Positive impacts on the PCE by using thiazole instead of thiophene in soluble electron-donor small molecules for OPV.

The inclusion of organic light emitting diodes (OLEDs) in high‐end devices, such as TVs and smart‐phones, along with the insertion of cameras embedded in daily use devices, provides the opportunity to establish optical camera communication (OCC) systems based on OLED emitters for Internet of Things (IoT). This Letter presents an experimental demonstration of this OLED‐based OCC system for IoT. The results suggest that despite the low emitted power of OLED devices, long range links can be established based on OCC. One outdoor and two indoor scenarios are tested, validating BER below for short range and give just for long range links.

Nowadays, the study of viable applications for smart cities has the direct interest of the research community. The generalized use of LED-based devices with larger dimensions and affordable costs, and the insertion of cameras with better characteristics in devices such as tablets and smart-phones, impulse the use of Optical Camera Communication (OCC) as a practical solution for future Internet of Things (IoT) and smart cities implementations. A real long distance OCC system for relatively slow data rate applications in smart cities is described along with its advantages and possible difficulties. A real scenario experiment has been held showing the viability of the proposed system.

Due to the massive insertion of embedded cameras in a wide variety of devices and the generalized use of LED lamps, Optical Camera Communication (OCC) has been proposed as a practical solution for future Internet of Things (IoT) and smart cities applications. Influence of mobility, weather conditions, solar radiation interference, and external light sources over Visible Light Communication (VLC) schemes have been addressed in previous works. Some authors have studied the spatial intersymbol interference from close emitters within an OCC system; however, it has not been characterized or measured in function of the different transmitted wavelengths. In this work, this interference has been experimentally characterized and the Normalized Power Signal to Interference Ratio (NPSIR) for easily determining the interference in other implementations, independently of the selected system devices, has been also proposed. A set of experiments in a darkroom, working with RGB multi-LED transmitters and a general purpose camera, were performed in order to obtain the NPSIR values and to validate the deduced equations for 2D pixel representation of real distances. These parameters were used in the simulation of a wireless sensor network scenario in a small office, where the Bit Error Rate (BER) of the communication link was calculated. The experiments show that the interference of other close emitters in terms of the distance and the used wavelength can be easily determined with the NPSIR. Finally, the simulation validates the applicability of the deduced equations for scaling the initial results into real scenarios.

Communications for IoT sensor networks in Smart City applications are demanding new technologies to avoid the radio frequency spectrum saturation and support the massive nodes situation required in this kind of network. Visible Light Communications are gaining interest as an alternative scheme for solving this problem. In particular, Optical Camera Communication (OCC) takes advantage of the presence of cameras in a wide range of devices (smartphones, surveillance systems). Several transmission and modulation schemes, specifically developed for OCC, have been proposed but they present different problems as the communication range, the flickering effects in the transmitted signal, or the system complexity. In this work, an Optical Camera Communication modulation scheme that addresses the considerable variability of the transmitter–receiver distance is proposed. As will be shown, the modulation scheme works properly independently of this separation for a wide range of distances. Additionally, it performs a flickering free transmission to avoid undesired blinking effects for humans and uses a simplified transmission and reception scheme, reducing the system complexity and cost. Results of the modulation’s performance for short (60 m) ranges are presented in the paper, showing a 16 bps transmission rate with Bit Error Rate below the Forward Error Correction (FEC) limit (3.8 · 10⁻³).