Knowledge Base Enabled Semantic Communication: A Generative Perspective

TL;DR

The paper addresses the need for efficient semantic communication in 6G by introducing a generative semantic knowledge base (KB) framework. It decomposes the KB into three sub-KBs—source KB, task KB, and channel KB—and describes how large generative AI models can construct and operate these KBs to enable generative encoding/decoding and KB-guided transmission. A case study demonstrates that a KB-driven generative scheme outperforms traditional JPEG+LDPC and Deep JSCC, particularly at low SNR, by leveraging semantic metalets and residual generation. The work outlines future directions in consistency, multi-agent KB updates, and privacy/security to advance practical deployment of environment-aware, cross-modal semantic communications for 6G networks.

Abstract

Semantic communication is widely touted as a key technology for propelling the sixth-generation (6G) wireless networks. However, providing effective semantic representation is quite challenging in practice. To address this issue, this article takes a crack at exploiting semantic knowledge base (KB) to usher in a new era of generative semantic communication. Via semantic KB, source messages can be characterized in low-dimensional subspaces without compromising their desired meanings, thus significantly enhancing the communication efficiency. The fundamental principle of semantic KB is first introduced, and a generative semantic communication architecture is developed by presenting three sub-KBs, namely source, task, and channel KBs. Then, the detailed construction approaches for each sub-KB are described, followed by their utilization in terms of semantic coding and transmission. A case study is also provided to showcase the superiority of generative semantic communication over conventional syntactic communication and classical semantic communication. In a nutshell, this article establishes a scientific foundation for the exciting uncharted frontier of generative semantic communication.

Figures (4)

• Figure 1: A comparison of syntactic coding, semantic coding without KB, and semantic coding with KB.
• Figure 2: Generic schematic diagram of a generative semantic communication system.
• Figure 3: Conceptual structures of the three sub-KBs.
• Figure 4: PSNR comparison and image visualization for different schemes.