Design of timing tracker for quality of service of energy management based on dimmable lighting: Proposal of architecture of timing tracker for dimmable VPPM-VLC system

Visible light communication (VLC) is widely useful to various application. VLC in indoor energy management is attractive due to characteristics that data are transferred through light and possible to be spatial security and localization. Variable pulse position modulation (VPPM) especially is suitable for the indoor energy management because of supporting a full dimming range and being implemented simply. This paper proposes a timing tracker for timing synchronization in the VPPM-VLC system. The proposed timing tracker is evolution of the early-late detection to the VPPM-VLC system by considering characteristics of the VPPM-VLC signaling in perspective on the timing tracker. This paper describes design results for a VPPM-VLC receiver with the proposed timing tracker, and presents behavioral simulation results for the verification of the proposed timing tracker. The simulation results shows that the proposed VPPM-VLC timing tracker estimates the timing-offset and compensates timing mismatch through buffer control.