4-Ary CSK Modulation Scheme Better than RGBW for LCD-Screen Camera Communications

Gordillo A.C. · Proceedings - 2021 20th International Conference on Ubiquitous Computing and Communications, 2021 20th International Conference on Computer and Information Technology, 2021 4th International Conference on Data Science and Computational Intelligence and 2021 11th International Conference on Smart Computing, Networking, and Services, IUCC/CIT/DSCI/SmartCNS 2021 (2021) · DOI: 10.1109/iucc-cit-dsci-smartcns55181.2021.00023

Resumen

The extended adoption of portable computing equipment allows cheap and effortless access a screen and a camera, which can be exploited to suggest a wireless optical communications structure for specific applications. However, it faces low data rate performance because of the camera and screen physical limitations. Color shift keying (CSK) arises as a modulation alternative to circumvent this problem and the particular case of 4-Ary CSK is addressed in this paper. We focus our attention on how machines perceive color and identify two 4-Ary sets of equidistant colors employing communications theory. We emphasize the use of a LCD screen as a transmitter and an off-The-shelf smartphone camera as a receiver. Our results show that color set formed by aqua, fuchsia, yellow and black outperforms the color set comprising red (R), green (G), blue (B) and white (W) in a 4-CSK modulation scheme. In addition, we found that the mean value of the received pixels color components is adequate for detection when a LCD screen is the transmitter. Moreover, we identify some optical distortions that degrade the system performance when distance between transmitter and receiver is 18.2 cm.

Instituciones: Universidad Nacional Tecnológica de Lima Sur