Another investigation on a physical model was conducted by Miya and Kajikawa, 18 in which they developed a simulation interface for the user depending on their own proposed base-station layout. 17 Although the ceiling lighting layout gives the best performance of the VLC system, improvements have not yet been made to the corner lighting layout. Recently, the study of the effectiveness of the ceiling lighting and corner lighting layouts for visible light applications has been presented by Ding et al. However, neither paper discussed the influence of lighting layout on the performance of the system. With this technique, they could double the transmission rate up to 32 Mb / s. The same layout was proposed by Lubin et al., 16 focusing on the data rate transmission using equalizer. According to these studies, interference affects the performance of the communication system. Then, in Ref. 15, the numerical studies of the influence of intersymbol interference (ISI) on the visible-light communication system are carried out. The first model of ceiling lighting layout for indoor communication was proposed previously by Fan et al., 5 which addressed the effect of reflection. 14 To apply the VLC system for both illumination and communication, a study on the physical model of the lighting layout, which affects the system efficiency, was recently conducted. 10 – 13 In fact, a VLC system can be considered as a candidate for the wireless indoor links because it uses an illumination device that is easy to install. 7 – 9 These systems are usually referred to as visible light communication (VLC) systems, which have many attractive features such as unlimited, unregulated bandwidth (BW), immunity to interference caused by other electronic equipment, and the possibility of frequency reuse in adjacent rooms. 4 – 6 LEDs can also be modulated at high speed, offering the possibility of using sources for simultaneous illumination and high-data rate communication. 1 For these reasons and due to concerns regarding environmental issues, 2, 3 LEDs are predicted to replace existing lighting sources, such as incandescent and fluorescent lamps, in next-generation illumination.
Recently, light emitting diodes (LED) have been utilized in a wide range of applications in visual signaling, information display, and the automotive industry because of their high brightness levels, long life span, and low power consumption.
Thus, this system is applicable to modern lighting layouts. The model of HWLL is chosen as the best layout, since 61% of the office area is considered as an excellent communication area and the difference between the area classification, Δ p, is 22%. The key factor that affects the SNR performance of visible light communication is the reliance on the design parameter that is related to the number and position of LED lights. Based on the analysis, the relationship between the space adversity and the signal-to-noise ratio (SNR) performance is demonstrated for each model. A dual-function system is applied to three models of modern lighting layouts: the hybrid corner lighting layout (HCLL), the hybrid wall lighting layout (HWLL), and the hybrid edge lighting layout (HELL).
The growing interest in using these devices for both illumination and communication requires attention to combine this technology with modern lighting layouts. The ability of LEDs to be modulated at high speeds offers the possibility of using them as sources for communication instead of illumination. White light-emitting diodes (LEDs) are predicted to be widely used in domestic applications in the future, because they are becoming widespread in commercial lighting applications.
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