Distributed Precoding for Satellite-Terrestrial Integrated Networks Without Sharing CSIT: A Rate-Splitting Approach
share
Satellite-terrestrial integrated networks (STINs) are promising architecture for providing global coverage. In STINs, full frequency reuse between a satellite and a terrestrial base station (BS) is encouraged for enhancing spectral efficiency, which accounts for non-negligible amount of interference. To address the interference management problem in STINs, this paper proposes a novel distributed precoding method. Key features of our method are: i) a rate-splitting (RS) strategy is incorporated for efficient interference management, ii) precoders are designed in a distributed way without sharing channel state information between a satellite and a terrestrial BS. Specifically, to design precoders in a distributed fashion, we put forth a spectral efficiency decoupling technique. This technique disentangles the total spectral efficiency into two distinct terms, each dependent solely on the satellite's precoder and the terrestrial BS's precoder, respectively. Then, to resolve the non-smoothness raised by adopting the RS strategy, we approximate the spectral efficiency expression as a smooth function; thereafter we develop a generalized power iteration inspired optimization algorithm built based on the first-order optimality condition. Simulation results demonstrate that the proposed method improves the spectral efficiency (around 20 29 existing distributed precoding schemes.
READ FULL TEXT