Enhancing Physical Layer Security Based On Massive MIMO

Due to the broadcast nature of wireless channels,security and privacy is of utmost concern for future wireless technologies.Although security was originally viewed as a high-layer problem to be solved using cryptographic methods,physical layer security is now emerging as a promising means of defense to realize wireless secrecy in communications,besides,the massive MIMO technology has a great advantage in ensuring the physical layer security.Hence,it is importance to exploit the characteristics of wireless channels to design efficient secure transmission strategies,such that the message from the source to the intended receiver are kept confidential from both passive and active eavesdroppers.In this paper the main innovation points are as follows.1.The problem of optimizing the secrecy capacity by optimizing antenna layout is studied.A suboptimal iterative algorithm is presented for optimization of antenna layout in terms of secrecy capacity.In the proposed algorithm,the multi-dimensional optimization problem is reduced to one-dimensional problems within each iteration,hence the computation complexity is reduced greatly.The numerical results show that compared to uniform layouts,the capacity of optimized layouts is improved effectively.2.The problem of antenna selection is investigated based on a group switch-and-examine combining scheme.The scheme is used in different scenarios which are dependent on the wiretap channel information is perfectly known or not.The results show that compared to select antennas randomly,the scheme has better capacity performance and also could save switch time while introduce a threshold.3.For independent massive MIMO channel,the physical layer security based on spatial modulation is improved.For three different transmission schemes,we employ MF,ZF and SVD precoding scheme respectively and simulate the symbol error rate of the legitimate receiver and the eavesdropper.4.Combining antenna selection,artificial noise and spatial modulation,we present a new secure transmission scheme.For independent and correlated MIMO channel,the error symbol rate is simulated.Compared to traditional transmission scheme,the safety performance is significantly improved.