中文摘要：

由于自由空间光通信（FSO）受到大气湍流效应的影响,运用信道编码技术来保证FSO系统的稳定性。研究LT码原理,并将其引入FSO系统。分析LT码度分布需要满足的条件,引用泊松鲁棒孤子度分布来减小LT码译码开销、降低编译码复杂度,并应用于FSO系统来提高FSO系统性能。采用MATLAB进行仿真,比较泊松鲁棒孤子度分布与鲁棒孤子度分布的性能,并模拟在不同湍流信道中的FSO系统误码率。结果表明,泊松鲁棒孤子度分布具有较小的平均度值,能够减小LT的译码开销、降低编译码复杂度;且应用泊松鲁棒孤子度分布的LT码能够降低FSO系统中的误码率,保证FSO系统稳定。

英文摘要：

As free space optical communication （FSO） is affected by the atmospheric turbulence, the channel coding technique is used to ensure the stability of FSO system. The principle of LT code was studied, and LT code was intro- duced to the FSO system. The required conditions of the LT code distribution were analyzed, the Poisson robust soliton degree distribution（PRSD） was used to reduce the decoding cost of LT codes and reduce the complexity of coding and decoding, and it is applied to FSO system to improve the performance of FSO system. The performances of PRSD and RSD were compared, and the bit error rate of FSO system in different turbulence channels was simulated by MAT- LAB. The results show that PRSD has a smaller average degree, and can reduce the decoding cost, the encoding and decoding complexity of LT code. The LT code using PRSD can reduce the bit error rate in FSO system, so it improves the stability of FSO system.