Research On Security And Reliability Of Multiple-input Multiple-output Communication System Based On Precoding Technolog

In the case of limited spectrum resources,multi-input multi-output(MIMO)communication technology effectively improves the channel capacity and transmission rate of communication system by utilizing space resources.With the development of communication technology,researchers have found that,MIMO communication technology in the new generation of communication systems can also improve the channel capacity and transmission rate of the communication system,such as the fifth generation(5G)mobile communication system using millimeter wave and the sixth generation(6G)mobile communication system using visible light.Based on the number of service users,MIMO communication is divided into single-user MIMO communication and multi-user MIMO(MU-MIMO)communication.No matter how rapid the development of MIMO communication technology,the security and reliability of communication system is always an important index to evaluate the performance of communication system.MIMO communication technology in the traditional radio frequency(RF)field has been deeply studied,the reliability of MIMO communication system has been greatly improved,but there are still some security problems in the MIMO communication system.At present,MIMO communication technology has been applied in the field of visible light communication.Improving the reliability of multi-user MIMO visible light communication system is also an important research trend.To solve the above problems,this paper firstly studies the security of single-user MIMO communication system using frequency hopping precoding.Secondly,this paper studies the reliability of multi-user MIMO visible light communication system using joint precoding.The main research contents of this paper are as follows:Under the background of single-user MIMO communication system,this paper proposes a single-user MIMO communication system based on space time block coding(STBC)assisted by frequency hopping precoding.By using frequency hopping precoding and chaotic communication,the purpose of improving the security of a single-user MIMO communication system is achieved,Orthogonal frequency division multiplexing(OFDM)is used to alleviate the delay line circuit problem of differential chaos shift keying(DCSK).For multi-user MIMO visible light communication system,this paper proposes that singular value decomposition and geometric mean decomposition are combined to generate the corresponding precoding matrix of multi-user MIMO communication system,and finally to improve the reliability of multi-user MIMO communication system.In view of the two proposed precoding schemes,this paper respectively carried out simulation verification of the two proposed schemes.This paper firstly simulates the proposed single-user MIMO communication system using STBC coding aided by frequency hopping precoding and compares it with the comparison scheme.In the simulation results of the proposed scheme,the bit error rate of the eavesdropper is close to 1,which indirectly verifies that the proposed scheme can effectively improve the security of the single-user MIMO communication system.In addition,the secrecy capacity of the proposed scheme is much higher than that of the comparison scheme which is close to 1.The results directly prove that the proposed scheme can effectively improve the security of single-user MIMO communication system.Secondly,the proposed multi-user MIMO visible light communication system using singular value decomposition and geometric mean decomposition is simulated and compared with the comparison scheme.The symbol error rate of the proposed scheme is lower than that of the comparison scheme in the three environments.Therefore,the simulation results verify that the proposed scheme can effectively improve the reliability of the multi-user MIMO visible light communication system.