Design,Implementation And Performance Analysis Of CSI Feedback Enhancement Based On FDD Channel Reciprocity

In 5G(The 5th Generation)mobile communication technology,the high performance of massive MIMO(Multiple Input and Multiple Output)systems cannot be achieved without accurate and efficient CSI(Channel State Information)feedback.As the antenna size increases,the CSI feedback overhead grows linearly,which will seriously affect the data transmission efficiency.In the FDD(Frequency Division Duplex)system,the codebook-based CSI feedback is used to reduce the feedback overhead,but the high-precision Type Ⅱ codebook still causes a large feedback overhead,which should be further enhanced.Therefore,the study of CSI feedback enhancement based on FDD channel reciprocity is important for system performance improvement.The topic of this paper is based on "Evaluation and Validation of 5G International Standard Candidates" in the National Science and Technology Major Project Ⅲ "New Generation Broadband Wireless Mobile Communication Network".This paper aims to design and implement a system-level simulation platform for CSI feedback enhancement based on FDD channel reciprocity,and to perform simulation verification and performance analysis in the context of 5G NR(New Radio)standardization research.The main research of this paper is divided into the following three parts:(1)A review of massive MIMO-related technologies and simulation platforms.Firstly,this paper analyzes the current research status of massive MIMO enhancement for 5G NR.Secondly,this paper conducts an in-depth study on channel state information feedback enhancement technology.Thirdly,this paper conducts a study on CSI feedback enhancement technology based on FDD channel reciprocity,and analyzes the principle of using partial reciprocity to reduce CSI feedback overhead.Finally,the research status of 5G NR system-level simulation platform is summarized to provide the basis for the design and implementation of system-level simulation platform in this paper.(2)The system-level simulation platform design of CSI feedback enhancement based on FDD channel reciprocity.In this paper,we first analyze the requirements and complete the overall design of the systemlevel simulation platform.Secondly,according to the functional requirements,we focus on the design of the FDD channel module and the CSI feedback enhancement module in the system-level simulation platform,in which we complete the design of two sub-modules,FDD reciprocal channel and FDD system error,in the CSI feedback enhancement module,we divide it into CSI feedback enhancement based on three-level codebook and CSI feedback enhancement based on two-level codebook.The CSI feedback enhancement module is divided into two kinds of CSI feedback schemes based on three-level codebooks and two kinds of CSI feedback enhancement based on two-level codebooks.According to the design scheme,the base station can use part of the reciprocal uplink channel for pre-processing,and thus reduce the CSI feedback overhead of users.(3)Implementation and performance analysis of CSI feedback enhancement system-level simulation platform based on FDD channel reciprocity.In this paper,we firstly study the development and operation environment of the simulation platform based on the characteristics of the system-level simulation platform designed in this paper.Secondly,under the guidance of the design ideas,we implement the FDD channel module and the CSI feedback enhancement module respectively,and complete the development of the system-level simulation platform built in this paper.Finally,module calibration and performance analysis are performed to verify the functional correctness of the FDD channel module by analyzing the simulation results,and to show that compared with the R16 CSI feedback scheme,the three-level codebook-based CSI feedback enhancement can effectively reduce the CSI feedback overhead but will lead to a certain performance loss,and the two-level codebook-based CSI feedback enhancement can effectively reduce the CSI feedback overhead and get better performance.Based on the performance analysis of the system-level simulation platform based on the calibration results,it is demonstrated that both CSI feedback enhancement schemes can effectively improve the overall performance of the system.