A Multi-Dimensional Robustness Evaluation Framework for Ultra-Dense IoT Networks in Smart Cities

Abstract

This paper presents a multi-dimensional robustness evaluation framework for ultra-dense Internet of Things (UD-IoT) networks in smart city environments. The framework addresses the need to assess robustness beyond isolated indicators such as latency, throughput, packet loss, or availability by integrating operational continuity (OC), scalable resource efficiency (SRE), network flexibility (NF), and security (SEC) into a unified robustness metric (R). Building on an earlier formulation of the metric, the present study extends its interpretation toward smart city IoT deployments, strengthens the perception layer perspective, and introduces a controlled fifth-generation (5G) connectivity validation procedure. The evaluation is performed in two complementary stages. First, simulation-based analysis is conducted across critical, essential, and basic deployment scenarios to examine the mathematical behavior of the metric under different operational priorities and parameter ranges. Second, a validation setup based on free5GC and UERANSIM is used to transform observable control-plane, user-plane, service-connectivity, and security indicators into comparable robustness components through an explicit normalization and mapping procedure. The results show scenario-dependent robustness degradation across the evaluated smart city IoT conditions, with the strongest degradation in the combined stress scenario where endpoint density, traffic intensity, service recovery stress, and abnormal access conditions occur simultaneously.