Abstract
The security of wireless information transmission in large‐scale multi‐input and multioutput (MIMO) is the focus of research in wireless communication. Recently, a new artificial noise—SCO‐AN which shows no orthogonality to the channel, is proposed to overcome the shortcomings of traditional artificial noise. In the previous research, the optimization function of SCO‐AN is not convex, and its extremum cannot be obtained. Usually, nonconvex optimization algorithms or iterative relaxation algorithms are used to get the maximum value of the optimization objective function. Nonconvex optimization algorithms or iterative relaxation algorithms are greatly affected by the initial value, and the extremum cannot be obtained by a nonconvex optimization algorithm or iterative relaxation algorithm. In this paper, we creatively apply the strong law of large numbers to obtain the optimal value of the optimization function of SCO‐AN under the condition of large‐scale MIMO: the strong law of large numbers is applied to obtain the ergodic lower bound (ELB) expression of SC for SCO‐AN. The power allocation (PA) problem of the SCO‐AN system is discussed. We use a statistical method to get the formula for calculating the optimal power distribution coefficient of the SCO‐AN system. The transmitter can use the optimal power ratio of PA to distribute the transmitted power without using the PA algorithm. The effect of imperfect channel state information is discussed. Through simulation, we found that more power should be generated for SCO‐AN if the channel estimation is imperfect and the proposed method can achieve better security performance in the large‐scale MIMO system.
Highlights
Security is the core issue of wireless communication [1]
It can be seen from (15) that Nk is located on the molecule, and Nk plays a positive role in the promotion of secrecy capacity (SC)
Aiming at the problem that traditional optimization algorithms cannot find the maximum value of nonconvex power allocation (PA) function, this paper uses statistical methods to study the PA technology of SCO-Artificial noise (AN) in large-scale multi-input and multioutput (MIMO) systems
Summary
Security is the core issue of wireless communication [1]. In this paper, the security of wireless information transmission is discussed. A novel method to select the Wireless Communications and Mobile Computing proper antenna and PA in massive MIMO is proposed in [8], the algorithm in [8] makes the wireless communication system to adjust the PA coefficient, and the communication quality of eavesdropper is reduced effectively. Base on the optimal PA coefficient, in a large-scale MIMO system, we can allocate the power without calculating. From the reconstructed PA function, we can deduce the channel capacity of the legitimate channel and eavesdropping channel in large-scale MIMO. We reach a crucial conclusion: the PA objective function of the channel between transmitter and receiver depends mainly on the partition of power and the number of transmitting antennas (ii) Based on the reconstructed PA function, we derive the optimal PA coefficient. We conclude that we should generate more power for SCO-AN once the level of imperfect CSI increases.
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