针对星间激光通信受瞄准误差影响较为严重的问题,提出了一种基于Marcum Q函数表示法的动态束腰控制方案。在不需要采取任何近似的情况下,利用Marcum Q函数给出了计算瞬时信道状态的闭合解析式,并建立了优化模型,通过模型求解,得到在已知瞬时瞄准误差角时的最优光束束腰半径的简单代数表达式,并给出了相应的动态束腰控制方案,该方案可有效抑制瞄准误差的影响。数值计算结果表明,采用动态束腰控制方案的系统性能要明显优于采用固定束腰控制方案的系统性能,且所提方案在系统误码率和中断概率性能上较传统动态束腰控制方案有一定的提升。

We propose a dynamic beam waist adjustment scheme based on Marcum Q-function to solve the problem that the inter-satellite optical communication is deeply affected by pointing error. In the absence of any approximation, a closed-form expression for calculating the state of the instantaneous channel is given by Marcum Q-function. The optimization model is set up and a simple algebraic solution for the optimal dynamic beam waist radius is derived by the model, when the instantaneous direction error angle is known. A new dynamic waist adjustment scheme is given, which can effectively reduce the effect of the pointing error. Numerical results show that the system performance with dynamic beam waist is obviously better than that with fixed beam waist, and the proposed scheme here can improve the performance of bit error rate and outage probability to a certain extent.