Improved transmission length in the presences of ambient noise and scintillation effect using duobinary modulation in 40 Gbps free space optical channel

Abstract

Free space optical (FSO) communication has gained significant popularity in recent years due to large bandwidth, license‐free spectrum, high data rates, less power consumption, and low mass requirements. However, system performance strongly depends on atmospheric conditions and ambient noise. In this letter, the duobinary modulation technique is applied and the system performance is investigated in the presence of ambient noise. The system is evaluated on the basis of Q‐factor, eye diagram, input power, transmission distance, and bit error rate. A significant improvement is observed in the presence of noise while using duobinary modulation. This study exploits extensive simulations to investigate the performance of the system. All simulations are performed for a single link of FSO communication network having a data rate of 40 Gbps in the Optisystem simulator and ambient noise is created using LEDs. After the exhaustive set of simulations, a significant improvement in transmission length is observed. It is also observed that at low input power, doubinary modulation provides better results when compared with on‐off keying (OOK) format. Scintillation effect has also be observed for doubinary modulation and compared with OOK modulation format. It is concluded that doubinary modulation provides better results in the presence of low and moderate scintillation.

Performance of finite energy Airy Hermite Gaussian beam in strong atmospheric turbulence

“…It is shown in 2 that higher received power can be obtained since scintillation is less for far infrared wavelengths. Doubinary modulation shows better performance than on-off keying under scintillating conditions 3 .…”

A Study on the Irradiance Scintillation Characteristics of Monochromatic LED-Based Visible Light Communication Systems in Weak-to-Strong Turbulence

“…Among them, irradiance scintillation has the most serious impact on signal reception. Although there have been many studies on the propagation characteristics of LED-based VLC systems affected by atmospheric turbulence, few studies have considered the effects of the random phase of incoherent light sources, and the channel propagation characteristics of LED-based VLC affected by atmospheric turbulence are mainly approximated by the propagation theory of coherent light [16][17][18][19][20]. Since coherent light has a single frequency and a fixed phase difference, while incoherent light has a random phase, studying the propagation characteristics of incoherent light in weak-to-strong turbulence in VLC systems is challenging.…”

Properties of hyperbolic sinusoidal Gaussian beam propagating through strong atmospheric turbulence

“…Since scintillation is so effective on communication link performance, scientists take into account this noise factor while a system or model is designed. Considering scintillation effect, it is shown in 2 that performance of doubinary modulation is better than on–off keying. Besides this, link performance reduces when bit rate increases 3 .…”