Research On Multi-eavesdropper Physical Layer Security Performance Based On Antenna Spatial Correlation

With the rapid development of internet technology,people have higher and higher requirements for the secure transmission of information in the communication system.Traditional schemes to ensure information security are implemented at the upper layer of the network,but they are all based on error-free links at the physical layer.Therefore,secure transmission at the physical layer is important.At present,multi-input multi-output(MIMO)technology is favored by many scholars,but because of the broadcast characteristics of wireless channel,the information in the transmission process is easy to be wiretapped by the eavesdropper.Therefore,it is necessary to improve the security performance of wireless communication system.It is worth noting that the limitation of space resources in the MIMO system makes the antennas particularly close to each other,which will result in the spatial correlation of antennas.Therefore,the influence of antenna spatial correlation on the security performance of communication system must be considered.Moreover,in the process of communication,information is often wiretapped by multiple potential eavesdroppers at the same time.Therefore,it is very important to study the multi-eavesdropper physical layer security performance based on antenna spatial correlation.The main contributions of this paper are as follows:Firstly,the security performance of multi-eavesdropper single input multiple output(SIMO)eavesdropping system based on antenna correlation is studied.Under the condition that both the receiver and eavesdroppers adopt the maximum ratio combination(MRC)scheme,the theoretical expressions of the secrecy outage probability and the probability of non-zero secrecy capacity are obtained based on the Rayleigh fading channel,and then the asymptotic secrecy outage probability is obtained.At the same time,the diversity order and array gain as the average SNR of the receiver approaches infinity are also obtained.In addition,Monte Carlo simulations are conducted for two typical spatial correlation models,namely uniform correlation and exponential correlation,and the influence of spatial correlation on the security performance of the system is analyzed based on the experimental results.Secondly,the security performance of multi-eavesdropper MIMO eavesdropping system based on antenna correlation is studied.Under the condition that the transmitter adopts the optimal order antenna selection(TAS),the secrecy outage probability,the probability of non-zero secrecy capacity and the asymptotic secrecy outage probability are obtained,and then the diversity order and array gain of the system are obtained.Finally,the Monte Carlo simulations based on uniform correlation and exponential correlation are used to analyze the influence of antenna spatial correlation on the security performance.The results show that in the presence of multiple eavesdroppers,when the average SNR of the main channel is larger,the spatial correlation of the antenna is harmful to the security performance of the system,and the harm of increasing the antenna correlation of the receiver is more obvious.When the average SNR of the main channel is smaller,the antenna spatial correlation is beneficial to the system security performance,and the benefit of increasing the eavesdropper antenna correlation is more obvious.In addition,the diversity order of multi-eavesdropper SIMO eavesdropping system isN_B,and the diversity order of multi-eavesdropper MIMO eavesdropping system isN_A N_B.The number of eavesdroppers and the antenna correlation are independent of the diversity order,but the array gain is affected.