Analysis of TCP Packet Transmission Characteristics in 5G Networks

Congestion control is an indispensable mechanism for the transmission control protocol (TCP) to provide reliable communication. Although many congestion control algorithms (CCA) have been proposed, traffic volume has increased significantly over the years due to technological advances and the growing number of radio devices, and the networks have grown larger and more complex. Inspired by this, we conduct experiments to re-investigate the performances of CUBIC and BBR in the context of recent 5G cellular networks to reveal interesting RTT fluctuations. These unexpected RTT fluctuations can negatively impact mechanisms that rely on RTT for congestion control. We analyze the causes of this phenomenon, provide insights, and briefly discuss the potential for improving CCA based on our observations.