Performance investigation of the polar coded FSO communication system over turbulence channel

In this paper, for the first time, to the best of our knowledge, polar codes are introduced and experimentally implemented in a free space optical (FSO) communication system to combat atmospheric turbulence induced fading. By analyzing the characteristics of the turbulence channel, a method of evaluating the channel state information for polar decoding is proposed that can achieve good trade-off between the performance and the computational complexity of this polar coded system. To verify our scheme, an intensity modulation direct detection FSO communication experimental platform with a turbulence chamber is established. For the weak turbulence condition, comparing with the low-density parity check codes, the experimental results show that our proposed scheme has stronger error correcting capacity and lower computational complexity in combating the turbulence induced fading. Moreover, for moderate and strong turbulence conditions, the gamma-gamma turbulence model is adopted for constructing the Monte Carlo simulation. The results of the experiment and simulation both show that our proposed scheme can effectively combat atmospheric turbulence induced fading with a relatively low computational complexity in a wide range of turbulence conditions.