# Optical Wireless Fronthaul-Enhanced High-Throughput FC-AE-1553 Space Networks
## 5 Simulations, Results, and Discussions
### Weighted Factors' Effects on the HSN
#### 5.4.2 Results and Discussion  
It can be observed in the simulation results (Figure 13) that high-throughput and strong real-time transmissions tended to choose the Li-Fi channel more frequently. The number of transmission services provided by the Li-Fi channel was approximately 20 times that  
\begin{table}
\begin{tabular}{l c c c c} \hline \hline  & \multicolumn{2}{c}{**Pure FC System**} & \multicolumn{2}{c}{**Hybrid System**} \\ \hline  & **Bandwidth/Gbps** & **Proportion/\%** & **Bandwidth/Gbps** & **Proportion/\%** \\ \hline Priority Level 1 & 0.26928 & 7.55\% & 7.1352 & 9.79\% \\ \hline Priority Level 2 & 0.53856 & 15.09\% & 14.4966 & 19.88\% \\ \hline Priority Level 3 & 0.80784 & 22.64\% & 21.4237 & 29.38\% \\ \hline Priority Level 4 & 1.9523 & 54.72\% & 29.8582 & 40.95\% \\ \hline Sum & 3.56798 & 100\% & 72.9137 & 100\% \\ \hline \hline \end{tabular}
\end{table}
Table 4: Bandwidth comparison of different priority levels.  
of the FC for high-throughput transmissions and approximately 4 times that of the FC for high-reliability transmissions. This is due to the following reasons:  
1. The Li-Fi timeline can allocate multiple different bursty traffic transmissions within a small cycle, whereas the FC timeline can only allocate one bursty traffic transmission within a small cycle. This is because Li-Fi uses an end-to-end protocol, where task initiation is determined by the terminal itself, allowing it to fully utilize the remaining time slots within the small cycle. On the other hand, FC-AE-1553 uses a master-slave protocol, where all transmissions need to be initiated through the NC and cannot be initiated by the task requester (the NT). Hence, only one bursty-type transmission is scheduled within the small cycle for the FC.
2. Due to the higher network bandwidth of the Li-Fi channel, the same number of transmissions require less time in the Li-Fi channel, thereby increasing the possibility of allocating more transmissions.
3. The algorithm requires selecting another channel to offload the transmission when one channel has no available time slots for allocation, ensuring that transmissions can be serviced as much as possible.  
The selection of the Li-Fi channel for high-reliability transmissions was significantly lower compared to high-throughput and strong real-time transmissions. This is primarily due to the higher packet-loss rate in the Li-Fi channel compared to the FC. When high reliability is a critical requirement for a transmission, the FC is given priority.  
Figure 13: Performance of different weighted factors.  
Additionally, the network topology in this system consists of a two-level network with relatively simple relationships. In such a setup, prioritizing higher bandwidth and lower latency leads to the selection of the Li-Fi channel. Consequently, the results in the first and second rows of the figure are identical.  
In actual scenarios, transmission requirements for bandwidth, latency, and packet-loss rate are multifaceted factors that vary depending on specific demands. As a result, the corresponding weight coefficients would also vary accordingly.