AI 中文总结
该研究针对IRS关联策略的次优问题，提出基于几何模型的混合IRS全局最优部署方法与机会关联策略，仿真显示其性能显著优于传统最近关联策略。
AI 中文摘要
混合智能反射表面（IRS）架构是一种新型技术，兼具无源IRS与有源IRS的优势：无源IRS拥有大孔径，有源IRS可提供额外功率放大。现有研究表明，在假设IRS位于收发信机之间、且IRS与收发信机的高度差远小于收发信机间链路距离的前提下，当无源IRS部署在收发信机附近、有源IRS更靠近接收机且放大功率递减时，IRS辅助无线网络可达到最优性能。然而，多数现有IRS相关研究在IRS关联策略中盲目采用该假设，本质上成为一种局部选择策略，虽具备分析简便性，却以次优性能为代价。这一局限性促使我们针对所有类型的IRS寻找全局最优部署策略。为此，我们首先采用集成路径损耗距离的几何模型（对应乘积型路径损耗律的卡西尼卵形线、对应和型路径损耗律的椭圆），利用这些模型确定混合IRS的最优位置；随后，基于集成路径损耗模型，为混合IRS设计一种新颖的机会关联策略。此外，我们通过仿真验证了所提方法的有效性，结果显示其性能显著优于传统最近关联策略，尤其在混合IRS和有源IRS场景中表现突出。
英文摘要
The hybrid intelligent reflecting surface (IRS) architecture is a novel technology that leverages the advantages of both passive and active IRS; the passive IRS offers a large aperture, while the active IRS provides additional power amplification. Prior studies have shown that the optimal performance of IRS-assisted wireless networks is achieved when the passive IRS is deployed near the transceivers and the active IRS is closer to the receiver with decreasing amplification power, assuming that the IRS is located between transceivers and that the height difference between IRS and transceivers is much smaller than the link distance between transceivers. However, most of the prior works on IRS blindly adopted this assumption in the IRS association policy, which essentially becomes a partial selection strategy that offers analytical simplicity at the cost of sub-optimal performance. This limitation motivated us to find the globally optimal deployment strategy for all types of IRS. To this end, we first employ the \emph{geometric models} for integrated path loss distance (known as Cassini oval and Ellipse for product- and sum-distance path loss laws, respectively) and use them to determine the optimal locations of the hybrid IRS. Then, we design a novel \emph{opportunistic association policy} for hybrid IRS based on the integrated path loss model. Furthermore, we validate our proposed methods through simulations and show that they significantly outperform the conventional nearest association policy, especially for hybrid and active IRS.
