Coverage and Spectral Efficiency of NOMA-Enabled LEO Satellite Networks with Ordering Schemes

2025-01-10

AI Summary

This study addresses the joint optimization of coverage performance and spectral efficiency in low-Earth-orbit (LEO) satellite downlink non-orthogonal multiple access (NOMA). We develop an analytical framework integrating stochastic geometry, successive interference cancellation (SIC) reception, and weather-aware channel modeling. First, we propose the instantaneous signal-to-interference-plus-noise ratio (ISINR)-based user ordering criterion, quantifying the impacts of mainlobe gain, constellation size–altitude trade-offs, and SIC residual interference on coverage probability. Second, we jointly optimize power allocation and user pairing to maximize fairness-aware spectral efficiency. Analytical and simulation results show that NOMA outperforms orthogonal multiple access (OMA) only within a specific SINR threshold range; the aggregate spectral efficiency improves by up to 35% over OMA; two-user NOMA achieves optimal sum rate; and distinct power allocation schemes exhibit well-defined effective SINR operating boundaries.

Technology Category

• Planning, Routing, and Scheduling: Optimization of Spatio-temporal Systems
• Search and Optimization: Evaluation and Analysis
• Constraint Satisfaction and Optimization: Constraint Optimization

Application Category

• Security and Privacy: Large-scale security measurements
• Systems and Infrastructure for Web, Mobile and WoT: Energy management for devices in mobile Web and WoT environments
• Search and Retrieval-Augmented AI: Efficiency and scalability of Web search engines

Abstract

This paper investigates an analytical model for low-earth orbit (LEO) multi-satellite downlink non-orthogonal multiple access (NOMA) networks. The satellites transmit data to multiple NOMA user terminals (UTs), each employing successive interference cancellation (SIC) for decoding. Two ordering schemes are adopted for NOMA-enabled LEO satellite networks, i.e., mean signal power (MSP)-based ordering and instantaneous-signal-to-inter-satellite-interference-plus-noise ratio (ISINR)-based ordering. For each ordering scheme, we derive the coverage probabilities of UTs under different channel conditions. Moreover, we discuss how coverage is influenced by SIC, main-lobe gain, and tradeoffs between the number of satellites and their altitudes. Additionally, two user fairness-based power allocation (PA) schemes are considered, and PA coefficients with the optimal number of UTs that maximize their sum spectral efficiency (SE) are studied. Simulation results show that there exists a maximum signal-to-inter-satellite-interference-plus-noise ratio (SINR) threshold for each PA scheme that ensures the operation of NOMA in LEO satellite networks, and the benefit of NOMA only exists when the target SINR is below a certain threshold. Compared with orthogonal multiple access (OMA), NOMA increases UTs' sum SE by as much as 35%. Furthermore, for most SINR thresholds, the sum SE increases with the number of UTs to the highest value, whilst the maximum sum SE is obtained when there are two UTs.

Problem

• NOMA Technology
• Signal Optimization
• Low Earth Orbit Satellites

Innovation

• NOMA Technology
• Sorting Strategies
• Power Allocation Schemes