Pixelated VLC-backscattering for Self-charging Indoor IoT Devices

TL;DR

This paper introduces a pixelated VLC backscatter system that significantly increases data rates for indoor IoT devices by enabling multi-level modulation schemes, achieving up to three times higher throughput than traditional methods.

Contribution

A novel pixelated VLC backscatter design that allows multi-level modulation, overcoming channel capacity limits of existing VLC backscatter systems.

Findings

Data rate tripled with 8-PAM at 2 meters

n-fold throughput enhancement with n smaller VLC backscatters

Negligible additional energy consumption for increased throughput

Abstract

Visible light communication (VLC) backscatter has been proposed as a wireless access option for Internet of Things (IoT). However, the throughput of the state-of-the-art VLC backscatter is limited by simple single-carrier pulsed modulation scheme, such as on-off keying (OOK). In this paper, a novel pixelated VLC backscatter is proposed and implemented to overcome the channel capacity limitation. In particular, multiple smaller VLC backscatters, switching on or off, are integrated to generate multi-level signals, which enables the usage of more advanced modulation schemes than OOK. Based on experimental results, rate adaptation at different communication distances can be employed to enhance the achievable data rate. Compared to OOK, the data rate can be tripled when 8-PAM is used at 2 meters. In general, $n$-fold throughput enhancement is realized by utilizing $n$ smaller VLC backscatters while incurring negligible additional energy using the same device space as that of a single large backscatter.