Software-Defined Visible Light Communication for Internet of Things: A Low-Complexity Approach

This work presents a software-defined visible light communication (SD-VLC) system that integrates carrierless amplitude and phase (CAP) modulation with an adaptive sign-data least mean squares (SDLMS) equalizer. The proposed solution is designed to address key challenges in VLC systems, such as LED bandwidth constraints, inter-symbol interference, and nonlinear distortions, and leverages the PYNQ platform to offer a flexible, reconfigurable, and cost-effective communication architecture tailored for IoT applications. Simulation results demonstrate that CAP modulation not only delivers high spectral efficiency but also inherently mitigates issues such as IQ imbalance and phase noise, thereby reducing hardware complexity. Moreover, the adaptive SDLMS equalizer significantly improves performance in multipath fading environments and reduces the bit error rate by approximately two orders of magnitude. These results underscore the potential of the proposed SD-VLC system to achieve low-cost and highly flexible wireless communication.