Advanced Mobility: Integrating Visible Light Communication and Sensing Technologies

Visible light communication technology is a wireless optical communication technology based on LED lighting. [1] Making use of the high speed response characteristic of LED, visible light communication technology can realize the dual functions of lighting and communication. As a new way of data access and a supplement to radio frequency communication, visible light communication has been widely concerned. This paper is based on the development of application-oriented visible light communication system based on intelligent terminal, in order to accelerate the practical process of visible light communication. By changing the traditional visible light receiving scheme and using smart phone as the receiving device of the visible light system, a visible light communication system based on intelligent terminal is built [2]. Through the research on the existing receiving algorithm, a new receiving algorithm is proposed to improve the adaptability and BER performance of the system.

Li-Fi stands for Light-Fidelity. This technology is very new and was proposed by the German physicist Harald Haas in 2011. Light based communication system is the backbone of the future of the communication system. Li-Fi is a wireless technology that uses light emitting diodes (LEDs) for transmission of data. The development of the wireless communication leads to advance research in LiFi technology. The term Li-Fi states to visible light communication (VLC) technology that uses as medium to deliver high-speed communication in a fashion similar to Wi-Fi. Li-Fi comprises a wide range of frequencies and wavelengths, from the Infrared through visible and down to the Ultraviolet spectrum. The immense use of Li-Fi may solve some bottleneck of data transmission in Wi-Fi technology. With the innovation in technology and the number of users, the existing radio-wave spectrum fails to accommodate this need. To resolve the issues of scalability, availability and security, we have come up with the concept of transmitting data wirelessly through light using visible light communication (VLC) technology. This paper objective is to study and describe the LiFi technology. The improvement of the wireless communication leads to advance research in LiFi technology through Visible Light Communications (VLC) Technology.

Indoor visible light positioning becomes attractive due to the increasing demands of location-based services. In this paper, we presented a model of an indoor positioning system based on visible light communication technology firstly. The system uses white light emitting diodes (LED) as light sources, so it has the dual role of communication and lighting. Then, the transmitter and receiver of visible light communication in the system have been designed and realized. Next, a coding protocol was designed and implemented, which can be used to transmit ID of each light source. Finally, the error performance in experiments of the proposed system is analyzed and several suggestions on future research of indoor positioning based on visible light communication were given.

The fifth-generation (5G) mobile network is the next paradigm shift in the revolutionary era of the wireless communication technologies that will break the backward compatibility of today’s communication systems. Visible Light Communication (VLC) and Light Fidelity (LiFi) technologies are among the potential candidates that are expected to be utilized in the future 5G networks due to their indoor energy-efficient communications. Realized by Light Emitting Diodes (LEDs), VLC and LiFi possesses a number of prominent features to meet the highly demanding requirements of ultrahigh-speed, massive Multiple-Input Multiple-Output (MIMO) device connectivity, ultra-low-latency, ultra-high reliable and low energy consumption for 5G networks. This paper provides an overview contributions of VLC and LiFi towards 5G networks. Furthermore, we explain how VLC and LiFi can successfully provide effective solutions for the emerging 5G networks.

Visible Light Communications (VLC) technology is restricted by the transmission coverage, which is short by nature. This is imposed by the lighting range which barely reaches a couple of hundred meters. The number of applications of VLC technology is therefore limited by this specific characteristic of the light propagation. As a result, VLC cannot be used in long and medium distance communication systems. The technology is suitable for exploitation in optical wireless personal area networks (OWPAN) in which the mobile terminal (MT) and the VLC access point (VLC AP) are placed in the same room. It is then essential that the access point is fed by a backhaul network. In this paper, we propose an access network in which the backhaul or backbone network exploits fibre optic (FO) technology to feed the VLC access point with data to be retransmitted. The channel is analyzed for a few parameters of the entire system including the FO attenuation factor, α, the transmission range, L, and the indoor VLC wall, ceiling and floor reflection coefficient, ρ.

This article reviews the visible light communications (VLC), a technology in which the visible spectrum is modulated to transmit data. It presents the VLC communication system: the transmitter, the channel, and the receiver. The single and multichannel transceivers are presented. The channel for a system that uses a single light‐emitting diodes (LED) and the matrix representing the multicolor channel are discussed. Various modulation schemes, basic techniques used to implement a VLC system, and different causes of dimming are discussed. In addition, standardization of the VLC technology, applications, as well as challenges for VLC practical implementation and commercialization are reviewed.

The radio frequency spectrum has become very congested and scarce. A response to this dilemma is the implementation of visible light communications (VLC) technology, which is enabled by the dramatic development of light emitting diodes (LEDs) and laser diodes (LDs). VLC has become the most popular emerging telecommunication technology. This is due to the interesting advantages that it provides, which include an unlicensed and large bandwidth, a high throughput capability and a low implementation cost. VLC needs a pivot network in medium and long distance transmissions. The amplify‐and‐forward scenario between the backbone network and VLC is cost‐effective owing to its simplicity when compared to the decode‐and‐forward scenario. MPSK‐CSK is a typical example of cascaded systems in AF scenario with VLC where the backbone channel utilises PSK to convey the message. In this paper, we investigate a forward error correction scheme for cascaded MPSK‐CSK systems. A convolutional encoder is added to the MPSK‐CSK scheme to construct the hybrid trellis coded modulation scheme. Selected 8HTCM systems using set partitioning are investigated and results for a Gaussian channel are presented. Numerical results reveal that 8HTCM achieves up to 2.129 dB of asymptotic coding gain when compared to the corresponding un‐coded MPSK‐CSK system.

Facing the current shortage of radio frequency spectrum resources, visible light communications (VLC) technology has been proposed to be a candidate technology in the sixth generation (6G), especially in the application of Intelligent Transportation Systems (ITS). And the propagation characteristics of VLC channel are critical for VLC system design and optimization. Furthermore, the impact of weather conditions on VLC channel cannot be ignored considering the vehicular VLC in ITS. In this paper, we experimentally investigate the impact of different weather types including fog and relative humidity (RH) on VLC in a laboratory atmospheric chamber. To simulate adverse weather conditions, we change the levels of fog density and water vapor introduced into the chamber, respectively. Then we measure the power attenuation and the bit error rate (BER) performance of VLC system under fog and RH conditions. We find that the VLC system will exhibit worse BER performance in the fog impaired channel than RH conditions. Besides, the results show that the bit errors will not happen until the attenuation reaches the threshold, i.e. attenuated by about 60% for both fog and RH conditions in our experiments. After that, the BER will deteriorate badly even up to 20%.

Power line communications (PLC) and visible light communications (VLC) are two emerging communication technologies which have several similarities. Among them, the advantage related to cost effectiveness is considered as strong research motivation. These two technologies are also characterized by the fact that each one of them barely form a complete communication system without the need of other supporting technologies. In this paper, based on the positive aspect of VLC technology, we exploit the Hermitian symmetry to design an hybrid system combining PLC and VLC technologies using orthogonal frequency division multiplexing (OFDM). A DC biased optical OFDM (DCO-OFDM), employed in VLC, is investigated when combined with PSK-OFDM (used in PLC). In the hybrid PLC-VLC system proposed in this paper, we exploit the inherent clipping feature of DCO-OFDM to combat impulsive noise found in the PLC channel, where the optimal combination of the DC bias level for optical communication, DC and impulse noise clipping threshold, T <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</inf> are investigated through simulations. We also exploit the fact that both DCO-OFDM and PSK-OFDM employ the FFT, to simplify the system.

Visible light communication (VLC) has emerged as a viable complement to traditional radio frequency (RF) based systems and as an enabler for high data rate communications for beyond-5G (B5G) indoor communication systems. In particular, the emergence of new B5G-based applications with quality of service (QoS) requirements and massive connectivity has recently led to research on the required service-levels and the development of improved physical (PHY) layer methods. As part of recent VLC standards development activities, the IEEE has formed the 802.11bb “Light Communications (LC) for Wireless Local Area Networking” standardization group. This paper investigates the network requirements of 5G indoor services such as virtual reality (VR) and high-definition (HD) video for residential environments using VLC. In this paper, we consider such typical VLC scenarios with additional impairments such as light-emitting diode (LED) nonlinearity and imperfect channel feedback, and propose hyperparameter-free mitigation techniques using Reproducing Kernel Hilbert Space (RKHS) methods. In this context, we also propose using a direct current biased optical orthogonal frequency division multiplexing (DCO-OFDM)-based adaptive VLC transmission method that uses precomputed bit error rate (BER) expressions for these RKHS-based detection methods and performs adaptive BER-based modulation-order switching. Simulations of channel impulse responses (CIRs) show that the adaptive transmission method provides significantly improved error rate performance, which makes it promising for high data rate VLC-based 5G indoor services.

Nowadays, with the incursion of solid state lighting technology in our daily life, visible light communication (VLC) systems are becoming more important. This fact has generated a lot of attention on VLC to provide solutions on multiple applications where this technology can be exploited. At the same time, the growing of automation processes has created the necessity of knowing the localization of different objects and devices. Indoor localization based on radio frequency signals is one of the most used techniques (Wi‐Fi, Bluetooth, UWB, RFID, etc); however, VLC is a new and interesting method, which is gaining enormous research attention. Moreover, there are environments where the use of RF technologies is restricted or even prohibited. In such cases, VLC technology becomes an interesting alternative to solve this problem. In this paper, we design and implement a novel VLC‐based indoor localization system that combines the application of a VLC scheme for downlink and an ultrasonic communication for the uplink. Practical localization experiments are carried out in an actual office room environment, and results show a localization accuracy of 4 cm on average for direct links and 10 cm for indirect links.

Intelligent Transportation Systems (ITSs) are being proposed, examined, and applied to enhance road safety and traffic efficiency. However, the automotive industry has stringent criteria for safety applications that demand connections that are dependable and have low latency, and high data rates. In this paper, it is widely agreed that both Visible Light Communication (VLC) and Free Space Optics (FSO) represent promising solutions, because of their complementary advantages compared to Radio Frequency (RF). VLC technology is chosen in ITS overall other optical wireless systems primarily due to its low cost and lack of licensing or new infrastructure requirements. Hence, a comparative study is applied between standalone VLC system, and a hybrid FSO/VLC system in term of Bit Error Rate (BER), coverage distance, and Signal to Noise Ratio (SNR). The VLC/FSO system provides a reliable communication link over a long distance (900 m) compared to VLC standalone system with 10−6 BER and acceptable SNR of ∼\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\sim$$\\end{document} 25 dB.

The emerging visible light communication (VLC) technology, which has the advantages of short-distance communication and indoor lighting, has become a research hotspot of indoor wireless communication technology. Polar codes, as the only forward error correction (FEC) coding technology that has been theoretically proven to achieve Shannon's capabilities, are adopted to reduce the bit error rate (BER) in VLC systems. However, the individual polar codes are still unable to correct burst errors in VLC channels. This paper proposes concatenated polar codes with interleaving technology for VLC systems. The results show that it can effectively correct random errors and burst errors in VLC systems. Compared to the non-systematic polar codes, the systematic polar codes are more suitable as the inner code of the concatenated polar codes. The concatenated polar codes exhibit a lower error floor in VLC systems under burst errors than the individual polar codes. Compared with BCH-polar schemes, Convolutional-polar schemes have better robustness.

The visible light communication (VLC) technology based on the lighting system of space station is put forward. The VLC has advantages of not taking up radio spectrum, no electromagnet interference and radiation, high emission power and good secrecy. This paper mainly studies to improve inter-symbol interference and fading problem caused by multipath effects in VLC system using RAKE receiving technology. The simulation results in this paper indicate that optical receiving technology utilizing RAKE can not only resolve the inter-symbol interference and reduce the bit error rate (BER), but also improve the signal to noise ratio of the system output.

Advances in high brightness light emitting diode (LED) technology are enabling myriad applications in lighting including visible light communications (VLC) technology that has the potential to complement RF technology to provide wireless data access for indoor coverage. This chapter reviews various dimming techniques suitable for VLC, and presents an LED driver circuit architecture incorporating digitally controlled analog circuit blocks to deliver concurrent dimming control and data transmission for VLC-enabled lighting. To achieve this target, a bi-level pulse-width modulation (PWM) driving scheme is applied to enable data transmission during the “off” period of the LED drive current while concurrently providing dimming control. The proposed architecture is compatible with digital baseband modulation schemes and implements a mechanism for ease of integration with commercial off-the-shelf (COTS) LED drivers for VLC system realization. This chapter also discusses a dimming compatible analog baseband modulation scheme. The reverse polarity optical orthogonal frequency-division multiplexing (RPO-OFDM) is a recent approach to realize compatibility between any format of an analog OFDM signal suitable for optical transmission and the concept of a digital pulse-width modulation (PWM) technique for dimming control. We also describe an implementation of the RPO-OFDM approach as part of a wireless access testbed. Experiments reveal that bit-error and bit-rate performances are maintained over a wide range of dimming.