# Research on Tbps and Kilometer-Range Transmission of Terahertz Signals
## 5 Conclusions  
This paper summarizes our advances in long-distance terahertz communication, systematically tackling the 'dual attenuation dilemma' of path loss and atmospheric attenuation through co-designed photonic-electronic architectures and adaptive signal processing. By developing hybrid THz generation schemes--including photonically assisted probabilistic 64 QAM achieving a record 1.0488 Tbps throughput in the 330-500 GHz band--we established seamless FiWi integration capable of bridging fiber and Tbps wireless links. To overcome severe path loss exceeding 120 dB/km, our multi-pronged approach syn  
Figure 16: Simulation results of high-sensitivity SIMO satellite–ground communication architecture: (**a**) time vs. communication distance; (**b**) time vs. received power; (**c**) BER before diversity combining; (**d**) BER after diversity combining; (**e**) SNR before diversity combining; (**f**) SNR after diversity combining; (**g**) SNR under clear sky conditions; (**h**) SNR under fog attenuation; (**i**) SNR under rain attenuation.  
ergizes high-gain antenna-lens systems, InP semiconductor amplifiers enabling the first 3 km fog-penetrating link at 312 GHz, and modulation-robust DSP algorithms like MIMO-VNE. These innovations culminated in a landmark 30.2 km D-band transmission with 543.6 Gbps\(\cdot\)kn capacity-distance product, representing an 8-fold improvement over prior records. For dynamic channel adaptability, the proposed MIMO-MRC architecture demonstrated 9 dB diversity gain through polarization-multiplexed transmission and coherent combining, while real-time VQ-VAE-based processing maintained a BER below 3.4 \(\times\) 10\({}^{-2}\) under orbital dynamics and weather impairments. Critically, our satellite-ground simulation validated THz viability for space-terrestrial integration, achieving 100 Gbps over 36,000 km at 300 GHz with MRC diversity reducing the BER from the order of 10\({}^{-2}\) to 10\({}^{-3}\). Collectively, these breakthroughs provide a scalable framework for 6G integrated SAG networks, delivering three foundational capabilities: terabit-per second-capable ultra-high-capacity backhaul via fiber-THz convergence; robust long-haul connectivity across distances reaching 30 km over land and extending to 36,000 km for space links, enabled through photonic-electronic co-optimization; and dynamic channel resilience enabled by intelligent MIMO-DSP adaptation. Future work will extend to non-line-of-sight scenarios using reconfigurable intelligent surfaces and standardization pathways for THz-enabled 6G deployments.  
Conceptualization, J.Y.; Methodology, J.Y.; Writing original draft, J.C.; Data curation, J.C.; Formal analysis, J.C.; Writing review and editing, J.Y. and J.C.; Supervision, J.Y.; Project administration, J.Y. All authors have read and agreed to the published version of the manuscript.  
This work was supported by the National Key R&D Program of China (2024 YEE0200202), National Natural Science Foundation of China (No. 62127802, 62331004, 62305067, U24B20142, U24B20168, and 62427815), and Key Project of Jiangsu Province of China (No. BE2023001-4).  
The data presented in this study is available on request from the corresponding author. The data is not publicly available due to privacy restrictions.  
The authors sincerely thank colleagues from the Key Laboratory for Information Science of Electromagnetic Waves (MoE), Fudan University, and the Purple Mountain Laboratory for their invaluable contributions to this research.  
The authors declare no conflicts of interest.