다양한 의료데이터 전송을 위한 가시광통신의 멀티채널 파장분할 멀티플렉싱

Abstract

Wireless communication had always been the most popular data communication method due to its portability. Wireless eliminates the use of extra space and wires to transmit data. Radio Frequency (RF) had dominated the wireless communication field for its reliability and easy to use coverage. But there is also a never ending debate on the effect of RF radiation to our human health. Visible Light Communication (VLC) is a type of wireless data communication system. VLC uses visible light spectrum which resides in electromagnetic spectrum to transmit data. Ever growing interest in solid state lighting research and its application had flourish the use of visible light not just as an illumination but also a data transmission device. Promising development in light emitting diode (LED) technology also fostered the growth of VLC technology. VLC now emerged as an alternative, no radio frequency radiation, and energy efficient wireless data communication system. With such benefits over general RF wireless technology, VLC is able to provide a cleaner, pollution-free and energy efficient transmission medium. In this study, critical medical healthcare information are being transmitted simultaneously in a multichannel environment using different color of LED. Wavelength Division Filtering (WDF) method is implemented to enable simultaneous recognition of multiple data stream transmission in the same wireless channel. This thesis describes the hardware development of the Multichannel VLC system such as commonly found color LED, color sensors and microcontroller. While in the software section, modulation demodulation techniques, signal conditioning and multiplexing simultaneous data streams are furthered explored and discussed. The multichannel VLC system is developed to wirelessly transmit and receive multiple critical medical healthcare data information streams such as Electrocardiograph (ECG) signals, Photoplethysmograph (PPG) signal and body temperature. Received data are then multiplexed into a single data stream so the further signal analyzing medium can easily process the collected data. Recorded experimental data shows a positive result on the implemented wireless multichannel VLC system.