The Research And Simulation Of Detection Algorithms In Large Scale MIMO Systems

Large-scale Multi-Input Multi-Output(MIMO) multi-antennas transmission system which is based on traditional MIMO transmission techniques has tens or hundreds of transmit and receive antennas. Because of the larger antennas configuration structure, Large-scale MIMO system has bigger system capacity and spectral efficiency which makes it to be a kind of core technology for future mobile communication system. With the further development of multi-antenna technology,enhanced multi-antennas technology based on large-scale multi-antenna arrays with more transmit and receive antenna has become a popular research subject. Spatial Multiplexing and Spatial Modulation are two major branches of MIMO multi-antennas technology. Spatial Multiplexing has high data transfer rate and system capacity, but the serious inter-channel interference leads to high detection complexity. Spatial Modulation(SM) which chooses the active transmit antenna indices by input bits is proposed. Compared to traditional multi-antennas technology, the inter channel interference(ICI) is mostly avoided in SM systems because of only one or part of the transmit antennas are activated in each instance.This thesis focuses on Large-scale MIMO multi-antennas transmission technology, optimizing detection algorithms and proposing new low-complexity detection algorithms.This thesis works for above-mentioned problems in multi-antenna technology system. The main work and content of this dissertation is introduced as follows:In Chapter 1, the system models of Spatial Multiplexing, Spatial Diversity and Spatial Modulation MIMO system are introduced.In Chapter 2, the classical detection algorithms for Vertical Bell Labs Layered Space-Time(VBLAST) and Spatial Modulation(SM) systems are presented in details. We also briefly analyse and compare the complexity and Bit Error Rate(BER) performance of these detection algorithms based on simulation tool MATLAB.In Chapter 3, we focus on the Large-scale MIMO multi-antennas transmission technology based on Spatial Multiplexing technology. We summarized the linear detection algorithms and near maximum likelihood detection algorithms. Specially, we present the complexity of all algorithms introduced above and compare the bit error rate performance by simulation tool. We also propose a kind of improved Matched Filter(MF) detection algorithm which is applicable to special transmit and receive antennas configuration structure. This improved Matched Filter detection algorithm adopts the sub-region detecting methods to obtain the lower bit error rate performance compared to the traditional Matched Filter.In Chapter 4, we focus on the Large-scale MIMO multi-antennas transmission technology based on Spatial Modulation technology. We summarized the linear detection algorithms and near maximum likelihood detection algorithms. Specially, we present the complexity of all algorithms introduced above and compare the bit error rate performance by simulation tool. We also propose three kinds of improved detection algorithm for Large-scale MIMO systems. These proposed detection algorithms can obtain near maximum likelihood bit error rate performance with low complexity or enhance the bit error rate performance with the complexity higher.Chapter 5 draws the conclusion about this thesis and discusses the possible future research directions of enhanced multi-antennas techniques.