一种用于空间光通信的LT-AF码

LT-AF code for space optical communication

为克服大气湍流效应对空间光通信(FSO)的影响,采用LT码作为信道编码技术。针对传统LT码用于FSO时,译码开销较大这一问题,通过对接收端反馈信息的有效利用,提出一种具有反馈修正特性的喷泉码—LT-AF码。该编码方案利用对理想孤子度分布进行修正得到一种反馈修正度分布函数,根据反馈信息,对编码方案进行调整,来降低译码开销。通过建立Gamma-Gamma信道模型对LT-AF码的性能进行仿真。结果表明:LT-AF码能够在明显降低空间光通信系统译码开销的同时,减小系统误码率。

In order to overcome the influence of atmospheric turbulence on space optical communication （ FSO）, LT code is used as channel coding technique. The overhead is very large when traditional LT codes are applied in space optical communication. In this paper, the new fountain codes （LT-AF） with feedback are designed by utilizing information of receiver. The coding scheme uses the modified ideal soliton distribution to obtain a feedback correction distribution function. The coding scheme is adjusted according to the feedback information to reduce the decoding overhead. Through the establishment of Gamma-Gamma channel model, the performance of LT-AF code is simulated. The results show that the system adopting LT-AF codes can significantly degrade the overhead and reduce BER.