LED-based Visible Light Communication System for Low Data Rate Point-and-Grab Applications

Recently, the use of LED-based visible light communication (VLC) for short-range and low data rate applications has become an area of great interest for research and development communities. LED-based VLC systems consume less power and offer more secure communication link when compared with other wireless technologies. This article introduces the use of LED-based VLC systems for "point-and-grab" applications using smartphones and photodiodes. Different real life point-and-grab application scenarios, with one in particular relating to restaurant-consumer communication, are discussed where LED-based VLC can act as potential replacement for existing bluetooth or infrared technologies. A low cost photodiode dongle is developed to be used with smartphones which can provide reasonably high data rates for new possible commercial applications discussed in this paper. The data rates achieved by the developed test bed supplants the existing limitations on rates achievable by smartphone cameras. Experiments with the test bed are performed with the achievable rates of 1 Mbps which are greater than the highest achievable rates of up to 3 kbps with smartphone camera only. The proposed test-bed is also used for experimental measurement of different design characteristics like baud rate and symbol error rate, and to study the impact of several design parameters like tilt angle and range on the former characteristics.