Dual-polarized transmission offers a promising approach to improve spectral efficiency in multiantenna networks by reusing frequency and time resources across orthogonal polarization domains. Building upon this advantage, this paper investigates interference management in mixed dual-polarized integrated satellite-terrestrial networks (MDP-ISTN), comprising a circularly polarized (CP) satellite sub-network and a linearly polarized (LP) terrestrial sub-network. To this end, we employ rate-splitting multiple access (RSMA), which enables flexible non-orthogonal transmission through partial interference decoding and partial interference treating-as-noise. Specifically, to jointly mitigate both inter-network interference between the CP low Earth orbit (LEO) satellite and LP terrestrial sub-networks as well as intra-network interference within each sub-network, we propose an MDP-RSMA framework that incorporates inter-network rate-splitting (RS) with a super-common message together with intra-network RS. Moreover, we account for practical challenges in MDP-ISTN, including polarization mismatch, channel depolarization, and imperfect channel state information at the transmitter. To maximize the minimum user rate among all satellite and terrestrial users, we formulate a robust precoder optimization problem and develop a weighted minimum mean square error (WMMSE)-based algorithm tailored to the proposed MDP-RSMA. Numerical results demonstrate that the proposed scheme significantly improves the minimum user rate over several baseline schemes across diverse MDP-ISTN scenarios.

翻译：双极化传输通过在正交极化域复用频率和时间资源，为多天线网络提升频谱效率提供了有效途径。基于该优势，本文研究了包含圆极化(CP)卫星子网与线极化(LP)地面子网的混合双极化集成卫星-地面网络(MDP-ISTN)中的干扰管理问题。为此，我们采用速率分裂多址接入(RSMA)技术，通过部分干扰解码与部分干扰视作噪声的处理方式实现灵活的非正交传输。具体而言，为联合抑制CP低轨(LEO)卫星与LP地面子网间的跨网络干扰，以及各子网内部的同网络干扰，我们提出MDP-RSMA框架，该框架融合了包含超公共消息的跨网络速率分裂(RS)与同网络速率分裂。此外，我们考虑了MDP-ISTN中的实际挑战，包括极化失配、信道去极化效应及发射端非完美信道状态信息。为最大化所有卫星和地面用户中的最小用户速率，我们构建了鲁棒预编码器优化问题，并针对所提出的MDP-RSMA设计了基于加权最小均方误差(WMMSE)的算法。数值结果表明，在多种MDP-ISTN场景下，所提方案较若干基线方案显著提升了最小用户速率。