Semantic-Enhanced Downlink LEO Satellite Communication System With OTFS Modulation
Wenbin Chen, Songyan Li, Cheng Ju, Dongdong Wang, Jin Li, Danshi Wang
Abstract
As an important technology for achieving 6G global access, low Earth orbit satellite (LEO-Sat) communication still encounters the challenges of scarce spectrum resources and the serious Doppler effect. To improve the performance of image transmission in the LEO-Sat system, this paper proposes an approach that combines semantic communication with orthogonal time-frequency space (OTFS) modulation to effectively mitigate the severe Doppler effect and enhance transmission efficiency. The NTN-TDL-D model in 3GPP is employed to simulate satellite channels and introduce noise into the training process of the semantic model. The performance of semantic-enhanced and traditional LEO-Sat systems is further evaluated under various conditions. Ultimately, simulation results demonstrate that the proposed solution achieves a minimum 6dB signal-to-noise ratio gain, reduces communication overhead by 50%, and ensures higher spectrum utilization efficiency in high-speed scenarios compared to existing solutions.