Enhancing the Efficiency of Optical Filtering for Visible Light Communications

Abstract

Visible light communication is one of the most promising branches of wireless communications that is witnessing rapid development in recent years. It involves the usage of the visible region of the electromagnetic spectrum to transmit data from one point to another. High rate of data transmission, high security of the transferred data, harmlessness to surrounding human subjects as well as to sensitive equipment are some of the great promising advantages of Visible Light Communications systems. But this new branch is not without its own disadvantages. One of the crippling problems faced by Visible Light Communications systems are its susceptibility to noise signals incident on the receiver of the signal by the surrounding sources of illuminations or sources of optical noises. Hence, in this new area of research designing suitable filters for filtering the signal from the noises is still considered one of the prime challenges towards its rapid deployment all over the world. In this work, we have designed four solutions that intend to solve different aspects of the problem of optical noises at the receivers of the Visible Light Communications system. newlineThe first solution that have been discovered by us is that of designing a Sallen Key All-Pass Filter for the receiver of a typical Visible Light Communications system. The Sallen Key filter, which is an All-Pass Filter have been chosen by us because of its simplicity of design which makes it easily integrable in most commonly used receivers of a Visible Light Communications systems. The output obtained by using the designed Sallen Key All-Pass Filter with the VLC receiver have been found to produce much better SNR versus BER performance compared to recently proposed filter solutions for receivers of Visible Light Communications systems. The next solution designed is an adaptive filter that is operating by machine learning principles to study the incoming noise characteristics and accordingly alter the signal power of the transmitter and the filter qualities