Performance of OFDM-FSO link with analog network coding

Free space optical (FSO) communication link based on orthogonal frequency division multiplexing (OFDM) gives improved performance because of high bandwidth efficiency, improved robustness against fading, and narrow-band interference. Any FSO system requires line-of-sight (LoS) link and in non-LoS (NLoS) situation, the two users cannot communicate directly resulting in link outage. To solve this problem, this paper proposes to use relay-assisted NLoS-FSO link with energy-saving three time-slotted analog network-coding approach to make the successful communication with increased throughput and improved error performance. The error performance of laser link is evaluated in terms of receiver sensitivity. Gamma-Gamma distribution is used for atmospheric turbulence in this analysis. The performance of relay-assisted intensity modulated/direct detected-OFDM FSO link with and without analog network coding (ANC) is compared.