Study Of Method In Physical Layer Secure Communication Based On Artificial Interference

Wireless communications have increasingly huge influence on modern people’s life work study and other aspects. Two basic problems of wireless communication systems is the reliability and validity of the data. However, the data propagate in the space in the form of electromagnetic waves. The fundamental characteristics of the wireless medium, namely broadcast fading and accessible, present different challenges in ensuring reliable and secure communications in the presence of adversarial users. An unauthorized receiver tries to extract information from an ongoing transmission without being detected, a malicious transmitter (jammer) tries to degrade the signal at the intended receiver. While jamming physical layer strategies have been of long-standing interest especially in military networks, the security of data transmission has traditionally been entrusted to key-based cryptographic techniques at the network layer, the issues such as complex key distribution, and high computational complexity of cryptosystems drive the creating and improvement of the physical layer security based on artificial noise.The physical layer security is to enable the exchange of confidential messages over a wireless medium in the presence of eavesdroppers without relying on higher-layer encryption. The fundamental principle behind physical layer security is to exploit the inherent randomness of noise and communication channels to limit the amount of information that can be extracted at the ’bit’ level by an unauthorized receiver. More importantly, no limitations are assumed for the eavesdropper in terms of computational resources or network parameter knowledge, and the achieved security can be quantified precisely by secrecy rate or secrecy capacity. This paper studies one of the physical layer security strategies, the transmitter transmits the desired signals, while utilizing some of the available power to produce ’artificial noise’, such that only the eavesdropper’s channel is degraded. With appropriately designed coding and transmit precoding schemes in addition to the exploitation of any available channel state information, physical layer security schemes enable secret communication over a wireless medium without the aid of an encryption key.This paper studies the application of artificial noise in a single-user MIMO system firstly, introduces lattice detection theory, the artificial noise can force Eve’s received signal to settle around the borders of the decision region, by normalizing the length of the random vector to a specific value, and overcome the restriction NE< NA, we aim at improving the eavesdropper’s error probability. This paper proposes an artificial noise method based on interference alignment to secure communications technique in the Multi-user Multi-eavesdropper MIMO interference channels, the sender sends useful signals and artificial noise signal at the same time, with appropriately designed transmit precoding schemes,the precoding matrix of the useful signals transmitter satisfy I A, the precoding matrix of the artificial noise signal is used to interference the eavesdropper degrade the quality of its channel, cancel the interference between the users, and improve secrecy rate. We simulate the two methods use Matlab software and make an analysis for the results.