双向跳空通信系统的物理层安全方案

Secrecy Scheme of Two-Way Space Hopping Transmission in Physical Layer

为了保证双向无线通信物理层传输的安全,提出一种基于双向权值训练的多天线跳空方案.合法通信双方利用双向训练得到彼此之间互易且唯一的信道特性,根据跳空图案生成算法由信道特性生成一致的跳空图案,双方按此跳空图案切换天线来收发信息.传统的"反向训练"的是通过隐藏发送方跟窃听方的信道特性,使窃听方无法正确地加权接收信息,从而达到信息保密的目的;其默认的是接收方单纯接收,如果接收方发送信息则安全得不到保障,而该方案是利用合法双方共有的天线切换方式来保证通信的安全.引出一种空频复用的训练方式,能够在保证准确性的同时大大提高权值训练效率.仿真结果表明,所提出的安全方案可以在双向通信中使得窃听方保持较高的误比特率,具有较好的防侦听能力.

In this paper, a bidirectional training based technique is proposed for multiantenna space hopping transmission, which ensures information security of two-way transmission in the physical layer. The proposed scheme can guarantee the identity of channel characteristics obtained by two legitimate transceivers via bidirectional training. A space hopping pattern generation algorithm is presented, which calculates the pattern according to channel characteristics. The antenna switching mode is controlled by the pattern that selects several antennas for fast switching transmission. Conventional schemes resort to a backward training method, hiding the channel between transceiver and eavesdropper so that an eavesdropper cannot receive correctly with wrong weighting, thus achieving security of transceivers. The default mode is that a receiver only receives. Contrarily, the proposed scheme uses a switching mode to ensure transmission secrecy. To improve training efficiency, a spatial frequency multiplexing training method is used, with almost identical accuracy and significantly enhanced efficiency. Simulation results show that the proposed scheme has good performance in anti-eavesdropping as it causes a high bit error rate for the eavesdropper.