Abstract: Narrow Band Internet of Things(NB-IoT) is a Low Power Wide Area Network(LPWAN) technology designed for mMTC scenarios.It can handle large scale low power connections and provide large coverage while providing deep indoor penetration.To explore the performance of NB-IoT in practical applications,this paper introduces its standardization process,technical characteristics,physical layer structure and main signaling process,and compares Control Plane(CP) and User Plane(UP) data transmission modes.On this basis,the main indicators of NB-IoT communication quality,namely,signal intensity at different distances,actual transmission rate at upstream and downstream,PING delay,and penetration performance in semi-closed environment,are tested outdoors to describe the structure and working process of the closed-loop communication system.The BC95NB module based on Huawei Boudica120 chip is used for testing.The results showed that,within a range of about 250 m,the signal strength of NB-IoT is -70 dBm~-80 dBm,the average uplast transmission rate is about 4 kb/s,the average downlink transmission rate is about 13 kb/s~18 kb/s,and the PING delay at different distances is controlled at 350 ms~380 ms.

Key words: Narrow Band Internet of Things(NB-IoT), Low Power Wide Area Network(LPWAN), physical layer structure, signaling procedure, delay, signal quality

摘要： 窄带物联网（NB-IoT）是一种针对mMTC场景设计的低功耗广域网技术，可处理大规模低功耗连接并提供超大覆盖范围，同时具有深度室内穿透性能。为探究NB-IoT在实际应用中的性能表现，介绍其标准化历程、技术特点、物理层结构和主要信令流程，对比控制面和用户面数据传输模式。在此基础上，针对反映NB-IoT通信质量的主要指标进行户外测试，即不同距离下的信号强度、上下行实际传输速率、PING时延以及半封闭环境下的穿透性能，描述闭环通信系统的结构和工作过程。使用基于华为Boudica120芯片的BC95NB模块进行测试，结果表明，在250 m左右的范围内，NB-IoT的信号强度为-70 dBm~-80 dBm，平均上行传输速率约为4 kb/s，平均下行传输速率为13 kb/s~18 kb/s，不同距离下的PING时延控制在350 ms~380 ms。

关键词: 窄带物联网, 低功耗广域网, 物理层结构, 信令流程, 时延, 信号质量

CLC Number: 

• TN929.531