BER performance analysis of a non-Hermitian coherent optical OFDM FSO system with polarization diversity using various atmospheric turbulent channel models

In this research article, we investigate the impact of different atmospheric turbulence along with polarization crosstalk on the bit error rate (BER) performance of a non-Hermitian orthogonal frequency division modulated (OFDM) free-space optical (FSO) system with polarization diversity. Analysis is carried out for a non-Hermitian coherent optical OFDM followed by differential quadrature phase shift keying FSO system with polarization diversity in presence of atmospheric turbulence for all weather conditions. We considered Log-normal, Gamma-Gamma and Negative exponential turbulence fading model for weak, medium and strong atmospheric turbulent channel respectively and for cross polarization induced crosstalk, the random misalignment angle is Maxwellian distributed. The system average BER is calculated by averaging the conditional BER over the probability density function of the channel irradiance along with Maxwellian distributed random misalignment angle. Results are evaluated in terms of BER, power penalty due to polarization crosstalk along with atmospheric turbulence and receiver sensitivity due to OFDM. Results show that the system suffers almost 7.5, 11 and 16 dB power penalty due to polarization crosstalk along with weak, medium and strong turbulence respectively at a constant BER of 10(-12) when the system link length is 3000 m. It is clearly observed that, almost 19, 16 and 10 dB receiver sensitivity is achieved when number of subcarriers increase into 512 for weak, medium and strong turbulence conditions, respectively at a constant BER of 10(-12).

Automated summary

This research article investigates the impact of atmospheric turbulence and polarization crosstalk on the performance of a non-Hermitian OFDM FSO system. The results show the power penalty and receiver sensitivity vary under different turbulence conditions.