A Global Beam Placement and Resource Allocation Design for MEO-Constellation-Based Satellite Communication Systems

Non-terrestrial networks (NTNs) are expected to become a key component of 6G by extending connectivity beyond terrestrial footprints and by improving service resilience and coverage at a global scale. In this context, medium-earth-orbit (MEO) constellations offer an attractive balance among coverage, latency, and capacity, but their large-scale and time-varying topology makes beam orchestration and radio resource management highly challenging. This paper investigates the joint design of beam placement, bandwidth allocation, and power control for large-scale MEO-based NTNs under payload resource constraints and user quality-of-service requirements. We propose a centralized three-stage framework that first clusters users into beam-service groups, then estimates cluster-specific bandwidth and power through convex optimization, and finally performs MEO-cluster matching to minimize the total power consumption of the constellation. The proposed design captures the dynamic visibility of MEO satellites and the tradeoff among beam activation, spectrum usage, and energy expenditure. Simulation results for a 15-satellite MEO constellation serving 1112 globally distributed users over 150 time slots show that the proposed method satisfies more than 97% of users while significantly reducing total power consumption compared with benchmark approaches. Cross-interference and frequency-reuse tradeoffs are also examined to highlight spectrum-sustainability aspects. These results position the proposed framework as a practical and scalable enabler for resource-efficient orchestration in 6G NTN systems.