Handover-Aware Power Minimization for Networked LEO Satellite Communications: Joint Cooperative Beamforming and Scheduling

TL;DR

This paper proposes a handover-aware, power-efficient transmission scheme for networked LEO satellite systems, optimizing joint beamforming and scheduling to reduce power consumption amid frequent handovers and orbital dynamics.

Contribution

It introduces a novel two-segment frame structure and an iterative optimization algorithm for joint beamforming and scheduling under handover constraints in LEO satellite networks.

Findings

Significant power savings demonstrated in simulations.

Improved feasibility over baseline schemes.

Effective handling of handover-related power costs.

Abstract

Networked low Earth orbit (LEO) satellite constellations enabled by inter-satellite links offer a promising path toward ubiquitous broadband non-terrestrial services. However, fast orbital motion induces frequent scheduling updates and handovers, while stringent on-board constraints (e.g., limited radio-frequency chains) tightly couple user scheduling with cooperative beamforming. This paper investigates handover-aware power-efficient downlink transmission in networked LEO systems under statistical channel state information. We introduce a two-segment frame structure that separates handover-related operations from user-plane transmission, and propose a power consumption model that captures both the switching cost of newly established satellite-user links and the reduced effective transmission window during handover. Using a hardening-bound ergodic-rate metric, we formulate a per-frame network-wide power minimization problem with joint cooperative beamforming and implicit scheduling under segmented quality-of-service constraints, per-satellite power budgets, and serving-cardinality limits. To address scheduling-induced combinatorial sparsity and nonconvex fractional rate constraints, we develop an iterative algorithm that combines a reweighted $\ell_2$ surrogate with a penalty-based relaxation and a fractional-programming inner loop, yielding a sequence of convex second-order cone programs. Simulations based on time-varying orbital dynamics with frame-wise serving-set evolution and maritime user data quantify the power-handover tradeoff and demonstrate consistent power savings and improved feasibility over non-cooperative and pre-scheduled cooperative baselines.