This book features selected papers presented at the 3rd International Conference on Wireless Communications and Applications (ICWCA 2019), held at Hainan University, China. Focusing on applications of the latest smart theories and approaches, and recent advances in the field, it covers topics such as OFDM and multi-carrier techniques; smart antenna and space-time signal processing; MIMO, multi-user MIMO, and massive MIMO; modulation, coding, and diversity techniques; dynamic spectrum access and cognitive radio; interference management and radio resource allocation; equalization techniques; synchronization, estimation, and detection techniques; and wireless multiple access (e.g. CDMA, OFDMA, NOMA, ).