Efficient and Low-Complexity Rate and Dimming Control of VLC for Industrial IoT Applications

Visible light communication (VLC) has emerged as a promising complementary technology to millimeter-wave communications for short-range communications to meet the increasing industrial Internet of Things (IIoT) capacity demands. Efficient illumination and data transmission face specific challenges, such as controlling dimming without compromising transmission capacity. In this article, we revisit multipulse pulse-position modulation (MPPM) for joint rate–dimming control in VLC. MPPM is widely considered a highly efficient modulation for optical communications. However, the computational complexity of current MPPM coding methods grows exponentially as the code rate is increased. To overcome this limitation, we propose novel encoding and soft-decision decoding strategies that allow fine-tuning dimming control and increase the data rate. Performance results show higher data rates with lower energy demands as compared to current standards. Moreover, the proposed encoding and decoding methods exhibit linear time complexity, which makes them suitable for implementation in low-cost VLC devices for massive IIoT deployments.