Multiple STAR-RISs-Empowered Multi-User Communications with Diversified QoS Provisioning

TL;DR

This paper introduces a QoS-aware multi-user communication system using multiple STAR-RISs, optimizing configurations to maximize aggregate data rates while ensuring minimum QoS requirements for diverse users.

Contribution

It develops an optimization framework employing Lagrangian duality and block coordinate descent to enhance sum rate with guaranteed QoS in STAR-RIS-assisted networks.

Findings

Significant sum rate improvement demonstrated through simulations

Effective QoS provisioning for heterogeneous users achieved

Optimization approach converges to near-optimal solutions

Abstract

This paper proposes a quality-of-service (QoS)-aware multi-user communication framework facilitated by multiple simultaneously transmitting and reflecting reconfigurable intelligent surfaces (STAR-RISs). The user groups are established based on their QoS requirements specified by the minimum data rate, which is provisioned by the optimized transmission and reflection configurations of the STAR-RISs. Particularly, we formulate an optimization problem to maximize the aggregate link rate across all users, under group-specified rate requirements by jointly considering the transmit beamforming and STAR-RIS configurations. Then, we employ the Lagrangian duality with quadratic transformation to tackle the non-convexity of the objective. We decompose the problem within a block coordinate descent framework, and the subproblems are solved through convex approximation and iterated to approach the optimal solution. Simulation results demonstrate the effectiveness of the proposed method in enhancing the system sum rate with guaranteed QoS performance for heterogeneous users, offering valuable insights for the deployment of STAR-RISs in future QoS-aware wireless networks.