STAR-RIS Integrated Nonorthogonal Multiple Access and Over-the-Air Federated Learning Framework, Analysis, and Optimization

Abstract :

This project combines nonorthogonal multiple access (NOMA) and over-the-air federated learning (AirFL) using one simultaneous transmitting and reflecting reconfigurable intelligent surface (STAR-RIS).

The STAR-RIS optimizes hybrid user decoding order for interference mitigation and omnidirectional coverage extension. A closed-form expression for the optimality gap (also known as the convergence upper bound) between the actual loss and the optimal loss captures the effect of nonideal wireless channels on AirFL.

This analysis shows that active and passive beamforming schemes and wireless noise significantly impact learning performance. The optimality gap explicitly converges with a linear rate as the learning rate decreases during training.

By jointly designing user transmit power and STAR-RIS configuration mode, a mixed-integer nonlinear programming (MINLP) problem is formulated to accelerate convergence while meeting quality-of-service requirements.

Next, a trust-region-based successive convex approximation method and a penalty-based semidefinite relaxation approach handle the decoupled nonconvex subproblems iteratively. To find a suboptimal MINLP solution, an alternating optimization algorithm is developed.

Extensive simulation results show that: 1) the proposed framework can efficiently support NOMA and AirFL users via concurrent uplink communications; 2) our algorithms converge faster on independent and identically distributed (IID) and non-IID settings than the baselines; and 3) the well-tuned STAR-RIS improves spectrum efficiency and learning performance.

Keywords : Noma, Wireless Communication, Wireless Sensor Networks, Convergence, Optimization, 6g Mobile Communication, Uplink, Approximation Theory, Array Signal Processing, Concave Programming, Convex Programming, Integer Programming, Interference Suppression, Iterative Methods, Learning (Artificial Intelligence), Nonlinear Programming, Nonorthogonal Multiple Access, Quality Of Service, Radio Spectrum Management, Radiofrequency Interference, Telecommunication Computing

Note: Please discuss with our team before submitting this abstract to the college. This Abstract or Synopsis varies based on student project requirements.