Turbulence Channel Modeling and Non-Parametric Estimation for Optical Wireless Scattering Communication

We adopt mixed Poisson distribution to characterize the channel turbulence for the optical wireless scattering communication. The expectation-maximization algorithm is applied to estimate each component of the mixed Poisson distribution. We analyze the temporal correlation of the turbulence-induced fading, which is crucial for designing the frame length and the training signal pattern for channel estimation. Computer simulations show the good performance of the proposed estimation approaches for the mixed Poisson distribution and the temporal correlation. The outdoor experimental results with the transceiver distance of 1500 m are also presented. It is shown that the coherence time length can reach the order of several hundred milliseconds.