Digital Fairness Algorithms for Satellite Uplink NOMA

2025-02-04

AI Summary

To address user access unfairness arising from spatiotemporal heterogeneity in link budgets within satellite-based uplink NOMA IoT systems, this paper proposes a single- and multi-slot joint optimization framework to achieve user rate fairness. We innovatively design a receiver-coordinated power control and successive interference cancellation (SIC) decoding order co-optimization mechanism, and develop a low-complexity multi-slot rate-fairness algorithm tailored to onboard real-time constraints. The proposed method significantly improves the worst-user achievable rate under limited SIC steps—yielding a minimum rate gain of over 92%—while simultaneously satisfying stringent onboard computational and latency requirements. By ensuring digital fairness without compromising system deployability, our solution enables efficient and equitable access for large-scale, geographically dispersed IoT terminals in satellite networks.

Technology Category

• Planning, Routing, and Scheduling: Optimization of Spatio-temporal Systems
• Search and Optimization: Mixed Discrete/Continuous Search
• Constraint Satisfaction and Optimization: Distributed CSP/Optimization

Application Category

• User Modeling, Personalization and Recommendation: Fairness-aware retrieval and ranking
• Systems and Infrastructure for Web, Mobile and WoT: Energy management for devices in mobile Web and WoT environments
• Economics, Online Markets and Human Computation: Economics and fairness of platforms and recommendation systems

Abstract

Achieving digital fairness by using NOMA is one of the more pressing issues in modern wireless communication systems for 5G/6G networks. This is particularly true in the case of satellite uplink systems supporting a population of IoT wireless devices scattered in a wide coverage area. In this scenario, the variability of the link budget across space and time increases the challenges of preventing a situation where only a subset of network users can transmit while others are left unable to do so. This work investigates the characteristics of an uplink NOMA system with the goal of equalizing the achievable rate of the IoT network subscribers. Within the context of single-slot NOMA, two key outcomes are achieved: the determination of the optimal SIC ordering at the receiver and the exploration of power moderation, coordinated by the receiver, to maximize the minimum user rate. In the context of multi-slot NOMA, which is particularly relevant to the satellite scenario under consideration, a user rate equalization algorithm is proposed and its performance is analyzed numerically. The trade-off between network performance, measured in terms of user rates, and complexity, determined by the number of SIC steps implemented at the receiver, is thoroughly evaluated for the satellite scenario under consideration.

Problem

• Achieving digital fairness in 5G/6G satellite uplink NOMA
• Equalizing IoT network subscribers' achievable rates
• Optimizing SIC ordering and power moderation in NOMA

Innovation

• Optimal SIC ordering determination
• Receiver-coordinated power moderation
• Multi-slot user rate equalization