Semantic communications. Theories, technologies and applications

The last seventy years have witnessed the transition of communication from Shannon's theoretical concept to current high-efficiency practical systems. With respect to Shannon information theory, to fulfill the high-bandwidth utilization, any further increase in the data rate requires a significant augmentation in the received signal power unless the bandwidth is extended in proportion to the incremental data rate. Although many such technologies have achieved tremendous success in today's communication systems, they also lead to severe high-frequency coverage costs, complicated signal processing, high energy consumption, etc. Together with extraordinary promises, naively increasing channel capacity cannot address all communication problems, especially in future intelligent eras. It is the very time for radical rethinking of classical communication mechanisms.