Design and Implementation of Angular Diversity Receiver for VLC IoT Sensor Networks

In this paper, we propose a novel angular diversity receiver (ADR) for visible light communication (VLC) in Internet of Things (IoT) sensor networks. Square frustum type ADR with five photodetectors (PDs) is applied to provide a wide field of view (FOV). In the ADR system, equal gain combining (EGC) is also utilised for signal-to-noise ratio (SNR) enhancement. For experimental verification, the ADR and the analog front end (AFE) of the transceiver are designed and prototyped. The proposed ADR system shows a 6 dB increase in received SNR compared to a single PD receiver. With this design, the bit error rate (BER) is improved and the link coverage is more than doubled. Additionally, to show the feasibility of the IoT application, a real-time sensor network system using the ADR is demonstrated. This experimental system supports a duplex VLC communication link. The demonstration indicates the benefits of the proposed system in a practical IoT scenario.