To initiate mobile communication, user devices must undergo authentication, authorization, and session setup, all handled by the mobile core network (MCN). Thus, an MCN outage can critically disrupt these procedures and degrade the user quality of experience (QoE). To address this, we propose the soft guarantee MCN (SG-MCN), an architecture inspired by the soft guarantee behavior from three-tier web systems. This technique achieves quick responses by bypassing bottleneck-prone datatier processing and utilizing information from the application and presentation tiers. SG-MCN adopts this behavior to enhance resiliency while maintaining compliance with 3GPP security standards. Specifically, it verifies devices in a presentation-tierequivalent function using a device-side-encrypted identifier and a precomputed identifier from the data tier. Mutual authentication is then performed using a precomputed authentication vector. Authorization and session setup are speculatively performed using enriched per-device contexts retrieved in previous procedures. Emulation results demonstrate that the SG-MCN sustains QoE scores close to those of the MCN under normal conditions, even in normal conditions with additional processing overhead and in outage conditions where data-tier functions are unavailable.

In mobile networks, network performance can be severely degraded by a signaling storm, a phenomenon characterized by control plane (C-plane) congestion due to excessive signaling messages. This paper identifies congestion of inter-site links and overload of a specific NF instance as factors leading to a signaling storm. To address these problems, we propose a combined placement and routing algorithm approach. Firstly, our joint placement and routing algorithms perform geographically distributed deployment of C-plane NF instances according to the fluctuating mobility patterns of each user equipment (UE). Secondly, our routing algorithm identifies an appropriate C-plane NF instance to manage each UE, considering both the utilization rate and the number of contexts possessed by each NF instance. Extensive simulation evaluations demonstrate that our proposed methods significantly reduce inter-site signaling messages compared to existing placement scenarios. Furthermore, the dispersion of C-plane NF instances’ utilization rate is reduced, enhancing network performance and efficiency.

With the 5th Generation mobile communication system (5G), ultrahigh capacity and ultralow latency communication are realized. Toward the next generation, i.e., 6th Generation mobile communication system (6G), even higher capacity or lower latency is needed. This paper focuses on the significant processing delay in the control plane when a User Equipment (UE) state transitions from Radio Resource Control (RRC)-IDLE to RRC-CONNECTED. On the transition, many interactions exist between a UE and a Base Station (BS) or a mobile core system, such as a connection establishment or context data exchange. We propose eliminating the effect of processing delay by introducing an Always-Connected Enablement BS (ACE-BS). We conduct experiments in an actual local 5G environment with UEs, BSs, and mobile cores, demonstrating the low latency communication by using the ACE-BS.