This book gathers selected papers presented at the 4th International Conference on Wireless Communications and Applications (ICWCA 2020), held at Hainan University, China. The first volume of the proceedings will focus on the newest methods and algorithms in smart wireless communications in the areas of multimedia communications over wireless; smart antenna and space-time signal processing; antenna, wireless propagation, and channel modeling; OFDM and multi-carrier techniques; localization and navigation techniques; software-defined networking (SDN) and network function virtualization (NFV); knowledge-defined networking (KDN) and the applications of artificial intelligence (AI) in future networks; future data-center networks; resource allocation and orchestration in future networks and many others.