Research Of Precoding Based On Mmwave Massive MIMO System

With the development of a variety of new media technology and intelligent terminal technology,people have explosive demand for larger wireless network capacity,higher speed requirements and more stable quality of service.Among them,millimeter wave technology and large-scale MIMO technology are considered as the key technologies of 5g.In order to further eliminate inter user interference and inter cell interference,precoding technology is needed to fully realize the MIMO gain.This paper focuses on the millimeter wave large-scale MIMO system and precoding technology to simulate and analyze many existing precoding schemes.A hybrid precoding algorithm based on genetic algorithm is proposed to solve the problem of low energy efficiency in switched networks.The nonconvex function optimization problem is transformed into the local optimal solution problem,so as to further improve the transmission rate and energy efficiency of the system.Furthermore,an adaptive codebook precoding scheme based on 5gnr with low complexity is proposed to solve the problem that the codebook based precoding scheme specified in 3GPP protocol cannot dynamically select codebook.The receiver can select dynamically according to the channel state information and feed back in the form of PMI,which greatly reduces the computational complexity.Aiming at the problem of high complexity in codebook search,two low complexity codebook search algorithms are proposed based on the idea of codeword selection and optimal linear combination selection.