The first-level discipline of information and communication engineering is divided into two disciplines: communication and information system and signal and information processing. Both disciplines are based on signals, but signal and information processing pays more attention to the bottom layer and considers more local problems. Therefore, there are more technologies to learn, mainly signal and image processing, and more contact with hardware, especially the foundation of studying complex objects such as radar! Communication and information systems consider more overall problems and contact software. At present, the hot topics mainly focus on mobile communication and optical fiber communication.