无线光通信光功率衰减模型分析

Analysis of power attenuation model for wireless optical communication

现有的无线光通信系统中，光功率衰减模型普遍采用的是平面波假设下的模型，而实际无线光通信系统发射的激光是高斯光束。因此，建立高斯光束下的光功率衰减模型更加符合实际情况。利用理论推导结合仿真的方法，分析了高斯光束下发射光功率计算中积分限的选取，在综合考虑精确性和简易性的原则下，建立了高斯光束的光功率衰减模型，并以此为基础，比较了平面波和高斯光束下的光功率衰减模型，研究了平面波近似带来的误差。结果表明：两种模型明显不同，平面波假设下的模型会低估无线光通信系统的性能，在分析最大可通信距离时会带来12％-13％的相对误差。

The optical power attenuation model often uses the model under the plane wave assumption in the existing wireless optical communication system. But in fact, the emitting laser is Gaussian distribution, so the optical power attenuation model under Gaussian model is in line with the actual situation. The selection of integral limits in the caculation of the emitting optical power of the Gaussian laser was analyzed with theoretical deduction and simulation. Under the principle of overall consideration of accuracy and simplicity, the optical power attenuation model of the Gaussian laser was established. For the purpose of studying the error brougth by the plane wave assumption, the differences between the optical power attenuation models of plane wave and Gaussian laser were analyzed then. Simulated results indicate that the plane wave model can underestimate the performance of wireless optical communication system, and will bring 12%-13% relative errors when analyzing the possible maximum communication distance.