Abstract: In engineering practice, due to the influence of the factors such as manufacturing process, source design, and package technique, most commercially available optical sources have unique radiation characteristics which belong to the range of non-Lambertian emitters. However, the physical channel characterization of current wireless optical local area network is based on the Lambertian emitter which taking the started optical source as a standard. Aiming at this problem, the radiation characteristics of two typical non-Lambertian emitters were incorporated into the physical multipath channel characterization of wireless optical local area network. The focus was the induced effect on the coverage performance of indoor wireless optical local area network by the comparison with the traditional Lambertian emitter. The numerical results indicate that, the non-Lambertian emitters, especially the one with bowl-shaped radiation characteristic, are capable of significantly improving the spatial uniformity of optical path loss and the respective increase can be up to 0.5 dB. However, in the time delay characteristic of coverage domain, both the two non-Lambertian emitters can elevate the level of Root Mean Square (RMS) delay spread to different extent. Specifically, the respective elevations are 0.27 ns and 0.38 ns respectively.

Key words: wireless optical local area network, indoor coverage, non-Lambertian emitter, diffuse multipath

摘要： 在工程实践中,由于制造工艺、光源设计、封装技术等因素的影响,大部分的商用发射器光源有各自独特的辐射特性,属于非朗伯发射器的范畴。但现有无线光局域网的物理信道表征都是基于发端光源为标准的朗伯发射器。针对该问题,将两种典型的非朗伯发射器的辐射特性引入无线光局域网的物理多径信道表征,并通过与传统朗伯发射器比较,重点分析其对室内无线光覆盖表现的影响。量化结果显示,非朗伯发射器,特别是呈现碗状辐射特性的发射器可以有效提高光路径损耗的空间一致性,提升幅度可达0.5 dB。然而,在覆盖区域的时延特性上,两种非朗伯发射器都不同程度地抬升了均方根时延扩展,抬升幅度分别达到了0.27 ns和0.38 ns。

关键词: 无线光局域网, 室内覆盖, 非朗伯发射器, 漫射多径