The authors incorporate Alamouti space-time block coded orthogonal frequency division multiplexing (OFDM) with signal space diversity (SSD) in order to significantly strengthen the physical layer security of the communication network. The coordinate interleaving step of SSD is performed amongst OFDM subcarriers, according to distinct strategies that make the correlation coefficients between the subcarrier channel gains equal to zero. The proposed system model can improve the security by enabling a legitimate user to have much less error than an eavesdropper, even under the worst-case scenario where the unauthorised receiver somehow captures the interleaving strategy compromised by the transmitter and legitimate receiver. It is shown that a legitimate user with the introduced scheme can provide up to 14% more performance gain as compared to an unauthorised receiver for a bit error rate (BER) of 10 ⁻⁴ under worst-case scenarios with different parameters. An exact closed-form expression of the BER is derived for the legitimate user and shown to match with the simulation results. Finally, it is demonstrated that the system is also capable of enhancing the resistance against channel estimation errors at the receiver. The proposed system does not require high complexity or additional bandwidth or time resources.

中文翻译：

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通过子载波坐标交织提高Alamouti OFDM系统中的物理层安全性

作者将Alamouti空时分组编码正交频分复用（OFDM）与信号空间分集（SSD）结合在一起，以显着增强通信网络的物理层安全性。根据使子载波信道增益之间的相关系数等于零的不同策略，在OFDM子载波之间执行SSD的坐标交织步骤。所提出的系统模型可以使合法用户比窃听者拥有更少的错误，从而提高安全性，即使在最坏的情况下，即未经授权的接收器以某种方式捕获了由发送器和合法接收器损害的交织策略。 ⁻⁴在最坏情况下使用不同的参数。为合法用户导出了BER的精确封闭形式表达式，并显示为与仿真结果匹配。最后，证明了该系统还能够增强接收器对信道估计误差的抵抗力。所提出的系统不需要高复杂度或额外的带宽或时间资源。