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Summary: The integrated OWC‐PON architecture has a potential to overcome the limitations of existent RF technology and eliminate the last mile bottleneck in geographically constrained access networks thus providing real sense broadband from core to user. However, phenomenon such as atmospheric turbulence causes performance degradation in such systems. In the dissemination of multimedia services, the performance is the ultimate quality as perceived by end user's visual senses. To ascertain this quality in quantitative terms, full reference quality metrics are employed for communication purposes. This paper deals with classification, evaluation and analysis of various image quality assessment metrics for image transmission over OWC channel under varying turbulent conditions. The performance enhancement in terms of these metrics is investigated by deploying MIMO diversity reception. Moreover, a prediction model for SSIM is developed and compared for both SISO and MIMO links. The results show an improvement in IQA metrics with diversity reception. SSIM can be predicted in terms of log of refractive index structure parameter by a fourth order polynomial model for both SISO and MIMO receptions under all regimes of turbulence. The goodness of the fit statistics is presented along with the models to provide for their accuracy and reliability. [ABSTRACT FROM AUTHOR]

Summary: The dimming control feature of light‐emitting diode (LED) makes it a viable candidate for indoor lighting applications. In this study, the performance of variable pulse position modulation (VPPM) based visible light communication (VLC) system is investigated in detail for an office room of 5 × 5 × 3‐m3 dimensions. A total of four LED lamps having Lambertian radiation patterns are mounted over the ceiling of the room. Several receiver locations are chosen over the three different trajectories to evaluate the error performance of the proposed system. The height of the receiver plane is also varied to find the optimum height where error‐free data reception is achieved. Moreover, an effort is made to optimize the dimming percentage of the transmitted signal using VPPM in terms of bit error rate (BER), where the illumination requirements over the receiver plane are also as per the International Standards of Organization (ISO). The results show that the duty cycle of 50% is optimum for efficient system performance. Furthermore, a colored image is transmitted through the proposed system and the computed results reveal that satisfactory BER performance and good quality of the image is received at receiver heights ranging from 0.85 to 1.7 m, that is, approximately 2.75 to 5.6 ft above the ground plane. [ABSTRACT FROM AUTHOR]

Summary: In this article, an indoor environment of 5 × 5 × 3 m3 dimensions is considered and a total of nine LED lamps are installed at the ceiling in a symmetrical pattern. The inter‐spatial separation between LED lamps is varied to achieve the dual purpose of lighting and communication services. The multipath channel impulse response for distinct receiver locations is also calculated under line‐of‐sight (LOS) and non‐line‐of‐sight (NLOS) channel conditions. Several performance parameters, that is, illumination uniformity, received power fluctuations, root‐mean‐delay spread (RMDS), are evaluated to estimate the performance of the proposed system. The results show that spatial separation of 1.5 m between the LED lamps outperforms the other considered spatial separations, and the error‐free data transmission rate for the proposed system comes out to be about 40 Mbps across the entire receiver plane. Furthermore, an RGB image is transmitted at 40 Mbps and the received image quality is estimated in terms of image quality parameter, that is, structure similarity index (SSIM) over the receiver plane. The results outlined that the received image shows 100% similarity with the transmitted image, and thus, the proposed system can be effectively deployed in practical indoor environments. [ABSTRACT FROM AUTHOR]