Analog filters design in VLC analog front-end receiver for reducing indoor ambient light noise

Abstract

Visible Light Communication (VLC) technology in indoor implementation is challenged by ambient light and other lighting noise, such as fluorescent lamp and bulb. The ambient light could create a DC offset or signal with specific frequency range. Thus, we propose analog filters design in the VLC Analog Front-End (AFE) receiver that can eliminate the ambient light noise. The proposed design uses DC offset removal, incorporated with automatic and manual adjustment mode. In automatic mode, we design the analog filter using High Pass Filter (HPF) which have fc = 10Hz; meanwhile, in manual mode we design a reference circuit using potentiometer and differential amplifier for direct current blocking. For reducing signal interference from lamp flickering, the proposed design uses Band Stop Filter (BSF) which has fc = 100Hz. The experimental results, both simulation and realtime, show that our proposed design can reduce signal interference and ambient light. We also test the design using PWM and BPSK modulation to evaluate Bit Error Rate (BER) performance.