Visible light communication (VLC) is seen as a potential candidate for next generation communication networks. In the last decade VLC has emerged out as complementary technology to radio frequency wireless communication according to different requirements and applications. This technology can be considered as a valuable contributor to the present communication networks issues like spectrum congestion and system’s capacity. This paper provides a comprehensive review of the VLC system. The various benefits and applications of VLC system along with the possibility for the next generation communication systems has been discussed. Different modulation techniques are discussed and comparison is also provide with MATLAB simulations. It also provides comprehensive review of various challenges faced by VLC system.

A Comprehensive Survey of Visible Light Communication: Potential and Challenges

Abstract This work aims to investigate the integrated ultra-dense wavelength division multiplexing (UDWDM) and polarization division multiplexing (PDM) schemes incorporated in the free space optic (FSO) communication system. Erbium-doped fiber amplifiers (EDFAs) are used as post and pre-amplifiers in the proposed UDWDM–PDM–FSO system to boost the transmission power for increasing the distance. Thirty-two channels are transported over the FSO link to realize the total data transmission of 160 and 320 Gbps with 0.08 and 0.1 nm channel spacing, respectively. Results are also reported with non-return to zero modulation schemes. The performance of the proposed UDWDM–PDM–FSO transmission system is measured in terms of bit error rate (BER) and eye diagrams. The transmission distances are 100 and 87 km under clear weather and have acceptable BERs with 0.08 and 0.1 nm channel spacing, respectively. The weather conditions may worsen due to the increase in atmospheric turbulence. Hence, the transmission distances decrease to 3.93 and 2.6 km for heavy rain weather conditions. The UDWDM–PDM–FSO communication system exhibits an excellent performance due to the use of EDFAs with high achievable maximum distance and good and acceptable BER performance. The UDWDM–PDM–FSO communication system considerably enhances the transmission distance compared with the UDWDM–FSO communication system.

320 Gbps Free Space Optic Communication System Deploying Ultra Dense Wavelength Division Multiplexing and Polarization Mode Division Multiplexing

The winter season starts suddenly in the mid of the Dew and ends in Spring. If we will analyze in a better way, the cold starts in the mid of October and continue up to mid of February month. Generally, some the states like Jammu, Kashmir, Uttar Pradesh, Uttarakhand, Punjab etcetera the people are suffering from a heavy cold. At that time the temperature is as much as decreased so that the old generation people cannot tolerate it. Sometimes also the meteorological department is very busy predicting temperature because in India other natural disasters like floods, droughts, cyclones etcetera are also coming suddenly. So in this investigation work, we have designed an automatic model for crisp weather forecasting which may be considerate to the people, so that they can take precautions earlier. For this work, we have worked for Odisha state for the investigation purpose which uses barometric parameters as well as the machine learning techniques like Support Vector Machine along with Random Forest for our investigation work. The dataset that we have used is IMD which is used for both training and testing. In this model, we have used two prognoses which are based on five and seven days respectively. The contrast result babbles 5 days produce better classification accuracy than 7 days' prediction.

Forecasting of Statistical Crisp Weather in India by Exploration of Different Machine Learning Techniques

The present work discusses the development and simulative investigation of a high-capacity wavelength division multiplexed free space optics (FSO) transmission system. A novel 3-D orthogonal modulation scheme is proposed, which simultaneously capitalizes on different signal properties of an optical laser beam, i.e., intensity, phase, and state of polarization to transmit three independent 40 Gb/s data streams on a single optical carrier signal, realizing a net 120 Gb/s transmission rate per wavelength channel. 32 such independent wavelength channels are multiplexed in the proposed FSO system and its performance is numerically investigated over different climate conditions with respect to range, Quality factor, bit error rate, and eye diagrams of the information signal using Optisystem simulation software. Through numerical simulations, we report faithful 3.84 Tb/s transmission over free space channel with maximum link range varying from 1.6 to 40 km depending on the external climate conditions.

Performance investigation of a 3.84 Tb/s WDM-based FSO transmission system incorporating 3-D orthogonal modulation scheme

Free space optical (FSO) communication links offers an emerging alternative to RF communication links because of high speed, secure and cost-effective options to provide the last mile connectivity to end-users. They may be deployed for quick network access temporarily during link failure and natural disaster. This paper focusses on the performance of FSO communication link impaired with strong turbulence and atmospheric attenuation added through varying climatic conditions. A closed-form expression for outage probability is derived to evaluate the performance under different levels of atmospheric attenuation and turbulence strengths. The mathematical analysis clearly shows inimical effects added by atmospheric attenuation over the performance of the communication link. The impact of wavelength diversity on the outage probability of such a link is analyzed with three carrier wavelengths 1550 nm, 1310 nm and 850 nm. The simulation results with wavelength diversity for different atmospheric attenuation levels and turbulence are plotted and analyzed.

Analysis of Outage Probability in Wavelength Diversity Based FSO Link Under Gamma–Gamma Fading with Varying Atmospheric Attenuation

FSO (free-space optics) is a new technology used to solve last mile problem in point-to-point communication. As name indicated, FSO link is a seamless communication link using air as a medium for transmission of optical information. For successful transmission, medium should be free of attenuation caused by different weather conditions like rain, haze, fog. In this paper, analysis of FSO systems has been done using two 32-channel WDM systems and then compared at a constant data rate of 2.5 Gbps. The system with single laser outperforms the system employing an array of 32 CW lasers in terms of link distance under different rain conditions.

Performance Enhancement of Point-to-Point FSO System under Rain Weather Conditions

There is a rainy season occurs during the period from June to august in almost all geographical parts of India. Moreover, some of the states like Uttarakhand, Cherapunji, Mumbai, Tamil Nadu etc. may suffer from some natural disaster. If we early predict such misfortunes through the variety of big data collected for such distinct positions at a particular amount of time then certainly can save the life and goods from such big natural calamities. Such normalized data can be updated at a regular interval of time. In view of this, the time series data analysis provides a method to early aware and protects the life of people from such natural disasters. The proposed method exploited the use the Radial Basis Function Neural Network Model with back propagation algorithm to make compatible with time series data analysis to forecast the predication of rainfall for the state of Punjab, India. In this technique, two types of predictions are used which are based on fifteen and twenty days. The comparison results reveal those fifteen days prediction provides more effective classification accuracy than twenty days prediction.

Sanjeev Kumar

Papers

Performance Enhancement of Point-to-Point FSO System under Rain Weather Conditions

Forecasting of Precipitation in India by Different Data Types using Investigation of Radial Basis Function Neural Network Model