Spatial Diversity and Multi Hop in FSO Communication Over Turbulence Channels

Free-space optical (FSO) communication systems have high data rate and perfect end-user communication solutions. On the other hand, FSO bit error rate (BER) performance degrades with the atmospheric turbulence and the weather attenuation. Spatial diversity and relay assisted techniques have been proposed in literature as a solution for these problems. However, authors concentrate on the comparison between either spatial diversity and single-input single-output (SISO) or relay assisted techniques and SISO. In this paper, comparisons between a multi hop decode and forward (DF) relay and a multiple-input single-output (MISO) system are driven under different turbulence and weather conditions. Our results show that multi hop DF relay outperforms MISO, with number of transmitters equal to the number of hops, using repetition codes for correlated case in the BER performance under different conditions.