# Performance Analysis of a Color-Code-Based Optical Camera Communication System
## 1 Introduction  
Visible light communication (VLC) is an alternative to radio frequency (RF) communication and covers the visible light region of the electromagnetic spectrum in the 400-800 THz band. Since the operating frequency is much higher than RF, the communication distance is shorter, but VLC has a much higher bandwidth and is insensitive to electromagnetic noise in the RF band. Due to these advantages, it is widely used in security systems, health sector, avionics systems, underwater communication, and vehicle-to-vehicle communication [1, 2]. VLC has been recognized by both industry and academia as a feasible solution to realize the wireless communication networks of the future. VLC-compatible light-emitting diode (LED) luminaires convert an ordinary luminaire used for lighting into a high-speed modern. Due to the high-frequency flickering of light, it is not possible for persons in the environment to detect the data transfer. Today, VLC-compatible LED luminaires are released by various companies [3]. Free-space optical (FSO) communication, similar to VLC, uses light to transmit data. However, the light used is not limited to visible light. Ultraviolet (UV) and infrared (IR) are also included in this category. Optical wireless communication (OWC) is a general term used to refer to all forms of optical communication and includes visible light communication, light-fidelity (Li-Fi), FSO communication, and infrared remote-control systems [4]. Most VLC systems use LEDs as optical emitters and photodiode arrays as optical receivers. The light emission mechanism of LEDs is based on the laws of quantum physics and when current flows through the P-N junction, light is emitted at a frequency corresponding to the visible light region of the spectrum. The range of 380-780 nm is recognized by the International Commission on Illumination (Commission Internationale de l'Eclairage, CIE) as the visible light band [5]. LEDs in VLC systems, which provide communication at high bps values, have high luminous fluxes and low junction capacities [6]. Ordinary LED chips produced for general lighting can be used in VLC communication systems with some compromise in data communication speed. The photodiode used as an optical sensor is very sensitive to light, and when biased in the opposite direction, the leakage current changes with the light incident on it. Since a photodiode, unlike a light-dependent resistor (LDR), reacts very fast to changes in light (a few ns), silicon photodiodes, positive-intrinsic-negative (PIN) diodes, and avalanche photodiodes are preferred as optical receivers in visible light communication systems [7]. Other alternatives used as optical receivers in VLC systems are charge-coupled device (CCD) and complementary metal oxide semiconductor (CMOS) type image sensors [8; 9; 10]. The visible light communication technology called \"Li-Fi\" was announced in a TED Talk in 2011 by Professor [PERSON] from the University of Edinburgh and attracted worldwide attention [11]. In the following period, many technical developments have emerged. There are many academic studies in the literature on VLC communication and different technical terms are used other than VLC, for example, optical camera communication (OCC), optical spatial modulation (OSM), camera-screen communication (CSC), light-to-camera communication (LCC), color intensity modulation (CIM), and high-density modulation (HDM). Several studies on VLC systems using a cell phone camera as the receiver are mentioned below. In [12], [PERSON] et al. proposed a new flicker-free, distance-independent modulation method for OCC. An OCC-based modulation is presented that can operate at short, medium, and long distances for both indoor and outdoor scenarios. In the VLC system [13] with a CMOS-based mobile phone camera and a quadichromatic light-emitting diode (QLED), unlike color intensity modulation (CIM), color ratio modulation (CRM) is proposed to increase the data rate and improve the illumination effect at the same time.