Ing. Klára Eöllős Jarošíková

We present a design approach for a long-distance optical camera communication (OCC) system using side-emitting fibers as distributed transmitters. We demonstrate our approach feasibility by increasing the transmission distance by two orders up to 40 m compared to previous works. Furthermore, we explore the effect of the light-emitting diode (LED) modulation frequency and rolling shutter camera exposure time on inter-symbol interference and its effective mitigation. Our proposed OCC-fiber link meets the forward-error-correction (FEC) limit of 3.8 · 10−3 of bit error rate (BER) for up to 35 m (with BER= 3.35 · 10−3) and 40 m (with BER=1.13 · 10−3) using 2-mm and 3-mm diameter side-emitting fibers, respectively. Our results at on-off keying modulation frequencies of 3.54 kHz and 5.28 kHz pave the way to moderate-distance outdoor and long-distance indoor highly-reliable applications in the Internet of Things and OCC using side-emitting fiber-based distributed transmitters.

We demonstrate for the first time the application of LED-based optical camera communication using a side-emitting fiber in wearable applications. A 1.2-m long plastic side-emitting fiber with a 4-mm outer diameter acts as a distributed transmitter. The side-emitting fiber is attached to a T-shirt over the shoulder with a 50-cm section of the fiber both on the front and back side of the T-shirt. This expands the possibilities of data detection by the rolling shutter camera. The light from a white LED is coupled into the side-emitting fiber with LED on-off keying (OOK) modulation frequencies of 2.64 kHz, 3.54 kHz, and 5.31 kHz. The results show bit error rate bellow 3.8 • 10 −3 for up to 200 cm fiber to camera distance.

We present a distributed receiver for visible light communication based on a side-emitting optical fiber. We show that 500 kbps data rate can be captured with a bit-error rate below the forward-error correction limit of 3.8·10−3 with a light-emitting diode (LED) transmitter 25 cm away from the fiber, whereas by increasing the photodetector gain and reducing the data rate down to 50 kbps, we improve the LED-fiber distance significantly up to 4 m. Our results lead to a low-cost distributed visible-light receiver with a 360° field of view for indoor low-data rate, Internet of Things, and sensory networks.

We present a novel concept of visible light communication (VLC) uplink by introducing a distributed receiver (Rx) formed by an illuminating optical fiber (IOF) connected to the photodetector. The major functionality of IOF-distributed Rx is to sense/detect the light signal along the fiber span at a range of modulation frequencies coming from an on-off keying modulated light-emitting diode (LED) transmitter. We show that our proposed proof-of-concept of distributed Rx performs below the forward error correction limit of 3.8⋅10−3 at frequencies up to 400kHz. We unveil the signal-to-noise ratio (SNR) limit of 19dB must be maintained for successful data reception. Higher data rates are predicted once the concept is optimized, especially in terms of SNR. The proposed IOF-based scheme can be considered as a solution to the current challenges of VLC uplink.

We have recently presented a novel concept of optical camera communications (OCC) based on illuminating optical fibers (IOF) as transmitter (Tx). In this paper, we further investigate this concept of IOF-based OCC system by replacing a straight IOF by an L-shaped IOF as the transmitter. An intensity modulated light from a white light emitting diode in the on-off keying format at frequencies of 1800 and 2400Hz is launched into the IOF. We experimentally investigate the impact of IOF bending as well as horizontal and vertical orientations of camera-based receiver on the performance of the IOF-based OCC system. The results depict 100% success of reception is achieved over a transmission distance of 50cm for the IOF bending angle in the range of 0 to 90°, and horizontal and vertical orientations of the camera.

In this paper, we study the novel idea of fiber optic lighting - optical camera communications. We carry out analyses of the proposed scheme employing a light emitting diode (LED) illuminated plastic optical fiber (POF) and a rolling-shutter-based camera as the transmitter and the receiver (Rx), respectively in an indoor static environment. We also provide optical and electrical characterization of the LED and LED coupled POF illumination sources. The experiment results demonstrate that, despite the small diameter of the illuminating POF, flicker-free wireless communications at modulation frequencies of 300 and 600 Hz over the transmission distances of 50 and 75 cm can be achieved. Consequently, we show that a 100 % reception success rate is achieved for the camera-based optical Rx with the exposure time and the gain of 400 µs and 25 dB, respectively.

In this Letter, we propose and demonstrate a novel wireless communications link using an illuminating optical fiber as a transmitter (Tx) in optical camera communications. We demonstrate an indoor proof-of-concept system using an illuminating plastic optical fiber coupled with a light-emitting diode and a commercial camera as the Tx and the receiver, respectively. For the first time, to the best of our knowledge, we experimentally demonstrate flicker-free wireless transmission within the off-axis camera rotation angle range of 0–45° and the modulation frequencies of 300 and 500 Hz. We also show that a reception success rate of 100% is achieved for the camera exposure and gain of 200 µs and 25 dB, respectively.