SANDRAN: A Modular System-Level Simulator for Real-Time Evaluation of 6G Radio Access Networks

Abstract

System-level simulation is a key tool for the design and evaluation of 6G radio access networks, especially when heterogeneous scenarios and diverse radio-access technologies must be assessed under a common evaluation framework. However, existing full-stack simulators often couple protocol implementations and simulation logic, making the development and comparison of new algorithms and network architectures cumbersome. This paper presents a modular system-level simulator for the performance evaluation of 6G radio access networks. The proposed framework integrates the fundamental components governing radio-access performance, including propagation, cell association, inter-cell Signal-to-Interference-plus-Noise Ratio (SINR), modulation and coding adaptation, traffic generation, and resource scheduling, while providing the flexibility required to rapidly instantiate and evaluate different networking scenarios. The simulator supports a broad range of emerging 6G use cases, including Urban Air Mobility (UAM), O-RAN architectures, multi-connectivity, and other advanced radio-access paradigms. Latency, throughput, Block Error Rate (BLER), and outage are treated as real-time Quality of Service (QoS) metrics, allowing latency-constrained services to be evaluated directly from per-user statistics. A representative 6G case study demonstrates the effectiveness of the proposed framework in assessing the impact of radio-resource management and interference on network performance. The snapshot-based simulation approach enables fast and scalable performance evaluation, complementing high-fidelity event-driven simulators for rapid algorithm development, design-space exploration, and lightweight network digital-twin applications.