Guest Editorial: Semantic Communications: Transmission Beyond Shannon.

The Shannon paradigm, or conventional communication, primarily focuses on how to accurately and effectively transmit symbols from the transmitter to the receiver. With the development of cellular communication systems, the transmission rate has been improved tens of thousands of times and is gradually approaching the Shannon limit. However, the existing communication paradigm is facing a serious bottleneck as a massive number of devices require wireless connectivity while spectrum resources are limited. In addition, due to the increasing deployment of intelligent loT applications, e.g., human-computer interactions and machine-machine communications, semantic-agnostic communications are no longer ideal. Motivated by this, researchers have dedicated efforts for developing systems to process and exchange semantic information for more efficient communications. In contrast to the Shannon paradigm that focuses on correct reception of the transmitted packet regardless of its meaning, semantic communication is concerned with the issue of how to efficiently transmit and receive the desired meaning of the source content to the destination. By transmitting only the meaning or semantics of the source content, semantic communication holds the promise of making wireless networks significantly more energy-efficient, robust, and sustainable than ever before.