中文摘要：

物理层安全是一种密钥缺省的安全方案,其研究模型基于窃听信道,并利用物理层传输资源通过信号处理或编码等技术保证合法接收者正常通信,同时抑制非认证的窃听者通信,使其不能恢复发送消息。与此同时,多天线技术除在提高信道容量上的优势外,还为无线通信系统提供了更多冗余来进行物理层安全方案设计,因此多天线系统中的物理层安全问题有着广阔的研究前景。文章对多天线系统中物理层安全问题的四个主要研究方向进行综述,首先是多天线窃听信道问题,该模型是经典窃听信道的改进,也是多天线系统物理层安全其他问题的基本模型;其次为多用户多天线信道的物理层安全问题,该问题包括了多天线广播信道、多天线多址信道和多天线干扰信道;再次为多天线协同通信中物理层安全问题,根据中继用户是否可信,该问题可分为可信中继和不可信中继的物理层安全方案;最后是多天线系统中跨层安全问题,现有研究主要包括了利用物理层进行密钥协商和利用信道进行安全认证。文章通过总结现有方案的研究思路与方法,提出了进一步研究的可行方向。

英文摘要：

Physical layer security lies in the benefit of key sharing needlessness. The premise of physical layer security is based on the wiretap channel to prevent the transmitted signals cannot be recovered by the undesired eavesdroppers with signal processing or coding methods. Meantime, multiple antennas technique has been proved a efficient to improve channel capacity, besides that the redundancy brought by the multiple antennas technique can provide more possibilities to reduce the wiretapping level of the eavesdroppers. Thus, it is desired to overview the existing physical layer schemes. The existing researches on physical layer security issues in multiple antennas system can be classified as four categories： firstly MIMO wiretap channel has been investigated as the basic model; secondly, multiple users with multiple antennas is another important model including broadcast channel, multiple access channel, and interface channel; thirdly, focusing on MIMO cooperation communication, the existing researchers consider trusted relay and untrusted relay scenarios; lastly, cross layer security framework including physical layer is also desired to be considered with two key problems, physical layer key sharing and physical layer authentication. By summarizing the existing scheme design principle, the future research direction is demonstrated.