# A Hybrid RF/FSO Transmission System Based on a Shared Transmitter
## 5 Conclusions  
This paper demonstrates the first prototype of a hybrid RF/FSO transmission system with a shared transmitter and transmission link. The system is based on the design of the dielectric board and the properties of light and millimeter waves, and uses photonics-assisted signal generation to enable the FSO and the RF link to share a single transmitter and communication link. In this system, the RF link is used as a complement to the FSO link, which greatly improves the stability and environmental adaptability of the system and reduces the complexity of such hybrid transmission systems by sharing the transmitter design. Experimental results show that the system can support 50 GBit/s hybrid RF/FSO transmission, satisfying the 20% soft-decision forward error correction (SD-FEC) threshold of 2.4 \(\times\) 10\({}^{-2}\), and can individually support 100 GBaud QPSK and 32 GBaud 16 QAM transmission for the FSO link. The proposed shared transmitter architecture introduces  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Modem Format** & \
\begin{tabular}{c} **RF Link Transmission** \\ **Rate (bit/s)** \\ \end{tabular} &
\begin{tabular}{c} **FSO Link Transmission** \\ **Rate (bit/s)** \\ \end{tabular} \\ \hline QPSK & 50 G & 200 G \\
16 QAM & Invalidate & 128 G \\ \hline \hline \end{tabular}
\end{table}
Table 1: Results of the system performance.  
a novel technical framework for wireless communication in dynamic environments. Its optimized hardware integration provides significant advantages in space and power-constrained scenarios, such as satellite relays and mobile backhaul assisted by unmanned aerial vehicles (UAVs). However, current research is primarily confined to laboratory validation, lacking comprehensive assessment of transmission performance degradation under extreme environmental conditions, including atmospheric turbulence, pointing errors, and adverse weather phenomena such as dense fog or heavy rainfall. Future research will focus on long-distance outdoor field trials to systematically evaluate system performance across diverse atmospheric conditions, facilitating its practical implementation in 5G/6G networks. This hybrid structure has the potential to offer high-speed, long-distance, and reliable communications in all environments for future networks.  
Conceptualization, J.Y. and Q.Z.; methodology, Q.Z. and J.Y.; software, J.L.; validation, Q.Z., J.L. and C.W.; formal analysis: Q.Z., J.C. and X.L.; investigation, Q.Z., J.C. and X.L.; resources, J.Y.; data curation, Q.Z., J.L. and C.W.; writing--original draft preparation, Q.Z.; writing--review and editing, J.Y.; visualization, Q.Z. and J.C.; supervision, J.Y.; project administration, J.Y.; funding acquisition, J.Y. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the National Key R&D Program of China (Grant No. 2023 YFB2905600), the National Natural Science Foundation of China (Nos. 62127802, 62331004, 62305067, U24B20142, U24B20168, and 62427815), and the Key Project of Jiangsu Province of China (No. BE2023001-4).  
Not applicable.  
The raw/processed data required to reproduce these findings cannot be shared at this time, as the data form part of another ongoing study.  
The authors declare no conflicts of interest.