This proceedings constitutes the refereed proceedings of the 16th International Conference on Communications and Networking, China Com 2021, held in November 2021. Due to COVID-19 pandemic the conference was held virtually. The 47 full papers and 5 workshop papers presented were carefully selected from 130 submissions. The papers are organized in topical sections on Scheduling and Transmission Optimization in Edge Computing; Complex System Optimization in Edge Computing; Network Communication Enhancement; Signal Processing and Communication Optimization; Deep Learning and Vehicular Communication; Edge Computing and Deep Learning; Finite Blocklength and Distributed Machine Learning; Deep Learning and Network Performance Optimization; Edge Computing and Reinforcement Learning.