en.Wedoany.com Reported - China Telecom (Research Institute, Shanghai Company, and China Telecom Emergency Company), in collaboration with Beijing University of Posts and Telecommunications and Pengcheng Laboratory, has completed a knowledge base-based cross-modal semantic communication test for high-orbit satellites at the China Telecom Research Institute Beijing campus.

This test leverages the high-orbit real satellite verification capability of China Telecom's cloud-network convergence pilot platform, conducting cross-modal semantic communication verification via the AsiaSat-9 satellite, achieving two core technological breakthroughs. First, by integrating a semantic knowledge base with joint source-channel coding (JSCC) technology, the satellite-ground link transmission efficiency has been improved by more than 3.5 times. This technology reduces the proportion of key frames to approximately 0.5% through efficient and reliable JSCC transmission of key frames and text vector mapping of non-key frames. Specifically, only one frame of video image is transmitted for every six seconds of video, while nearly 200 non-key frames are mapped to text vectors, enabling low-dimensional representation of high-dimensional information. Under the premise of maintaining similar video quality (Frechet distance FID<50), the measured satellite-ground transmission efficiency is 5.5 times higher than the traditional H.264 scheme and 3.5 times higher than the H.265 scheme.

Second, the test has solved the multimodal transmission challenge of semantic communication, improving multimodal transmission quality by over 70%. Through generative semantic recovery based on the semantic knowledge base and cross-modal fusion alignment technology for video and audio, high-quality multimodal transmission over satellite-ground links has been achieved. When using a similar video compression ratio, video quality (FID) is improved by 92% compared to the traditional H.264 scheme and by 70% compared to the H.265 scheme.

China Telecom, Beijing University of Posts and Telecommunications, and Pengcheng Laboratory will deepen collaborative research in the 6G field, jointly promoting innovation, standard setting, and industrial progress in key technologies such as semantic communication.