Heuristic Solution to Joint Deployment and Beamforming Design for STAR-RIS Aided Networks
Bai Yan, Qi Zhao, Jin Zhang, J. Andrew Zhang
TL;DR
The paper studies joint deployment and orientation of STAR-RIS in a downlink MU-MISO system to maximize sum rate. It introduces a point-point user-grouping representation and a differential evolution-based solver (DEBG) that combines DE with SDP for hybrid beamforming, plus a balanced grouping mechanism to select boundary users. Key contributions include offline optimization of location, orientation, and beamforming, as well as a structured framework that demonstrates substantial performance gains and robustness under imperfect CSI. The approach provides practical guidance for deploying STAR-RIS in quasi-static scenarios, highlighting that symmetric, user-near deployments yield the best outcomes and that balancing groupings across transmission and reflection sides is crucial for fully leveraging STAR-RIS capabilities.
Abstract
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.
