多中继与多用户选择的中继系统安全性能分析

为了考察使用多中继选择与多用户选择的放大转发（AF）中继系统的物理层安全性能，推导了其在瑞利衰落信道上和联合发送天线选择/接收最大比合并天线分集下的非零安全容量概率和安全中断概率的精确表达式以及在高信噪比下的渐近安全中断概率解析表达式。AF中继系统的非零安全容量概率和安全中断概率的数值计算和仿真结果相吻合，验证了以上理论分析的正确性；分析结果表明，其安全分集增益为源节点发射天线数、最优中继节点接收天线数、中继节点数的三者乘积与最优中继节点发射天线数、最优用户接收天线数、用户数三者乘积之间的最小值，且与窃听信道无关。

Secure performance analysis of relay systems with multi-relay and multi-user selection

The exact expressions for the non-zero secrecy capacity probability,secrecy outage probability of AF relay systems with transmit antenna selection and receive maximal ratio combining and its asymptotic secrecy outage probability at high signal to noise ratios over Rayleigh fading channel were derived respectively.The numerical results of the non-zero secrecy capacity probability and secrecy outage probability of AF relay systems with multi-relay and multi-user selection match well with their corresponding simulations,which proves the correctness of the above theoretical analysis.The analysis result of the asymptotic secrecy outage probability of AF relay systems with multi-relay and multi-user selection indicates that its secrecy diversity gain is the minimum value between the product of the number of transmit antennas at source,the number of receive antennas at the optimal relay node,and the number of relay nodes,and the product of the number of transmit antennas at the optimal relay node,the number of receive antennas at the optimal destination node,and the number of destination nodes,which is independent of the eavesdropper channel.