A Manchester-OOK Visible Light Communication System for Patient Monitoring in Intensive Care Units

Visible Light Communication (VLC) is an interesting solution in Intensive Care (IC) medical environments to, among others, prevent the spread of emerging diseases. This work presents the design of a low-cost and stable VLC transceiver system in addition to practical characterizations and experimental performance evaluations for application in IC environments. The application focuses on the transmission of Manchester-based on-off keying signals, in a proof-of-concept apparatus that makes use of the Eye Opening Penalty (EOP) metric to illustrate a comprehensive picture of the potentials of the evaluated VLC system. Parameters such as Light-Emitting Diode (LED) bias current, modulation frequency, line-of-sight link distance, and signal pattern were analyzed here. Experimental results show an outstanding behavior considering an LED bias current of 400 mA, a signal frequency of 1 MHz and a VLC transmission link length of 2.5 m. To validate our system, vital parameters as heart rate, oxygen saturation, pulse rate, respiration rate, temperature and non-intrusive blood pressure signals were transmitted for VLC links of 1.5, 5 and 15 m, which were received by a multi-parameter monitor, with EOP values of 0.89, 0.96 and 2.67 dB, respectively.