Ultra-Dense LEO: Integration of Satellite Access Networks into 5G and Beyond

To support the explosive growth of wireless devices and applications, various access techniques need to be developed for future wireless systems to provide reliable data services in vast areas. With recent significant advances in ultra-dense low Earth orbit (LEO) satellite constellations, satellite access networks (SANs) have shown their significant potential to integrate with 5G and beyond to support ubiquitous global wireless access. In this article, we propose an enabling network architecture for dense LEO-SANs in which the terrestrial and satellite communications are integrated to offer more reliable and flexible access. Through various physical-layer techniques such as effective interference management, diversity techniques, and cognitive radio schemes, the proposed SAN architecture can provide seamless and high-rate wireless links for wireless devices with different quality of service requirements. Three extensive applications and some future research directions in both the physical layer and network layer are then discussed.