  In this paper, we propose a terrestrial-satellite network (TSN) architecture
to integrate the ultra-dense low earth orbit (LEO) networks and the terrestrial
networks to achieve efficient data offloading. In TSN, each ground user can
access the network over C-band via a macro cell, a traditional small cell, or a
LEO-backhauled small cell (LSC). Each LSC is then scheduled to upload the
received data via multiple satellites over Ka-band. We aim to maximize the sum
data rate and the number of accessed users while satisfying the varying
backhaul capacity constraints jointly determined by the LEO satellite based
backhaul links. The optimization problem is then decomposed into two closely
connected subproblems and solved by our proposed matching algorithms.
Simulation results show that the integrated network significantly outperforms
the non-integrated ones in terms of the sum data rate. The influence of the
traffic load and LEO constellation on the system performance is also discussed.
