Performance comparison of Duobinary, AMI, CNRZ and CSRZ for next generation FSO communication system

FSO, known as free-space optics, is a competent technology in wireless communication for providing license free spectrum, bandwidth, and high efficiency in next-generation networks. In this paper, an experimental approach is used to deploy FSO channel communication using different intensity modulation schemes such as CSRZ, chirped NRZ, duobinary and AMI. The performance of FSO link is adversely affected by weather conditions like haze, rain, and fog. By using different techniques, it is possible to overcome the effect of atmospheric turbulences. Therefore, four different modulation formats are compared and analyzed by testing different parameters like laser power, range, attenuation, and data rates. Quality of received signal is judged by taking Q-factor, bit error rate (BER), and eye-diagrams. An operating wavelength of 850 nm has been used to simulate the system designs. This paper aims to conclude the best intensity modulation scheme for its use in next generation networks such as 5G where direct deployment of optical fiber is not possible or feasible.