论文标题
通过可重构智能表面进行自适应编码和频道成型：信息理论分析
Adaptive Coding and Channel Shaping Through Reconfigurable Intelligent Surfaces: An Information-Theoretic Analysis
论文作者
论文摘要
研究了由可重构智能表面（RIS）帮助的通信链接，其中发射器可以通过有限速率控制链路控制RIS的状态。通道状态信息（CSI）是根据试点辅助的通道估计在接收器中获取的，并且可能与发射器共享也可能不会共享。考虑到具有不完美CSI的准静态褪色通道，显示能力调整的信号传导可实施传输信号的关节编码和RIS的响应。这证明了基于RIS的调制或“单RF MIMO”系统的信息理论最优性。此外，提出了基于单独的分层编码的新型信号传导策略，该策略提出了在接收器上实用连续取消型解码。数值实验表明，固定RI的反射模式的常规方案，与传输信息无关，以最大化可实现的速率是严格次优的，并且在所有实用的信噪比（SNR）水平上所提出的自适应编码策略的表现均优于所提出的自适应编码策略。
A communication link aided by a reconfigurable intelligent surface (RIS) is studied in which the transmitter can control the state of the RIS via a finite-rate control link. Channel state information (CSI) is acquired at the receiver based on pilot-assisted channel estimation, and it may or may not be shared with the transmitter. Considering quasi-static fading channels with imperfect CSI, capacity-achieving signalling is shown to implement joint encoding of the transmitted signal and of the response of the RIS. This demonstrates the information-theoretic optimality of RIS-based modulation, or "single-RF MIMO" systems. In addition, a novel signalling strategy based on separate layered encoding that enables practical successive cancellation-type decoding at the receiver is proposed. Numerical experiments show that the conventional scheme that fixes the reflection pattern of the RIS, irrespective of the transmitted information, as to maximize the achievable rate is strictly suboptimal, and is outperformed by the proposed adaptive coding strategies at all practical signal-to-noise ratio (SNR) levels.
