Undersampled Pulse Width Modulation for Optical Camera Communications | IEEE Conference Publication | IEEE Xplore

Undersampled Pulse Width Modulation for Optical Camera Communications


Abstract:

An undersampled pulse width modulation (UPWM) scheme is proposed to enable users to establish a non- flickering optical camera communications (OCC) link. With UPWM, only ...Show More

Abstract:

An undersampled pulse width modulation (UPWM) scheme is proposed to enable users to establish a non- flickering optical camera communications (OCC) link. With UPWM, only a digital light emitting diode (LED) driver is needed to send signals using a higher order modulation. Similar to other undersample-based modulation schemes for OCC, a dedicated preamble is required to assist the receiver to indicate the phase error introduced during the undersampling process, and to compensate for nonlinear distortion caused by the in-built gamma correction function of the camera. To test the performance of the UPWM- based OCC system, an experimental test-bed is developed. The experimental results show that the proposed system is able to achieve a data rate of 150 bps (spectrum efficiency of 5 bits/symbol) at a bit error rate of 6.76×10^-4, which is well below the forward error correction limit of 3.8×10^−3, over a link span of 1 m using a Huawei Nexus 6P smartphone with a frame rate of 30 fps.
Date of Conference: 20-24 May 2018
Date Added to IEEE Xplore: 05 July 2018
ISBN Information:
Electronic ISSN: 2474-9133
Conference Location: Kansas City, MO, USA

I. Introduction

As superior imaging sensors (ISs) and faster smartphone processors are becoming commonplace, the latest smartphones are as powerful as professional digital single-lens reflex (DSLR) cameras on the photography side. In Dec. 2017, the top 3 ranked mobiles from DxOMark are Google Pixel 2, Apple iPhone X, and Huawei Mate 10 Pro with an overall score of 98, 97, and 97, respectively [1]. According their product specifications, each of these devices are capable of 720p or 1080p video capture at up to 240 frames per second (fps). Such an ability to capture high speed video streams by a smartphone paves the way for future optical camera communication (OCC) technology, mostly for low speed applications such as vehicular communications and indoor positioning [2].

References

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