This paper tackles the deployment challenges of Simultaneous Transmitting and Reflecting Reconfigurable Intelligent Surface (STAR-RIS) in communication systems. Unlike existing works that use fixed deployment setups or solely optimize the location, this paper emphasizes the joint optimization of the location and orientation of STAR-RIS. This enables searching across all user grouping possibilities and fully boosting the system's performance. We consider a sum rate maximization problem with joint optimization and hybrid beamforming design. An offline heuristic solution is proposed for the problem, developed based on differential evolution and semi-definite programming methods. In particular, a point-point representation is proposed for characterizing and exploiting the user-grouping. A balanced grouping method is designed to achieve a desired user grouping with low complexity. Numerical results demonstrate the substantial performance gains achievable through optimal deployment design.

翻译：本文解决了通信系统中同时透射反射可重构智能表面（STAR-RIS）的部署难题。与采用固定部署方案或仅优化位置的现有工作不同，本文强调对STAR-RIS的位置和方向的联合优化。这使得能够搜索所有可能的用户分组方案，从而充分提升系统性能。我们考虑了一个涉及联合优化与混合波束成形设计的和速率最大化问题。针对该问题提出了一种基于差分进化与半定规划方法的离线启发式求解方案。特别地，提出了一种点对点表示方法来表征和利用用户分组特性。为以低复杂度实现理想的用户分组，设计了一种均衡分组方法。数值结果证明了通过优化部署设计所能获取的显著性能增益。