Technologies And Performance Analysis Of Security Transmission In Multiple-Antenna Cooperative Network

In recent years, the requirements of performance and service for the wireless communication networks further improve with the rapid popularization of mobile internet. However, due to rapid increases in computation capability, traditional encryption technology depending on complex mathematical algorithms also face enormous challenges, and such encryption technology may be easily cracked in the future. Thus, secure communications using physical layer security technology become a research focus. Cooperative relaying and multi-antenna technology are the key technologies for the wireless communication networks in the future. Cooperative relaying technology has great advantage in the aspects of enhancing the capacity of the network, signal coverage, and transmission power utilization. However, the cooperative relaying encounters complex issues in secure transmission in the netwoks with many network nodes, more complex structure, and more strong openness. In cooperative relay networks, the multi-antenna cooperative jamming technology and opportunistic transmission technology can be applied to protect the security of information transmission, by taking advantage of the complex spatial and time-varying characteristics of the wireless channel.This paper proposes and analyzes multi-antenna artificial noise source secure transmission scheme, opportunistic relay selection secure transmission scheme and joint source relay transmit antenna selection secure transmission scheme in multi-antenna cooperative relay network including an eavesdropper node. This paper studies fixed decode-and-forward protocol and adaptive decode-and-forward protocol, the Rayleigh fading channel and Nakagami channel fading in the channel design, the maximal ratio transmission scheme and selection transmission scheme in the transmission scheme, and the maximum ratio combining technique in the receiving scheme. This paper analyzes the secrecy performance indicators of the system which include the ergodic secrecy capacity, the positive secrecy probability, and the secrecy outage probability, then further taking the asymptotic performance analysis or the optimal power allocation design for the ergodic secrecy capacity and secrecy outage probability. Finally, the results of theoretical analysis can be verified the correctness by the Monte Carlo simulations in MATLAB platform.The results show that: Three secure transmission schemes can significantly improve the security transmission performance of system designed by this paper. Corresponding performance indicators can be effectively improved by increasing the number of source node which using artificial noise, the number of opportunistic relay node and the number of antennas for transmitter. The influence of the system parameters on the security performance of the system can be visually obtained by results of asymptotic performance analysis. The optimal power allocation scheme designed by the derived performance metrics indicate this paper has great guiding significance for the actual system design.