Experimental DCO OFDM Optical Camera Communication Systems With a Commercial Smartphone Camera
Modern handheld mobile devices are equipped with a complementary metal oxide semiconductor (CMOS) image sensor. These image sensors are capable of perceiving intensity changes in optically modulated signals, driving the rapid development of optical camera communication (OCC) In this study, direct current offset orthogonal frequency division multiplexing (DCO OFDM) was developed for a rolling shutter OCC system in order to improve the data transmission rates of OCC systems. Two DCO OFDM OCC signal detection algorithms, namely the parabolic column vector selection (P CVS) algorithm and the decomposition of extremely low frequency component (D ELFC) algorithm, were proposed, along with a frequency domain downsampling scheme, to eliminate the influence from both the blooming effect and shot noise. The experimental results, obtained after using a self built DCO OFDM OCC testbed with a general commercial smartphone camera, demonstrated that the D ELFC algorithm outperformed in the bit error rate (BER) in comparison to the P CVS algorithm and achieved a data transmission rate >22 kbps under the conditions of the BER being below the 20% forward error correction (FEC) limit and the illuminance being higher than 510 lux.
IEEE Photonics Journal