基于速率分割的可重构智能表面辅助星地融合网络鲁棒安全传输方案

Rate splitting based robust secure transmission scheme in RIS-assisted satellite-terrestrial integrated network

首先,考虑一个可重构智能表面(RIS)辅助的星地融合网络,卫星采用速率分割多址技术服务多个地球站,而地面基站则在RIS的协助下利用多播技术服务多个地面用户,同时还存在多个窃听者企图获取卫星的隐私信号。其次,在仅已知窃听者非完美信道状态信息的条件下,以所有用户的通信质量要求及最大窃听概率为约束条件,建立一个以最小化系统总发射功率为目标函数的联合优化问题。为了求解该非凸问题,采用S-procedure和连续凸逼近方法将复杂的窃听概率约束转化为可行的凸约束;利用基于核范数的惩罚函数方法提出一种鲁棒联合优化算法以迭代求解波束成形权矢量和发射功率。最后,计算机仿真结果验证了所提传输方案的有效性和优越性。

Firstly,considering a reconfigurable intelligent surface(RIS)assisted satellite terrestrial integrated network,the satellite employed the rate splitting multiple access technique to serve multiple earth stations in the presence of multi-ple eavers-droppers(Eves),while the terrestrial network leveraged multicast technique to serve many ground users with the assist of RIS.Secondly,assuming that only the Eves’imperfect channel state information could be obtained,a joint optimization problem was formulated to minimize the total transmit power,while ensuring the quality-of-service re-quirement for all users,and adhering to intercept probabilistic constraints.To tackle this noncom vex problem,the S-procedure and the successive convex approximation approach were employed to convert the intercept probabilistic constraints into solved ones.And then a nuclear norm-based penalty function was employed to propose a robust joint al-gorithm to obtain the robust beamforming weight vectors and transmit power.Finally,the simulation results demonstrate the effectiveness and superiority of the proposed transmission scheme.