大气激光通信中多光束传输性能分析和信道建模

多光束传输技术是克服大气激光通信中大气湍流效应的有效途径之一。首先从理论上分析了大气湍流对多光束大气激光通信系统性能的影响和多光束大气传输的光强起伏特性，然后利用统计分析的方法，建立了一个以传输距离z、光束数目n、发射孔径之间的距离St、接收孔径Dr等为参量的多光束大气传输信道模型。最后，结合相关文献提供的实验结果对该信道模型进行了实验验证和误码性能分析。结果表明，当S1≥√λz或Dr远大于大气湍流相干长度ρo时，随着n的增大，接收光强将趋于对数正态分布．降低了大气激光通信系统的误码率，从而验证了多光束传输对于克服大气湍流影响的有效性。

Performance Evaluation and Channel Modeling of Multiple-Beam Propagation for Atmospheric Laser Communication

The multiple-beam propagating technique is one of the effective ways to mitigate the effect of atmospheric turbulence. The influence of atmospheric turbulence on multiple-beam atmospheric laser communication and the characteristics of optical intensity fluctuation after the multiple beams passing through atmospheric turbulence are analyzed theoretically. Then a new channel model of multiple-beam laser propagation through atmospheric turbulence is put forward applying the method of statistical analysis. The model is developed with 1) range z, 2) number of laser beams n, 3) laser transmitter spacing St, 4) receiver aperture Dr as variables. The model is validated by the experimental results in related reference. The results show that the multiple-beam approach with a proper aperture (Dr?恙?0) receiver and transmitter spacing (st≥λz) is a very effective way for intensity fluctuation reduction induced by turbulence, thus reduces the bit-error-rate of the atmospheric laser communication system. And the intensity fluctuation will provide a good match to log normal distribution with multiple beams.