Simultaneously Transmitting and Reflecting Reconfigurable Intelligent Surfaces Empowered Cooperative Rate Splitting...

Area of Science:

• Wireless Communication
• Information Theory
• Metamaterials

Background:

• Cooperative Rate Splitting (CRS) enhances spectral efficiency in wireless networks.
• Reconfigurable Intelligent Surfaces (RIS) offer a promising approach to control wireless propagation environments.
• Integrating CRS with advanced RIS technologies presents new opportunities for system optimization.

Purpose of the Study:

• To propose a novel STAR RIS-assisted CRS transmission framework.
• To investigate the benefits of synergizing CRS with user relaying and STAR RIS.
• To maximize the minimum user rate under power and energy constraints.

Main Methods:

• A unified Successive Convex Approximation (SCA)-based Alternative Optimization (AO) algorithm is proposed.
• Joint optimization of beamforming, rate allocation, and time allocation.
• A low-complexity algorithm with closed-form passive beamforming design is developed.

Main Results:

• The proposed framework significantly enhances user fairness compared to conventional CRS schemes.
• The novel framework outperforms other STAR RIS-empowered multiple access schemes.
• The low-complexity algorithm achieves performance close to the AO method with reduced computational burden.

Conclusions:

• Synergizing CRS with user relaying and STAR RIS offers substantial advantages in wireless communication.
• The proposed optimization framework effectively improves user fairness and system performance.
• The low-complexity design provides a practical solution for efficient STAR RIS-assisted CRS systems.