In this6study, the channel estimation problem is investigated for a wireless communication system assisted by a reconfigurable intelligent surface (RIS). The RIS thus creates an assistant channel, which has the features of positivity and dominance. Owing to these features, the channel estimation problem is formulated as a constrained residual sum of squares minimisation problem, which differs radically from the traditional channel estimation issue. An efficient Lagrange multiplier and dual ascent-based estimation scheme is then designed to obtain an iterative solution for the estimator. Moreover, the Cramér–Rao lower bounds are deduced as a performance benchmark. Simulation results show that the authors' designed scheme improves the estimation accuracy up to 33%, compared with the conventional least-square method in the low signal-to-noise ratio regime.

中文翻译：

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可重构智能地面辅助无线通信系统中面向特征的信道估计

在本研究中，研究了可重构智能表面（RIS）辅助的无线通信系统的信道估计问题。因此，RIS创建了一个具有积极性和优势性的辅助通道。由于这些特征，信道估计问题被表述为约束残差平方和最小化问题，这与传统的信道估计问题根本不同。然后设计一种有效的拉格朗日乘数和基于对偶上升的估计方案，以获得估计器的迭代解。此外，推导了Cramér-Rao下界作为性能基准。仿真结果表明，作者设计的方案将估计精度提高了33％，