In this paper, the effect of jamming in free space optical (FSO) link, is evaluated by deriving closed-form expressions of the bit error rate (BER) and outage probability (OP) for single-input single-output (SISO) and multiple-input single-output (MISO) FSO systems. The effects of partial-band jamming and broadband jamming over the error performance of the considered FSO systems are also analyzed. The jammer behaves as a random noise source, following the negative exponential distribution–due to the atmospheric turbulence. Therefore, in the presence of jammer, the error performance of FSO systems is governed by the additive negative exponential noise. It is shown by a rigorous analysis that a MISO FSO system can significantly mitigate the effect of jamming. Specifically, we consider a $2\times 1$ FSO system for analysis, and demonstrate the improvement in BER and OP performance an FSO system can gain by using an additional spatial dimension, in the presence of a random jammer. The mitigation of jamming, due to implementation of arbitrary transmit apertures, is also verified through simulation results; which lies in complete agreement with the analytical results. Also, the error performance under the jamming effect is studied numerically over the Gamma-Gamma fading channel incorporated with pointing error effect.

中文翻译：

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自由空间光学系统中的干扰：缓解和性能评估

在本文中，通过推导单输入单输出 (SISO) 和中断概率 (OP) 的比特误码率 (BER) 和中断概率 (OP) 的闭式表达式来评估干扰在自由空间光 (FSO) 链路中的影响。多输入单输出 (MISO) FSO 系统。还分析了部分频带干扰和宽带干扰对所考虑的 FSO 系统误差性能的影响。由于大气湍流，干扰机表现为随机噪声源，遵循负指数分布。因此，在干扰存在的情况下，FSO 系统的误差性能受加性负指数噪声控制。严格的分析表明，MISO FSO 系统可以显着减轻干扰的影响。具体来说，我们考虑一个 $2\times 1$ FSO 系统进行分析，并证明在随机干扰存在的情况下，FSO 系统可以通过使用额外的空间维度来提高 BER 和 OP 性能。由于实施任意发射孔径，干扰的减轻也通过仿真结果得到验证；这与分析结果完全一致。此外，在包含指向误差效应的 Gamma-Gamma 衰落信道上，对干扰效应下的误差性能进行了数值研究。