Congestion Control by Mobile Core and RAN Coordination in 5G Mobile Network

Large-scale failures in mobile networks cause congestion due to User Equipment (UE) reconnection. Though the 3rd Generation Partnership Project (3GPP) defines congestion control functions in Network Functions (NFs), such as the Access and Mobility Management Function (AMF), the control parameters are expected to be calculated in AMFs with depleted computational resources under congestion conditions. This paper proposes a congestion control scheme based on coordinating the Radio Access Network (RAN) and core networks. In this scheme, the orchestration platform calculates the traffic reduction rate at the base stations based on the statistics of RAN and core networks instead of the AMF during congestion. Simulation results show that the proposed method increases the time to convergence by only 8.9 percent compared to the theoretical limit. The study also discusses the issues to be considered in the 3GPP and O-RAN specifications for implementing the proposed method.