Deep Reinforcement Learning-Based Cooperative Rate Splitting for Satellite-to-Underground Communication Networks
Kaiqiang Lin, Kangchun Zhao, Yijie Mao
TL;DR
This paper tackles the challenge of reliable downlink communication in satellite-to-underground networks plagued by soil attenuation and air–soil refraction. It introduces a cooperative rate-splitting (CRS) framework with an aboveground relay that decodes and forwards the common stream, and formulates a max-min fairness problem over power allocation, message splitting, and time-slot scheduling. A proximal policy optimization (PPO) based DRL framework with distribution-aware action modeling and a multi-branch actor is developed to solve the non-convex problem under uncertain channels. Across realistic underground pipeline scenarios, the PPO-based CRS significantly outperforms SDMA, RSMA, and greedy CRS benchmarks, demonstrating strong potential for robust, fair, and efficient satellite-to-underground communications.
Abstract
Reliable downlink communication in satellite-to-underground networks remains challenging due to severe signal attenuation caused by underground soil and refraction in the air-soil interface. To address this, we propose a novel cooperative rate-splitting (CRS)-aided transmission framework, where an aboveground relay decodes and forwards the common stream to underground devices (UDs). Based on this framework, we formulate a max-min fairness optimization problem that jointly optimizes power allocation, message splitting, and time slot scheduling to maximize the minimum achievable rate across UDs. To solve this high-dimensional non-convex problem under uncertain channels, we develop a deep reinforcement learning solution framework based on the proximal policy optimization (PPO) algorithm that integrates distribution-aware action modeling and a multi-branch actor network. Simulation results under a realistic underground pipeline monitoring scenario demonstrate that the proposed approach achieves average max-min rate gains exceeding $167\%$ over conventional benchmark strategies across various numbers of UDs and underground conditions.
