Mentor-Telemachus Bond: Transferring Knowledge in Semantic Communication via Contrastive Learning

Encoder, decoder and knowledge base are three major components for semantic communication. Recent advances have achieved significant progress in the encoder-decoder design. However, there remains a considerable gap in the construction and utilization of knowledge base, which plays important roles in establishing consensus among communication participants through knowledge transferring and sharing. Current knowledge base designs typically involve complex structures, which lead to significant computational overheads and heavy reliance on manually annotated datasets, making it difficult to adapt to existing encoder-decoder models. Hence, without knowledge transferring and sharing within the network results in poor generalization of encoder-decoder. This necessitates model training for specific tasks and datasets, significantly limiting the scalability of semantic communication systems to larger networks. To address these challenges, we propose an innovative Contrastive Representations Learning based Semantic Communication Framework (CRLSC). In CRLSC, the server-side pre-trained large model utilizes large-scale public datasets to construct shared knowledge base. Local-side encoders in terminal devices conduct training guided by shared knowledge base. These trained encoders can then build private knowledge bases from private datasets and fine-tune decoders for specific tasks. This simple and effective approach can facilitate the knowledge transferring across large-scale heterogeneous networks.