In practice, residual transceiver hardware impairments inevitably lead to distortion noise which causes the performance loss. In this letter, we study the robust transmission design for a reconfigurable intelligent surface (RIS)-aided secure communication system in the presence of transceiver hardware impairments. We aim for maximizing the secrecy rate while ensuring the transmit power constraint on the active beamforming at the base station and the unit-modulus constraint on the passive beamforming at the RIS. To address this problem, we adopt the alternate optimization method to iteratively optimize one set of variables while keeping the other set fixed. Specifically, the successive convex approximation (SCA) method is used to solve the active beamforming optimization subproblem, while the passive beamforming is obtained by using the semidefinite program (SDP) method. Numerical results illustrate that the proposed transmission design scheme is more robust to the hardware impairments than the conventional non-robust scheme that ignores the impact of the hardware impairments.

中文翻译：

---

RIS 辅助 MISO 系统中具有硬件缺陷的安全无线通信

在实践中，残留的收发器硬件损伤不可避免地会导致失真噪声，从而导致性能损失。在这封信中，我们研究了在收发器硬件损坏的情况下可重构智能表面 (RIS) 辅助安全通信系统的稳健传输设计。我们的目标是最大化保密率，同时确保基站有源波束成形的发射功率约束和 RIS 无源波束成形的单位模数约束。为了解决这个问题，我们采用交替优化方法来迭代优化一组变量，同时保持另一组变量不变。具体来说，采用逐次凸逼近（SCA）方法来求解主动波束成形优化子问题，而无源波束成形是通过使用半定规划（SDP）方法获得的。数值结果表明，与忽略硬件损伤影响的传统非鲁棒方案相比，所提出的传输设计方案对硬件损伤具有更强的鲁棒性。