Gbit/s ultraviolet-C diffuse-line-of-sight communication based on probabilistically shaped DMT and diversity reception.

Omar Alkhazragi,Boon S Ooi,Fangchen Hu,Tien Khee Ng,Chun Hong Kang,Yuan Mao,Nan Chi,Peng Zou,Yinaer Ha

doi:10.1364/oe.389262

Abstract

We demonstrated a high-speed 1×2 single-input and multiple-output (SIMO) diffuse-line-of-sight (diffuse-LOS) ultraviolet-C (UVC) solar-blind communication link over a distance of 5 meters. To approach the Shannon limit and improve the spectral efficiency, we implemented probabilistically shaped discrete multitone modulation. As compared to a single-input and single-output (SISO) counterpart, we observed significant improvement in the SIMO link in terms of the angle of view of the receiver and the immunity to emulated weather condition. A wide angle of view of ± 9° is achieved in the SIMO system, with up to a 1.09-Gbit/s achievable information rate (AIR) and a minimum value of 0.24 Gbit/s. Moreover, the bit error rate of the SIMO link in emulated foggy conditions is lowered significantly when compared to that of the SISO link. This work highlights the practicality of UVC communication over realistic distances and in turbulent environments to fill the research gap in high-speed, solar-blind communication.

Highlights

Optical wireless communication (OWC) has emerged as an important means of data communication to mitigate the expected increase in radio frequency (RF) spectrum-crunching in the fifth-generation networks and beyond
To have a fair comparison, we set two conditions for the single-input and single-output (SISO) diffuse-LOS link: (1) its achievable information rate (AIR) at θ=0° must be around the same value of that of the single-input and multiple-output (SIMO) link (∼1.1 Gbit/s), and (2) the AIR cannot drop below 0.1 Gbit/s at all angles
Since a single detector is used in this case, more power is needed to achieve a similar AIR, which means that the beam divergence must be smaller to increase the received intensity

Summary

Introduction

Optical wireless communication (OWC) has emerged as an important means of data communication to mitigate the expected increase in radio frequency (RF) spectrum-crunching in the fifth-generation networks and beyond. The sunlight spectrum in the ultraviolet-C (UVC) region (200 - 280 nm) is completely absorbed by the molecules in the Earth’s stratosphere This allows one to use UVC light for outdoor OWC without being susceptible to solar background noise. Advances in UVC light-emitting diodes (LEDs) have only been achieved recently This opens the door for broad-bandwidth and high-speed communication [2,3], as well as safe UVC links based on optimally low-power light sources to minimize health risks [4]. In an early UVC link demonstration based on a mercury lamp emitting at a wavelength of 254 nm over a 18-m NLOS link, only a low data rate of 1.2 kbit/s was achieved [7]

Methods

Results

Conclusion