From Analog to Digital Semantic Communications: Architectures, Challenges, and Future Directions

Semantic communication (SemCom) aims to achieve an efficient and intelligent communication model by deeply understanding and accurately transmitting the semantics of information, thus surpassing traditional communication. However, analog semantic communication (A-SemCom) systems exhibit significant shortcomings in compatibility and flexibility, making it difficult to adapt to diverse network environments and rapidly changing demands. This has led to the development of digital semantic communication (D-SemCom) systems. In this article, we first compare the architectures of traditional communication, A-SemCom, and D-SemCom systems by analyzing their respective advantages and disadvantages. Subsequently, we propose a novel D-SemCom system that can accurately transmit semantics of the message by overcoming the limitations of analog systems, providing stronger adaptability and flexibility, and meeting the demands for efficient semantic transmissions in complex network environments. Finally, we briefly outline potential avenues for future research in SemCom that include the further development of theoretical frameworks, the enhancement of security mechanisms, and the integration with advanced communication technologies.