Network Simulations for Non-Terrestrial Networks: Overcoming Deployment Challenges and Advancing System Optimization

Non-Terrestrial Networks (NTNs) including satellites, Unmanned Aerial Vehicles (UAVs), and High Altitude Platforms (HAPS), are increasingly seen as essential for extending coverage and enhancing reliability in modern communication systems, particularly in the context of the growing demand driven by IoT and V2X applications. However, their deployment faces significant technical challenges, such as path loss, atmospheric conditions, and Doppler effects. To address these issues, standardization bodies and academic researchers are actively investigating novel architectures to optimize NTN communications. However, the high costs associated with satellite launches, infrastructure deployment, and large-scale testing make physical experimentation infeasible in most cases. Moreover, real-world tests lack the flexibility to assess a wide range of configurations under controlled conditions. To address these limitations, network simulations have become an essential tool for evaluating NTN performance, testing new protocols, and optimizing system parameters before deployment. This paper presents a novel NS3-based simulation tool that integrates advanced energy and channel models from 3GPP TR 38.811, accounting for diverse environmental settings (dense urban, suburban, rural) and atmospheric effects to ensure accurate SNR computations. The simulator also features a sophisticated mobility model for representing satellite constellations and ground user mobility, including pedestrians, vehicles, and airplanes. A case study is presented, demonstrating the simulator’s application in the development and performance evaluation of an energy-aware satellite handover strategy. This work highlights the critical role of simulation tools in advancing NTN technologies and supporting the development of next-generation communication standards.