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, thereby supporting cloudified, flexible, minimalist, intelligent/secure endogenous and open networks, and providing the distributed, cross-domain, flexible and agile capability. Although ubiquitous communication systems have been discussed in both academia and industry in recent years, the research on its network architectures, theories, key technologies, and challenges is still in its infancy. For this reason, the School of Telecommunications Engineering of Xidian University initiates the International Conference on Ubiquitous Communication (Ucom), aiming to establish a broad communication platform to invite world-renowned experts and scholars to propose innovative insights, methodologies, architectures, theories, modeling approaches, and industry development visions for ubiquitous communication systems. This conference will result in high-quality academic papers to jointly promote the development of ubiquitous communication systems. The technical scope of the conference includes, but is not limited to, communication theory and techniques, signal processing and image processing, networking, optical communication, machine learning and optimization for wireless systems, and emerging technologies, standards and applications in the field of ubiquitous communications. All teaching, research staff, and students engaged in the new theory of communication technology and its applications are welcome to attend.