Cascaded PLC-VLC channel using OFDM and CSK techniques

Abstract: This paper puts in Cascade the power line communications (PLC) channel and the visible light communications (VLC) channel, in order to use the PLC channel as backbone for the VLC channel. This combination is suitable for applications in which hybrid PLC-VLC systems are needed. We investigate the behaviour of the cascaded channels for a full link transmission. Quadrature phase shift keying combined with orthogonal frequency division multiplexing (QPSK-OFDM) is used over the PLC channel and color shift keying (CSK) is deployed over the VLC channel to convey the information. Cascaded channel variances are analyzed. Complete simulated bit error rate (BER) is analyzed and presented for multiple scenarii that could occur in the two channels

Constellation design for cascaded MPSK-CSK systems

Abstract: This paper proposes a constellation design for color shift keying (CSK) based on phase shift keying (PSK) conversion, to be used in cascaded power line communications (PLC) and visible light communications (VLC) systems integration. We optimize the design of MPSK-CSK constellations and analyze the performance of MPSK-CSK systems based on the optimized Euclidean distance calculated on the red-green-blue (RGB) color space

Inter-building PLC-VLC integration based on PSK and CSK techniques

Abstract: This paper presents the implementation of an integration technique used to combine power line commu- nications (PLC) and visible light communications (VLC) channels in inter-building scenarios. It considers the narrow band PLC (NBPLC). Phase-shift keying (PSK) is used to convey the information over the PLC link and colour shift keying (CSK) technique is used on the VLC link. The colour wheel method is exploited to map PSK symbols to colours.We define a parameter x, which represents different magnitudes of the PSK complex symbol observed over the PLC channel. x is adjusted to an optimal value to meet the requirement of the CSK design. The bit error rate (BER) is analysed and the performance of the system is presented for multiple values of the modulus of the detected PSK symbol. A practical implementation is performed to verify the PSK-CSK mapping method. The impact of the sun’s rays on the red-green-blue (RGB) symbols is analysed and the interference source is highlighted

Closed-form SER expression for APSK based on the kite structure

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Impulsive Noise Evaluation on PLC-VLC based on DCO-OFDM

Abstract: 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 (DCOOFDM), 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, Tc are investigated through simulations. We also exploit the fact that both DCO-OFDM and PSKOFDM employ the FFT, to simplify the system

A simplistic channel model for cascaded PLC-VLC systems

Abstract: In this a paper, we propose a simplistic channel model for cascaded PLC-VLC system which highlights the noise scenario in such hybrid systems. The model utilises previously proposed channel transfer functions of both PLC and VLC channels and highlights the effects of the LED supply in the system. The noise scenario implemented on the model is based on the observations obtained from a practical measurement of PLC and VLC noise amplitude spectrum (NAS). The PLC-VLC channel is generalised and then simulated based on realistic data. In our results, we highlight the effect of the model’s parameters and noise present in both PLC and VLC channels

AF cooperative VLC communication systems : cascaded channel analysis

Abstract: Visible light communications (VLC) technology is a relatively new emerging telecommunication paradigm. It offers the opportunity to design cost-effective communication systems due to the dual use of the light sources, which are exploited as illumination devices and as communication antennas. However, this technology is mostly deployed in short-range communication applications because of the light diffusion range, which is short by nature. One good response to this dilemma is the imple- mentation of relay-assisted cooperative communication systems. Cooperative VLC systems provide three advantages, which are an increase in the transmission range, an improvement of the detection, hence of the bit error rate (BER), and an improved lighting system. In this paper, we analyze the channel response of a single-relay indoor VLC system based on an amplify-and- forward (AF) strategy. The system takes into account the fact that the relay also receives a reflected message. Results show the influence of the room’s reflection index, Lambertian index, the number of scattered rays on the overall channel response and confirms the importance of relay-assisted strategies in improving systems’ reliability

PSK to CSK mapping for hybrid systems involving the radio frequency and the visible spectrum

Abstract: This paper presents an efficient technique to map phase shift keying (PSK) signalling to colour shift keying (CSK) constellation, to establish a full link in hybrid systems involving the radio frequency (RF) and the visible spectrum. It fits in systems combining (first link) wireless communication technologies such as the wireless fidelity (WiFi) or wired communication technologies such as power line communications (PLC) to visible light communications (VLC) technology (second link). On the first link, PSK technique is used to convey the information, while, on the second link, a technique based on colour variation is deployed. WiFi standards targeted are those that employ PSK as sub-carrier modulation techniques (IEEE 802.11a/11g/11n). The PSK complex constellation observed at the output of the first link is converted into colours using the hue-saturationvalue/ intensity (HSV/I) colour models. The constant lighting required in VLC corresponds with the coordinate I of the HSI and the colour constraint is met by assigning adequate current intensities to the red-green-blue LEDs (RGB-LEDs) used. The design meets the requirements of CSK constellation design outlined in IEEE 802.15.7. The performance of the system is analysed through bit error rate curves obtained by simulations, for binary PSK (BPSK) and quadrature PSK (QPSK), 8PSK and 16PSK constellations. The results show that as the constellatio

VLC-Based Networking: Feasibility and Challenges

VLC has emerged as a prominent technology to address the radio spectrum shortage. It is characterized by the unlicensed and unexploited high bandwidth, and provides the system with cost-effective advantages because of the dual-use of light bulbs for illumination and communication and the low complexity design. It is considered to be utilized in various telecommunication systems, including 5G, and represents the key technology for light-fidelity. To this end, VLC has to be integrated into the existing telecommunication networks. Therefore, its analysis as a network technology is momentous. In this article, we consider the feasibility of using VLC as a network technology and discuss the challenges related to the implementation of a VLC-based network, as well as the integration of VLC into existing conventional networks and its inclusion in standards