Advances in wireless communications and applications : smart wireless communications: algorithms and network technologies : proceedings of 5th ICWCA 2021 Joint Power and Channel Allocation for D2D Communication in Cellular Networks Design of Laser Holographic Digital Image Compensation Resource Cloud Storage Platform Research on Librarian Demand Prediction Based on the GM (1 1) model and BP Neural Network Combined Model Offloading Strategy of Computing Tasks in Cooperative Vehicle Infrastructure Systems Analysis and Implementation of Safe Transmission and Cluster Expansion Based on Tomcat Research on Key Technologies of New Generation Vehicle Wireless Network. This book features selected papers presented at the 5th International Conference on Wireless Communications and Applications (ICWCA 2021) held at Hainan University China. The book will focus on the presentation of the newest trends and achievements in the development of intelligent algorithms and network technologies in smart communications with application in underwater communications IoT based marine surface communications as well as state of the art real time precise location technologies Wi Fi Bluetooth locationing array signal processing and many others.