This book gathers selected papers presented at the 4th International Conference on Wireless Communications and Applications (ICWCA 2020), held at Hainan University, China. The second volume will involve research works aimed at the contemporary applications: emerging wireless/mobile applications, context and location-aware wireless services; wireless telemedicine and e-health services; intelligent transportation systems; RFID technology and application; cognitive radio and sensor-based applications; content distribution in wireless home environment and many others.