大规模MIMO多用户双向中继系统的物理层安全性能分析

对大规模多输入多输出(multiple input and multiple out，MIMO)多用户双向中继网络的物理层安全性能进行分析。系统模型中假设窃听节点可以获取第一跳用户发送信号和第二跳中继发送信号，分析大规模MIMO中继采用最大比合并和最大比传输信号处理时的系统保密速率，进一步推导出中继天线数趋于无穷时的系统渐近保密速率表达式，并进行仿真验证。理论分析和仿真结果显示，即使在不采用专门的物理层安全技术时，大规模MIMO双向中继系统也能获得可观的保密速率。证明即使当窃听节点具备多用户干扰消除能力时，通过设置合理的用户和中继发送信号功率，大规模MIMO双向中继系统仍然具有较好的物理层安全性能。

On the physical layer security performance of multi-user massive MIMO two-way relay system

The physical layer security performance of multi-user massive multiple-input multiple-output (MIMO) two-way relay based network is studied. The eavesdropper can receive the signals sent by the user nodes in the first stage and the relay in the second stage, we investigate secrecy rate of the system when maximum ratio combining and maximum ratio transmitting are used at the relay. Furthermore, the asymptotic secrecy rate expressions of the system are derived and verified by simulation when the number of relay antennas grows to infinity. The theoretical analysis and simulation results show that a considerable secrecy rate for massive MIMO two way relay system can be achieved even if we do not adopt special physical layer security technology. It is proved that even if the eavesdropping node has multi user interference cancellation capability, massive MIMO two way relay system still has better physical layer security performance through setting the reasonable signal power of the users and relay.