Optimal Handover Strategies in LEO Satellite Networks

Existing theoretical analyses of satellite mega-constellations often rely on restrictive assumptions, such as short serving times, or lack tractability when evaluating realistic handover strategies. Motivated by these limitations, this paper develops a general analytical framework for accurately characterising the ergodic capacity of low Earth orbit (LEO) satellite networks under arbitrary handover strategies. Specifically, we model the transmission link as shadowed-Rician fading and introduce the persistent satellite channel, wherein the channel process is governed by an i.i.d. renewal process under mild assumptions of uncoordinated handover decisions and knowledge of satellite ephemeris and fading parameters. Within this framework, we derive the ergodic capacity (persistent capacity) of the persistent satellite channel using renewal theory and establish its relation to the non-persistent capacity studied in prior work. To address computational challenges, we present closed-form upper and lower bounds on persistent capacity. The optimal handover problem is formulated as a non-linear fractional program, obtaining an explicit decision rule via a variant of Dinkelbach's algorithm. We further demonstrate that a simpler handover strategy maximising serving capacity closely approximates the optimal strategy, providing practical insights for designing high-throughput LEO satellite communication systems.