  The ultra-dense deployment of interconnected satellites will characterize
future low Earth orbit (LEO) mega-constellations. Exploiting this towards a
more efficient satellite network (SatNet), this paper proposes a novel LEO
SatNet architecture based on distributed massive multiple-input multiple-output
(DM-MIMO) technology allowing ground user terminals to be connected to a
cluster of satellites. To this end, we investigate various aspects of
DM-MIMO-based satellite network design, the benefits of using this
architecture, the associated challenges, and the potential solutions. In
addition, we propose a distributed joint power allocation and handover
management (D-JPAHM) technique that jointly optimizes the power allocation and
handover management processes in a cross-layer manner. This framework aims to
maximize the network throughput and minimize the handover rate while
considering the quality-of-service (QoS) demands of user terminals and the
power capabilities of the satellites. Moreover, we devise an artificial
intelligence (AI)-based solution to efficiently implement the proposed D-JPAHM
framework in a manner suitable for real-time operation and the dynamic SatNet
environment. To the best of our knowledge, this is the first work to introduce
and study DM-MIMO technology in LEO SatNets. Extensive simulation results
reveal the superiority of the proposed architecture and solutions compared to
conventional approaches in the literature.
