MIMO Based Indoor Visible Light Communication for Internet of Things via Data Encryption

Visible light spectrum has a large unused bandwidth and that can be employed to handle the growing data traffic for the Internet of Things (IoT) devices. In this study, visible light communication (VLC) based multiple-input multiple-output (MIMO) system was used to facilitate IoT connectivity in indoor environments. To cover long range with low transmission error on-off keying (OOK), and power-efficient multiple pulse position modulation (MPPM) were tested with MIMO. Also, a lightweight encryption technique is designed for the transmitted data to ensure security. Two single LEDs and two photodiodes were employed to test a $2 \times 2$ MIMO configuration. Plano-convex lens is employed for each transmitter to cover a wide area, which can achieve long-distance communication. The system evaluated in real-time and empirical results shows 15 m distance communication with a reliable error rate.