Research On Detection Techniques In 5G MIMO Systems

Multi-Input Multi-Output(MIMO)technology has significant advantages in enlarging the capacity of communication systems,increasing the transmission rate and improving the transmission quality.Therefore,performance excavation of the MIMO technology has aroused widespread concern in 5G systems.Orthogonal Frequency Division Multiplexing with Index Modulation(OFDM-IM)technology has the characteristics of high energy efficiency and strong resistance to frequency offset,so it is suitable for the scenarios of high reliability and low power consumption in 5G systems.Sparse Code Multiple Access(SCMA)technology is a class of powerful non-orthogonal multiple access technologies,which can provide more connections and higher spectral efficiency.It has great potentials on the massive-connection scenario in 5G systems.For 5G systems,single transmission technology will be difficult to meet the needs of emerging businesses.In different scenarios,5G systems are more likely to adopt different transmission technologies.Therefore,this thesis studies the OFDM-IM and SCMA system based on the MIMO channel.The advanta ges and disadvantages of the existing receiver detection algorithm for the two systems are analyzed,and several improved detection algorithms are proposed,which can achieve a flexible trade-off between bit error rate(BER)performance and complexity.The contents and detailed works for this thesis are shown as follows.In chapter 1,the evolution of mobile communication is reviewed,then the research status on 5G is introduced,finally the main contents and the arrangement of this thesis are summarized.In chapter 2,the potential wireless transmission technologies in 5G systems are summarized.The system model,technical characteristics and classical detection algorithms of MIMO,OFDM-IM and SCMA technology are analyzed and introduced in detail respectively.In chapter 3,the detection algorithms of OFDM-IM based on multi-antennas system are studied.Firstly,the system model of MIMO-OFDM-IM and existing classical detection algorithms are introduced.Then,to overcome the shortcomings of the existing algorithms,two improved algorithms are proposed.Finally,the BER performance analysis and complexity comparison of the above algorithms are given through simulations.In chapter 4,the detection algorithms of SCMA based on multi-antenna systems are studied.F irstly,the system model of MIMO-SCMA is introduced,and three common detection algorithms are summarized.Then,three low-complexity detection algorithms are proposed against the defects of high complexity or poor BER performance.Finally,the BER performance analysis and complexity comparison of the above algorithms are carried out through simulations.In chapter 5,the conclusion on this thesis is summarized,and the potential future research points are discussed.