes  
Figure 5: Simulation results for FCRP. (**a**) BO = 0.9. (**b**) BO = 0.5. (**c**) BO = 0.1.  
preserving buffer availability to accommodate potentially more critical messages in the future. Even when other parameters suggest forwarding opportunities, the risk of buffer overflow discourages forwarding to maintain overall network efficiency.  
In the medium buffer occupancy scenario (BO = 0.5), as shown in Figure 5b, RD values exhibit more variation depending on the values of AD and UC. When the number of unique connections is low (UC = 0.1), RD values remain below 0.5, indicating a higher likelihood of not forwarding messages. This occurs because the lack of diverse connections reduces the probability of successful delivery, and the protocol avoids unnecessary forwarding to minimize resource wastage. However, for higher UC values (UC \(\geq\) 0.5) and for smaller AD values (AD \(\leq\) 0.5), RD values exceed 0.5, signifying an increased likelihood of forwarding. In these cases, the combination of moderate buffer availability and strong connectivity increases the chances of successful message delivery, making forwarding a favorable decision.  
In the low buffer occupancy scenario (BO = 0.1), depicted in Figure 5c, RD values are generally high, reflecting a strong preference for forwarding messages. The abundance of available buffer space reduces the risk of overflow, enabling nodes to handle more messages without compromising performance. This scenario encourages opportunistic forwarding, especially when AD values are low, suggesting a close alignment with the destination. However, when UC is very low (UC = 0.1 and AD = 0.9), RD values decrease because the limited number of unique connections and the large angle to destination reduces the likelihood of finding suitable forwarders, thereby lowering the delivery probability. This highlights the importance of maintaining a balance between buffer availability and connectivity to ensure effective message dissemination.