Considering imperfect channel state information (CSI), we study robust precoding design for multiuser multiple-input–multiple-output (MIMO) indoor visible-light communication systems, where one transmitter with several light-emitting diodes sends messages to multiple receivers each with several photodiodes. We model the imperfect CSI with bounded channel uncertainties by worst-case model, aiming to maximize the worst-case sum capacity of all receivers via optimizing the precoders at the transmitter under optical power constraints. The robust precoding problem is nonconvex and thus hard to solve. To overcome this difficulty, we first separate the logarithm function and the precoders in the objective function, then employ the sign-definiteness lemma to eliminate the channel uncertainties, and finally develop an effective iterative optimization algorithm to compute the precoders. Simulation results are provided to demonstrate the effectiveness of the proposed scheme.

中文翻译：

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具有受限信道不确定性的MU MIMO VLC系统的容量最大化的发射机预编码

考虑到不完美的信道状态信息（CSI），我们研究了针对多用户多输入多输出（MIMO）室内可见光通信系统的鲁棒预编码设计，该系统中一个带有多个发光二极管的发射器向多个带有多个发光二极管的接收器发送消息光电二极管。我们通过最坏情况模型对具有边界信道不确定性的不完美CSI进行建模，旨在通过在光功率约束下优化发射器处的预编码器来最大化所有接收器的最坏情况总和容量。健壮的预编码问题是非凸的，因此很难解决。为了克服这个困难，我们首先将对数函数和目标函数中的预编码器分开，然后使用符号确定性引理消除信道不确定性，最后开发出一种有效的迭代优化算法来计算预编码器。仿真结果证明了该方案的有效性。