The Limits of D2D

Direct-to-device (D2D) satellite connectivity has emerged as a notable development in the mobile ecosystem, promising to extend mobile services beyond the reach of terrestrial networks. It has the potential to enhance coverage in remote and underserved areas and to provide an additional layer of resilience for emergency communications. However, while the technology has clear benefits, is advancing rapidly, and attracting significant attention, its practical role remains constrained by fundamental limitations in capacity and spectral efficiency.

Understanding D2D’s strengths with realistic expectations and not expecting it to substitute terrestrial networks but to supplement mobile’s coverage, will help define its use cases. To do this, the GSMA has studied the impact of different constellation and spectrum scenarios on D2D’s capabilities. Our analysis considers extremely positive scenarios where D2D has, for example, every MHz of mobile spectrum available to it and the maximum planned number of satellites in orbit. While this is an optimistic scenario, it paints the greatest extent of connectivity that can be offered through D2D.