Transmissive Beyond Diagonal RIS-Mounted LEO Communication for NOMA IoT Networks

TL;DR

This paper introduces a novel transmissive beyond diagonal RIS framework for LEO satellite networks with NOMA, optimizing power and phase shifts to significantly improve spectral efficiency in next-generation IoT communications.

Contribution

It proposes a new T-BD-RIS architecture for LEO satellites, with optimized NOMA power allocation and phase shift design, advancing satellite-based IoT network performance.

Findings

T-BD-RIS enhances spectral efficiency in satellite networks.

Optimized power and phase shift design improves system performance.

Numerical results confirm advantages over traditional methods.

Abstract

Reconfigurable Intelligent Surface (RIS) technology has emerged as a transformative solution for enhancing satellite networks in next-generation wireless communication. The integration of RIS in satellite networks addresses critical challenges such as limited spectrum resources and high path loss, making it an ideal candidate for next-generation Internet of Things (IoT) networks. This paper provides a new framework based on transmissive beyond diagonal RIS (T-BD-RIS) mounted low earth orbit (LEO) satellite networks with non-orthogonal multiple access (NOMA). The NOMA power allocation at LEO and phase shift design at T-BD-RIS are optimized to maximize the system's spectral efficiency. The optimization problem is formulated as non-convex, which is first transformed using successive convex approximation and then divided into two problems. A closed-form solution is obtained for LEO satellite transmit power using KKT conditions, and a semi-definite relaxation approach is adopted for the T-BD-RIS phase shift design. Numerical results are obtained based on Monte Carlo simulations, which demonstrate the advantages of T-BD-RIS in satellite networks.