论文标题
面向公平的多个RISS辅助MMWave传输：随机优化方法
Fairness-Oriented Multiple RISs-Aided MmWave Transmission: Stochastic Optimization Methods
论文作者
论文摘要
在毫米波（MMWAVE）系统中，由于其对存在的敏感性，确保通信的可靠连接性是一项挑战。为了在随机阻塞的存在下提高MMWave系统的鲁棒性，部署了多个可重构的智能表面（RISS）以增强空间多样性的增益，然后根据随机优化的优化设计可靠的光束成形，以最大程度地减少多个用户中的最大打故障概率，以确保多个用户的公平性。 Under the stochastic optimization framework, we adopt the stochastic majorization--minimization (SMM) method and the stochastic successive convex approximation (SSCA) method to construct deterministic surrogate problems at each iteration for new channel realizations, and obtain the closed-form solutions of the precoding matrix at the base station (BS) and the passive beamforming vectors at the RISs.两种随机优化方法已被证明融合到原始随机问题的一组固定点。最后，仿真结果表明，与基准溶液相比，与RIS ADED系统中提出的稳健光束形成可以有效补偿由随机阻塞的存在，尤其是在高阻滞概率下引起的性能损失。
In millimeter wave (mmWave) systems, it is challenging to ensure the reliable connectivity of communications due to its sensitivity to the presence of blockages. In order to improve the robustness of the mmWave system under the presence of the random blockages, multiple reconfigurable intelligent surfaces (RISs) are deployed to enhance the spatial diversity gain, and robust beamforming is then designed based on a stochastic optimization for minimizing the maximum outage probability among multiple users to ensure the fairness. Under the stochastic optimization framework, we adopt the stochastic majorization--minimization (SMM) method and the stochastic successive convex approximation (SSCA) method to construct deterministic surrogate problems at each iteration for new channel realizations, and obtain the closed-form solutions of the precoding matrix at the base station (BS) and the passive beamforming vectors at the RISs. Both stochastic optimization methods have been proved to converge to the set of stationary points of the original stochastic problems. Finally, simulation results show that the proposed robust beamforming in the RIS-aided system can effectively compensate for the performance loss caused by the presence of the random blockages, especially at high blockage probability, compared with the benchmark solutions.
