中文摘要：

为克服空间光通信（FSO）链路受大气湍流效应的影响,将LT码应用到FSO系统中。多进制LT码具有较高的传输效率。提出一种新型度分布函数来改善多进制LT码的译码性能。计算不同进制LT码的译码失败率,并模拟强湍流信道,对采用不同编码方案的FSO性能进行仿真。结果表明：采用新型度分布的LT码能够降低译码失败率,且能有效改善FSO系统在强湍流情况下的性能。

英文摘要：

In order to overcome the influence of atmospheric turbulence on the free space optical communication（FSO）link,LT code is applied to FSO system.M-ary LT codes have higher transmission efficiency.A new degree distribution function is proposed to improve the decoding performance of M-ary LT codes.The decoding failure rate of LT codes with different base is calculated.The strong turbulence channel modeling is carried out and the performance of FSO with different coding schemes is simulated.The results show that the LT code with new degree distribution can reduce the failure rate of decoding,and can effectively improve the performance of FSO system in strong turbulence.