The emergence of visible light communication (VLC) as a subset of optical wireless communication (OWC) in the early 2000s has turned any light-emitting diode (LED) source into a potential data transmitter. The design process for any VLC or OWC system typically involves a link budget analysis performed by studying the signal-to-noise ratio (SNR) at the receiver. Since this SNR strongly depends on the radiant flux collected by the receiver, an accurate model for this parameter is required. The point-source model has been widely used since 1979 and generally provides a good approximation of the received radiant flux. However, it might be less accurate for typical extended lighting sources like LED panels or large-area organic LEDs. In this paper, the radiant flux distribution of flat Lambertian rectangular or circular sources is derived from a vector analysis of their irradiance. It is then validated through actual measurements in the case of a circular source. The resulting extended-source models thus better capture the light beam pattern of such transmitters to enable a more accurate link budget. It provides at the same time almost identical results to the point-source model for small sources and can, therefore, be seen as a natural extension of this already widely used model.

中文翻译：

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多个倾斜平面朗伯光源的全场辐射通量分布

可见光通信（VLC）作为光学无线通信（OWC）的子集的出现，已将任何发光二极管（LED）光源变成了潜在的数据发射器。任何VLC或OWC系统的设计过程通常都涉及通过研究接收器的信噪比（SNR）进行链路预算分析。由于此SNR很大程度上取决于接收器收集的辐射通量，因此需要该参数的精确模型。点源模型自1979年以来已被广泛使用，通常可以很好地近似接收到的辐射通量。但是，对于典型的扩展光源（如LED面板或大面积有机LED）而言，其准确性可能较低。在本文中，平面朗伯矩形或圆形光源的辐射通量分布是通过对它们的辐照度进行矢量分析得出的。然后，在使用圆形光源的情况下，通过实际测量对其进行验证。因此，得到的扩展源模型可以更好地捕获此类发射器的光束方向图，以实现更准确的链路预算。同时，它为小源提供了与点源模型几乎相同的结果，因此，可以将其视为此已广泛使用的模型的自然扩展。