The future communication system will be a ubiquitous communication system integrating air, space, ground, and sea, which can not only effectively improve the key performance of the network, but also break the geographical limitation, realize global seamless three-dimensional coverage, support users' access anytime and anywhere, and narrow the digital divide between different regions. In addition, the emergence of new services and scenarios (such as immersive experiences, unmanned services, digital twins, etc.) and their increasingly demanding key performance indicators require ubiquitous communication systems to integrate communication, information, big data, AI, control, and other technologies.