Enhancement of Signal Performance in bidirectional RSE-based CVLC system employing NPM modulation scheme

Camera-based visible light communication (CVLC) exploiting rolling shutter effect (RSE) is a cost-effective technique that ensures secure data transmission. In this paper, a bidirectional CVLC system is experimentally demonstrated using smartphone/laptop as downlink/uplink transceiver in an experimental prototype testbed. Meanwhile, a Nyquist pre-distorted Manchester (NPM) modulation scheme is proposed and validated in the experimental testbed system. The proposed scheme is based on low-complexity transmitter-side digital signal processing (DSP) techniques, Nyquist shaping and linear pre-distortion, which can be employed for mitigation of the impact of extinction ratio (ER) fluctuation and exposure overlapping in the RSE-based CVLC system. The experimental results show that by using the proposed NPM modulation, the uplink and the downlink can both achieve about 4.8 Kb/s transmission with bit error rate (BER) of below than 3.8e−3. It verifies the effectiveness of the proposed NPM scheme and the corresponding transmitter-side DSP techniques.