The main difficulty concerning optimizing the mutual information (MI) in reconfigurable intelligent surface (RIS)-aided communication systems with discrete signaling is the inability to formulate this optimization problem in an analytically tractable manner. Therefore, we propose to use the cutoff rate (CR) as a more tractable metric for optimizing the MI and introduce two optimization methods to maximize the CR, assuming perfect knowledge of the channel state information (CSI). The first method is based on the projected gradient method (PGM), while the second method is derived from the principles of successive convex approximation (SCA). Simulation results show that the proposed optimization methods significantly enhance the CR and the corresponding MI.
翻译:在可重新配置智能表面辅助通信系统的相互信息(MI)优化方面,使用离散信号的辅助通信系统的主要困难是无法以可分析的可移动方式提出这一优化问题,因此,我们提议使用截断率作为优化MI的更可移动的衡量标准,并引入两种优化方法,以最大限度地实现CR,假设对频道状态信息有完全的了解。第一种方法是以预测的梯度法为基础,而第二种方法是从连续的二次曲线近似(SCA)的原则衍生而来。模拟结果表明,拟议的优化方法大大加强了CR和相应的MI。