Visible light communication with OLEDs for D2D communications considering user movement and receiver orientations.

With the increasing use of organic light emitting diodes in lights, smart phones, wearable smartwatches, and computers, visible light-based device-to-device (D2D) communications has become more and more relevant. We propose D2D communications using smart phones' display pixels and their built-in cameras. We investigate the impact of receiver orientation and user mobility on the link performance. We derive a Gaussian model for the probability density function of the delay spread and optical path loss (OPL), and show that the channel delay spread decreases for a typical furnished room compared with an empty room, whereas the former has an increased OPL. In addition, we show that for the case of a furnished room and considering user mobility, the peak OPL values are about 64 and 62 dB, with and without considering the receiver's random orientation, respectively.

Coverage of a shopping mall with flexible OLED-based visible light communications.

Visible light communications (VLC) can utilize light-emitting diodes (LEDs) to provide illumination and a safe and low-cost broadcasting network simultaneously. In the past decade, there has been a growing interest in using organic LEDs (OLEDs) for soft lighting and display applications in public places. Organic electronics can be mechanically flexible, thus the potential of curved OLED panels/displays devices. This paper provides unique characteristics of a flexible OLED-based VLC link in a shopping mall. We show that, for curved OLED the radiation pattern displays a symmetry, which is wider than Lambertian. A number of scenarios of VLC system with flexible OLED are analyzed. Numerical models for the delay spread and optical path loss are derived, which followed a 2-term power series model for both empty and furnished rooms. We show that using a full-circular OLED for both empty and furnished rooms offers a uniform distribution of emitted power for the same transmission link spans. The link performance using full and half-circular OLED in an empty room shows that the average optical path losses are lower by 5 and 4 dB, compared with the furnished room.