A study of indoor VLC system based on TLS receiver

What is it about?

In this paper, the effect of different types of filters on the performance of a total least square–based receiver for a visible light communication system is studied. In the literature, the most common type of filter that is used is a matched filter. This is considered to be an optimal filter and it is commonly available. In the computationally limited environment, where there are not enough resources to match the needs of an optimal filter such as matched filter, this paper investigates the use of other potential filters such as Butterworth, elliptical, and Chebyshev filters. This paper also investigates the effect of choosing a suitable transmission band to countermeasure the effects of noise from artificial light sources and sun. The proposed system is analyzed on the parameter of bit error rate. In this paper, the effect of different types of filters on the performance of a TLS‐based receiver for a VLC is studied. A low‐cost system based on a Butterworth filter is proposed which performs better than a matched filter. The system was also analyzed by choosing a suitable transmission band to countermeasure the effects of noise.

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Why is it important?

This paper's main objective is to tackle challenges such as cost, energy consumption, artificial light interference, and node relocation. Starting with the cost factor, it plays an important part in the success of a technology or its failure. Ultimately the main goal of any new upcoming technology is to be used in everyday life with affordable cost. As an example, take a case of using a simple Butterworth filter over a complex matched filter. The cost of making a matched filter is around $7 to $10 in the market, while a simple Butterworth filter costs a fraction, which is around $3.19. The performance of the system is affected by this change of price. To counter the drop of performance advance signal processing techniques such as total least square (TLS) can be used to achieve performance, which is comparable to the matched filter. In this paper, a Butterworth filter is introduced while keeping the cost to a minimum. The second challenge to be considered is energy consumption and artificial light interference. The LEDs have a very good energy consumption rate and are environment-friendly. Several studies have proposed various kinds of VLC systems, but the research into which band is more suitable is still a big debate for indoor environment applications. This includes the study of which visible light band color is more effective in natural daylight or artificial ambient lights. The key to a robust VLC system is to study the visible light band and choose a particular wavelength, which delivers the best performance for an indoor environment. The third challenge faced in literature is node relocation. There are studies that calculate the bit error rate(BER) and signal-to-noise ratio (SNR) of the optical signal and improve the overall system performance; there is not much work done on the problem of electrical SNR, which results due to the relocation or movement of the node in an indoor environment. The main objective of this research is to decrease the cost of the equipment by determining suitable modulation and filtering techniques to identify a suitable transmission wavelength to counter the effect of natural and artificial light noise.

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