Department of Signal Theory and Communications, Universitat Politècnica de Catalunya, 08034 Barcelona, Spain.
Sensors (Basel). 2022 Nov 28;22(23):9238. doi: 10.3390/s22239238.
In this paper, we address the design of multi-user multiple-input single-output (MU-MISO) precoders for indoor visible light communication (VLC) systems. The goal is to minimize the transmitted optical power per light emitting diode (LED) under imperfect channel state information (CSI) at the transmitter side. Robust precoders for imperfect CSI available in the literature include noisy and outdated channel estimation cases. However, to the best of our knowledge, no work has considered adding robustness against channel quantization. In this paper, we fill this gap by addressing the case of imperfect CSI due to the quantization of VLC channels. We model the quantization errors in the CSI through polyhedric uncertainty regions. For polyhedric uncertainty regions and positive real channels, as is the case of VLC channels, we show that the robust precoder against channel quantization errors that minimizes the transmitted optical power while guaranteeing a target signal to noise plus interference ratio (SNIR) per user is the solution of a second order cone programming (SOCP) problem. Finally, we evaluate its performance under different quantization levels through numerical simulations.
在本文中，我们针对室内可见光通信（VLC）系统中的多用户多输入单输出（MU-MISO）预编码器设计问题进行了研究。我们的目标是在发送方信道状态信息（CSI）不完善的情况下，最小化每个发光二极管（LED）的发射光功率。在文献中，针对 CSI 不完善的稳健预编码器包括噪声和过时的信道估计情况。然而，据我们所知，尚无工作考虑针对信道量化添加稳健性。在本文中，我们通过处理由于 VLC 信道量化而导致的 CSI 不完善情况来填补这一空白。我们通过多面体不确定性区域对 CSI 中的量化误差进行建模。对于多面体不确定性区域和正实信道（如 VLC 信道的情况），我们证明了在保证每个用户的目标信噪比加干扰比（SNIR）的情况下，最小化发射光功率的稳健信道量化误差预编码器是二阶锥规划（SOCP）问题的解。最后，我们通过数值模拟评估了它在不同量化水平下的性能。
