Study On Secure Transmission Techniques Of Novel MIMO

Due to the broadcast nature of the wireless propagation medium,protecting the confidentiality of wireless communications is believed to be more challenging compared to that in its wireline counterpart.For enhancing the security of wireless communications,physical layer security techniques have recently gained increasing research attention.Several novel multiple-input multiple-output(MIMO)techniques have attracted considerable research in recent years,which are candidate techniques for guaranteeing physical layer security.In this paper,based on directional modulation(DM),beamforming and spatial modulation(SM),we propose a class of efficient secure transmission schemes.Both analytical and simulation results are presented to show that the proposed schemes significantly outperform the benchmark.The main research contents and contributions are summarized as follows:In Chapter 1,three novel MIMO techniques and the corresponding research status are introduced,while the limitation of conventional schemes are discussed.In Chapter 2,the system model with distributed and cooperative receivers is introduced,and the conventional array transmission is analyzed.Furthermore,we propose a new directional modulation scheme with cooperative receives(DM-CR)for secrecy communications.Moreover,we investigate the average bit error probabilities(ABEPs)of the proposed DM-CR scheme and also provide the simulation results.In Chapter 3,a spatial and directional modulation scheme with scrambling(SDM-S),and a spatial and directional modulation(SDM)in the context of random frequency diverse array(RFDA),are proposed for increasing the throughput of conventional scheme and guaranteeing the transmission security.In addition,the upper bound is derived to theoretically analyze the ABEPs of the proposed schemes.In Chapter 4,a novel hybrid beamforming algorithm is proposed in the context of sub-connected structure,and a new hybrid beamforming algorithm is proposed for multi-user large-scale MIMO systems when the frequency selective fading channel is considered,and a limited feedback hybrid beamforming algorithm is developed for improving the secrecy performance of hybrid beamforming systems.Our performance results demonstrate that the proposed algorithms perform better than the benchmark.In Chapter 5,we summarize the main contribution of this paper and discuss the possible research directions.