Research And Application On Physical Layer Security Of Multi-Antenna Cognitive Relay Network

The combination of the multi-antenna relay network and cognitive radio form a new multi-antenna cognitive relay network.It not only solves the original problem of limited transmission distance of communication signals,but also improves the utilization of the existing spectrum.Decode-and-forward technology is an important signal processing method in multi-antenna relay networks.However,due to the accessibility of wireless communications,signals are extremely vulnerable to theft by the outside world.Therefore,it is of great significance to study the physical layer security of a multi-antenna cognitive relay network using a decoding and forwarding protocol.This paper studies three different multi-antenna relay system models,and analyzes the practical application of the communication system from the actual cell communication model.First,in the multi-antenna relay network with two hops,the secrecy performance of the system is studied under the decode-and-forward protocol.It adopts the transmission antenna selection and selection combining scheme at the multi-antenna end.The sender,receiver,and eavesdropping are all equipped with a single antenna and there are M interference at the eavesdropping end.Under the hypotheses that all channels obey Rayleigh fading,the closed-form expressions for the secrecy outage probability,asymptotic expression under the high signal to noise ratio(SNR)and the probability of non-zero secrecy capacity are derived.We compare the theoretical data with the simulation data to determine the accuracy of the analysis.The analysis results have guiding significance for optimizing multi-antenna relay networks.Second,we study the secrecy performance of the system in a multi-antenna cognitive relay network.Specifically,at this time,the system has introduced a cognitive network to implement frequency spectrum sharing,and equipped with multiple antennas at the receiving end and eavesdropping end.The relay still uses decode-and-forward techniques,but the antenna terminals will use the maximum ratio of combining and transmitting antenna selection scheme to receive and transmit signals.After calculation,the closed expressions of the system's secrecy outage probability and eavesdropping probability are derived.At last,Monte Carlo simulations verify the accuracy of the theoretical analysis.The final analysis result has great significance for improving the practical application of the multi-antenna relay network in life.Finally,the paper studies the secrecy performance of multi-antenna cognitive relay networks with co-channel interference.At this point,there are multiple primary users in the system model,and the receiver is affected by co-channel interference.Assuming that all channels obey Rayleigh fading,the closed expression of the system's secrecy outage probability is calculated,and the influence of each parameter on the system's secrecy performance is analyzed.Furthermore,the accuracy of theoretical analysis is verified by simulation.The analysis results have guiding significance for optimizing the application of multi-antenna relay network with co-channel interference.