Energy-Efficient LEO Satellite-to-Terrestrial Communication via Pinching-Antenna Relay System
Abstract
Low Earth orbit (LEO) satellite communications face critical challenges in serving blocked users due to severe penetration loss and signal blockage. Conventional active relay solutions incur high energy consumption and hardware costs. This letter introduces a pinching-antenna relay system (PARS) for energy-efficient LEO satellite communication in blockage environments. By using dielectric waveguides with dynamically reconfigurable PAs, PARS provides flexible spatial diversity and beamforming gains with the circuit control and PA actuation power. We formulate an energy-efficiency (EE) maximization problem by jointly optimizing the satellite precoding and PA positions. A Dinkelbach-based block coordinate descent (BCD) algorithm is proposed to solve the non-convex fractional program via iterative weighted minimum mean square error (WMMSE) transformation and projected gradient descent (PGD) updates. Simulations show that the proposed PARS achieves superior EE over direct transmission, fixed-PA, decode-and-forward (DF) and zero-forcing (ZF) baselines. The resulting performance crossover further identifies the PARS-dominant region, providing practical deployment guidance for blockage-affected scenarios.