在无线光通信中，通信系统发射的光束通常近似看作平面波或球面波，而实际的发射光束是高斯波束，所以在研究通信系统性能指标时必然会存在差异。运用理论分析和实验仿真的方法，在不考虑湍流内、外尺度影响和弱湍流的前提下，对比分析了平面波、球面波以及高斯光束模型条件下孔径平均效应的差异。在此基础上，进一步分析了三种传输模型在误码率(BER)性能方面的差异。结果表明，高斯波束条件下孔径平均对误码率的影响明显，最先达到饱和状态，球面波次之，平面波较为平缓。

The transmitting beams are usually approximated as plane wave or spherical wave in free space optical communication (FSO) systems. But the actual beam is a Gaussian beam, and there are many differences when we study the performance of FSO system with the approximation model. By using the methods of theoretical analysis and simulation, without considering the impact of the inner and outer scales of turbulence, we analyze the difference of aperture averaging effect among different transmitting beams. The differences of bit-error rate (BER) performance are then analyzed. The results show that Gaussian wave has apparent impact on the improvement of BER performance by aperture averaging, and saturation is reached firstly, followed by spherical wave. Plane wave is relatively gentle.