A bandwidth efficient hybrid multilevel pulse width modulation for visible light communication system: experimental and theoretical evaluation

Visible light communication (VLC) is considered a new technology for interconnecting devices in 5G and beyond. VLC can provide additional bandwidth for communicating devices which can help to reduce the radio frequency bandwidth congestion. In this work, we aim to maximize the bandwidth usages for VLC. The proposed modulation technique can impose more bits due to the combined utilization of both pulse height and width changes. Moreover, we subdivide the single bit duration to impose more bits for data transmission. The proposed modulation is capable of transmitting more bits by utilizing fewer optical pulses than other traditional modulation techniques such as multilevel modulation, on-off keying, pulse width modulation, pulse position modulation, pulse amplitude modulation, and multiple pulse position modulation. We have evaluated the theoretical bit error rate (BER) expression in terms of average signal to noise ratio and compared the experimental BER performance for the proposed system. The experimental results demonstrate that the proposed modulation technique can achieve a communication distance of 3 m in an indoor environment.