This book constitutes the refereed post-conference proceedings of the 12th International Conference on Broadband Communications, Networks, and Systems, Broadnets 2021, which took place in October 2021.

Broadband communications, Networks, and Systems: Theory and Applications.- A Machine Learning-based Elastic Strategy for Operator Parallelism in a Big Data Stream Computing System.- End-to-End Dynamic Pipelining Tuning Strategy for Small Files Transfer.- Containers’ Privacy and Data Protection via Runtime Scanning Methods.- Digital Twin For Cybersecurity: Towards Enhancing Cyber Resilience.- Differential Privacy-based Permissioned Blockchain for Private Data Sharing in Industrial IoT.- Efficient Privacy-Preserving User Matching with Intel SGX.- Developing an Online Examination Timetabling System Using Artificial Bee Colony Algorithm in Higher Education.- A Topology-Aware Scheduling Strategy for Distributed Stream Computing System.- Data Stream Prediction Strategy for Elastic Stream Computing Systems.- Blockchain Enabled Integrity Protection for Bodycam Video.- Road Rage Recognition System Based on Face Detection Emotion.- A Drip Irrigation Remote Control System using 5G-IoT Technology.- Multipath QUIC - Directions of the Improvements.- One New Adaptive Elliptical Weighting Model Combining with the Tikhonov-ffp-norm for image reconstruction.- Calculation and Numerical Simulation of Building Integrated Photovoltaic System Based on Connected Autonomous Vehicle Platoon Control through Multi-Agent Deep Reinforcement Learning.- 5G-enabled Smart Building: Technology and Challenge.- Accurate Estimation on the State-of-Charge of Lithium-ion Battery Packs.- Fire Simulation and Optimial Evaluation Based on BIM Technology.- Discrete Sliding Mode Control of PMSM with Network Transmission.- Smart Medical and Nursing Platform Based on 5G Technology.- Time-domain predictable trajectory planning for autonomous driving based on Internet of Vehicles.- 5G: The Advances in Industry.- Rate-compatible shortened polar codes based on RM code-aided.- Research on wheat impurity image recognition based on convolutional neural network.- Based on Energy Router Energy Management Control Strategyin micro-grid.