Narrowband Internet of Things (NB-IoT) is a promising technology designated specially by the 3rd Generation Partnership Project (3GPP) to meet the growing demand of massive machine-type communications (mMTC). More and more industrial companies choose NB-IoT network as the solution to mMTC due to its unique design and technical specification released by 3GPP. In order to evaluate the performance of NB-IoT network, we design a system-level simulation for NB-IoT network in this paper. In particular, the structure of system-level simulator are divided into four parts, i.e., initialization, pre-generation, main simulation loop and post-processing. Moreover, three key techniques are developed in the implementation of NB-IoT network by accounting for enhanced coverage, massive connection and low-power consumption. Simulation results demonstrate the cumulative distribution function curves of signal-to-interference-and-noise ratio are fully compliant with industrial standard, and the performance of throughput explains how NB-IoT network realize massive connection at the cost of data rate.

翻译：窄带物联网（NB-IoT）是由第三代合作伙伴计划（3GPP）专门设计以满足海量机器类通信（mMTC）增长需求的前沿技术。凭借3GPP发布的独特设计和技术规范，越来越多的工业企业选择NB-IoT网络作为mMTC解决方案。为评估NB-IoT网络的性能，本文设计了一套NB-IoT系统级仿真方案。该仿真器结构划分为四个部分：初始化、预生成、主仿真循环和后处理。此外，在NB-IoT网络实现中开发了三大关键技术，以兼顾增强覆盖、海量连接与低功耗特性。仿真结果表明，信干噪比的累积分布函数曲线完全符合工业标准，吞吐量性能则阐释了NB-IoT网络如何以数据速率为代价实现海量连接。