Although the multi-antenna or so-called multiple-input multiple-output (MIMO) transmission has been the enabling technology for the past generations of radio-frequency (RF)-based wireless communication systems, its application to the visible light communication (VLC) still faces a critical challenge as the MIMO spatial multiplexing gain can be hardly attained in VLC channels due to their strong spatial correlation. In this paper, we tackle this problem by deploying the optical intelligent reflecting surface (OIRS) in the environment to boost the capacity of MIMO VLC. Firstly, based on the extremely near-field channel condition in VLC, we propose a new channel model for OIRS-assisted MIMO VLC and reveal its peculiar ``no crosstalk'' property, where the OIRS reflecting elements can be respectively configured to align with one pair of transmitter and receiver antennas without causing crosstalk to each other. Next, we characterize the OIRS-assisted MIMO VLC capacities under different practical power constraints and then proceed to maximize them by jointly optimizing the OIRS element alignment and transmitter emission power. In particular, for optimizing the OIRS element alignment, we propose two algorithms, namely, location-aided interior-point algorithm and log-det-based alternating optimization algorithm, to balance the performance versus complexity trade-off; while the optimal transmitter emission power is derived in closed form. Numerical results are provided, which validate the capacity improvement of OIRS-assisted MIMO VLC against the VLC without OIRS and demonstrate the superior performance of the proposed algorithms compared to baseline schemes.
翻译:虽然多antenna或所谓的多投入多输出传输(MIMO)是过去几代以无线电频率为基础的无线通信系统的赋能技术,但其在可见光通信(VLC)中的应用仍面临严峻的挑战,因为由于VLC频道空间关系密切,MIMO空间多氧化增长很难在VLC频道上实现。在本文中,我们通过在环境中部署光智能反射表面(OIRS)增强IMO VLC的能力来解决这一问题。首先,根据VLC极近距离的频道条件,我们提议为OIRS辅助的MIMO VLC系统开发一个新的频道模型,并展示其独特的“无交叉连接通信”特性。 OIRS反映各要素的配置可以分别与一对一的发报机和接收天线相协调,而不会引起相互交接。我们把OIRS辅助的IMOVLC系统排量能力置于不同的实际电力制约之下,然后着手通过联合优化OIRS组件的校准和发射系统排放能力。特别是为了优化OIRS的S基准定位和精确度调整,我们提议将O-ral-ral-lalalalalal-al-alalalal-lation-lationaldaldaldaldaldaldaldaldaldaldaldaldaldaldaldaldaldald 。