根據愛立信發布的行動趨勢報告指出，由於蜂窩式物聯網(Internet of Things, IoT)的大規模部署，物聯裝置將在2026年將達到35億。滿足物聯網廣大市場的新訴求，低功耗廣域覆蓋的新技術日趨被重視。在眾多被看好的技術中，窄帶物聯網(NarrowBand Internet of Things, NB-IoT)技術於3GPP的Release-13標準中提出，既可滿足低功耗且可達到廣域覆蓋的優勢，再加上其可覆用GSM或LTE時頻資源得以降低裝置建布的複雜與成本的優點使各家電信業者在近幾年紛紛積極推出相關的通訊方案。有鑑於該技術的重要性，本篇論文將回顧過去幾年有關窄帶物聯網的相關文獻和3GPP標準，討論其演進與重要性。並詳細介紹通訊網路中的一項重要的技術，為用戶初始接入網路的隨機接入過程，並且建立馬可夫鍊解析模型加以討論其性能之外，為了滿足大量裝置接入的需求，我們更進一步提出將時下5G的關鍵技術功率域的非正交多重接取技術(Power domain NOMA)，加入隨機接入過程藉以提高用戶接入網路的吞吐量。

According to the Ericsson mobility report released, due to the large-scale deployment of the cellular Internet of Things (IoT), the number of Massive IoT connections is expected to have doubled, reaching close to 200 million connections in 2020. And By the end of 2026, the IoT devices are expected to reach 3500 million, and 44 percent of cellular IoT connections will be broadband IoT, with 4G connecting the majority. To meet the demands of the Internet of Things, new technologies with low power and wide-area coverage are increasingly being emphasized. Among many promising technologies, Narrow-Band Internet of Things (NB-IoT) technology was first proposed in 3GPP Release-13 to not only meet the low-power wide-area coverage but also reuse GSM or LTE time-frequency resources. The advantages of resource reduction in the complexity and cost of device construction have led various telecom operators to actively launch related communication plans recently. Because of the importance of this technology, this paper will review the relevant literature and 3GPP standards related to NB-IoT in the past few years, and discuss its evolution and importance. Besides, we introduce one of the important technologies in the communication network for users to initially access the network in detail, the random access process and establish analytical models to discuss its performance. To meet the needs of a large number of accessing the device. We further propose to add power domain NOMA, a key technology of 5G, to the random access process to improve the throughput of users’ access to the network.

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