Visible Light Communication

A Comprehensive Theory and Applications with MATLAB®

Suseela Vappangi, Vakamulla Venkata Mani, Mathini Sellathurai

• Publisher: CRC Press
• Year: 2021
• ISBN:
  9781000416220
• Edition: 1
• Topic: Tecnologia e ingegneria
• Subtopic: Ingegneria civile

The field of visible light communication (VLC) has diverse applications to the end user including streaming audio, video, high-speed data browsing, voice over internet and online gaming. This comprehensive textbook discusses fundamental aspects, research activities and modulation techniques in the field of VLC.

Visible Light Communication: A Comprehensive Theory and Applications with MATLAB ® discusses topics including line of sight (LOS) propagation model, non-line of sight (NLOS) propagation model, carrier less amplitude and phase modulation, multiple-input-multiple-output (MIMO), non-linearities of optical sources, orthogonal frequency-division multiple access, non-orthogonal multiple access and single-carrier frequency-division multiple access in depth. Primarily written for senior undergraduate and graduate students in the field of electronics and communication engineering for courses on optical wireless communication and VLC, this book:

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• Provides up-to-date literature in the field of VLC
• Presents MATLAB codes and simulations to help readers understand simulations

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• Discusses applications of VLC in enabling vehicle to vehicle (V2V) communication

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• Covers topics including radio frequency (RF) based wireless communications and VLC

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• Presents modulation formats along with the derivations of probability of error expressions pertaining to different variants of optical OFDM

1Introduction to OWC-VLC

1.1 Current State-of-the-Art

The explosive magnification of the wireless communication industry over the last decade revolutionized change in our daily life. The present day lifestyle has become very flexible and almost everyone residing on the globe relishes the advances in wireless services which include live video streaming, web browsing, online gaming, and many other such services. Additionally, the expeditious escalation of smartphone applications and overwhelming ultimatum for efficient and convenient wireless communication paved the way for the origination of a huge amount of business opportunities for both mobile manufacturers and wireless network operators. In this scenario, it becomes very difficult for the network providers to capture the needs of the end users. This is valid because during the past few decades, the exceptional augmentation in traffic carried out by the telecommunication networks has been endorsed around the globe [436]. Consequently, this enormous demand for several high-speed internet-oriented services—including high definition television (HDTV), streaming audio, video, video conferences, video calls, cloud-based computing, machine-tomachine (M2M), and augmented and virtual reality (AR/VR) — has reinforced the need to formulate innovative research problem statements, as well as ushered the emergence of novel communication-based technologies which are proficient in imparting high data rate communication to the end subscribers.

Hence, in this sort of scenario where huge amounts of data are required, the radio frequency (RF) spectrum becomes overcrowded [231]. According to the predictions of CISCO, the traffic that is fostered because of AR/VR was expected to increase twenty-fold between 2016 and 2021. Furthermore, the overall intensification of networked devices was anticipated to reach 27:1 billion by 2021. Also, these devices are expected to generate an overall annual global internet traffic of 3:3 zettabytes. Explicitly by the year 2021, the total traffic induced by several wireless and mobile devices was expected to account for an increase of 73% of the total internet traffic. The drastic increase in the growth of mobile data traffic during 2016 and 2021 is delineated in Fig. 1.1, which clearly shows that in 2021, the mobile data traffic is envisaged to increase exponentially by 49 exabytes per month. In addition, even in the coming years, it is predicted that mobile data traffic will increase at an alarming rate. As a result, because of continuous increased depletion of the RF spectrum, it will be one of the most inadequate resources in the near future. This is, in turn, referred to as a “Spectrum Crunch” which is one of the most vital aspects needed to be urgently addressed. It is because this issue is more pronounced, it manifests deterioration of the reliability of services by enforcing a huge increase in latency and decrease in network throughput.

Figure 1.1: Global mobile data traffic between 2016–2030 in the range of exabytes as predicted by CISCO.

So, to alleviate this RF spectrum scarcity problem, it is of paramount importance to explore novel communication-based technologies. One such communication which can be exploited is optical wireless communication (OWC), the most alternative form of communication that utilizes infrared (IR) and visible and ultraviolet (UV) subbands as the propagation medium. Compared with RF-based wireless communication, OWC provides diverse and remarkable advantages that include its huge bandwidth in the order of several terahertz (THz) frequency, which is not being subjected to any sort of electromagnetic interference, as well as is very cost-effective, since it does not impose any licensing charges for the offered bandwidth, and ensures a huge amount of security.

1.2 History of the Origin of OWC

The most startling peculiarity of OWC is that it can be claimed to be any form of telecommunication that utilizes light as a transmission medium of communication. Maneuvering OWC for rendering communication goes back to the old days when smoke signals and beacon fires were employed as shown in Fig. 1.2. It is reported in the literature that semaphore lines, which can also be termed as installation that is employed for transmitting optical signals, can be confirmed to be the preliminary form of technological application of OWC. In 1792, the fundamental optical telegraph network was built by the French engineer, Claude Chappe. Principally, this work witnessed the transmission of 196 information symbols by utilizing the semaphore towers. Heliograph is another example of OWC, a simple and effective instrument used during the late 19^th and early 20^th centuries. Particularly, this instrument is meant for enabling instantaneous optical communication over long distances. Generally, this device, which is called wireless solar telegraph, is meant for signalling flashes of sunlight by means of pivoting a mirror or interrupting the beam with a shutter. Later, in 1836, the invention of Morse Code facilitated navy ships to communicate with onshore lighthouses by means of a signal lamp. In [58], it is clearly evident that Alexander Graham Bell exemplified the first implementation of a free space optical (FSO) link in the form of the photophone, which is basically a telecommunication device that allows for the transmission of a speech signal upon a beam of light. The illustration of a photophone is depicted in Fig. 1.3. The underlying phenomenon involved in the operation of a photophone is that by employing a vibrating mirror at the transmitting end and crystalline selenium cells at the focal point of a parabolic receiver, a voice message signal is modulated onto a light signal. From early research as stated in [177], it can be portrayed that the advancements of OWC technology gained significant momentum only after the tremendous efforts instigated by Gfeller and Bapst in 1979. This research work illustrates the caliber of OWC for high-capacity in-house networks where the system has the potential to impart 260 Mbps data rates by employing a simple ON-OFF keying (OOK) modulationtechnique at a center wavelength of 950 nm in the IR spectrum. This is further fueled by the rapid amelioration in semiconductor-based lighting sources which facilitated the evolvement and success of OWC.

Figure 1.2: Exploitation of smoke signals for communication support.

Figure 1.3: Visual of photophone.

One classification of OWC is FSO, which is intended to support long-distance coverage, and, in fact, can be professed that the fortune of OWC has been changed in the 1960s with the invention of several optical sources, more importantly, the laser. Though the study of laser-based OWC is beyond the scope of this book, it is worthwhile to have an understanding of its usage in OWC. In general, an FSO link is established by the exploitation of highly directional laser diodes at the transmitting end, while photodiode (PD) is employed at the receiving side. The outbreak of FSO demonstrations were witnessed during the early 1960s and late 1970s. The authors in [333] demonstrated the transmission of 50 Mbps data at low bit error rates (BERs) by exploiting diffused infrared radiation. This work employs OOK as the modulation format and employs decision feedback equalization (DFE) to counteract the effects of multipath induced intersymbol interference. In the later works as witnessed in [84], the authors demonstrated the implementation of faster OOK IR systems which achieved data rates of 70 Mbps. The research work in the aforementioned reference [84], portrays the design and analysis of the performance of a prototype angle diversity infrared communication system. In this system, the achievable BER is ${10}^{-9}$ over a 4 m range. The other branch of OWC, which is directedtoward the successful implementation of indoor mobile wireless...