Contention-based uplink small data transmission for massive MTC in 5G

In the research of 5th Generation (5G) cellular networks for small data transmission in the massive Machine-Type Communication (mMTC) scenario, contention-based transmission (CBT) returns to sight due to its potential of lower latency and smaller signaling overhead compared to traditional scheduling-based transmission (SBT). However previous works do not give enough research on what the collision and how the collision can impact the performances of the CBT. In order to efficiently transmit small data for mMTC services, we design respective solutions to solve differentiated two collision problems together with improved feedback design to help the system to recover from the collision state with reduced signaling overhead. We also propose systematic evaluation methods for CBT with proper traffic models and metrics definitions. Simulation results show that the proposed schemes outperform relevant existing approaches under various metrics at a reasonable cost.