Design And Implementation Of The NB-IoT Downlink Physical Layer On Software Defined Radio Platform

With 5G launching global mass commercialization in 2020,the era of Internet of everything is coming.As an important solution for large-scale IoT scenarios,Narrow Band Internet of Things communication technology has been widely concerned by communication companies all over the world after being proposed by 3GPP in 2016.With the rapid development of Narrow Band Internet of Things technology,the pace of protocol standardization evolution has not stopped.During this period,a large number of Narrow Band Internet of Things new technologies and new algorithms have emerged.In order to better carry out research on Narrow Band Internet of Th:ings technology,researchers need a platform that is accurate,efficient,and close to the real system to test and evaluate new technologies and algorithms.The Narrow Band Internet of Things system has been redesigned based on the LTE protocol and has the characteristics of small bandwidth,flexible deployment,and massive connection.Reconstruction of signal patterns requires researchers to redesign and deploy physical layer processes and technologies.However,there is currently no common platform for testing and evaluating Narrow Band Internet of Things technologies and algorithms.Designing and developing a narrowband IoT test platform can fill the gaps in this field and have certain engineering value.Based on the Software Defined Radio platform,this paper proposes a downlink platform design around Narrow Band Internet of Things physical layer and develops a downlink test platform.The platform can be used for testing and evaluation of new technologies and new algorithms for Narrow Band Internet of Things downlink physical layer to ensure the reliability and compatibility of the technology.This paper focuses on the platform design and implementation process.The main research work includes:Firstly,the theoretical basis of Narrow Band Internet of Things and the architecture of OpenAirInterface platform are introduced.The implementation process of downlink physical signals and channels is described.Then the platform requirements and evaluation indicators are analyzed.This paper descirbes the overall architecture and process design scheme of the platform.And the implementation process of the process and function modules is described in detail.Then the design and implementation of the key mechanisms of the physical layer involved in the system are designed.The design and implementation steps of the statistical functions of the user-side platform are given.Finally,we explain the configuration of the test environment.The platform was tested according to the evaluation indicators while completing the physical layer verification of the platform.The results show that the Narrow Band Internet of Things downlink platform designed in this paper is accurate and effective,and can be used for evaluation and verification of physical layer technology and algorithm performance.