Radio resource allocation for direct-to-device services with distributed satellite systems

Distributed satellite architectures are a promising solution to enhance telecommunication services over densely populated regions. However, splitting a large antenna across multiple platforms introduces significant interference challenges, particularly due to the presence of grating lobes. Previous studies have explored mitigating grating lobes by adjusting satellite positions, with encouraging results. Yet, from a resource management perspective, the optimal strategy to serve user terminals in device-to-device (D2D) applications, where high signal strength is essential for maintaining link consistency, remains unclear. This work examines a scenario where multiple platforms are arranged in a regular spatial configuration, whether physically connected in a single large satellite or distributed across several smaller ones. Leveraging the regularity of the radiated power pattern, we propose a resource allocation strategy designed to avoid interference from grating lobes. We compare the conventional N-color frequency reuse schemes with a null-grid-based approach that exploits the system’s spatial regularity. Results are presented for varying numbers of colors, with additional analysis of users fairness, which does not always align with maximizing total system capacity. The findings provide valuable insights into selecting resource allocation strategies that maintain strong communication links while ensuring a more equitable distribution of service among users.