The invention discloses an MU-MIMO system safety transmission emission signal synthesis method, which belongs to the technical field of wireless communication, and can significantly improve the safetyof an MU-MIMO system. The method comprises the following technical steps of 1, randomly selecting channel vectors: randomly selecting corresponding channel vectors from all users to form a new matrix, 2, null space matrix calculation: performing singular value decomposition on the matrix, and calculating a null space matrix corresponding to a part of user channel vectors to obtain a null space matrix, 3, artificial noise calculation: designing an artificial noise vector by taking each element as a vector of a zero-mean complex Gaussian random variable and a null space matrix, 4, calculating adata signal vector: calculating a power normalization factor to obtain a pre-coding matrix of the data signal and a transmitted data signal vector, and 5, calculating an emission signal vector: calculating a final emission signal vector, and completing emission signal synthesis.

MU-MIMO system safety transmission emission signal synthesis method

The invention provides a safe precoding method based on an alternating direction multiplier method. According to the method, digital pre-coding and analog pre-coding are designed to improve the safetyperformance of a system. The method comprises the following steps that: on the basis of the fact that a transmitter only activates one antenna subarray to send information each time, an overall precoding matrix is cut, and a consistency optimization problem is established; secondly, a new matrix variable and a dual variable are introduced, the problem is converted from a non-convex problem to a convex problem; thirdly, the overall precoding matrix is updated through the alternating direction multiplier method, and the Euclidean distance of the overall precoding matrix before and after updating is calculated until a termination condition is satisfied; and finally, analog precoding and digital precoding are respectively obtained through overall precoding. The method of the invention is different from a traditional full-digital-based spatial modulation system in that a partially-connected hybrid structure is adopted in a transmitter, so that circuit cost is remarkably reduced; and through the design of safety pre-coding, the hybrid space modulation has good safety performance.

Safe precoding method based on alternating direction multiplier method

The invention belongs to the technical field of communication anti-interference, and particularly relates to an antenna selection method based on a channel factor Aiming at a specific structure of anOSM-MIMO system, the invention provides a relatively simple antenna selection method suitable for the OSM-MIMO system, namely, after channel coefficient modulus values are sorted, an antenna with themaximum modulus value and Ns-1 antennas with relatively small modulus values are selected to form an antenna set to bear bits On one hand, the bit error rate of the system is reduced while the advantages of the OSM-MIMO system are reserved; and on the other hand, compared with other antenna selection methods, the method has extremely low complexity, so that the method can be suitable for large-scale antenna selection

Antenna selection method based on channel factor

A linear precode method based on maximize approximate safety rate in a secure spatial modulation system is provided. By transmitting artificial noise signal and designing linear precoding, the artificial noise signal is projected onto the null space of the desired user channel, which does not affect the normal decoding of the desired user, but interferes with the decoding of the eavesdropping user. At the same time, the linear precoding is designed according to the maximum approximate safe rate criterion. For the optimization problem of maximizing approximate safety rate, which is a quadraticprogramming problem with non-convex quadratic constraints, by deriving the gradient of the objective function and iteratively solving it with the gradient descent method, the convergence to the localoptimal solution can be determined, and the safety rate performance of the system can be improved. Compared with the traditional method based on maximum approximate secure rate, this method has greatadvantages in computational complexity and achieves the performance close to that of the traditional method.

A precoding method based on maximum approximate secure rate in secure spatial modulation

The invention provides an antenna selection method based on signal leakage in a secure spatial modulation system. Unlike traditional MIMO systems, in a spatial modulation system, only one antenna is activated to transmit modulated signals, so the problems of channel interference and symbol synchronization can be effectively solved. The complexity of the transmitter and receiver is greatly reduced,and the sequence number of the active antenna also carries bit information, which improves the spectral efficiency and energy efficiency of the system. In order to improve the safety performance of physical layer of spatial modulation system, artificial noise and antenna selection are transmitted by transmitter, wherein the artificial noise signal is located in the null space of the desired userchannel. By using the concept of signal leakage, the signal-to-noise ratio is maximized by antenna selection, thus the safety rate performance of the system is improved. Compared with the traditionalantenna selection method based on Euclidean distance maximization, this method has great advantages in terms of security rate and computational complexity.

Li Jun

Papers

A precoding method based on maximum approximate secure rate in secure spatial modulation

Antenna selection method based on signal leakage in secure spatial modulation system