Our society is increasingly dependent on digitization. For example, different types of physical and virtual objects are connected to the Internet of Things, all services are digitized, and the number of connected devices continues to grow, which leads to the exchange of large amounts of data. The current communication network 5G cannot meet the needs of the future. Therefore, the demand for high-speed mobile communications is essential to better prepare for the arrival of new services and emerging applications. Namely, extended reality, holographic communication, sensory internet, human digital twin, smart city and industry, etc. These new use cases are applied in many different areas. For example, health, autonomous transportation, climate, network security, etc. Therefore, the research of the new generation network 6G has begun to bear the limits of 5G and deal with new challenges. This paper conducts a related investigation on the sixth-generation communication network. First, the vision, requirements, and expected application scenarios of the 6G network are introduced. Then, it describes the integration of intelligent architecture and space, air, ground, and sea networks. Subsequently, the most important potential key technologies needed for the future sixth-generation were exposed and analyzed. Finally, the main research activities carried out are introduced.
