Narrowband Internet of Things (NB-IoT) is a technology specifically designated by the 3rd Generation Partnership Project (3GPP) to meet the explosive demand for massive machine-type communications (mMTC), and it is evolving to RedCap. Industrial companies have increasingly adopted NB-IoT as the solution for mMTC due to its lightweight design and comprehensive technical specifications released by 3GPP. This paper presents a system-level simulation framework for NB-IoT networks to evaluate their performance. The system-level simulator is structured into four parts: initialization, pre-generation, main simulation loop, and post-processing. Additionally, three essential features are investigated to enhance coverage, support massive connections, and ensure low power consumption, respectively. Simulation results demonstrate that the cumulative distribution function curves of the signal-to-interference-and-noise ratio fully comply with industrial standards. Furthermore, the throughput performance explains how NB-IoT networks realize massive connections at the cost of data rate. This work highlights its practical utility and paves the way for developing NB-IoT networks.

翻译：窄带物联网（NB-IoT）是第三代合作伙伴计划（3GPP）为满足海量机器类通信（mMTC）爆发式需求而专门制定的技术，并正在向轻量化（RedCap）方向演进。由于其轻量化设计及3GPP发布的完整技术规范，工业界已越来越多地采用NB-IoT作为mMTC解决方案。本文提出了一种用于评估NB-IoT网络性能的系统级仿真框架。该仿真器在结构上分为四个部分：初始化、预生成、主仿真循环和后处理。此外，本文研究了三个关键特性以分别增强覆盖范围、支持海量连接并确保低功耗。仿真结果表明，信号与干扰加噪声比的累积分布函数曲线完全符合工业标准。吞吐量性能的评估进一步阐释了NB-IoT网络如何以数据速率为代价实现海量连接。本工作凸显了该框架的实际应用价值，并为NB-IoT网络的开发铺平了道路。