Automatic Gain Control Design for Dynamic Visible Light Communication Systems

TL;DR

This paper designs and validates an automatic gain control system for dynamic visible light communication, improving signal stability and system performance amid rapid terminal movement.

Contribution

It provides a theoretical analysis and practical implementation of AGC tailored for VLC systems, addressing signal fluctuations caused by terminal mobility.

Findings

AGC stabilizes BER performance in dynamic VLC links.

Experimental validation shows improved system reliability at 1m/s speed.

Theoretical derivation of AGC design principles enhances VLC receiver robustness.

Abstract

For dynamic visible light communication (VLC) systems, received optical power fluctuates largely due to the fast movement of VLC terminals. Such fluctuations will cause possible signal clipping and quantization noise at the analog-to-digital converters (ADCs) and thus aggravate signal-to-noise ratio (SNR) and reliability of the communication link. To mitigate this effect, the automatic gain control (AGC) technique is often introduced in the receiver front-end to adaptively adjust the electrical signal strength. In this paper, we provided a VLC front-end analysis considering AGC model. Based on the model, some design principles of AGC are theoretically derivated: the effects of AGC index $m$, AGC maximum gain $g_{max}$ and AGC equilibrium range $DR$. Next, an analog AGC amplifier was carefully implemented and the effectiveness of our AGC modeling was proved through BER experiments. Finally, realtime 25Mb/s on-off-keying (OOK) experiments with AGC function were demonstrated in a dynamic link with different speeds. Experimental results show that the AGC can stabilize the BER performance and improve the system performance in the speed of 1m/s.