| 5G mobile communication puts forward higher requirements for mobile communication,lots of new wireless technologies have emerged.In order to meet the higher system capacity and rate requirements in 5G,the use of Massive MIMO is an important means of implementation.Massive MIMO also has a interference problem that cannot ignored.Precoding can effectively suppress interference in Massive MIMO and increase the peak rate of the link.In the initial stage of 5G technology research and development,the use of the simulation platform for technical evaluation can promote technology development more efficiently.However,how to effectively evaluate the impact of precoding in 5G on performance indicators has become one of the practical problems that need to be solved in the research process.The topic of the thesis comes from the national major project:"2018ZX03001024--5G International Standar-d Candidate Evaluation and Verification".This thesis builds a 5G link-level simulation platform based on MATLAB language,that combined the 5G technology collection phase and the new technology discussed in the standard formulation process,and evaluates performance of precoding.The main resear-ch content of this thesis is divided into two parts:The first part is to design and implement a 5G link-level simulation platform.Aiming at the transmission performance requirements in 5G and the evaluation requirements of candidate technologies,the modularization principle is adopted,and the 5G link-level simulation platform is designed and implemented with high flexibility and high scalability and achieves the end-to-end single-user communication link.The platform focus on the unique frame structure in 5G,high-order modulation and MIMO transmission module including layer mapping,precoding,beamforming and feedback module to improve the reliability of communication transmission.Finally,combined with the TDL wireless channel model in 5G,the link-level simulation platform is corrected.The second part is the performance evaluation of precoding.For the interference problem in Massive MIMO transmission,combined with the technical solution in 3GPP 38.214,two different precoding techniques for uplink:codebook-based precoding and non-codebook-based precoding and k three different precoding for downlink are used:precoding t based on Type I codebook,precoding based on Type II codebook,and precoding based on non-codebook are designed and implemented respectively.At the same time,combined with the link-level simulation platform,the performance of precoding under different antenna port numbers is evaluated.The simulation results show that in the case of low-speed mobility,the performance of precoding based on non-codebook is better in the downlink and uplink from the perspective of system throughput. |
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