Research On Physical Layer Security Technology Under The Malicious Jamming

The physical layer security provides new ideas to ensure the communication security based on the characteristics of the wireless channel. However, the existing physical layer security technologies are mainly for the passive eavesdropping. When the illegal users send the malicious jamming which can enhance the eavesdropping performance and interrupt the legitimate communication, the physical layer security meets new challenges. The physical layer security technologies for the malicious jamming still have the following problems:1) According to the pilot contamination from the eavesdropper, there are no effective physical layer security transmission schemes to guarantee the legitimate communication; 2) According to the correlated jamming in the case of the single user scene, there are no effective physical layer security transmission schemes so that the transmitter can not maximize the secrecy rate. To cope with the above problems, this paper studied the physical layer security technology under the malicious jamming from National Natural Science Fund.This paper first gives a quantitative analysis of malicious jamming on the system security performance so as to obtain some important conclusions, such as the fundamental factor of the jamming threats, the parameters of reducing the jamming performance and so on. On this basis, a physical layer security transmission scheme based on the pilot pattern and the artificial noise is proposed for the pilot contamination and a physical layer security transmission scheme based on the continuous zero-sum game is proposed for the correlated jamming. The main content includes:1. The security performance under the malicious jamming is analyzed to guide the security transmission schemes:1) According to the pilot contamination, we analyze the effects of malicious pilot contamination on channel estimation and deduce the secrecy rate in the data transmission phase. Then, the fundamental factor of the jamming threats is obtained that the estimation result is the linear sum of the main channel and the eavesdropping channel. This indicates that eliminating the eavesdropping channel part in the jammed channel estimation results is a way for the pilot contamination.2) According to the correlated jamming, we deduce the secrecy rate and study the performance of the system noise, jamming position and other elements. Then, we obtain that the jamming performance decreases with the. This indicates that increasing the system noise artificially is a solution for the correlated jamming.2. A physical layer security transmission scheme based on the pilot pattern and the artificial noise is proposed. First, the legitimate receiver transmits the pilot based on the arranged pilot pattern. Then, the transmitter obtains the approximate estimation of the eavesdropping channel and eliminates the eavesdropping channel part in the jammed channel estimation results, thus reducing the effects of pilot contamination. Besides, the transmitter designs the proper precoding matrix based on the obtained CSI and transmits both the signal and the artificial noise, realizing the secure transmission. Finally, the simulation results show that the average security rate of the proposed scheme improves 1.34bit/s/Hz when the jamming power is 100mW.3. A physical layer security transmission scheme based on the continuous zero-sum game is proposed. First, the transmitter and the malicious jammer were modeled as a continuous zero-sum game with the utility function of secrecy rate. The transmitter transmits both the signal and the structural noise to maximize the secrecy rate while the malicious jammer sends the correlated jamming to minimize the secrecy rate. Then, their strategies were determined according to the channel state, and the corresponding Nash equilibrium was analyzed. Finally, the equilibrium was used to guide the power allocation for source signals and structural noise to enhance the system performance. Numerical simulation results show that the average secrecy rate of the proposed method increases 0.141 bit/s/Hz comparing to that of only transmitting the source signals.