<p>➀ Satellite and terrestrial networks are rapidly converging to achieve global seamless connectivity, driven by consumer demand for ubiquitous access;</p><p>➁ Direct-to-device (D2D) technology enables standard smartphones to connect directly to satellites without additional hardware, exemplified by Vodafone's trials with AST SpaceMobile;</p><p>➂ Challenges include latency in transparent satellite architectures, high costs of maintaining satellite constellations, and balancing technical viability with commercial sustainability.</p>