Infrared-Based Multiple-Patient Monitoring in Indoor Optical Wireless Healthcare Systems

In recent years, optical wireless communication (OWC) is recognized as a propitious technology for indoor data communications, offering reduced electromagnetic interference (EMI) in sensitive indoor communication environments such as hospitals and nursing homes, and has thus emerged as a good candidate for healthcare monitoring applications. In this paper, we investigate the use of infrared (IR) communication for multiple-patient biomedical data transmission. To transmit the multiple-patient data, we propose a novel periodic data transmission (PDT) scheme with a real-time experimental demonstration. The transmit modules consist of IR light emitting diodes (LEDs) as the transmitter, and the receiver module comprises a narrow bandpass filter (BPF) followed by an IR photodiode (PD). Biomedical signals for the transmission include electrocardiography (ECG), blood pressure (BP), and body temperature. We consider the line-of-sight (LOS) data transmission with multiple transmitters corresponding to each patient and a single receiver where each patient is allowed to transmit the data periodically. Experiments are carried out to verify the effectiveness of the proposed system. The experimental results demonstrate that it achieves a bit error rate (BER) of better than 10^-6, thus offering accurate health monitoring applications with negligible interference from multiple patients.