MIMO系统发射端多天线选择保障物理层安全传输

针对MIMO系统信号传输策略中单天线选择方案在增大系统保密容量方面存在的局限性,本文提出发射端多天线选择方案以保障物理层安全通信。文中首先在已知全局信道状态信息的理想条件下讨论最优多天线选择方案；然后考虑较为实际的情况,即在未知窃听方信道状态信息条件下提出次优多天线选择方案；最后,为改进次优方案在低信噪比条件下系统保密容量较小的不足,提出次优多天线选择发射功率分配方案。通过理论推导保密容量表达式和数值分析,结果表明,与现有单天线选择方案相比,所提的多天线选择方案有效地提高了系统的保密容量。

Guaranteeing physical layer security using multi-antennas selection at the transmitter in MIMO system

Due to the secrecy capacity of MIMO system is limited utilizing single antenna selection scheme, we propose multi-antennas selection schemes at the transmitter to guarantee physical layer security. First, we assume that the global channel state information of both main channel and wiretap channel is known to the transmitter, and propose optimal multi-antennas selection (OMAS) scheme. Then we consider a more practical condition that the wiretap channel state information is unknown to the transmitter, and come up with suboptimal multi-antennas selection (SMAS) scheme. Finally, we consider a suboptimal multi-antennas selection and power allocation (SMAS-PA) scheme to improve the secrecy capacity of SMAS scheme in lower signal to noise ratio condition. We discuss the secrecy performance of SMAS-PA scheme then. The expression of secrecy capacity and numerical results demonstrate that the proposed scheme can improve the secrecy capacity of MIMO system effectively compare to the existing works about antenna selection scheme which selects only one antenna at the transmitter.