光学可重构智能表面对VLC系统信道估计的影响
Impact of Optical Reconfigurable Intelligent Surfaces on Channel Estimation for VLC Systems
AI总结：
本文研究实际非理想信道估计场景下ORIS对VLC系统的影响，采用PSAM和ST两种导频估计技术，发现ORIS结合PSAM可实现约5 bit/s/Hz的频谱效率，性能优于无ORIS的理想信道场景，且系统对ORIS方向不完美具有鲁棒性。
AI中文摘要：
可见光通信（VLC）为室内提供无线数据连接，但其性能受链路遮挡严重限制。光学可重构智能表面（ORIS）已被提出用于克服这些遮挡，但现有文献大多依赖理想信道状态信息的不切实际假设。本文在实际非理想信道估计场景下研究ORIS元件对VLC系统的贡献，采用两种基于导频的估计技术：导频符号辅助调制（PSAM）和叠加训练（ST），分析通信性能，评估数据功率分配因子和平均正交频分复用（OFDM）符号的影响。结果表明，部署ORIS的PSAM可实现最优大数据功率分配因子，其频谱效率提升超过无ORIS部署的理想信道估计场景；ST在平均OFDM符号数量多时表现良好，但部署ORIS时无法超越PSAM的性能。还发现系统对ORIS方向不完美具有鲁棒性，即使仅一半元件准确对齐，性能仍可接受。最终表明，使用ORIS结合PSAM可实现约5 bit/s/Hz的频谱效率，性能与无遮挡视距链路相当甚至更优。
英文摘要：
Visible light communication (VLC) offers wireless data connectivity indoors, yet its performance is severely limited by link blockages. While optical reconfigurable intelligent surfaces (ORISs) have been proposed to overcome these blockages, existing literature predominantly relies on the unrealistic assumption of ideal channel state information. In this paper we investigate the contribution of ORIS elements in VLC systems under practical, non-ideal channel estimation scenarios. We analyze the communication performance using two pilot-based estimation techniques: pilot symbol assisted modulation (PSAM) and superimposed training (ST), evaluating the impact of data power allocation factors and averaged orthogonal frequency division multiplexing (OFDM) symbols. Our results show that PSAM with an ORIS deployment enables optimal large data power allocation factors, resulting in spectral efficiency improvements that surpass scenarios with ideal channel estimates but without ORIS deployment. While ST performs well with a large number of averaged OFDM symbols, it is unable to overcome the performance of PSAM when ORIS elements are deployed. We also find the system robust to imperfect ORIS orientation; even with only half of the elements accurately aligned, performance remains acceptable. Ultimately, we show that spectral efficiency values of approximately 5 bits/s/Hz are achievable using ORIS with PSAM, a performance comparable to, or even exceeding, that of unobstructed line-of-sight links.
