Undersampled Pulse Width Modulation for Optical Camera Communications

Pengfei Luo (1) , Tong Jiang (1) , Paul Anthony Haigh (2) , Zabih Ghassemlooy (3) , Stanislav Zvanovec (4)

1 Huawei Technologies France [Boulogne-Billancourt]
2 UCL - University College of London [London]
3 University of Northumbria at Newcastle [United Kingdom]
4 CTU - Czech Technical University in Prague

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.

Keywords: Optical camera communications; undersampled pulse width modulation; visible light communications

Domains: Engineering Sciences [physics]; Signal and Image processing

Pengfei Luo, Tong Jiang, Paul Anthony Haigh, Zabih Ghassemlooy, Stanislav Zvanovec. Undersampled Pulse Width Modulation for Optical Camera Communications. 2018 IEEE International Conference on Communications Workshops (ICC Workshops), May 2018, Kansas City, United States. pp.1-6, ⟨10.1109/ICCW.2018.8403732⟩. ⟨hal-02060129⟩