In this paper, we investigate the physical layer security based on space shift keying (SSK) in which bit-to-spatial mapping of antenna indices dynamically adapts according to the partial channel state information (CSI) of the legitimate channel at the transmitter (Tx). Further, the Tx also adapts transmit power allocation to each transmit antenna according to partial CSI. Since an eavesdropper (Eve) is not (usually) aware of the legitimate CSI, it cannot successfully decode the antenna index; thus, transmission over the legitimate channel is secured from the wiretapping of Eve. An important virtue of the proposed scheme is that the Tx does not require full CSI of the legitimate and eavesdropper channels to secure the confidential information. The proposed work focuses on the secrecy rate (SR) and bit error rate (BER) of the considered multiple-input single-output system over Rayleigh fading channels. Approximate expressions of Bob’s data rate for 2-ary and 4-ary SSK modulations are derived in closed-form. Furthermore, an upper-bound of Bob’s data rate for $N_{a}$ -ary SSK modulation is also derived. In order to obtain the secrecy rate for the proposed scheme, we also evaluate Eve’s data rate. Analytical results of SR and BER demonstrate the robustness of the proposed scheme. All numerical results are thoroughly verified by using extensive Monte Carlo simulations.

中文翻译：

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SSK 调制的保密分析：自适应天线映射和性能结果

在本文中，我们研究了基于空间移位键控 (SSK) 的物理层安全性，其中天线索引的位到空间映射根据发射机 (Tx) 上合法信道的部分信道状态信息 (CSI) 动态适应。 ）。此外，Tx 还根据部分 CSI 对每个发射天线进行发射功率分配。由于窃听者（Eve）（通常）不知道合法的 CSI，因此无法成功解码天线索引；因此，通过合法渠道进行的传输可以防止 Eve 被窃听。所提议方案的一个重要优点是 Tx 不需要合法和窃听通道的完整 CSI 来保护机密信息。所提议的工作重点关注瑞利衰落信道上所考虑的多输入单输出系统的保密率 (SR) 和误码率 (BER)。鲍勃数据速率的近似表达式对于 2 进制和 4 进制 SSK 调制以封闭形式导出。此外，Bob 的数据速率上限为 $N_{a}$ -ary SSK 调制也被推导出来。为了获得所提出方案的保密率，我们还评估了 Eve 的数据率。SR 和BER 的分析结果证明了所提出方案的鲁棒性。所有数值结果都通过使用广泛的蒙特卡罗模拟进行了彻底验证。