## 1 Introduction  
Wireless communications have driven the desire for improved connectivity since its inception, and it has been used since the time when humans used smoke signals and birds for wireless communication. [PERSON] subsequently discovered mobile panels in 1684 that coded the letters of the alphabet. The optical telegraph was developed towards the end of the 18 th century and can relay coded words over long distances. Since then, many developments have advanced with telecommunications technologies in response to customer demands for faster and more reliable connectivity. When it comes to radio communication, using coded information transmitted through electromagnetic (EM) waves, after the advent of electromagnetic waves, wireless telegraphy and the invention of radio, wireless communication has gone through many paradigm changes [1; 2]. EM waves have a wide variety of applications in today's life that include numerous uses of mobile phone communication, radio broadcasting, Wi-Fi, medical applications, etc., and EM waves can be categorized into radio, infrared, visible, ultraviolet, etc. Among those, radio frequency (RF) is the one that is the widely used portion of the EM spectrum for communication purposes, as RF transmission occurs at light speed, does not require a travel medium and can travel long distances. In addition, RF does not require a line of sight between the transmitter and receiver, is not susceptible to interference from bright to light sources, and has low interference in the frequency band and broad area coverage [1]. RF communication, however, faces some challenges such as interference, as the use of cell phones in aircraft causes interference with communication and navigation systems; bandwidth limitations, security issues, as they can easily penetrate through walls; transmission power limitations, as they can result in risks to human safety; power inefficiency; etc. [3; 4; 5; 6]. Therefore, developing an alternative solution is imperative in order to solve these challenges. Visible Light Communication (VLC) is evolving as a workaround for wireless communications networks to tackle crowded radio spectrum. VLC is an emerging technology that employs visible light for communication to facilitate high-speed internet connectivity exclusively in the indoor environment. In VLC, data are transmitted by modulating the amplitude of an optical source that operates at much faster speed within the visible range of the EM spectrum, and, thus, due to its high switching rate, light-emitting diodes (LEDs) are the most desirable light source for VLC. The VLC systems occupy the EM spectrum ranging from 380 nm to 750 nm corresponding to the frequency range of 430 THz to 790 THz, and the availability of this wide bandwidth in VLC solved the problem of low bandwidth in RF communication. Security issues in RF communication can be solved in VLC, as optical source lights cannot pass through opaque bodies and confined in an intended region, nor does VLC cause any interference with the RF signals resulting in enhancing VLC security [7]. It is a well-known fact that exposure to high-intensity RF signals can result in burns and damage to body tissues, thus limiting the system's own transmitting power, which affects system performance [8]. VLC uses LEDs as the non-harmful optical source for the human body, which can be used for both lighting and communications that can save extra electricity [9]. In addition, VLC systems cost considerably less than existing RF modules and can even provide higher data speeds [1]. Considering the above advantages, VLC is considered one of the promising candidates for wireless communication systems due to its high bandwidth, low power consumption, no health hazards, and the fact that it is a more efficient method of data transmission system. Some of the potential applications of VLCs include Light Fidelity (Li-Fi) [10], underwater communication [11; 12], smart transport network [13; 14], etc.